 So, role of ultrasound in the biliri tree. Now, I want to stress on protocols, now we are in the era of guidelines, protocols and checklist. So, for any study it is better to have a protocol. So, I will show the steps for studying the biliri tree, first is the knowledge of the anatomy. So, here you see the intriapatic biliri radicals of the right lobe joined to form the right hepatic duct and those in the left lobe joined to form the left hepatic duct, both of them joined in the apotheopatist anterior to the bifurcation of the portal way to form the common hepatic duct and which is joined by the cystic duct from the gallbladder to form the common bile duct. We cannot identify the ultrasound, the point of the cystic duct joining, so we use the term common duct to denote both the common hepatic duct and the common bile duct. So, the common bile duct enters the pancreas and opens into the second part of diodenum on the ample of beta. Now, there may be a slight variation in the termination of the common bile duct. The common one is it is joined by the pancreatic duct close to its termination into the ample of or the two ducts may open very close together on the summit of the ample of beta. So, this is a slight variation in termination. Now, the common clinical presentation of an abnormal biliri tree is jaundice. So, once the patient presents with jaundice, the role of ultrasound is to differentiate whether it is obstruction or parankamal replacement or mixed. So, that is the role of ultrasound to differentiate obstructive from non-obstructive jaundice. Obstructive jaundice, the role of ultrasound is to see signs of obstruction and then go to know the level of obstruction and finally, the cause of obstruction. As I said, the technique should involve the steps. So, what are the steps? Step one is you look for the peripheral biliri radical and step two is scan through the bifurcation of the portal vein where you will be able to see the right and left hepatic ducts anterior to the right and left branches of the portal vein and step three is the study of the gallbladder and step four is the long axis of the common duct and step five is the transverse scan of the pancreas. We will see one by one. Step one is the peripheral radical, you do a scan of the periphery of the liver. So, normally you will see the branch of the portal vein as a single tubular structure. Peripheral radical of the bile duct also accompanies the peripheral branch of the portal vein, but normally it is not seen, but when the bile duct is dilated, it will be seen coursing parallel to the branch of the portal vein. So, that is called the parallel channel sign or the double barrel gun sign. So, if you see this, then the bile ducts are dilated. So, this is again normal bile duct in the left load and the dilated bile duct in the left load. It is called the parallel channel sign. So, this is step one. With this, you diagnose whether the bile ducts are dilated. Then you go for the step two, that is the transverse scan along the bifurcation of the portal vein, where normally you will see the right and left branches of the portal vein and you will see the right and left hepatic ducts anterior to them and they are very thin. So, usually not seen or maybe seen like a hairline, but when the duct is dilated, then you will see the normal portal vein anterior to that you will see the dilated right and left hepatic ducts on the common hepatic duct. Now, here you see the right and left hepatic ducts are dilated, but at the confluence instead you see a irregular ill-defined mass. So, this is typical appearance of a Colangio carcinoma. Now, step three is gallbladder. So, gallbladder we must look for the long axis scan. It may be normal or it may be dilated or you may get gallstones in the gallbladder or it the gallbladder may be replaced by carcinoma in a case of jaundice. Then we study the step four that is the common duct. Now, common duct will not be readily seen. So, you have to go for it that approach is called the target approach, where it is a technique to get a small or a thin structure like CBD from a large known structure that is the portal vein here. So, from the portal vein which can be easily picked up, we go to the small thin structure by their anatomical relationship. So, we will see what is that. Now, this is the anatomy in a transverse scan of the portal vein, which is magnified. You see the portal vein, the cross section anterior and to the left, you get the branch of the car section of the hepatic artery. Anterior to the portal vein and slightly to the right of the hepatic artery is the common duct. So, this when you take an oblique scan of the right type of quantum, you will see the