Radiology Image Interpretation: Magic View Graphics for NEET-PG 2025

[00:00:00]Hi friends, look at this interesting quote. It's not what you look at that matters. It's what you actually see.

[00:00:10]Well, radiology images can be tricky.

[00:00:12]You are looking at a particular image and you think you see a particular finding, right? But you know actually the image is trying to show you something else. Well, how do we learn to see what you're supposed to see in radiology images? There's a learning curve to it. Well friends that is the reason why I am here at your service. So what we are going to try and do in this particular session is we are going to try and fall in love with this subject of radiology looking at beautiful images and we are going to use a very innovative way to look at the findings in radiology images. Before we get there let me just uh expand upon this line that we have started with. Now let me give you an example of what this quote actually is trying to tell you. And I'm going to use this image. This is from our very own Ayateshwara temple in Tanjaw district in the state of Tamil Nadu. It has a sculpture. It is very very intriguing and believe me it is one of the world's oldest optical illusion almost 900 years old. What do you see here in this particular sculpture? Well, let me try to help you with it. Well, a few of you may be able to see that in this particular sculpture, there's actually an elephant here which is facing towards the west. Well, a few of you if you come back to this original image may actually see that it's not an elephant. It's actually a bull, the nandi which is facing towards the east.

[00:01:48]Well, what are you supposed to look at here? Well, you need to look at the sculpture and admire its beauty and acknowledge that there in this particular sculpture there is indeed an elephant ayatwhara. There's indeed a bull that is Nandi and that is how radiology images can be sometimes it can be tricky especially for the untrained and unaccustomed eye and the brain right it can be tricky right what are you supposed to see here are you supposed to look at the bull are you supposed to look at the elephant well I'm showing you an image and I'm trying to show you a bird beak sign but some of you may actually look at it and think that it is a say a rat tail appearance where the diagnosis and implication changes I'm trying to show you a seashore sign but you might be seeing a stratosphere in there right so this is where things get a little bit tricky a bicconvex bleed or a crescentic bleed can change your diagnosis and implications and that is the reason why I am here today we are going to use a very innovative technique and this is the technique of this is the technique of magic view graphics is what I have prepared for you and we are going to apply them on all these spotter images that you need to look for you need to know when you're preparing for these exams and for your clinical practice and over the next few minutes you'll realize how when you look at these images these magic graphics superimposed on these images are going to make things and life simpler for you. So this is what we are going to do here. This discussion is not just for your exams but also for things beyond it. Of course, it is going to be of immense immense help, immense value for your upcoming exams. Each and every image that we are going to see in this particular discussion is the utmost high yield recently asked image. We are going to cover a lot of previous year recently asked questions and trends when we go to the go through these slides. But you know what happens when we are preparing for these exams? We become extremely shortsighted. We become myopic. We think exams are the ultimate thing. Well, I want you to realize that exam is one important step that you're going to clear in your attempt as you go into these exams. What lies beyond it is the far more important career. Your entire life of clinical practice that lies ahead of you. And this small short sweet discussion that we are going to have today is going to change your entire perspective towards the subject of radiology. My aim here is not just to help you crack all these images but for you to understand the finding in this particular image and most importantly to fall in love with this particular these particular images and to fall in love with the subject of radiology. That is how we are going to rock the subject of radiology together here. So on this note right let us try and jump into what we are actually going to see in these images. We are going to identify some focus areas. We are going to start with all these conventional procedures. Say in your GI tract, your barerium swallow, barerium meals, right? Berium meal follow through, berium enima spotters, absolute favorite of your examiners as well as very easily done investigations that can give you a definitive diagnosis. Similarly your IV use intravenous urographies mix maturating cystographies as well as your HSGs in women's imaging for various types of malarian anomalies and conditions right this is something you know which is commonly encountered in clinical practice as basic investigations as well as frequently asked in our exams we're going to start with them then of course we move on to the bread and butter of radiology and what is that it is chest x-rays though radiology has seen such significant advancement as far as the modalities of concerned do you know what is the most commonly done investigation in the ideology department today it is a chest X-ray right and it is so far important for your clinical practice ahead whatever stream whatever specialtity you're going to choose you must have a basic working knowledge for for making a few basic diagnosis on chest x-rays we're going to focus on that once we are done with this then we'll move on to your neuroiming spotter CT scan MRI spotters right very very very important critical time critical crucial conditions we must be able to diagnose and then we move on to certain spotters especially hepatilliary spotters for your ionizet exams vascular imaging spotters for your neat pattern exams and your FMG exams a lot of frequently asked questions so let us jump into conventional modalities first okay so just sit back relax and enjoy what you're going to see over the next hour or so now if you look at barerium studies we start with barerium swallow so barerium swallow will help us make diagnosis related to the esophagus proximal stomach and the junction of the stomach and the esophagus G junction.

[00:06:44]Well, this image is showing you this smooth elongated tapering at the lower esophasial sphincter. This is your bird beak sign of aia cardia. We're going to see this image in much more detail. What if I want to look at a condition that you know relates to the stomach say like a peptic ulcer or a CA stomach. Well, conventionally, right, of course, nowadays we do a gastroscopy, esophagoscopic gastroscopy, which is the best technique, but conventionally what was done was a barerium meal study which is done mainly for the stomach and the proximal diotam. Here, can you see these longitudinal prominent folds along the gastric wall? Well, these gastric folds, these are called as rugi. These are called as the gastric wall folds or rugi, right? These are what are identified. If you see that there is a filling defect within the rug depending upon the size, shape, configuration of the filling defect, you can classify it as being a benign ulcer or a malignant ulcer. Now if I want to evaluate the small bubble, what we do is a barium meal follow through where you are able to see this classic feathery appearance feathery appearance of junal loops.

[00:07:57]Whereas in the lower central abdomen you see these loops right they do not show any feathery appearance. So what is this called as? This is called as your featureless appearance of your ial loops. So this is your featureless appearance of your ial loops. So see just by having an introduction we know how junal loops look alike. Upper left abdomen with a feathery appearance junal loop because of the prominent vulva conventus and the mucosal folds. Whereas I loops are relatively featureless. They are in the lower central abdomen and of course all your spotters like CA colon diverticulosis ulcerative colitis lead pipe colon when we are trying to looking look at the colon right we do a barerium enema study now let us look at certain classic conventional modality spotters in the GI tract let us start with this patient now this patient has dysphasia so I'm going to help you with a little bit of clinical bits when we look at these images so that that will give you a good clinical perspective as well so this patient has dysphasia right And there's some when you pulpate the surface of the neck there you feel a crepitus like there's a swelling and you feel a crepitus because there's some content which is getting accumulated there. So what do you see? Look at this image very carefully. Right? See this is the esophagus. Look at the graphics. Can you see there? So this is the esophagus.

[00:09:14]This is a lateral spot image of the region of the neck. You can see the cervical vertebrae there from the lateral aspect. So this is the esophagus. Now what do you see from the esophagus is something is coming out. So it is an out pouching coming from the esophagus isn't it? So this is an out pouching coming from the esophagus it is directed posteriorly sometimes a little bit laterally. So posterior lateral out pouching from the esophagus. So when something comes out of the bowel what is it called as? It is a diverticulum.

[00:09:43]Correct. And what is the most common esophasial diverticulum? You should be knowing this is yes correct. This is the zener's diverticulum. Right now, Zenica's diverticulum where does this arise as as regards to Zen's diverticulum? You must be knowing a few things. One of those is what is this Kian's decisence? Kilas decence is an area of potential weakness in the in the fingial wall.

[00:10:10]Where is it exactly located? It is located between the transverse and oblique fibers. in between the transverse and oblique fibers of the inferior fangial constricted muscle and it is here where there is a potential weakness in the fangial wall from where this diverticulum actually pouches out right there's an out pouching that happens so this is the area where Zena's diaticulum arises now what is the most common complication associated with Zenra's diverticulum think of it logically there's some food content that stays is within this diverticulum. So what happens is that when the patient lies down, when the patient is asleep, right, this food content which is in the diverticulum will come out, go into the esophagus, right? And then what will happen? It will get aspirated. So aspiration is the complication. So it'll go into the trachea, it will go into the lungs cause aspiration pneumonia. Right?

[00:11:10]So this is what is the most common complication associated with Zenus diverticulum. Now look at the image now.

[00:11:15]Once you have seen the finding on the graphics, look at the image now. Can you identify the finding very easily now?

[00:11:20]Yes. So this is how magic view graphics is going to help us. So this is your zenus diverticulum. Now let us look at another patient and this patient remember has this patient has dysphasia mainly for liquids. Now see here if a patient comes to you with complaints of dysphasia mainly for solids rather than liquids then you should think of a diagnosis of CA esophagus. So this is a clinical clue that I'm helping you with. Whereas if a patient comes to you with a clinical picture of dysphasia which is more for liquids as compared to solids then that mainly could be very likely pointing towards a diagnosis of aclesia cardia.

[00:12:09]Right? So one small clinical clue that will help you distinguish between these two. This will be like the examiner is handholding you taking you one step closer to making a diagnosis. Now what do you see in this particular image?

[00:12:19]This is a barerium swallow image. First thing we see is that there is a dilation of the distal esophagus with with a hold up of berium within it. Ideally berium once the patient swallows it should go right into the stomach across the lower esophicial sphincter. Something is wrong at the sight of the lower sphincter and therefore there is a dilation and hold up of the barerium there. And what do you see at the sight of the lower sphincter? There is a smooth elongated tapering. Look at the inset image here.

[00:12:44]It is smooth. It is elongated. There is no mucosal irregularity. So this looks like this bird's beak and therefore this is what is called as your bird beak sign. What is this called as? This is what is called as your bird beak sign. Bird beak sign of achesia cardia. Yes. Now we are fond of this bird beak sign of achallesia cardia. It is very well seen on this particular image. But what if the examiner tells you that there is a bird beak sign which is seen on a barerium enema image. Now we know that a bird beak sign on a barerium swallow image right is a cardia but a bird beak sign on barerium enema image remember is seen in sigmoid wallvulus is seen in sigmoidvulus. Well, what happens here basically is that at the sight of the twist of the vulvville, the bowel walls usually converge and that is what gives rise to that bird appearance on a very minimal image in cases of sigmoid vulva. So look at the graphics there. Now, now can you see can you identify the smooth elongated tapering there. So this is aia cardia.

[00:13:54]Now a patient comes to you with complaints of mainly say dysphasia for solids. So now we know where the patient comes mainly with dysphasia for solids right rather than aia it is more suggestive of there being a neoplastic growth or a cisophagus. Now can you see a narrowing within the esophagus here?

[00:14:12]Yes. Is it a smooth narrowing or an irregular narrowing? It is an irregular narrowing. So look at this filling defect there. So look at this narrowing or luminal narrowing. Look at its surface. It is extremely irregular. Why is it irregular? Because in the wall of the esophagus around it what you're able to see is there is a tumor along the wall of the esophagus. Right? So this is what is giving rise to this irregular narrowing of the esophag is esophasial lumen. This is what is called as your rat tail appearance of copagus. Can you distinguish between the narrowing that we saw in achillesia? It was smooth elongated tapering no mucosal irregularity. Whereas here there is definite mucosal irregularity. There is an abrupt narrowing that is because of the tumor in the wall of the esophagus.

