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Portal venous gas

Portal venous gas is the accumulation of gas in the portal vein and its branches. It needs to be distinguished from pneumobilia, although this is usually not too problematic when associated findings are taken into account along with the pattern of gas (i.e. peripheral in portal venous gas, centr...

Portosystemic collateral pathways

Portosystemic collateral pathways (also called varices) develop spontaneously via dilatation of pre-existing anastomoses between the portal and systemic venous systems. This facilitates shunting of blood away from the liver into the systemic venous system in portal hypertension, as a means for r...

Portal hypertension

Portal hypertension is defined as a hepatic venous pressure gradient (HVPG) >5 mmHg. Hepatic venous pressure gradient is a surrogate for the portosystemic pressure gradient. Clinically significant portal hypertension is defined as a gradient >10 mmHg and variceal bleeding may occur at a gradient...

Pneumobilia

Pneumobilia, also known as aerobilia, is the accumulation of gas in the biliary tree. It is important to distinguish pneumobilia from portal venous gas, the other type of branching hepatic gas. There are many causes of pneumobilia and clinical context is often important to distinguish between th...

Phrygian cap

Phrygian caps are the most common congenital anatomic variant of the gallbladder. It denotes folding of the fundus back upon the gallbladder body and is asymptomatic with no pathological significance. Radiographic findings A Phrygian cap may be identified on ultrasound, multiphase CT/MRI, or c...

Pancreatic neoplasms

There are numerous primary pancreatic neoplasms, in part due to the mixed endocrine and exocrine components. Classification Classification based on function exocrine: ~99% of all primary pancreatic neoplasms pancreatic ductal adenocarcinoma (commonly known as pancreatic cancer) 90-95% acin...

Pancreatic ducts

The exocrine pancreas drains into the gastrointestinal tract via the main and accessory pancreatic ducts. There are several anatomical variations of the typical ductal drainage pattern, reflecting variations in the embryological development and fusion of the dorsal and ventral pancreatic buds 13...

Pancreatoblastoma

Pancreatoblastomas are rare pediatric tumors of the pancreas. However, they are the most common pancreatic neoplasm of childhood and are often associated with a raised alpha-fetoprotein. Epidemiology There is slight male predilection. Usually occurs in the first decade of life with a mean age ...

Nutmeg liver

A nutmeg liver appearance is due to a perfusion abnormality of the liver usually as result of hepatic venous congestion. When hepatic veins are congested, contrast is prevented from diffusing through the liver in a normal manner. This results in a mottled pattern of contrast enhancement in the a...

Mercedes-Benz sign (gallbladder)

In the gallbladder, the Mercedes-Benz sign describes a star-shaped pattern of gas-fissuring within gallstones initially described on an abdominal radiograph 2. Fissures, usually fluid-filled, are present in close to 50% of gallstones. Less than half of these fissured gallstones contain some amo...

Mallory bodies

Mallory bodies are cytoplasmic eosinophilic inclusions in hepatocytes, associated with ballooning and inflammation, found in: alcoholic fatty liver disease and hepatitis non-alcoholic fatty liver disease hepatocellular carcinoma (HCC) primary biliary cholangitis (PBC) cholestasis

AAST liver injury scale

The AAST (American Association for the Surgery of Trauma) liver injury scale, most recently revised in 2018, is the most widely used liver injury grading system 3. The 2018 update incorporates "vascular injury" (i.e. pseudoaneurysm, arteriovenous fistula) into the imaging criteria for visceral ...

Intraductal papillary mucinous neoplasm

Intraductal papillary mucinous neoplasms or tumors (IPMNs or IMPTs) are epithelial pancreatic cystic tumors of mucin-producing cells that arise from the pancreatic ducts. They are most commonly seen in elderly patients. On imaging, particularly MRCP, they are characterized by single or multipl...

Hypervascular liver lesions

Hypervascular liver lesions are findings that enhance more or similarly to the background hepatic parenchyma in the late arterial phase, on contrast-enhanced CT or MRI. Differential diagnosis Non-neoplastic vascular shunts intrahepatic arterioportal shunt intrahepatic arteriovenous shunt f...

Sinusoidal obstruction syndrome

Sinusoidal obstruction syndrome (SOS), previously known as hepatic veno-occlusive disease (VOD), is a condition arising from occlusion of hepatic venules. Clinical presentation right upper quadrant pain painful hepatomegaly ascites abnormal liver function tests Pathology Toxic injury to l...

Hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterized by abnormal blood vessel formation in the skin, mucous membranes, and organs including the lungs, liver, and central nervous system. Epidemiology Worldwide prevalen...