portal vein. You rotate to the transducer to get the long axis of the portal vein. So, this is easy to get. So, from here, by the knowledge of the anatomy relationship between the common duct and the portal vein. So, the common duct is anterior to the portal vein and slightly to the right. So, from the portal vein, you move the transducer, make it more vertical and then slightly move to the right. Then you will get the common duct coming into the field. So, this is the technique and this is called the target approach. We will see the video. So, first get at the portal vein and then make the transducer more vertical slightly to the right. You get the long axis of the common duct very well. So, this is the target approach. You see the common duct very nicely seen. So, this is the technique you have to use. And the small information about the terminal part of the common duct. So, the terminal part, if you see the common duct is vertical initially after entering the pancreas, it becomes transverse to open into the ampulla. So, if you keep on doing oblique scan of the common duct, you will fail to see this portion of the common duct, terminal portion. So, when you go to the transverse scan of the pancreas, so the common duct will be seen as a dot by the cross section. So, from there you must turn the transducer till the transducer to oblique to see the terminal end of the common duct like that. If you do not do this, you will miss the pathology of this terminal portion of the common duct. That is the video showing the tilt of the transducer to see the terminal part of the common duct. Another technique you can go from the common duct. Again, you can rotate the transducer to more transversely, you see the terminal portion of the common duct like that. Now, that is the common duct that is normal and the caliber is equal to the decade of the age. Now, here the common duct is dilated and it is cylindrical and when you trace it, you see the calculus in the medicinal common duct. So, that is the calculus causing obstruction. Next is the step five that is the transverse scan of the pancreas. So, here you will see the pancreas and you will see the common duct as a cross section in the head of the pancreas. When the common duct is dilated, you will see the dilated common duct in the transverse scan of the pancreas. If there is a calculus in the distal duct, you will be seen like this. And in the transverse scan of the pancreas, you also will make out a dilated pancreatic duct. And also you will make out the cause of obstruction as a carcinoma of the pancreas if it is present. So, these are all the things you have to see in this session. Now, we go to the diagnosis of the causes. Now, causes in the intrapathetic portion of the bile duct, the causes are cholangic carcinoma, sclerosing cholangitis and oriental cholangio hepatitis. Now, sclerosing cholangitis is an autoimmune disease, a very rare disease, causing multiple constrictions of the bile ducts, both intrapathic as well as extrapathetic. So, the dilated bile duct appears like a beaded structure. It appears multiple areas. And then in the bifurcation, again it is beaded. And the common duct also may show stitches. So, this is typical appearance of sclerosing cholangitis. Now, oriental cholangio hepatitis is a disease of recurrent cholangitis resulting in multiple stitches. And because of the stitches obstruction dilated, there may be multiple calculate in the intrapathetic bile ducts. You see the intrapathic calculate in the most of the periphery of the liver. And then you may see a calculate in the dilated gallbladder and also calculate in the dilated common duct, which may or may not be present. So, this is typical appearance of oriental cholangio hepatitis. Now, in the high war in the periphery, you may get cholangic arsonoma as seen here, which we have seen already. Dilated right and left hepatic ducts, mass in the confluence. Oiler obstruction can be one of these. So, this is the oblique scan. You see the dilated ducts and in the high lump, in the common duct, you see a large calculus. Or there may be a structure of the common duct in the proteapathis. That is the common duct up to proteapathis. And you do not see the dilated distal duct. And you do not see any cause of the obstruction, that is due to stricture. And again similar, but instead of stricture, you see a large irregular mass in the proteapathis, again a cholangio carcinoma. Or the obstruction in the high lump may be enlarged lymph nodes as that is the duct. And that is the enlarged lymph node and may be multiple enlarged lymph nodes in the proteapathis causing obstruction. The oiler obstruction can be due to an infiltrative carcinoma of the neck