[00:14:59]So this is your rat tail appearance of casophagus. Now what is the overall investigation of choice when you're suspecting a case of casophagus where today it is a esophagoscopy right esophagoscopy. So examiner may give you this image and ask you what will you do next? So you'll do the overall investigation of choice which will be an esophagoscopy right or an endoscopy along with a biopsy as in when you see the mass leion. Now you have diagnosed an esophasial cancer. The examiner asks you what is the investigation of choice for staging. Now this staging remember for almost all cancers is based upon whether there are distant metastasis or not. And what is that modality will which will give you the imaging of the entire body and tell you whether there are any metastasis or not. Well yes it is PET CT. So for staging where you want to look for distant metastasis it is always going to be PET CT. Well if the examiner specifically pokes you and asks you well he wants the TN staging right then we need to look at how deep the tumor has invaded into the layers of the esophasial wall and for which we need a very very high resolution imaging modality which will go to the site of the tumor and show us the layers of the esophasial wall. And what is that modality? It is endoscopic ultrasound. Endoscopic ultrasound. So endoscopic ultrasound. So that is how various techniques can be applied to make a diagnosis for different different purposes. So these are specific questions that the examiner may ask you or you may face in clinical practice and this is what the uh this is how the patient is to be evaluated. Now look at the graphics there. Can you see that irregular narrowing? Right? Why is that so? Because there's a tumor along its wall. Now you know where the tumor is located here. Now another classic spotter related to the esophagus is this. Well this is pretty easy. What is happening is that there is a uncoordinated tertiary non-propulsive contractions along the wall of the esophagus. The esophasial lumen right which is supposed to be straight and uniform is going is getting distorted and this appearance is what is called as is because of these uncoordinated tertiary non-propulsive uh contractions.

[00:17:08]Right? And this is what is called as your cork screw rosary bead or curling esophagus. So the esophacial muscle is undergoing spasm in a diffused manner.

[00:17:18]So what is this condition? This is your diffuse esophasial spasm. So diffused esophasial spasm multiple tertiary non-propulsive contractions giving rise to your rosary bead or a corkcrew esophagus. Right? Now there's another condition that I want you to know and that is what is called as the nutcrackers esophagus. Nutcracker esophagus is also an extremely painful condition where the esophasial muscle is contracting. But remember in diffuse esophasial spasm we know the appearance of the esophagus. We have seen this in this spotter. This is a cork screw or a rosary bead appearance. Whereas in nutcracker esophagus remember the barerium swallow study is usually normal. So how do you diagnose nutcracker esophagus? It is just by measuring the pressure in the esophasial lumen because when the muscle is going to contract the pressure is going to increase. So a diagnosis of nutcrackers esophagus is based only and only on doing by doing a manometry which helps us measure the pressure within the esophasial lumen. So that is how you try and distinguish between diffuse esophasial spasm which will show you a corkcrew esophagus on swallow nutcracker esophagus berium swallow is normal. So the diagnosis is based entirely on manometry. So look at the graphics there. This is your cork screw esophagus in diffuse esophasial spasm. Now a patient comes with pain in abdomen occasional blood in stools. Pain is mainly in the lower left abdomen in the left iliac fossa. We do a barerium enema study and if you look at the barerium enema study look at the wall of the colon carefully. What do you see? There are multiple out pouchings which are coming out from the colonic wall. Can you see it in the graphics there? So we saw in the esophagus something coming out of the lumen is a diverticulum. In esophagus we called it as a zenus diverticulum. So something popping out projecting out from the colonic wall are colonic diverticuli. These multiple diverticuli which are popping out which I have highlighted here with graphics.

[00:19:16]This is what gives rise to your saw tooth appearance on anium enema study.

[00:19:22]So what are we looking at? We are looking at colonic diverticulosis.

[00:19:26]Right? The most common site for development of colonic diverticulosis is the region of the sigmoid colon. And therefore you'll see that patients will most probably most commonly present with pain in the left lower abdomen that is where the sigmoid is the overall investigation of choice for colonic diverticulosis remember is a contrast enhanced CT because what happens at the site of the diverticulosis try to understand is that if there's a tiny perforation what is the content of the colon it is fecal matter. So the fecal matter comes out of that tiny breach of that colonic wall. Of course when it comes out it is going to incite a lot of inflammation in the surrounding misocolon right that is how it will get inflamed that is called diverticulitis. It is possible that there's a paracolic absis which is formed because of this extraversion of the fcal content and hence to look at this pericolic inflammation absis focal collections the investigation of choice for diverticulosis is contrast enhanced CT right. So look at the image now without the graphics. Can you see all those diverticuli popping out now? So this is your saw tooth appearance in colonic diverticulosis. Yeah. Another spotter right that I want you to know is this.

[00:20:39]This patient comes with altered bowel habits blood in stools and when we did a berium enema study watch carefully look at the graphics. This is the colonic outline. Now there is obviously a narrowing which is there involving the colonic lumen. Now this narrowing has taken a particular shape it as if there is an apple right which has been eaten from around its sides and the core is remaining right. So why is that so is because there is a tumor along it at this appearance is what creates the apple core sign. So apple core sign is seen in what? It is seen in CA colon. So apple core sign is seen in CA colon.

[00:21:23]Remember this apple core sign in CA colon is more commonly seen in a leftsided colonic CA rather than a right sided. Meaning it will be more commonly seen in a colonic CA involving the rectum sigmoid or descending colon rather than the secum and the ascending colon. Right? So look at the graphics there. Now can you see the apple core there? If I remove the graphic C, you can see the colonic outline. You can see the narrow lumen. Now, that is where the sight of the tumor is, right? And this is what is going to be the apple core sign of CA colon. More commonly seen in leftsided colonic cancer. Now, let us look at another colonic spotter. See here the entire colon is filled up with contrast. So, you're able to see it. We can see the seeum, ascending colon, transverse colon, descending colon, sigmoid colon and a part of rectum here.

[00:22:17]But what is very peculiar about this colon is that there are nostrations which are visible. So the colon almost looks as if it is a pipe. So the colon looks like a lead pipe. So lots of ostrations leading to a lead pipe.

[00:22:34]Appearance of the colon is a feature of what? It is a feature of an inflammatory condition involving the colon. What is that? It is ulcerative colitis. Yes. So this is ulcerative colitis. Remember patients with ulcerative colitis may have an acute presentation. And what is that? That complication associated with it? I want you to know is toxic mega colon. Right? Most commonly involves what part of the colon? Remember T for toxic, T for transverse colon is the most common part of the colon which is involved where there is progressive dilation of the transverse colon because of the transmural inflammation of the wall right and progressive dilation of more than 6 cm and perforation is imminent and then it is hence it is a surgical emergency which will require excision and colostomy. So toxic mega colon ulcerative colitis may present acutely with toxic mega colon most commonly involves the transverse part of the colon. So this is these are a few important spotters we have seen. See now can you see? All right. So these are important spotters. Now let us look at certain peculiar conditions. Now this is a child. So this is a child who presents at birth with bilious vomiting. Right? So neonate present at birth with billious vomiting. Why so? Is because a part of the bowel has probably not well developed. So this is the stomach diodithm. The bilary tree is going to open here in the second part of the diodenum. Just imagine that if this part of the diodenum has not developed, what will happen? The bile which is going to come into the bowel cannot pass ahead. If it cannot pass ahead, right?

[00:24:26]There's going to be obstruction. A part of bowel is not developed. All this bile is going to come back and the child or neonate is going to have bilious vomiting. So neonate with billious vomiting antinately. So what will happen is that the stomach will get dilated and this proximal part of the diodithm will also get dilated. If you look at the image there, can you see the two bubbles which are present there? One of those bubbles is the stomach one. The other bubble is giodinum proximal diodinum because the bovel wall is the bowel is atic at this particular site. And this appearance is what is called as your double bubble appearance or double bubble sign which is a feature of what?

[00:25:09]Which is a feature of diodinal atraasia.

[00:25:12]Which is a feature of diodinal atraasia.

[00:25:15]Even antiatally if you see this is the antiatal ultrasound image where in the fetal abdomen you are able to see two bubbles. This is the stomach the larger one the smaller one is the proximal diodenum. So double bubble sign is a feature of diodinal atraas. Well let us look at certain bubble signs. We've already seen a double bubble sign is geodinal atraasia where a single bubble single bubble sign is considered to be a feature of pyloric stenosis. A triple bubble appearance. Triple bubble appearance is a feature of junal atraasia right where there will be three bubbles stomach deodum and the proximal junum which will present as bubbles and a vague not very specific multiple bubble appearance is a feature of ireas where you'll see multiple bubble loops being dilated. So these are a few bubble signs that I want you to know. Look at the image. This is a classic spotter of double bubble sign right of diodinal atrelesia right now see this was a neonate with bilious vomiting. Now this is an infant not a neonate presenting immediately at birth. So this is an infant with projectile nonbilious vomiting. There is an olive shaped mass which was felt over the epicastrium. So do you understand how the clinical picture is going to be different in both of these conditions?

[00:26:40]Right. So one patient one child neonate presented at birth with billious vomiting because theodm was atritic.

[00:26:46]This child does not present at birth because this is not a conjural abnormality per se right it develops in a few weeks after birth and where does it develop? It develops at the distal stomach in the region of the pyloris.

[00:27:02]And because the bilary tree is draining very well into the bowel, it passes on the bile passes on into the intestine.

[00:27:09]And therefore the child now has non-belous vomiting because the obstruction is over here at the pylorus.

[00:27:15]What is happening? Look at this barerium meal study. In this barerium meal study, you can see that the berium is present within the stomach. But if you look at the distal part of the stomach, look at the pyloric canal there. What do you see? The pyloric canal is extremely extremely narrow. Why is it narrow is because there is a hypertrophy of the muscle layer along the pyloric wall. And what is this condition that we are looking at? We are looking at a case of We are looking at a case of yes hypertrophic hypertrophic pyloric stenosis. Though conventionally remember that a barerium meal study was done right for making a diagnosis of hypertrophic pyloric stenosis. These days it is usually not the uh barerium meal which is done because it involves radiation exposure. It is a procedure where the child is to be fed this barerium and then x-rays are to be taken and therefore nowadays a more readily available modality which in which there's no radiation exposure is used as the investigation of choice. What is that? It is an ultrasound. Because the pyloris is so superficial, it is felt as an olive shaped mass over the epigastrium. Right? If you keep an ultrasound probe on the surface of the abdomen because of the superficial location of the pyloris we are able to directly see the pyloric wall and the pyloric muscle right and that is how right we are able to make a easy diagnosis right the muscle thickness layer so thickness of the muscle layer of more than 4 mm or the length of the pyloric canal being more than 16 mm is considered to be the diagnostic feature to say that the pyloric muscle has hypertro Right? So these are few. Do you understand? So child comes with vomiting at birth. Belius vomiting is geodenatraasia. In a few weeks non-belius vomiting is usually hypertrophic pyloric stenosis. So that is how clinically also these cases can be differentiated. Yes. Now let us move on to certain spotters in the genetic urinary tract. Now see here this is an intravenous urography or pyography. Now this patient the first image look here.

[00:29:30]Can you see some finding which is present in the region of the renal fossa there? What is that hyper dense appearance that opaque opacity that you see close to the area of the renal hilum there? Possibly we are looking at renal calculi. One of them is sitting in the renal hilum. The other one is probably in the lower pole calix. Now that I've seen a calculus, I want to know whether this calculus is an obstructive calculus. Is it causing hydrononepherosis? So what do I do? I do an intravenous urography or pyography where I inject ienated contrast. As soon as I injectated contrast, as soon as it goes from the veins to the heart, right heart, lungs, left heart, comes into the arteries, a renal artery, it gets filtered at the glomeulus and then I am able to see the renal cortex being highlighted. Can you see that? So at a 0 minute film, as soon as the contrast reaches the renal tissue, I'm able to see the renal cortex. Now I can actually see the contrast getting filtered through the kidney into the kalis. So I wait for a few minutes and then when I take spot images say at 5 minutes look at the finding there. Can you see the leftsided pelvic system is more or less completely normal. Can you see that there's no dilation contrast is reaching up to the urinary bladder. But what has happened to the right? Can you see that?