Hepatocellular carcinoma

Hepatocellular carcinoma (HCC), also called hepatoma, is the most common primary malignancy of the liver. It is strongly associated with cirrhosis, from both alcohol and viral etiologies. Hepatocellular carcinomas constitute approximately 5% of all cancers partly due to the high endemic rates of...

Hepatic adenoma

Hepatic adenomas, also referred to as hepatocellular adenomas, are benign, generally hormone-induced, liver tumors. The tumors are usually solitary, have a predilection for hemorrhage, and must be differentiated from other focal liver lesions. Epidemiology The incidence of hepatic adenomas is ...

Hemochromatosis

Hemochromatosis is an iron overload disorder characterized by a progressive increase in total body iron stores and deposition of iron in some non-reticuloendothelial system (RES) body organs which results in some instances of organ dysfunction. This article focuses on the general principles of ...

Hypertension

Hypertension refers to an increase in blood pressure above the 'normal' for the age, sex, and ethnicity of the patient. This can be specified according to the vascular system involved. Although generally when it is not specified it is assumed to refer to the systemic type. systemic hypertension...

Gallstone ileus

Gallstone ileus is an uncommon cause of mechanical small bowel obstruction. It is a rare complication of chronic cholecystitis 7 and occurs when a gallstone passes through a fistula between the gallbladder and small bowel before becoming impacted at the ileocecal valve. Epidemiology Although ...

Focal hepatic steatosis

Focal hepatic steatosis, also known as focal hepatosteatosis or (erroneously) focal fatty infiltration, represents small areas of liver steatosis. In many cases, the phenomenon is believed to be related to the hemodynamics of a third inflow. Terminology The term 'fatty infiltration of the li...

Cystic lesions of the pancreas (differential)

The differential for cystic lesions of the pancreas includes: unilocular pancreatic pseudocyst intraductal papillary mucinous neoplasm (IPMN) serous cystadenoma uncommonly uni/macrolocular simple pancreatic cyst cystic neuroendocrine tumor of the pancreas diffuse pancreatic cysts pancrea...

Cystic fibrosis

Cystic fibrosis (CF), also called mucoviscidosis, is an autosomal recessive genetic disease that affects the exocrine function of the lungs, liver, pancreas, small bowel, sweat glands, and the male genital system 11. This is resulting in progressive disability and multisystem failure. This artic...

Cirrhosis

Cirrhosis (plural: cirrhoses) is the common endpoint of a wide variety of chronic liver disease processes which cause hepatocellular necrosis. Cirrhosis can be diagnosed with ultrasound, CT, and MRI, and these imaging modalities can also be used to evaluate for possible complications of cirrhosi...

Choledochal cyst

Choledochal cysts represent congenital cystic dilatations of the biliary tree. Diagnosis relies on the exclusion of other conditions (e.g. tumor, gallstone, inflammation) as a cause of biliary duct dilatation. Epidemiology Choledochal cysts are rare, with an incidence of 1:100,000-150,000. Alt...

Cholangiocarcinoma

Cholangiocarcinomas (bile duct cancers) are malignant epithelial tumors arising from the biliary tree, excluding the gallbladder or ampulla of Vater. Cholangiocarcinoma is the third most common primary hepatobiliary malignancy after hepatocellular carcinoma (HCC) and gallbladder cancer 23. They ...

Chemotherapy induced cholangitis

Chemotherapy induced cholangitis is caused when intra-arterial chemotherapy is introduced to treat liver metastases. This causes strictures of the common hepatic duct and main ducts, but spares distal and proximal (i.e. common bile duct and intrahepatic ducts). Radiographic features similar t...

Budd-Chiari syndrome

Budd-Chiari syndrome, also known as hepatic venous outflow obstruction (HVOO), refers to the clinical picture that occurs when there is partial or complete obstruction of the hepatic veins. There is no clear consensus regarding the number of occluded veins, some authors claim that there should...

Acute pancreatitis

Acute pancreatitis (plural: pancreatitides) is an acute inflammation of the pancreas and is a potentially life-threatening condition. Terminology There are two subtypes of acute pancreatitis as described by the Revised Atlanta Classification 1: interstitial edematous pancreatitis vast major...

Accessory right inferior hepatic vein

An accessory right inferior hepatic vein is the most common variation of the hepatic veins, and may be multiple 1. It is present in up to 48% of the population and drains the posteroinferior part of the right lobe directly into the inferior vena cava (IVC) 1-3. Variations in hepatic vascular an...

AIDS cholangiopathy

AIDS cholangiopathy refers to an acalculous, secondary opportunistic cholangitis that occurs in AIDS patients as a result of immunosuppression 1. Pathology Characterized by multiple irregular strictures essentially indistinguishable from primary sclerosing cholangitis (PSC). There are four pa...

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