of the gallbladder, as seen here. You see dilated fundus and irregular mass in the neck of the gallbladder, which can extend into the high lump and infiltrate the common duct, producing obstruction to the biliary. So, a patient may present as jaundice. And the rare cause of obstruction to the common duct and the high lump is mericis disease. Now here you see the constructed contracted gallbladder with calculate. And then the common duct is dilated. And just distal to the proteapathis, you see a calculus. So, this is actually a calculus in the cystic duct, which is due to fibrosis involving the common duct producing obstruction to the common duct. Now distal CBD obstruction may be due to one of these causes. We will see one by one. This is dilated intrapartic radicals, dilated common bile duct. And you see the calculus in the distal common bile duct. If you take a section, transverse section here, you see the dilated duct in the head of pancreas. And another section here, you will see the calculus in the dilated distal duct in the transverse scan of the pancreas. The calculus may be impacted at the ampulla. Again, dilated radicals, contracted gallbladder, dilated CBD. And as I said, you must turn the transducer, rotate the transducer to see the terminal end of the CBD. So, where you will see the terminal end in a transverse section. And you see the calculus in the ampulla impacted in the ampulla within the gas-filled diodenum. So, this is calculus at the ampulla. We may get calculus in the non-dilated CBD without jaundice. And here you see the CBD normal, but multiple calculus seen in the gallbladder as well as in the CBD. There may be calculus along with the stent after calculus seen in the CBD. In a patient with jaundice, they have applied stent. So, before removal of the stent, they would like to see whether the calculus is passed. So, here you see still the calculus by the side of the stent, which is seen as a tube. A very rare complication of obstructive jaundice is spontaneous perforation of the gallbladder. Here you see a site is because of bile, dilated CBD. And if you see the gallbladder, you see the thick walls here. And with high frequency, you see the thick walls, which is due to breach in the wall of the gallbladder, which leak of the bile. So, that is spontaneous perforation of the gallbladder in a patient with obstruction to the bile rate. Now, obstruction may be due to scary assist. Now, here you see a dilated common duct in both the cases. And in the distal part, you see that a scar is formed as another tube within the CBD. This is called the tube within tube appearance of a scar is causing obstructive jaundice. Now, here you see dilated gallbladder, dilated common duct. And you see a mass in the distal part of the common duct. And you see what is called the shouldering. So, shouldering indicates that there is a thickening of the both the walls of the common bile duct, like the apple core of the colon, carcinoma of colon. So, this is a typical appearance of carcinoma of the distal CBD causing obstructive jaundice. Now, here dilated common duct, the transistor scan of the pancreas, you see a cyst in the head, you see calcifications in the pancreas, and you also see dilated pancreatic duct, all features of chronic calcific pancreatitis. Now, dilated bile ducts, dilated right and left hepatic ducts, dilated gallbladder, dilated common duct. And when you see in the distal part, you see a mass that is the pancreas. And when you do transverse scan, you see that the entire pancreas is swollen. And ecopore. So, there is no focal mass. So, this is chronic pancreatitis producing obstructive jaundice, but there are no calcifications. Now, here dilated gallbladder, dilated common bile duct. And in the distal part, you see an ecopore mass. And when you do transverse scan of the pancreas, you see dilated pancreatic duct. And in the head, you see an irregular mass, diagnostic of carcinoma of the head of pancreas causing obstructive jaundice, dilated biliratory and obstructive jaundice. Now, obstruction may be at the ampulla, dilated gallbladder, dilated CBD, and dilated pancreatic duct. So, the obstruction has to be in the ampulla. So, again, as I said, you must do a transverse scan to see the terminal end of the CBD you see here. And at the end, you see the enlarged ampulla within the duodenum, fluid filled duodenum. You see a small mass in the ampulla. So, that is a periamplary growth, very small periamplary growth producing obstructive jaundice. And the last cause is carcinoma of the duodenum, dilated gallbladder with calcule, dilated duct. And transverse scan shows dilated common duct in the pancreas. And in the region of the duodenum, you see