[00:30:52]Look at the graphics there. What has happened to the right is that the kalis on the right side definitely appear to be dilated. So I am very likely looking at a possibility of hydro nephrosis. Why is there hydronosis?

[00:31:12]Because there is a calculus here I know which is sitting at the level of the renal hilum. Well I want to look at it more carefully. I wait for some more time where at 15 minutes the entire leftsided pelvic system which looks completely normal. Look at the kalis urator reaching right up to the urinary bladder. I'm able to see it very well.

[00:31:32]Well, now what do you see on the right side? The kalis are further filled up.

[00:31:36]Definitely they are obstructed. They are dilated. Why is it so? Is because there's this calculus which is sitting over here. So this finding that you see on an IVU, right? This is your hydronnephorosis because of the obstructive calculus at the renal hilo.

[00:31:52]Can you see that now? Yes. Now, so this is about how IVU will demonstrate hydrononepherosis or signs of obstruction. Now, IVUs, IVU spotters that are frequently asked in your exams.

[00:32:03]So, let us try to look at certain IV spotters. Now, this is a normal intravenous urography. As we inject contrast intravenously, right? As it goes into the heart, right heart, lung, left heart, arteries, aorta, renal artery, it gets filtered at the kidneys, we know it gets gets into the kalis, minor galax, major galaxy, renal, pelvis, urator and bladder. So first we see the kidneys. Look at the renal shadows there. Then as it fills up the kalis, can you see how beautifully here with the magic graphics you're able to see the entire pelvic system right from the minor to major calisnal pelvis to the urtors to the urinary bladder getting opacified. Just look at this image. Now this is a normal I view spotter image for you. Now when we know how a normal I view looks like, let us try and look at something which is not normal. See very interesting condition.

[00:32:53]Can you see that? Look here. Where is the right kidney? The right kidney appears to be somewhere over here. Where is the left kidney? The left kidney should have been here but it is not present here. Where is the left kidney gone? If you look at this image very carefully and if I help you with a little bit of magic view graphics here you'll see that the left kidney has actually crossed over across the midline gone to the right side and it is fused with the right kidney. So this is called as a crossfused ectopic left kidney. So this is a condition of crossfused ectopic kidney. Now let us add some finding to it. We know that the kidney has crossed over to the right and is fused. But if you carefully follow the kalisal system, right? Where is the chalial system extending from? See both the kidneys give rise to their own kalial system that form two urtors. And interestingly the urator arising from the crossfused ectopic left kidney that is this kidney actually crosses over starts begins on the right side crosses over to the left and then drains into the urinary bladder at its normal site.

[00:34:12]So what is this? This patient is clinically asytomatic. Right? If you look at the first image here look if I remove the graphics now right? Can you see the entire cal system there? Right?

[00:34:22]So magicior graphics will help you see things. Look at the second image here.

[00:34:26]Now this is a case of crossfused ectopic kidney. Can you see that? See here with the graphics normal I view and a crossfused ectopic kidney without the graphics. Right? This is how magic graphics will make your life easier.

[00:34:42]It'll show you right. This is like holding your hand and showing you where actually the finding is. And this is how you'll once you form the uh visual impression of this particular condition.

[00:34:51]and the next time you see the same condition you'll definitely be able to crack it and get the answer. So this is a crossfuse ectopic kidney. Let us look at a few more interesting IVU spotters.

[00:35:01]Now see here normally what happens as we have seen in the previous normal IVU image. If you have a right kidney and a left kidney right one pelvic system from each kidney right gets drained into one renal pelvis one urer from each side that drains into the urinary bl. This is how the normal configuration is and it is this normal configuration that you are able to see here on the left side.

[00:35:27]So what do you see on the left side? You see the region of the left kidney. There is a pelvic system. There is a renal pelvis. There is a single uretor that opens into the urinary bladder. There's something interesting happening on the right. Can you see that? So this patient is asymptomatic hardly present with intermittent uh urinary tract infection.

[00:35:48]That's it. And what do you see here is something very interesting. Can you notice the difference when you look at the magic graphics there? What do you see from the right kidney? You see that there is a pelvic system one and there is another pelvic system 2. They drain into a renal pelvis here P1. A renal pelvis here P2. These renal pelvises drain into two separate urators. a urator one and a urator 2 and somewhere along the course of these urators either these urators fuse with each other or they have just over overlapped and then are opening into the bladder. It's not very clear anatomically what is happening but what is clear definitely is that on the right side there are two pelvic systems right two collisionial systems two renal pelvises two urers so instead of one which is the rule which is seen on the normal left side on the right side you are seeing two of them right so what is this condition therefore called as this is what is called as a duplex pelvic system what is important what isant Importance of identifying a duplex pelvic system. Well, when instead of one urator, there are two urators. When these two urators drain into the urinary bladder at different sites, it could be associated with certain abnormalities. And therefore in surgery, you'll always study what is called as vagert mayor law. So whenever we study duplex pelvic system, we must quickly revise. We must know what is vgurt law. It tells us what will happen to the upper moeti or the upper urator and the lower moyeti means entity. So lower moyet means lower urator. So remember it this way upper moeti u me u. So upper u is for upper urator. It has a more medial and inferior insertion medial and inferior insertion on the urinary bladder and as a result of that it is more prone to the development of urero. There may be a cyst which may form at that site. So the upper urer has a more medial and inferior insertion is more prone to the development of urroil.

[00:38:10]Whereas the lower urator has a more loose or a lax insertion into the urinary bladder and therefore it is more prone to the development of waso uriteric reflux. It is more prone to developic reflux. Upper imo upper uru upper urator medial inferior insertion more prone to the development of uritrosil lower laxs reflux right so lower urator more lax or loose insertion therefore prone to development of psyacuritric reflux now look at the image here without the graphics can you see that now a single pelial system on the left two collisionial systems on the right well another question has been asked you know once before on this condition of duplex palial system where on The in the first image here, this is the image that we just saw where you can see two pelvic systems. But what is happening in the second one is that though you are able to see a normal leftsided normal leftsided pelvic system and urer on the right side the shape of the pelvic system is as if like that of a drooping lily. So this is what is called as your drooping lily sign. Well, this is the second pelvic system on the right. The upper one is not seen here because it is obstructed. It is blocked.

[00:39:40]It is dilated. And because it is obstructed dilated, it is pushing the second pelvic system downwards and that is what makes this lily droop down. So drooping lily sign is seen in what? So drooping lily sign is seen in duplex pelvic system with a obstructed with an obstructed and dilated upper system. Obstructed and dilated upper system. See here there are two pelvic systems on the right side. The mere presence of two pelvic systems on the right will not lead to drooping lily sign. As you can see in the first image here, we can see one pelvic system here.

[00:40:28]We can see the second pelvic system here. That doesn't create drooping lily.

[00:40:33]Drooping lily sina happens when this second pelvic system is being pushed down. What what is going to push it down? Why is it pushed down is because it is the upper system which is obstructed. So it is not opacified with contrast. Since it is not seen in the image and it is dilated. So therefore it is pushing the lower pelvic system down and that is what is giving rise to the drooping lily sign. So drooping lily sign is seen in a duplex pelvicial system in which the upper entity is obstructed and dilated. Okay. So that is your drooping lily sign of duplex pelvic system with obstructed dilated upper system. Yes. So look at that drooping lily here. Now can you see without the graphics? Yes. So this is your drooping lily appearance. Now we come to a peculiar condition. This patient, this finding was an incidental finding.

[00:41:22]Occasional pain on the left side is what the patient comes with. And if you see on the right side, the pelvic system, urator and the urinary bladder is normal. But something is not normal on the left side. Why? Just look at the size there. Right? So the left kidney is showing these dilated calis. So there is definitely hydrononepherosis. What is more prominent is can you see this big renal pelvis which is all like it has ballooned out right it is excessively dilated. This dilation is disproportionately large as compared to the kalisial dilation. If you see why is it so is because see the sight of obstruction is where this pelvis opens into the urtor because we are not able to see the urator at all. Why is the left urator not seen is because there's no contrast which is passing from the pelvis into the urator. So the site of obstruction is where the site of obstruction is at the junction of the pelvis and the urer. So what is your diagnosis? This is called as the pelvic uratoric junction obstruction. So this is pj obstruction. So pelv uritric junction obstruction. Now this appearance where the pelvis is excessively directed is called as a balloon on a string sign. A technique which is called as a diuretic renography can be used to uh distinguish between a true pelvic junction obstruction versus a extra pelvis. So true pelvic ureic junction obstruction versus a extra renal pelvis in which there is no obstruction. What is extraal pelvis? The pelvis is located out of the kidney. It is slightly exopitic. It is not obstructed. There is no obstruction. So when we give a diuretic, what will a diuretic do? It will increase the urine output. So there will be a further higher secretion of contrast. If there is a further higher secretion of or excretion of contrast from the renal system into the calis and the pelvis in the extraal pelvis because there is no obstruction there will be a wash away there will be a wash out of contrast where the entire contrast because it is being excreted forcibly out will go into the bladder whereas here there is true obstruction. So if more contrast is being put into the collalial system and the pelvis there will be a further dilation because of the obstruction at the pelvic junction there will be a further dilation whereas in external pelvis there is no obstruction there will be a wash out of contrast. All right so this is what is your this is what is your classic pelvic uritric junction obstruction causing hydronosis on the left side. So look at the graphics there. So this is your pelvic junction causing obstruction hydronosis.

[00:44:22]Yes. Now if you look at this same finding on a CT urography this is a CT urography right where you can see the right kidney it is normal normal renal pelvis kalis visualized part of the right urer is normal urinary bladder is normal. On the left side though there is hydronosis. Look at the kalis. The renal pelvis is dilated. Urator is not dilated. So this is a case of leftsided pelvotric junction obstruction. A slightly more challenging uh you know application of this condition was asked in one of the recent neat exams where there was a large cystic lesion right on the left side. If you see it had a very very very large and what is the key to diagnose pelvotric junction obstruction?

[00:45:10]It is this ballooning of renal pelvis.

[00:45:15]ballooning of renal pelvis where the dilation of the pelvis is much larger disproportionately larger as compared to the dilation of the calis because there is an obstruction at the distal end of the pelvis at the pelvic junction. So there was a very large dilotation of the pelvis almost crossing the midline and communicating with it in the region of the kidneys you could see that there was dilation of the kalis. So this is your hydronnepherosis but the pelvis was so massively dilated. It was crossing over the to the other side of the midline. It was connected to the kidney. It cannot be a polycystic kidney because usually they won't be communicating cysts.

[00:45:52]Multiple cysts of more or less the same sizes would be seen in a polycystic kidney. So what is this? This is again a case of pelvetric junction obstruction causing hydrophosis. So these are CT images that we have seen. Yes. Now let us look at a child who presents with recurrent UTI. This is an IVU image where we are able to see the distal urators and the bladder. Some very peculiar finding at the uh distal end of the left urator. That is where I want you to look for whether you see an elephant or a bull according to the right relating to the sculpture that we saw at the very start of the session. So watch carefully. This is the normal right urtor distal urator and the normal urinary bladder. But what do you see along the left urer? The left urer is slightly dilated. And at the distal end of the left urer, can you see that there is a cystic dilation along the wall of the urer there. Can you see that? So this is a cyst like dilation involving the distal urer at the site where it opens into the bladder. So a cyst involving a urer is called as what? So this is what is called as the urethroal.

[00:47:02]And this appearance of that cystic dilation is what is called as your yes cobra head appearance or yes adder head appearance or yes spring onion appearance of urro seal right. So look at the graphics there. Now can you see the dilated distal end of the urator there? See how magic your graphics will help you. It will show you the finding and once you see and understand the finding you'll never forget it. So this hallow around this can you see this hallow around the cyst or the urethroal?

