Presence of portosystemic collateral veins (PSCV) is common in portal hypertension due to cirrhosis. Physiologically, normal portosystemic anastomoses exist which exhibit hepatofugal flow. With the development of portal hypertension, transmission of backpressure leads to increased flow in these patent normal portosystemic anastomoses. In extrahepatic portal vein obstruction collateral circulation develops in a hepatopetal direction and portoportal pathways are frequently found. The objective of this review is to illustrate the various PSCV and portoportal collateral vein pathways pertinent to portal hypertension in liver cirrhosis and EHPVO. ( J CLIN EXP HEPATOL 2012;2:338-352) A lmost any vein in the abdomen may serve as a potential collateral channel to the systemic circulation. Presence of abnormal collateral vessels appears to be one of the most sensitive (70-83%) and specific sonographic signs for the diagnosis of portal hypertension. 1 When blood flow through a vessel or a vascular bed is obstructed due to occlusion, as in EHPVO, or distortion, as in liver cirrhosis, collateral pathways open up as blood bypasses the occlusion or obstruction, always flowing down a pressure gradient from a high pressure to a low-pressure vessel or bed. The formation of portosystemic pathways occurs due to reopening of collapsed embryonic channels or reversal of the flow within existing adult veins. 2,3 The number of collateral channels depends on the severity of portal hypertension i.e. the differential gradient driving the flow between the portal and the systemic circulations and the duration of portal hypertension. The more severe and more prolonged the portal hypertension, the higher are the number of portosystemic pathways. However, this traditional hypothesis has been challenged and it has been suggested that the formation of portosystemic collateral circulation may be due in part to angiogenesis driven by vascular endothelial growth factor. 4,5 Almost 50 years have passed since the first detailed description of portosystemic collateral veins (PSCV) in portal hypertension appeared. 6 Precise mapping of PSCV is essential to therapeutic decisions and multidetector computerized tomography (MDCT) is sometimes used for cartography of PSCV. 7 EUS is increasingly being used for evaluation of PSCV and additionally provides an option for performing therapeutic interventions. 8 In addition to PSCV, PPCV pathways are frequently found in extrahepatic portal vein obstruction (EHPVO). The objective of this review is to illustrate the various PSCV and PPCV pathways pertinent to portal hypertension in liver cirrhosis and EHPVO. NORMAL PORTOSYSTEMIC ANASTOMOSESThe left gastric vein (LGV) anastomoses with the esophageal veins, which in turn drain into the azygos vein (AV). The superior rectal vein (SRV) anastomoses with the middle and inferior rectal veins (IRV), which are, respectively, tributaries of the internal iliac and the pudendal veins. The paraumbilical vein (PUV) anastomoses with subcutaneous veins in the anterior abdominal...

Portal cavernoma cholangiopathy (PCC) is defined as abnormalities in the extrahepatic biliary system including the cystic duct and gallbladder with or without abnormalities in the 1st and 2nd generation biliary ducts in a patient with portal cavernoma. Presence of a portal cavernoma, typical cholangiographic changes on endoscopic or magnetic resonance cholangiography and the absence of other causes of these biliary changes like bile duct injury, primary sclerosing cholangitis, cholangiocarcinoma etc are mandatory to arrive a diagnosis. Compression by porto-portal collateral veins involving the paracholedochal and epicholedochal venous plexuses and cholecystic veins and ischemic insult due to deficient portal blood supply or prolonged compression by collaterals bring about biliary changes. While the former are reversible after porto-systemic shunt surgery, the latter are not. Majority of the patients with PCC are asymptomatic and approximately 21% are symptomatic. Symptoms in PCC could be in the form of long standing jaundice due to chronic cholestasis, or biliary pain with or without cholangitis due to biliary stones. Endoscopic retrograde cholangiography has no diagnostic role because it is invasive and is associated with risk of complications, hence it is reserved for therapeutic procedures. Magnetic resonance cholangiography and portovenography is a noninvasive and comprehensive imaging technique, and is the modality of choice for mapping of the biliary and vascular abnormalities in these patients. PCC is a progressive condition and symptoms develop late in the course of portal hypertension only in patients with severe or advanced changes of cholangiopathy. Asymptomatic patients with PCC do not require any treatment. Treatment of symptomatic PCC can be approached in a phased manner, coping first with biliary clearance by nasobiliary or biliary stent placement for acute cholangitis and endoscopic biliary sphincterotomy for biliary stone removal; second, with portal decompression by creating portosystemic shunt; and third, with persistent biliary obstruction by performing second-stage biliary drainage surgery such as hepaticojejunostomy or choledochoduodenostomy. Patients with symptomatic PCC have good prognosis after successful endoscopic biliary drainage and after successful shunt surgery. ( J CLIN EXP HEPATOL 2014;4:S2-S14)

The pattern of anatomical organization of the thoraco-abdominal visceral and vascular structures which is not the expected normal arrangement, is called as situs ambiguous or heterotaxy syndrome. Patients with heterotaxy syndrome exhibit a wide spectrum of anatomical variations involving thoraco-abdominal structures. We present here an incidental finding of heterotaxy syndrome associated with unique vascular anomalies in a 35 year old male patient evaluated initially for nephrolithiasis by ultrasonography, and intravenous pyelography. Further evaluation by multidetector row computed tomography showed bilateral bilobed lungs with hyparterial bronchi, cardiac apex to the left, five branches from left-sided aortic arch with retroesophageal right subclavian artery, interrupted inferior vena cava with azygos continuation, left renal vein continuing as hemiazygos vein and replaced common hepatic artery arising from the superior mesenteric artery. Other vascular anomalies include right internal iliac vein joining the left common iliac vein and precaval course of the single main right renal artery. Anomalies involving abdominal organs include right-sided stomach, midline liver, multiple splenules (polysplenia) in right upper quadrant of abdomen, short truncated pancreas, intestinal malrotation, inversion of superior mesenteric vessels and a preduodenal portal vein. To the best of our knowledge this is the first report of association of left renal vein continuing as hemiazygos vein, precaval right renal artery and anomalous branching pattern of aortic arch with heterotaxy syndrome.

Pancreas divisum (PD) is the most common developmental anatomic variant of pancreatic duct. Endoscopic ultrasound (EUS) is often performed to evaluate idiopathic pancreatitis and has been shown to have high accuracy in diagnosis of PD. The different techniques to identify PD by linear EUS have been described differently by different authors. If EUS is done with a proper technique it can be a valuable tool in the diagnosis of PD. The anatomical and technical background of different signs has not been described so far. This article summarizes the different techniques of imaging of pancreatic duct in a suspected case of PD and gives a technical explanation of various signs. The common signs seen during evaluation of pancreatic duct in PD are stack sign of linear EUS, crossed duct sign on linear EUS, the dominant duct and ventral dorsal duct (VD) transition. Few other signs are described which include duct above duct, short ventral duct /absent ventral duct, separate opening of ducts with no communication, separate opening of ducts with filamentous communication, stacking of duct of Santorini and indirect signs like santorinecele. The principles of the sign have been explained on an anatomical basis and the techniques and the principles described in the review will be helpful in technical evaluation of PD during EUS.

The current gold standard investigation for anatomic exploration of the pancreatic duct (PD) is endoscopic retrograde cholangiopancreatography. Magnetic resonance cholangiopancreatography is a noninvasive method for exploration of the PD. A comprehensive evaluation of the course of PD and its branches has not been described by endoscopic ultrasound (EUS). In this article, we describe the techniques of imaging of PD using linear EUS.