the pseudo kidney appearance. And when you do a long axis scan, you see irregular thickening of the second part of the duodenum with the dilated proximal duodenum and narrow lumbar. So, this is carcinoma of the duodenum producing obstructive jaundice. Some rare causes of obstructive jaundice. Now, here is a scan of the liver showing a hydrated cyst in the right lobe. What has happened is that is the membranes, that is the hydrated cyst. And when you see here, the dilated common duct, and you see the hydrated cyst and you see the communication action. So, the hydrated cyst has leaked into the biliary tree and the dotted cysts and the hydrated sand has caused obstruction to the distal CBD producing jaundice. Now, jaundice may be due to parenchymal causes of one of these. So, we need not cover this because the topic is biliary tree. But rarely the cause may be both parenchymal and obstructive. Like what happens in epitocelular carcinoma. Yeah, that is epitocelular carcinoma replacing most of the right lobe. And there is a metastatic lymph node in the pota apparatus obstructing the rest of the biliary tree causing jaundice. Similarly, a codange carcinoma in the right lobe infiltrating the pota and the left hepatic duct producing dilated biliary tree in the left lobe. So, it is both parenchymal and obstructive cause of jaundice. And then postcholestectomy follow up you get abdominal distension. So, there is asitis due to bile leak. And when you see the bile duct, you see the structure of the bile duct due to inadequate ligation of the common bile duct, injury to the common bile duct during surgery. Cholestectomy. Now, coming to jaundice in the newborn and children, we are worried about biliary atresia. So, in biliary atresia, the ultrasound may show an abnormal. You see an abnormal gallbladder or an absent non-visualistic gallbladder. And when you look for the bile ducts, you see the portal vein, but you do not see the dilated biliary. So, non-dilated biliary tree with an abnormal or absent gallbladder is diagnostic of biliary. Rarely, you may see a large cystic cyst in the hyalum in a child newborn with jaundice. But the ducts are not dilated. But this is actually a double atresia, atresia proximal, atresia distal. As a result, secretions are distending the common duct, mimicking a colidocal cyst. Now, here there is a siteus inversus in this child, the stomac on the right side, liver on the left side. And the bile ducts are not dilated. On the right side, you get polysplemia. So, this is a typical syndrome that is a siteus inversus, polysplemia. Syndrome, patient is jaundice, then it is biliary atresia, almost always. Then we come to the congenital bile duct dilatation, previously called colidocal cyst. And this is the classification, you see the types. And on ultrasound, you see the type 1, where the system dilatation of the common duct. And you see in transverse scan, the cyst in the region of the common duct and into the portal vein. When you do oblique scan, you see that the cyst is communicating with the common hepatic duct. That makes us the diagnosis of a colidocal cyst type 1. So, the difference is here there is a fusiform dilatation of the common duct. As opposed to all the other causes we saw where there was only cylindrical dilatation. Because in other causes, there is no fault with the muscles. Whereas in colidocal cyst, there is weakness of the muscles of the wall. So, as a result, there is fusiform dilatation. Whereas here it is cylindrical dilatation. Now here in type 4, we get a dilated common duct as well as right and left hepatic ducts. So, this is the gallbladder, this is the cyst. And you see the transverse scan, dilated right and left hepatic ducts. And you do the transverse scan of the pancreas, huge cystic dilatation of the common duct. In oblique scan, you see the dilated huge fusiform dilatation of the common duct with the dilated right and left hepatic ducts and the common hepatic duct. So, that forms the type 4 congenital bile duct dilatation. Now there is a congenital malformation of the bile ducts called the pancreatic biliary ductal malformation, where you see a long common channel. As I said before, the normally the right and the common duct and the pancreatic duct unite just before they are opening into the ampulla. Or they open very separately, very close together on the ampulla. But an abnormal variation is a long common channel. That is, the both of them join far away, remote from the ampulla. So, there is a very long common channel. So, when there is a very long common channel, what happens is, there can be reflex of pancreatic juice into the common bile duct, which destroys the muscles of the common bile duct