[00:47:39]It must be uniform right? If it is non-uniform if there is irregularity it could be a pseudo urero a pseudo urethroal. So if the hallow is irregular. So if the hallow around the cyst is irregular then we could be looking at a case of pseudo urethro seal and a pseudo seal may suggest a possibility of a tumor being there usually a transitional cell tumor at the site which is causing that dilation and irregularity. All right.

[00:48:14]Now let us look at this patient with a very classic spotter appearance. Look at the schematic image. I've already given you a clue. Look at the course of the urer. If you look at the left kidney and the left urator, it is coming straight down. Look at the right kidney. Where is the right urer going? The right urator is going behind the IVC aorta hooking around it and then coming down anterior to them and opening into the urinary bladder. So this abnormal course of the urer right is seen on this IVO image.

[00:48:49]Now look here this is where the IVC should be. Of course it is not visualized here. The contrast is in the renal pelvicial system. But can you see now that the uh pelvic system the proximal urator as we opacify the pelvic system the proximal urator goes behind the IVC right hooks around it and then comes down and drains into the urinary bladder. So this is what is called as a fish hook appearance of the urer which is seen in retrocable ura. Retro means behind cable means behind the inferior vennea ca because the urator is passing behind the inferior vennea. This is called as a retro caval urator and that hook-like shape is what is called as a fish hook appearance. Actually what is the effect of what is the result of a retro cavel urator? What is the implication is because it crosses behind the IVC the pressure from the IVC is going to press on that urator and hence as a result of that can you see proximal to that segment right there is a slight dilation of the urer so when you see a dilated right proximal urer and pelvis without any other explanation just trace the course of the urer you'll find that if it is passing behind the IVC right it is it is prone to the pressure coming from the IVC and that is what is going to give rise to a little bit of dilation if If I remove these graphics now, look at this image. Can you identify? Now this is your fish hook appearance of a retrocable uretor. Yeah. Now this is a child who presents with recurrent UTI.

[00:50:21]And when we did an ultrasound for this child, we found that there was bilateral dilation of the pelvic system and that led us to do this investigation which is what which is a mixturating systoure. What do we do in maturating systothrography? We pass a catheter or a tube into the bladder and we fill up the bladder with contrast. Can you see that in this image? Now the child is asked to pass urine and while the child is mixturating or passing urine we will take a spot radioraph of the abdomen. If the contrast is in the urinary bladder and if the child is passing urine this contrast should come out through the urethra and it should be passed out.

[00:51:09]That is what is expected to be seen isn't it? But what are we seeing here?

[00:51:13]Instead of it coming out into the along with it coming out into the urethra and being passed out the contrast we can see is going back in a retrograde manner reverse manner where into the urtors it is filling up the urtors going back in a reverse direction and filling up reaching right up to the kidneys and that is the result why the urtors are dilated the renal pelvis is dilated the kis are dilated hydronphosis. So what are we looking at? We are looking at a reflux of urine from the bladder that is the vasicus into the urator. So what is this condition called as? This is called as vasyouetric reflux. The investigation of choice for initial diagnosis of vascuritric reflux is what we are looking at and that is mixturating systo urethrography. Yes. So investigation of choice for initial diagnosis oftric reflux is MCO. That is what we are looking at. It will show us the contrast going up in a reverse manner into the urators and the pelvic system. But once we have made the diagnosis for followup, we use a technique which is called as radio nuclide.

[00:52:22]Radionuclide systoraphy radionuclide systography right where we introduce some contrast radioactive material into the bladder and then the same process is repeated, right? Its anatomic resolution is relatively poor but it is enough to make a diagnosis whether there is a reflux or not. Okay. So look at this graphics now.

[00:52:43]Look at this image. If I remove the magic graphics there you can see the contrast within the urinary bladder. It has gone out gone up reverse in the uh urtors and the pelvic system causing dilation. Right? So this is reflux of contrast causing vascuritic reflux.

[00:52:58]Another classic clinical clincher is that this is a a newborn male child with a very narrow urinary stream. Now when we did an antiatal ultrasound, what we saw on that antiatal ultrasound was that the fetal urinary bladder was dilated. So there is or over distended and when we looked at it carefully it was a small projection on the inferior aspect. So that was the posterior urethra which was also dilated. So if you look at this appearance, this looks something like this. And this is what is given a name.

[00:53:35]This is called as the keyhole appearance. So we suspected a particular diagnosis after the child was born. Right? It was a male child with a very narrow urinary stream. So we did a MCU study. And on the MCU study, what do we do in the MCU study? We start by putting a tube in the catheter and we fill up the bladder, right? We pass a catheter into the bladder. We fill up the bladder with contrast and then when the child is passing urine, look at the classic findings there. You can see the dilated posterior urethra and there is a wallve like mucosal fold which is seen in the distal part of the posterior urethra and these mucosal folds or wallves led to a diagnosis of a posterior urethral wallve or PUV. So PU wall valve is small mucosal folds in the posterior retra you can see her keyhole appearance on antiatal ultrasound on postnatal MCU you will see this dilated posterior urethra with a valve like fold in the distal part it is a clinical clincher right so how does it present it always presents in a male neonate presents immediately at birth with a very narrow urinary stream. So even if this history of a male neonate presenting with a narrow urinary stream should click it should you know give you a pointer towards the diagnosis of postureal wall and what is the investigation of choice that you do for postureal wall it is what we have done here and it is a mixturating systo urethrography. So it is a mixturating systothrography. So look at this image now right. So without the graphics can you see the dilated distra and can you see this wallve here in the posterior urethra which is actually the reason for this dilation of the posterior. All right so this is what is a posterior urethral wallve. Yes. So now let us jump into the bread and butter of radiology and that is chest x-rays. A lot of chest x-rays you encounter in your clinical practice. You're supposed to be able to make certain basic diagnosis. Why are these diagnosis that we are going to discuss in the next say 10 15 minutes why are they so frequently asked in your exams? There's a simple reason behind it. Your examiner is trying to ensure your competency in making these basic diagnosis. Most of these diagnosis are very frequently encountered in clinical practice. Some of them are potentially life-threatening. And so when you appear for all these exams, the examiner is testing your competency to detect or make this diagnosis whether you will be able to save the life of the patient and hence these conditions are so frequently asked. So let us look at this image.

[00:56:22]This is a patient who comes with sudden onset breathlessness. On one side if you examine this patient, there are hyper resonant notes. There are absent breath sounds. Before we go into any of the findings, just look at this chest X-ray.

[00:56:40]Look at the right lung field. Look at the left lung field or the right hemithorax and the left hemithorax. Can you see a difference? Yeah. The left hemithorax, the left side appears slightly blacker or hyper lucent, isn't it? Why is that so? Is because there is there is a big hyperucency on the left side. If you look at the graphics, what appears black on an X-ray? Can you tell me what appears black? Air appears black on an X-ray, isn't it? So there's a lot of air here. In fact, inside this hyperlucenency, there are no vascular markings at all. So this is called as this is called [Music] hyperucency with absent vascular markings. Why? Because there is a lot of air present within the left plural cavity. Because there's a lot of air present within the plural cavity. See in the plural cavity there are no blood vessels and therefore you do not see any vascular markings within it. And this is just air. So it is appearing excessively black. Now such large amount of air in the plural cavity. What is it going to do to the underlying lung? The underlying lung is being pushed inwards.

[00:58:00]And at the surface on the surface of the lung you see a sharp line. This line is called as visceral. This is called as the visceral plural line. So the the normally the plural cavity has a thin film of fluid within it. But when this thin film of fluid is replaced by a large amount of air, what is going to happen? This air is going to distend the plural cavity at high pressure. It is going to push the lung inwards. Sharp margin on the surface of the lung is visible. It is called visceral plural line. If it is going to push the lung, it is also going to push the trachea to the other side. It is also going to push the heart contrlaterally. So there is definitely evidence of mass effect.

[00:58:53]There is evidence of mass effect in the form of medastinal shift. In the form of mediainal shift to the opposite side. Now if this large amount of air in the plural cavity is pushing the medastinum contrlaterally, what is it going to do to the epsilateral diaphragm? See the ipsilateral diaphragm is also pushed down. Can you see that? Compare it with the location of the right hemi diaphragm. So this is again an evidence of mass effect. The diaphragmatic sulcus appears extremely deep and this is given a name. This is called as your deep sulcus sign. The diaphragm being pushed down the diaphragmatic sulcus appearing deep is what is called as the deep sulcus sign. So what is your diagnosis? See if I removed all the graphic. Can you see that now? Can you see that there is excessive air in the plural cavity which is causing that hyperlucency with absent vascular markings. The lung is being pushed inward. So you can see a sharp margin on the surface of the lung. This is what is called as your visceral plural line.

[00:59:55]There is mediastinal shift. Heart and trachea are being pushed. This is mass effect. The diaphragm is being pushed down. This is deep sulcus sign. So what is air within the plural cavity called as? So air within the plural cavity is called as pneumo. Yes. Numo thorax. Yes.

[01:00:13]So air within the plural cavity is called as pneumthorax. But then tell me should you be tense tension. So this is yes this because of the prominent mass effect mediast being pushed to the opposite side the diaphragm being pushed down right this intraplural air is at high pressure and hence the diagnosis is not just pneumothorax it is tension pneumothorax. tension pneumothorax when is when this intraplural pressure is a very high positive pressure right and hence it will compress the it will push the medastm contrlateral it will push the diaphragm down at this high pressure it will compress the IVC and the SVC where the venus return will be blocked the cardiac output will fall it is a potential life-threatening condition so this is what is tension pneumoax did you get that now let us so now we know this is tension pneumthorax let me just remove this findings things and now tell me what is the investigation of choice though the diagnosis can definitely be well made on this chest X-ray. The investigation of choice remember a concept we have studied fluid is friend of ultrasound. Fluid is fluid is friend of ultrasound. So wherever you want to detect fluid the investigation of choice will be ultrasound and air is enemy of ultrasound. Yes, we have studied that air is enemy of ultrasound and therefore wherever in the body you want to detect air ultrasound cannot be used and hence you must use the next best investigation and that is going to be CT. So anywhere in the body you want to detect air remember thorax mediastinum peronium kealis anywhere you want to detect air the investigation of choice is going to be CT. So the concept is fluid is friend of ultrasound air is enemy of ultrasound. Yes. So the investigation of choice for pneumthorax remember is CT.

[01:02:03]Now tension pneumthorax is a life-threatening condition. So your examiner will frequently ask you what is the first step in the treatment. The first step in the treatment is something that you can do rapidly at the bedside.

[01:02:14]This is called needle thoracicis or thoracictomy. You put a needle a wide bore needle. In children you put it in the second intercostal space in the midclavicular line. In adults you put it in the fifth intercostal space just anterior to the mid axillary line. When you put a needle within the thorax what will happen? See the intra plural pressure is at a very high positive pressure. The atmospheric air is at a pressure of zero. Intra plural air is at very high pressure. So along the pressure gradient the air will come out.

[01:02:48]It will come out until the time that the intra plural pressure also becomes zero.

[01:02:54]So when the pressure inside the plural cavity and the atmosphere becomes same the air will stop coming out. By doing this needle thoracicis you have relieved the tension component. Now what remains is plain simple neoorax and for it you do a intercostal drain tube insertion with a water seal at its distal end and gradually the remaining air will get resolved over the next few days to weeks as the lung slowly expands. So this is about pneumthorax and tension pneumthorax right very very very important condition can be diagnosed on a chest X-ray potentially life-threatening and therefore requires prompt treatment first step is needle thoracicis to relieve the tension component second is intercostal drain tube insertion to tackle with the remaining simple pneumthorax yeah now look at these images what do you see on this chest x-ray again we are able to see this jet black appearance s right within the hemithorax with absent vascular markings suggesting that there is air in the plural cavity but at the bottom you're able to see an opacity which could be suggestive of a fluid in the plural cavity and there is an distinct air fluid level in the plural cavity there look at the CT image as well on the right side you are able to see a jet black appearance which tells you that there is air in the plural cavity In the dependent part you can see opacity or density which could tell you that there is fluid and at the junction of them you see a distinct air fluid level. So when you see in the plural cavity there is air as well as fluid and forming an air fluid level. What are you looking at? This is called as hydro numoporax. So this is hydro numo thorax.

[01:04:41]Right? So you'll see in the air in the plural cavity there is air as well as fluid and there is a air fluid level right horizontal air fluid level in the dependent part this is a suggestive of hydrolyo thorax okay now we come to certain classic images I just want you to understand these images make a visual impression of them very frequently asked in your exams as well as a part of pocus ultrasound point of care ultrasound where ultrasound is used as a bedside tool for making certain critical diagnosis in the emergency unit in the casualty of a hospital So see when we do an M mode ultrasound so these appearances have been described on M mode ultrasound right on M mode ultrasound normally right the chest wall layers look like waves of the sea whereas the lung looks like the sand on the beach and therefore this appearance is called as the sea shore appearance which is seen in normal individuals. But this distinction between the waves and the sand is lost in a case of pneumthorax where you can see there are multiple layers and layers and layers striped or a banded appearance. This is what is called as a stratosphere sign or barcode sign which is seen in pneumorax. Can you see the difference between them? So there is no waves and sand which is seen you know as in as seen in normal cases.

[01:06:04]This is called seashore sign. Whereas inorax this distinction is lost. You see your striped or layered appearance stratosphere sign or barcode sign seen in pneumorax. Normally when we do a B mode ultrasound we can see certain lines. So B lines are usually seen in normal individuals. You can see these are like comet tail artifacts. So you can easily remember them. They look like comet tails. So these are comet tail like vertical lines. These are normally seen bel lines. Whereas in numothorax because of the air within the plural cavity there is a repeated reflection of the ultrasound beam. Again remember it's it is similar to stratosphere. So you see multiple layer layer horizontal lines these are called as a lines right these are because of the reverberation artifacts you can see multiple horizontal lines again similar to conceptually as you can see in stratosphere sign multiple layers. So here you can see multiple horizontal lines these are a lines. So these are findings on pneumorax on USG because USG is commonly used as point of care ultrasound point of care ultrasound at the bedside right so in on an emergency basis in the emergency department ultrasound becomes a very very quick bedside tool to make certain diagnosis and that is where all this comes into picture okay now let us look at another basic condition very commonly you'll encounter this if you look at this chest X-ray focus on the diaphragm especially I'll give you a clue look at the costrenic angles look here can you see a normal right costtophrenic angle what has happened to the left costtophrenic angle well can you see the difference now it is blunted why is it blunted is because there is fluid which is accumulating into the costtorenic angle which is creating that blunting of CP angle so this is suggestive of a mild eusion Right. So if you look at the right and left CP angles, you'll be able to identify the blunting of CP angle.

[01:08:02]This is the earliest finding on a chest X-ray PA view which suggests plural eusion. The plural eusion is mild when you just see the blunting. Right? The best X-ray if they ask you overall for plural eusion. It is usually the lateral decubitous view. Lateral decubitous view is the best X-ray projection which is used. But if they ask you investigation of choice, remember fluid is friend of ultrasound we have studied. So wherever in the body you want to detect fluid like a fusion the investigation of choice is going to be ultrasound. Air is enemy of ultrasound. So wherever you want to detect air like pneumothorax we have studied numo mediastinum numoparonium ultrasound will not be of any use.

[01:08:44]Therefore you use CT. Okay. So that is the concept that we have already seen.

[01:08:48]Look at the image now. Can you see a normal CP angle on the right? See when I remove the graphics versus a blunting of CP angle on the left side. Can you see that? Now suppose the amount of fluid is slightly larger. It becomes moderate.

[01:09:04]This is what you will see. Look at the right hemi diaphragm very well seen.

[01:09:07]Look at the right CP angle. Costtorenic angle very well seen. What is happening on the left is that there is an opacity which is seen in the left lower zone. If you follow that opacity from below to top you'll see as you come to the top right there is the margin becomes very illdefined and the shape is like that of a meniscus on the surface of water right if you hold water in a capillary tube or a test tube and this is what is called as the meniscus sign of moderate plural eusion. So as the amount of fluid increases from a simple blunting of CP angle in mild eusion as the amount of fluid increases the fluid will rise up up up create a meniscus illdefined upper margin. So this is what is suggestive of moderate plural eusion. See here now if I remove the graphics can you see moderate plural eusion there. Now what happens there is massive plural eusion.

[01:10:00]See another patient where the entire right hemthorax is completely full of fluid. So how will it appear? It will appear white, right? It will appear opaque. So what are you able to see here? You are seeing that there is marked plural eusion filling up the entire right hemthorax. It is opaque.

[01:10:18]But because of this large amount of fluid, say four five liters of fluid, it is going to cause mass effect. Mass effect in the form of what? Mass effect.

[01:10:26]In the form of pushing of the media towards the contrateral side. Is it seen here? Yes. Look at the trachea there. See if I just highlight the trachea. Look at the trachea and the karina right the bronchi they are being pushed to the opposite side. So what is your diagnosis? This is white out lung.

[01:10:47]So entire hemthorax is appearing or lung is appearing white. So this is called white out lung with contrlateral mediastinal shift. This is suggesting of a marked plural eusion. So this is a condition of white out lung or opaque hemthorax in which one hemthorax will appear completely white. It could be because of massive plural eusion we have seen in this particular image. It could be due to complete lung collapse. So the entire right lung has collapsed. It could give rise to opaque hemthorax.

[01:11:20]Right? It could be because of complete lung consolidation. The right lung is completely consolidated. Can we distinguish between opaque hemthorax due to these three underlying conditions based on chest x-ray? The answer is yes.

[01:11:33]We can definitely try and do it. Right.

[01:11:35]How to do that is very simple. Uh all you need to look for is to look for mediastinal shift. As we have seen in this image, if you look at this graphic here, see if I just remove the graphic there. Can you see now the trachea there? Can you see that black band which is bifurcating at the karina into two bronchi there it is being pushed to the opposite side because of the mass effect. So in plural eusion if you look at the medastinal shift there will be mediastinal shift to the opposite side. So you look for medastinal shift in plural eusion because of the mass effect the mediastinal shift to will be towards the opposite side. In lung collapse because the lung has collapsed it will lose its volume. So what will happen? There will be volume loss. So the medastinum will be pulled towards the same side. So the mediastinal side shift is towards the same or ipsilateral side. Whereas in consolidation there is neither volume loss there is neither a mass effect and therefore the mediastinum will be central. There will be no shift of the mediastinum. Okay. Now let us apply this what we have just seen. This is an image that we have just seen. We can see the medastinum being pushed on the other side. Look at this white out lung. Can you see that there is a right-sided opaque hemthorax? We know this could be because of plural eusion. This could be collapse. This could be consolidation.

[01:12:57]What is the key to differentiate between them? It is to look at the mediastinal shift. Where is the trachea and the mediastinum? Watch carefully. Look at the trachea and the medastinum there.

[01:13:08]Right? The they are pulled towards the same affected side. Right? So mediastinal shift towards the same side tells us that there is a collapse of the underlying lung lobe. So this is the collapsed lung. Right? and which is therefore there's volume loss and therefore the mediastenum is being pulled to the same side. So this is how you can crack radioraphs of opaque hemthorax. Right? We have seen two classic examples there. Now sometimes plural fluid behaves in a very atypical manner rather than settling down and forming a blunting of CP angle or a plural meniscus. This fluid can simply rise up parallel to the lateral thoracic wall like a band or a layer there. Can you see that this is what is called as lamelar plural eusion right?

[01:13:54]Occasionally now this most of the cases you know most of the cases of plural eusion there is free fluid within the plural cavity but sometimes this fluid can get trapped. Where can it get trapped? It can get trapped most commonly in the fissures. So it can present like a mass-like opacity. Look at the second X-ray there in the horizontal fissure when there are two layers of plura. There is a potential space between them and in this potential space the fluid can get trapped. It will create a mass-like opacity because there is a potential space within the two layers of the plura in the horizontal fissure. Fluid will get accumulated there. This is called loulated plural eusion and this creates a very classic clinical clincher which is called as vanishing lung tumor or phantom lung tumor. This opacity here. Now if you see this is lamela eusion and this is loulated or fisal plural diffusion. Well this opacity here is misinterpretated as a tumor. But is it a tumor? No. It is fluid within the horizontal fure. So what happens after this patient is treated say for underlying cause is congestive cardiac failure. When the patient is treated for say congestive heart failure which is the underlying cause when the heart function improves the back pressure on the pulmonary circulation is relieved. There is a fusion right which is drained off and then you see don't see any obvious opacity and so you think that the tumor has vanished and this is called your vanishing lung tumor or phantom lung tumor. It is not a tumor. It is a misnomer right? it is actually plural eusion which is located within the fissure. Okay. So this is these are a few typical ways in which plural eusion can present. Now if you look at a CT scan and if you see that there is fluid within the plural cavity and this fluid is free fluid. As you move the patient the fluid also moves into the new dependent part. It is in the dependent portion in the supine position right along the posterior wall. And there is no enhancement. You're probably looking at a case of simple transudative plural eusion, right? A simple transitative plural eusion.

[01:16:08]Whereas if you see a loulated collection, right? So you see a loulated collection, right? Within the along the plural wall in the non-dependent part.

[01:16:18]So it is not here, right? It is along the lateral wall. And there is an enhancement along its wall. As you can see here, this enhancement is as if it is splitting the plura visceral and the parietital plura is being split off. So this is what is likely to be a case of empima that is loated purulent plus absess collection within the plural cavity. And this is how you try and distinguish between a plural eusion versus an empima. Right? So plural eusion will be free fluid in the dependent part with no enhancement. Empa on the other hand will be a loulated collection mainly in the non-dependent parts right and there will be enhancement along its wall. This is what is called as the split plura sign. This is called a split plura sign. All right.

[01:17:04]So now we come to a very very very commonly encountered situation in your clinical practice as well as therefore as well as in your exams. So this is a child with acute onset respiratory distress.

[01:17:18]So clinically whenever you encounter a child who comes with acute onset respiratory distress the first thing you should think of is yes it is yes it is foreign body aspiration right foreign body aspiration. What is the most common foreign body to be aspirated? I know many of you think it is a coin but it is wrong. You've seen that X-ray with a nice coin there, right? And that is the reason why you remember it so fondly.

[01:17:46]But remember, it is not a coin which is aspirated. Usually the most common foreign body to be aspirated are small entities that the small things that the child is usually eating right and then also jumping at the same time and suddenly it gets aspirated. Usually it is a peanut or a ground nut. And if you see an X-ray of such a child, you will never see that peanut lodged within the broncus because peanuts are just not dense enough to be seen as opacities on a chest X-ray. So you'll be disappointed if I tell you that whenever you look at the X-ray of such a child, don't expect to see a period. Life is not that simple. So you have to look for some other findings. And these findings are very well seen here. Look at this image carefully. Compare the appearance of the right lung and the left lung. Can you see any difference between them? Watch carefully. I'll help you. Look at the left lung. Firstly, do you realize that the left lung is appearing slightly blacker as compared to the right? Can you see that? So, that is called hyperlooen. It is also slightly bigger in size. Right? So, there is a unilateral hyperlucency which is seen. Why is that so? It is because of air trapping. Why is there air trapping within the lungs? See if there is a ground nut lost within the bronchus during inspiration as the bronus dilates right there is air which is going to enter the lungs but during expiration the bronus has a tendency to retract and collapse on its lumen right so what will happen this groundnut or peanut within the lumen of the bronus is going to block it completely now if the bronus is being completely blocked the air within the lungs is not going to be able to come out right and as a result of which though the other lung is going to you know lose all that air in expiration.