wall, resulting in fusiform dilatation of the common bile duct. So, that is, becomes the congenital bile duct malformation, which is a theory that there is a pancreatic biliary ductal malformation in the form of long common channel. Otherwise, there can be reflex of bile juice into the pancreatic duct, which can induce acute pancreatitis. Now here, transverse scan of the head of pancreas. Here, you see the dilated common duct as well as the pancreatic duct. And when you come a little low down, you see very close together the dilated common duct containing sludge and the pancreatic duct. And then when you do an oblique scan, you see the long axis of both the common duct and the pancreatic duct with sludge balls in the long common channel. So, this is the long common channel. So, this is pancreatic biliary ductal malformation. And this video showing the same transverse scan, this is separate. When you come down, they unite together. And when I turn the transducer, you get the long axis of the two ducts and joining together to form the long common channel. So, that is the two ducts and that is the long common channel. That is the pancreatic biliary ductal malformation, which is confirmed by the MR holography. That is the long common channel. The bile-free syndrome is a biochemical abnormality viscous, highly viscous bile resulting in sludge formation forming the bile plugs in the gallbladder as well as in the filling the common bile duct cause transient obstruction to the bile duct. And the newborn will present as jaundice is a self-limiting disease they may get passed out. This is of jaundice. There is a condition called spontaneous perforation of the CBD, where patient presents acutely with pain abdomen and toxicity and distinctions of abdomen. Scan shows acitis and it is exudative acitis. The gallbladder is collapsed. And if you see the common right and lefty particulates are slightly dilated and you get a slightly dilated common duct with a sludge ball. So, the sludge ball causes temporary transient obstruction resulting in perforation of the CBD. Again, this is a self-limiting disease. Now, coming to nebobilia, there is gas in the bile ducts. So, here this is a typical appearance of gas in the bile ducts and the common duct in the oblique scan. And the gallbladder, you will fail to see the gallbladder because it is filled with gas. So, when there is nemobilia, it may be iotrogenic or it may be gallstone ileus or obstruction with cholangitis. Now, here this is a post stented nemobilia and you see the stent in the common hepatic duct and the common bile duct. So, in the patient who has been stented, you fail to see nemobilia that will point to obstruction to the stent. Now, here this is a patient presenting with small bowel obstruction. There was nemobilia and the gallbladder was contracted and the tracing the dilated bowels, it led to a lith causing obstruction. So, that was a post out gallstone. So, that is the gallstone ileus, that is the bowel and you see the gallstone there. Large gallstone perforating the gallbladder and the teodinum and causing small bowel obstruction. Rarely, there may be a cold doco diodenal fistula due to secondary to a calculus eroding or an ulcer eroding. Here you see nemobilia and you see dilated common duct with a large sledge ball and in real time you will see that there is fluid in the diodenum passing into the common bile duct confirming that it is a cold doco diodenal fistula. Now, patient presenting with jaundice and nemobilia. So, if nemobilia, we do not expect the patient to be jaundice because the indicates free flow of bile into the diodenum. But if both are together, we must suspect obstruction with the cholangitis. So, this is nemobilia and put the patient in erect to displace all the gas into the liver so that the CBD fills with fluid which is becomes visible on ultrasound. And so, you see the common duct fluid field and you see the calculus as the cause of obstruction. With obstruction, there is infection due to gas producing organism causing nemobilia. Rarely, there may be a very rare cause tumor of the bile duct that is called the biliary cystidinoma. It typically presents as a multi-subtracted cystic mass particularly in children. And it has to be differentiated mimics hydratid cysts. The pointers are the age. Hydratid cyst is in the middle and later whereas this biliary cystidinoma happens in children. Location is more towards the high lump and with the, there may be peripheral duct and dilatation because of obstruction. And you may see calcifications within the cystidinoma whereas calcification of hydratid cysts will be peripheral. So that is biliary cystidinoma. Thank you very much for your patient listen.