[01:19:33]The affected lung is not able to lose that air and so there is air trapping which will give rise to the lung appearing excessively black and expanded. So this is what is the finding which is seen here. It is also because it is larger in size because of air trapping it is going to push the trachea and the mediastinum towards the opposite side. It is going to push the diaphragm slightly down. And now if I remove all these findings, look at the image here.

[01:19:59]Look at the X-ray. Can you identify that unilateral hyperlucency, lung expansion, black appearing lung, slight push of the media to the opposite side, diaphragm being pushed down, this finding of air trapping along with a history of acute onset respirator distress will tell you that there is foreign body aspiration.

[01:20:18]And what should you do next? What should you do next is do try and do a broncoscopy and by doing the broncoscopy we are trying to uh get find that foreign body and get it out. Now let us come to the foreign body that you actually like which is a coin and I'm sure you've seen these x-rays multiple times. So where is the coin is what was the question which was asked very simple. Let us first say that let us assume the situation where the coin is going to go into the trachea. If it has to go into the trachea, it has to first pass through the larynx. And the opening of the larynx, say in my body, it is guarded by these two vocal cords. Right?

[01:20:56]Now, so the opening or the entrance way into the larynx is in the midsital plane in my body in between these two vocal cords. So if a coin has to pass through these vocal cords through the gautic opening into the larynx, it will have to pass in a midsital plane. And if it passes in the midsital plane like this, it'll be held in the midsital plane by the tracheal cartilagenous rings. And hence if a coin is in the sagittital plane, if you look at it from the front, you'll see it like a slit like opacity here. And therefore, where is this coin?

[01:21:28]This coin I can now say is in the trachea because of its orientation in the sagittital plane. We just discussed it. And therefore for this child I will immediately do a bronoscopy. I will immediately do a broncoscopy. Whereas in this child the first child see if the child keeps the coin on his tongue he'll keep it flat and then swallow it. So as it goes from the tongue down it goes into the fairings and the esophagus. It is maintained in the coronal plane. So if the coin is in the coronal plane you are looking at the coin right from the front n face. If you see a coin in a coronal plane, remember where is this coin? This coin is is in the esophagus. And therefore for this child, what will you do? You will do a esophagoscopy. You'll do a esophagoscopy. Yes. So that is where the coin is. Now another question based on a similar finding is this. Is this a coin? Watch carefully. It is not a coin.

[01:22:32]Because if you look at the shape of that opacity though primma face it looks like a coin when I zoom it up for you right I want you to realize that there are actually two rings that you are able to see one is an outer ring like this the other one is an inner ring like this the outer one is slightly larger the inner one is slightly smaller and this appearance is what is called as a double ring appearance or a hallow sign even on lateral radioraphs if you see there is a slight step off. So you see this is the larger ring. If you look at it from the side it is a small step off and this is what is called as the step off sign. So is this a coin? No. In fact it is a button battery. So what are we looking at? This is a small button battery that goes in your watches or small clocks. So this is a button battery. Well, is it safer or more dangerous than a coin being swallowed or aspirated? Well, it is more dangerous because coin is more or less inert. But a button battery has chemicals in it. The chemicals may get discharged may cause erosion of the mucosa. They could give rise to an electrical discharge as well. Right? So therefore button battery aspiration, right? swallowed sorrow cases you need to treat on an emergency basis and retrieve and remove it and then also check for the then also check for the complication. So anode and cathode remember this outer ring is usually the cathode the inner ring is usually anode and the anode remember is more dangerous. So if the anode is facing anteriorly you check the anterior esophical surface for erosions or damage. If the anode is facing posterior, you specifically check for that, right? And therefore it is more damaging. What is more damaging is anode is more damaging. We discussed and therefore we have to pay very careful attention to rule out the complications related to button battery swallowing.

[01:24:32]Okay. All right. Now I'm going to take you to certain classic spotters in brain imaging. Like say a patient presents with acute onset hemiplia. So the patient is presenting with say right-sided hemiplasia, hemiparasis. So what is your first thought? You are thinking of acute stroke. What is the onset? The onset is say 1 hour since the onset. So you are now looking at in fact hyperacute stroke. So less than 4 to 6 hours from the onset. At this time if you're trying to look for an inact within the brain on CT scan you will not be able to see that in fact because for an acute eskeemic in fact to become apparent on a uh CT image it takes about 4 to 6 hours. Here you are just 1 hour from onset you will not be able to see it. If there is hemorrhage yes definitely you'll be able to see it. So when we do a CT scan in a hyper acute stroke right less than 4 to 6 hours we have to look for certain subtle signs and look at this CT scan here look at the right side left side there is a finding that you see on the left side here and what is that finding an artery and this is the left this is the left middle cerebral artery is appearing slightly hyper er dense. So it is appearing hyperdense. Why is it appearing hyperdense? Is because there is a thrombus within the middle cerebral artery. A thrombus is nothing but a blood clot. Do you all realize that a blood clot is logically going to have a density which is higher than normal blood? Isn't it? And therefore if normal blood on a CT scan appears is dense or gray a blood clot which has a higher density is going to appear hyper dense isn't it and therefore this hyperdense blood clot or thrombus within the MCA is appearing bright white and this is called as the hyper dense MCA sign on a CT. One of the earliest findings which can be identified. So this is the hyperdense MCA sign in hyperaccute stroke on CT. Another very beautiful sign is seen and see how magic graphics is going to help you. I want you to focus on the landmarks within the brain on the right side in this patient because the right side is normal whereas the left side here is the side which is abnormal and therefore you are able to see some findings. Now watch carefully in the region of the basil ganglia we know that this is the head of the cordate nucleus. This is the phalamus and in between them wedged is the lentifiform nucleus which has the globus paladus and putamin. Outside it is the insular cortex. When you are able to identify all these structures on the right side, right? Can you identify these structures on the left side? See, you can see the cordate on the right, thealamus on the right, lentifiform nucleus, insular cortex. Can you see any of these structures on the left? The answer is no. You cannot see them. It appears as if the basil ganglia has completely disappeared. Look at these graphics there. Can you see that? So the basil ganglia appears to have disappeared. And this is called as the disappearing basil ganglia sign. Why? Because of the cytotoxic edema, because of the cytotoxic edema, right, the gray white matter distinction is becoming poorer as a result of which you're not able to identify, right? The distinction between the landmarks here. This is called as disappearing basil ganglia sign. Yeah.

[01:28:34]Now tell me so therefore what is that modality which will help us make a definitive diagnosis of uh an acute eskeemic in fact on CT in the hyperaccute stage. Well it is diffusion weighted MRI where see this image is a diffusion weighted imaging image. This is always combined with a DC map which is a mathematical image which is created by the MRI machine apparent diffusion coefficient map. So if you see an area which appears hyper intense on DWI, can you see it? An area is appearing bright or hyper intense on DWI and you see that the same area is appearing dark on ADC.

[01:29:15]So an area appears bright on DWI and appears dark on ADC. Combination of these findings, right, tells you that this is called as restricted diffusion. Restricted diffusion and restricted diffusion on DWI with a case of in a case of hemiplasia tells you that this is an acute or an hyperaccute in fact within the brain parenma. Diffusion weighted imaging is the earliest to diagnose an infact. Earliest to diagnose an infact.

[01:29:56]It can detect an infact as early as 15 to 30 minutes from onset. As early as 15 to 30 minutes from onset, it'll be able to detect an infact. And hence this is the best overall investigation in acute stroke because it is able to detect that in fact very quickly. So this is how the infact would look like. Hyper inensity on DWI, hypo inensity on ADC, bright on DWI, dark on ADC such as restricted diffusion, acute infact. Now how does an infact appear on CT? Very classic. See diffuse hypo density in that MCA territory which is a wedge-shaped territory. So can you see this appearance here? See how is it appearing? It is appearing as a wedge shaped area because that is the shape of that is the shape of the MCA middle cerebral artery vascular territory. Middle cerebral artery vascular territory is veg shape.

[01:30:54]How is it appearing? Is it appearing bright or dark? It is appearing dark.

[01:30:58]Dark on CT is called hypodensity. Why?

[01:31:01]Same reason because of the massive cytotoxic edema at the sight of that infect right it is affecting both gray matter as well as white matter with loss of distinction because both of them both gray matter and white matter are supplied by the same artery that is the MCA. So if the MCA is blocked both of them are going to get affected and because of this edema right there is mass effect. So because of this cytotoxic edema there is mass effect. So it is crossing the midline to the other side. The right lateral horn frontal horn is compressed. Even the left lateral horn is being pushed further towards the left. So this is your classic. Look at the graphics there. Now can you see this classic wedge shaped area of diffuse hypo density involving gray and white matter with loss of distinction in the affected area with evidence of mass effect. Can you see that midline shift? So this is how a classic acute in fact appears on CT.

[01:32:02]Right? We have not only described the appearance but we have also looked at the concept as to why each of these findings is visible on the CT. Now see the underlying pathology is the same.

[01:32:13]When there is eskeemia this cytotoxic edema the affected part of the brain appears as if it is hypodense or dark.

[01:32:21]So when this affects a small basil penetrating arteries of the brain such as a lenticular striate artery or a phalamoperforating artery each of these arteries supplies a small oval round area of the brain which will get infected there will be cytotoxic edema there. So that affected in fact will look like a round black area. If you look at the CT scan on the right side there can you see the round black area there? So this round lacuna shaped infact is what is called as lacunar infect. It presents as a small oval hypo density less than 15 mm in size. So these are called laconar. In fact of course the underlying pathology is the same. There is infection there is cytotoxic edema. What is different is the shape which is different. And why is that shape different? Because the shape of the vascular territory is different.

[01:33:14]In the hemispheres the MCA territory is wedge- shaped triangular. So the in fact is a large hemispheric wedge-shaped triangular hypodensity. In the basil ganglia the vascular territory shape is a round oval lacuna. So the appearance of a lacuna in fact is a round oval lacuna hypodensity less than 15 mm in diameter or size. Now this is one side of stroke. What is that? That is eskeemic stroke. We have seen eskeemia cytotoxic edema dark appearance hypodensity. What will happen if there is a hemorrhage? If there is a hemorrhage, right, there is a blood clot or a hematoma, the density will decrease or increase. The density will of course it will increase and hence remember the two sides two differentials of stroke is schemic stroke in in fact appears hypodense dark whereas hemorrhagic stroke because the density of a hematoma or blood clot is higher. It will appear bright or hyperdense. Look at this brain CT scan right and left. Can you see that hyperdense area? Look at the graphics there. So this is a hyperdense bleed or lesion within the brain paranka with the surrounding hypodense rim of edema around it. Think of it this way.

[01:34:26]Whenever there is bleed within the brain paranka, the brain is always going to react to it. How? By the brain paranka is going to react to it by creating a rim of edema around it. So whenever you see a bleed within the brain, right? You see a rim of edema around it. So this is uh a very classic appearance of an intra cerebral hemorrhage. If I remove the graphics now, can you see the bleed there? That hyperdense legion is nothing but the bleed within the brain paranca and the surrounding hypodense rim is nothing but the edema around it. Can you see that? Now see now we must know to identify the basil ganglia. Very important. This is corded nucleus head.

[01:35:07]This is theamus. Try to identify them on the CT. This is the lentififor nucleus which has the medial globus paladus lateral putamin. This is the internal capsule. This is the external capsule and this wavy cortex we have seen is the insula. Correct. A bleed in this area is always so this will be called as a basil ganglia bleed. Yes. So this will be called as a basil ganglia bleed. Right? And a basil ganglia bleed the most common underlying cause remember is hypertension. So it is always a hypertensive bleed because the most common sight of hypertensive bleed remember is the putamin which is in the basil ganglia. It could also be the second most common cause is the phalamus which is also in the basil ganglia. The third most common site. So the third most common site of a hypertensive bleed is pawns which is not in the basil ganglia but doesn't matter utaminalamus are most commons one and two in that sequence are most common sightes of hypertensive bleeds they are in the basil ganglia. So if you ever see a bleed in this part of the brain it is always always always going to be a hypertensive bleed. Now let us look at a finding inside a bleed. See a bleed with some finding within it. Can you see that hyperdense lesion within the brain? So this hyperdense leion within the brain is the bleed. Can you see that rim of edema around it? We have seen it before, right? So this is the hypodense edma rim of edema around it.

[01:36:47]But look something inside that bleed.

[01:36:49]Can you see that there is a dark area within the bleed. When you see a hypodensity within the bleed, just imagine it this way. The bleed will come out first. It will be exposed to the surrounding tissue and then it'll get clotted. Isn't it? But as in when it comes out, say it is coming out continuously, there'll be some part of that bleed which has not yet undergone clotting. Yes. So this dark area is because the density is less. So there is the bleed here is less dense. Why is it less dense? Is this is because of unclotted blood present. And this unclotted blood is telling us that there is a continuous ongoing bleed which is present continuous ongoing bleed which is present. And is this a good sign or a bad sign? If there is continuous ongoing bleed it is a bad sign. So this is going to predict the future expansion of the bleed. It predicts the expansion of the bleed.

[01:37:57]This appearance is what is called as the swirl sign. This swirl of hypod density within that active bleed right is because the blood there has not clotted.

[01:38:11]Look at the finding there now. Can you see that? Right. Why is it not clotted?

[01:38:14]Because it is continuous ongoing bleed.

[01:38:17]Correct? And therefore as a result of it, it is going to predict that this bleed is going to further expand in size. Right? This is the importance of identifying a finding within that bleed.

[01:38:28]Swirl sign predicts future expansion of the bleed. Now a bleed at a very peculiar site. This is the site of the basil sistns. The basil systems are usually filled up with what? They are filled up with CSF. So they should appear hypodense. But here you can see that it is appearing hyperdense. Looks like a star, isn't it? So this is a star sign or hyperdensity in the basil system. This is a typical history clincher. Where is that bleed? It is in the basal system. So what is the diagnosis? The diagnosis is anurismal.

[01:39:03]Anurismal sub arachnoid hemorrhage. It is a typical history clincher of a patient presenting with under clap headache. Thunderclap headache or yes worst headache of life.

[01:39:24]Underclap headache or worst headache of life followed by patient is unconscious or altered sensorium right so a patient presents with thunderclap headache worst headache of life altered sensorium right and you do a CT you see a star sign hyper density filling up the entire basil systems why because a berry anurism along the branching points of the circle of vis has ruptured where is The circle of wheel is located in the basil system.

[01:39:53]So this aneurysm in the basil system ruptures the first place the blood will accumulate will be entire basil systems.

[01:39:59]So you see a star- shaped hyper density star sign of anurismal SH. This is also called a star of death because it has very high mortality associated with it.

[01:40:09]Yes. Now classic bleeds you see a bicconvex bleed. Can you see the graphics there? See this is a bicconvex bleed. So bic convex bleed is suggestive of what it is a extra dural hemorrhage or epidural hemorrhage. If you see a crescentshaped bleed or a concabo convex bleed. So this is a suggestive of subdural hemorrhage SDH. Whereas if you see bleed which is either in the basil systems like a star we saw or it is linear line like because it is in the circle space. Look at the graphics there in the third image. So if you see line like linear bleed it is sub arachnoid hemorrhage. The source of bleed in EDH is usually middle menial artery whereas middle menial artery whereas in SDH it is bridging cortical veins. Bridging cortical veins. EDH you must know is associated with lucid interval.

[01:41:12]Yes. So unconscious, conscious, unconscious. This brief period of consciousness in between is called lucid interval. It is associated also with talk and die syndrome. So these are few specifics that you need to know. Now one more very important concept I'm going to add about these bleeds right is how do the appearance of this bleed changes with time. So suppose you see a acute bleed it is like a blood clot or a hematoma. So its density is high. So the appearance is bright. So this is called hyper dense appearance. Right? But as the time passes what happens? The blood clot is slowly broken down. Hemoglobin is broken down. It is fagocytos. The hemoglobin is degraded. It is fagocytos and carried away. So what is going to happen to the density of that hematoma? The density is going to decrease decrease decrease right? And as the density decreases from hyperdense it will become isodense and therefore a subacute bleed is dense. Look at the left STH here it is hyperdense acute but here it is very difficult to identify because it is gray almost similar density as compared to the underlying brain. So it is very difficult to detect it as it remains for a few months to years. All the blood products are broken down. Fagocytos carried away. So what remains there is simple fluid and fluid appears on CT scan as black or hypodense. So a chronic bleed appears hypodense. Look at this chronic SDH. Now you know why it is appearing hypodense is because over a long period of time the entire blood clot is being broken down. Hemoglobin is broken down. Fagocytos carried away. So the density is very low. If they specifically poke you and ask you what is the investigation of choice for a subacute bleed because it is very difficult to be diagnosed on CT because it looks similar to the underlying brain. The investigation of choice is going to be MRI. Yes. So therefore it is MRI. All right. So now we move on to another specific situation. If you see these round black hypo densities scattered throughout the you know over the surface of the brain there's obviously an EDH here by convex. So this is EDH extra dural bleed. So what is this? This is air within the capalic cavity. So frontal bone fracture means what? There is a frontal sinus wall fracture. Inside the frontal sinus there is air. Air goes into the cranial cavity. This is called pneumocalis right? If there is a lot of air within the cranial space what is going to happen is that there is going to be a lot of pressure right on the underlying brain because of this high pressure the underlying brain either looks like a peak or a sharp compressed appearance like that of Mount Fuji which is an active volcano right in Japan. So this is what is called as a peaking sign peaking sign or mount fuji sign in tension pneumocalis. Numo means air. Kefalis means inside the cranial cavity and because the air is at a high pressure it compresses the underlying brain and this is called tension pneumocalis. So what is this image showing you here? It is showing you the entire bilary tree or biliary system.

[01:44:41]What modality is it? It is a magnetic resonance collangio pancreatic. It has a very simple underlying concept. Remember MRCP images are heavily T2 weighted images. Now tell me we all know that water appears bright on T2. H2O is bright on T2. We have studied this fundamental of T1 versus T2 in our neuroiming part right in the main videos. So because the bilary tree is full of bile water, these MRCP images use heavily T2-ED images where the T28age is increased. So the water in the bilary tree appears bright, bright, bright. Everything else appears dark, dark, dark. It is say it is subtracted out digitally. The liver paranka right rest of the vascular structures they are subtracted out digitally from the image and we create a 3D image of the bilary tree itself. And this is called magnetic resonance collangio pancreatic. Now what do we see in this image? Now let us use some magic view graphics here. Well the liver paranka has been separated out.

[01:45:49]Right? Just imagine this is where the liver paranka is and this is the uh gallbladder. This is the bilary tree.

[01:45:58]Can you see the bilary tree being filled up with that fluid? It is heavily t2-8 image. The bilary tree is completely dilated. Now why is it dilated in its entire core? See here the common bile duct is also dilated. Why? Because there's something within the common bilary duct. And what is that? Within the common bilary duct there is an impacted calculus which is there. So this impacted calculus in the common bilary duct is called choleiththosis. This was asked in one of your recent exams. Now especially your ioniz exams are obsessed with hepatobilary abnormalities. So collidocal cyst, collidocal lithiais, various bilary abnormalities, ERCPs has been asked. Well, this is MRCP. Remember MRCP is the best non-invasive technique to look at the bilary tree. Whereas what most surgeons actually prefer doing is a ERCP endoscopic retrograde collangopancotic where you can see a scope has been passed the ampula has been canulated contrast has been injected and then an X-ray image has been taken. So you can see the common bilary duct as well as the pancreatic duct which is being opacified here. The advantage of ERCP is that though it is invasive, so invasiveness is a potential disadvantage. However, because you are able to canulate the can canulate the ampula, if there is a stricture there, you can dilate it. If there is a calculus there, you can try and extract it. You can put a stent in the bilary tree for bilary drainage. So there is a therapeutic or treatment related advantage that ERCP has and therefore it is considered to be the gold standard.

[01:47:39]Once a diagnosis is done to treat it to confirm that diagnosis and to treat it and ERCP is usually done by uh surgeons right. So look at the MRCP image there without the graphics. Now can you see the dilated bilary tree the gallbladder and that stone which will appear as a filling defect within the distal CBD there. This is choo lithiais. Now another uh you know application of doing these MRCPs and ERCPS is to look for various abnormalities of the bilary tree like bilary leak or dilation of the bilary tree. More specifically see this is the liver. You can see the dilated bilary tree gallbladder and look at the common bile duct. The common bile duct is fusififor dilated. So it is fusififor dilation of the common bile duct. So this dilation of common bile duct is right. It is called as choleocal cyst.

[01:48:28]What type? it is type one. So type one collidocal cyst is actually a fusififor dilation of the of the extrapetic part of the common bilary duct. So here without the graphics can you see that now? So this is collidocal cyst type one. Another favorite of your examiners and also seen very frequently in your clinical practice are cases where you see a chronic alcoholic comes with pain in epigastium with radiation to the back elevated serum and lipase levels. So epigastric pain could be gastritis but if you think of it radiation to the back points towards a diagnosis of pancreas involvement or inflammation. So it is confirmed by looking at elevated serums and lipase further suggested if you look at a CT scan here. Now this is a CT scan postcontrast study axial section through the upper midabdomen. On the right side you can see the liver. On the left side you can see the spleen. Remember this is always right. This is always left liver spleen. This is the right kidney. You can see a small part of the left kidney there. This is the aorta. You can see the IVC there. And in the central abdomen, you can see a transversely placed organ. You can see that organ throughout its length. What is it? Yes, it is pancreas. The size of the pancreas is obviously increased. Look at the margins or the surface of the pancreas.

[01:49:54]It's very irregular, right? It is fuzzy.

[01:49:57]So all these dark areas on the surface slightly hypodense areas this is nothing but fluid collected on the surface of the pancreas because of the perancreatic inflammation. Look at all this messentry which is hazy or edimeatus fats trending around the pancreas. So the pancreas is definitely enlarged bulky inflammatory fluid collection along its surrounding messentric inflammation. So this is inflammation of the pancreas. This is acute pancreatitis on CT scan. We create this inflammation using balazar in the olden days more commonly now by using the CT severity index. It tells us about the uh non-enhancing areas necrosis severity of pancreatic inflammation and it helps us prognosticate the outcome.

[01:50:42]This patient was treated responded well to treatment was discharged and after the patient was discharged the patient came back in a few weeks right say around 4 to 8 weeks. Why? because the patient started feeling some fullness over the upper abdomen or the epigastrium. Right? There was indeed a lesion which was felt there when we did a CT scan. See same patient. Now what changed? Liver spleen similar right kidney left kidney we are able to see similar but look at the pancreas now.

[01:51:13]Pancreas appears better. See very almost no perancreatic inflammatory changes as in the first image. But there is a lesion within the pancreas. What is that lesion? It is a hypodense lesion within the pancreas with a thin wall around it.

[01:51:27]Likely fluid content within it. So this is a loated inflammatory fluid collection within the pancreas presenting about four to 6 weeks after the episode of acute pancreatitis. What is this complication of pancreatitis?

[01:51:39]This is a pancreatic pseudocyst which most commonly happens in the region of the lesser sack. Now this patient this fluid was drained in by doing a gastrotomy. So this was drained into the stomach. He did not recollect again. But this patient you know continued to be an alcoholic presented with multiple multiple episodes of acute pancreatitis say 8 to 10 times over the next you know 8 to 10 years. Eventually this progressed into chronic calcific pancreatitis where you can see on this X-ray there is diffuse calcifications within the pancreatic paranka extending across the midline. That is how the position of the pancreas is. On CT you can see cross-section through the abdomen multiple calcifications. This is a combination of parenyal calcifications as well as intraductal calculi. So multiple episodes of pancreatitis comes with abdominal discomfort. This is chronic calcific pancreatitis. So the investigation of choice remember for chronic calcific pancreatitis is usually considered to be MRCP. You just saw magnetic resonance challenge pancreatic oraphy with secretin stimulation with secretin stimulation. Whereas the gold standard is usually considered to be ERCP because it can demonstrate the chain of lakes or chain of beads like dilotation of the pancreatic duct that happens in chronic pancreatitis. Yeah.

[01:53:10]Now we come to another now let's come to vascular imaging. Now in recent exams as well as these are very commonly clinically encountered conditions right a lot of emphasis has been done on vascular abnormalities such as pulmonary emolisms aotic dissections aotic anurisms let us quickly go through them see very peculiar history young patient prolonged immobilization due to leg fracture so there will be stasis within the veins this may lead to deep venus thrombosis or DVT one of the thrombus gets dislodged from the lower limb veins goes into the right it goes into the iliac veins IVC right atrium right ventricle pulmonary artery gets lodged in the pulmonary artery so as it gets lodged in the pulmonary artery the patient has breathlessness chest pain hemoptis on ECG there is right ventricular overload S1 Q3 T3 pattern now if you look at this CT this is a CT contrast CT thorax or pulmonary angography. This is right breast shadow, left breast shadow. This here is the SVC. So this is from right to left if you see the vessels. This is the SVC.

[01:54:25]This is the ascending aorta. This is the descending aorta. And in between them to the left of that is the main pulmonary artery. What is lodged inside the main pulmonary artery are two chunks of emboli or blood clots. Look if I remove the graphics now can you see those embuli there? So what are the condition?

[01:54:46]What is the condition that we are looking at? We are looking at a case of pulmonary emolism. Right? So we are looking at pulmonary emolism. Right? Now a d-dimer test in pulmonary emolism is much like a screening test. It is the earliest test.

[01:55:05]It has a very high negative predictive value. If it dimer comes as high, there is a very high likelihood of pulmonary emolism. Chest X-ray is usually normal.

[01:55:13]It is not preferred. The investigation of choice is a CT pulmonary angography is what we are looking at here. In olden days, there was a ventilation perfusion scan which was done. I want you to remember the name.

[01:55:27]Mismatched defect is what is on ventilation perfusion scan is suggestive of pulmonary emolism. And of course the gold standard the gold standard technique is invasive pulmonary angography. Right? So this is what you need to know as far as pulmonary emolism is concerned. Look at the graphics there. The main pulmonary artery and the large chunks of emboli loded within it. Okay. Now look at this aorta. Look at the first CT scan image.

[01:55:56]It is a postcontrast image because there is contrast within the aortic lumen. But what do you see inside the aortic lumen?

[01:56:03]There is an intimal flap within the aorta which is dividing the aortic lumen into a true lumen and a false lumen.

[01:56:12]Look at the second sagittital reconstructed image. There is an intimal flap within the aorta which is dividing the aortic lumen into a true lumen and a false lumen. So what we are looking at is a case of aortic dissection. Look at there without the graphics. Can you see them? So this is aortic dissection. when a the blood goes into the wall of the aorta creating an intimal flap which divides the aotic lumen within a into a true lumen and a false lumen right you'll study Stanford and DBK classification systems for aotic dissection one clue as far as the treatment of aotic dissection is involved remember whatever be the Stanford or DBK type if the ascending aorta is involved if the ascending aorta is involved usually It requires surgical intervention. This is a thumb rule. However, if only the descending aorta is involved, usually they can be conservatively tackled as well. More details about the management part and the graft that you're supposed to put.

[01:57:16]That's something that you'll study in surgery. Now similarly there was a condition which was asked right recently in one of your exams related to the aorta where the aorta was massively dilated and abnormally dilated aorta is what is called as right is what is called as an aotic anurism where you can see an out pouching coming out. So the diameter suddenly increases to more than 50% of what the normal diameter was or if an absolute cutff is being used. When do you say that the aorta is dilated or there is an aotic aneurysm is when the ascending aorta diameter is more than 5 cm. If the descending thoracic aorta diameter is more than 4 cm or the abdominal aotic diameter is more than 3 cm. This is the absolute size cutff. The most common sight of an aortic aneurysm is usually the descending aorta or the abdominal aorta. Right? And it is usually infraral in location that is after the origin of the uh renal arteries. Right? Now see this is a CT angog image of the intraanial arteries.

[01:58:30]The internal caroted artery. If you see the right internal caroted artery dividing into the MCA and the ACA whereas the left internal caroted artery is showing a big out pouching there before it divides. So on axial section this is the big anurism. So this is what this is again nothing but the internal carroted artery right which is going to supply the brain aneurysm. So internal caroted artery aneurysm do you remember we have studied the star sign of subacoid hemorrhage blood filling up the basil systems anurismal sh subaracoid hemorrhage right thunderclap headache so that is because of what that is because of a circle of villis anurism IC aneurysm which has ruptured right so this is how the IC anurism would look like another classic you know question which was asked in one of the exams is regarding a newborn male with congestive cardiac failure enlarged Fontineels and a loud cranial brewy is because there is a vascular mal foration called as vein of gallon malf for right in the region of the straight sinus right because there is a hyperdamic circulation which is there you're able to see that brewy when you oscultate from the region of the anterior fontel right because of the hyperdamic circulatory state the child develops neonate develops congestive cardiac failure and on imaging this is a sagittital reconstructed postcontrast CT image You're able to see this large vascular mal foration in the region of the straight sinus draining into the confluence of sinuses. This is what is called as vein of gallon malf for this.

[02:00:05]This is very specific. All right. Now suppose you evaluate a case of a young patient with hypertension. Right? An elderly patient with hypertension is usually essential hypertension. But when you think of a young individual, you're trying to rule out some underlying causes. One such underlying cause that you suspect is renal artery stenosis. You need to rule out a renal artery stenosis when you encounter a young patient, right, with hypertension. So what is the first investigation that you do in this patient? The first investigation is usually an ultrasound or Doppler screening which is called renal artery Doppler. If you see some findings on renal artery Doppler, If you see some findings on renal artery doppler which are suggestive of circulatory changes associated with renal artery stenosis, you proceed to the investigation of choice which is a CT angography which is more commonly done than a MR angography where you document that there is a renal artery stenosis. But if we ask you what is gold standard remember this as a concept gold standard investigation for any vascular abnormality from head to toe be it an anurism of the ICA anurism of the aorta or dissection or pulmonary emolism or renal artery stenosis the gold standard is always going to be invasive catheter angography invasive catheter angography which is what you're seeing here if you look at the graphic picture.

[02:01:40]This is the aorta. Now from the aorta you see the renal artery which is going towards the kidney. But you can see a narrowing involving the middle portion of the renal artery. What is this? This is renal artery stenosis. Well, we are looking at renal artery. Another important spotter right? Another important question which could be asked in renal art stenosis is if they ask you which technique gives you the functional significance of the renal artery stenosis. It is a test which is called as captopril dtpppa scan. So DTPA scan done for glomeular filtration rate GFR estimation. Right. Following an injection of captopil the GFR is going to drop in the renal artery stenosis.

[02:02:23]That is how we can pick up the functional significance. Right. Now uh another classic renal artery spotter that I want you to know is when the renal artery has alternate constrictions and dilations like this. So this gives rise to an appearance which is called as a string of beads or a string of pearls appearance. This is called fibrouscular displasia. Again presence in young to middle-aged individuals. Alternate dilotations and constrictions of the renal artery. This is called string of bead appearance in fibrouscular displas. Well friends we have seen a lot of images until now. I've said that sometimes interpretating radiology images can be tricky. So you have used magic view graphics superimposed on these images right they will help you identify the finding and remember it for a very long period of time. At this point uh I once uh had a very nice interaction with one of my teachers who taught me how to interpret these images and while describing the approach to radiology images when asked what to look for in images and how to look for them right he showed us a very very nice clip which we are going to see here now right when you look at this clip this actually pertains to how and what you should be looking for or in the radological images. Now if you look at this image, this image looks like there is a tree with a bunch of birds on it or crows. But you suddenly realize that oh one of the crow is actually not a crow on the hat of which you see an animal maybe a rabbit right if you zoom in you find that there could be a right astronaut on the top of that animal. If you go into a detail the astronaut is holding an atom. Can you see that? And inside each and every electron of that atom there is a different world of its own you can see that there is multiple fish in this ecosystem here right on one of the rocks there you're able to see you know a telescope and the telescope is actually being watched by a few creatures they can see a lot of them if you zoom out and go into another electron right in that particular tiny atom it has its world of its own so whether you choose to look at the second world or the world with the fish and the telescope and that they are able to see a lot of them.

[02:04:46]Whether you choose to look at the atom per se and restrict your viewing to that atom or its electron or whether you look at the say the astronaut who is holding that particular atom in the fingers or in the hand or whether you look at the funny creature maybe a rabbit on which the astronaut is or you rather focus on the cap of that particular or on the cap of that particular atypical crow or the crow itself right or the tree is entirely your choice. So inside a radiological image remember it is a combination of seouts or shadows right there is a saying it says that the eyes don't see what the mind doesn't know. So now in front of you on this tree you know that there are crows there is a say a rabbit there is an astronaut there is an atom which has electrons and multiple words inside those electrons. A radiological image is actually similar right you may see a image of a barerium meal followed through with bovel loops.

[02:05:57]Now you know that there is a feathery appearance loops which is suggestive of junal loops or an featureless appearance loops which are highly loops. When you see at a CT angio image of a pulmonary emolism you know that there is a SBC there aota there there is a main pulmonary artery branching into two divisions and within those main pulmonary arteries there are big chunks of emboli which are sitting there. So all these are details which your brain or your mind now already knows and the brain is a fantastic you know machine.

[02:06:26]The next time you come across a case of pulmonary emolism or an achalia cardia you know or a say a pyloric stenosis or an EDH or a star sign of subaracoid hemorrhage because there's already one file created in your brain by the name of this diagnosis the next time you see it your eyes will definitely pick it up because your mind already knows it and this is what we achieved by looking at all these images by using all these magic view graphics. Well, the intention here was to show you all these details within these images. I hope you loved it. I loved I absolutely loved creating these graphics and then using them to teach you and show all these details, right? And if I loved them so much while teaching them, I'm sure when you're looking at it and looking and appreciating the various findings, you absolutely loved it. Write to me, right? Whether you loved these particular graphics, how you found them, right? And that is how I hope I in my small attempt to make you fall in love with these particular images, you fell in love with the subject of radiology.

[02:07:25]Let's keep rocking radiology. So all the best.