Hepatofugal or non-forward portal flow (NFPF) is an abnormal flow pattern in which the portal venous flow is from the periphery of the liver towards the porta and backwards along the portal vein. This phenomenon is not uncommon in patients with liver disease 3.
It is the opposite of hepatopetal...
Hepatolithiasis is the presence of bile duct stones within the intrahepatic bile ducts, specifically before the confluence of the right and left hepatic ducts.
Hepatolithiasis is common Asia and the Pacific, with a prevalence of ~40%. It is rare in the West with a prevalence of ~...
Hepatomegaly refers to an increase in size or enlargement of the liver.
Hepatomegaly can result from a vast range of pathology including, but not limited to, the following:
Hepatopetal denotes flow of blood towards the liver, which is the normal direction of blood flow through the portal vein. The term is typically used when discussing the portal vein or recanalized vein of the ligamentum teres in patients with suspected portal hypertension.
It is the opposite of ...
Hepatopulmonary syndrome (HPS) refers to the combination of
hepatic dysfunction (cirrhosis)
hypoxemia (alveolar-arterial O2 gradient of >15 mmHg; >20 mmHg in >64 years old patients)
peripheral pulmonary arterial dilatation (due to right to left micro-shunts)
It is estimated to ...
Hepatosplenic candidiasis is a manifestation of disseminated candidiasis in immunosuppressed patients, particularly those receiving chemotherapy for hematological malignancies. Both hepatic and splenic infection usually happens simultaneously, the reason why they are approached together.
Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly).
Many, many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive!
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.
Hepatic manifestations of Hereditary hemorrhagic telangiectasia (HHT), which is also known as Osler-Weber-Rendu syndrome, are typically seen on imaging as multiple telangiectasias and arteriovenous malformations (i.e. arteriovenous and portovenous shunts). These multiple shunts lead to a hyperdy...
Hereditary pancreatitis is a rare subtype of chronic pancreatitis that has an autosomal dominant inheritance. Imaging plays a role in excluding underlying abnormalities.
As a congenital condition, presentation with acute pancreatitis attacks typically occurs in childhood,...
Hernias (or herniae) are a common pathological entity, in which an anatomical structure passes into an abnormal location via an opening.
The opening may be a normal physiological aperture (e.g. hiatus hernia: stomach passes through the diaphragmatic esophageal hiatus) or pathological. Iatrogeni...
HNF 1 alpha mutated hepatic adenomas are a genetic and pathologic subtype of hepatic adenoma. Their appearance and prognosis are different from other subtypes.
They are the second most common (30-35%) hepatic adenoma, after the inflammatory subtype. They occur only in female patie...
A Hutson loop, also known as an access loop, is variation of the Roux-en-Y choledochojejunostomy whereby a longer segment of jejunum is used to construct the hepatobiliary limb, and the upstream end is tacked to the anterior abdominal wall ("stomatization") 4.
The goal is to simplify future end...
Hyalinised hepatic hemangiomas, also known as sclerosing/sclerosed hepatic hemangiomas, are a rare variant of hepatic hemangioma. Because of their unusual imaging features, they cannot be reliably differentiated from malignant tumor without a biopsy.
A hyalinised hemangioma differs f...
A hyperattenuating gallbladder may occur from a number of different etiologies:
sludge in the gallbladder
vicarious excretion of intravenous contrast (iodinated contrast or gadolinium contrast)
A hyperechoic liver lesion on ultrasound can arise from a number of entities, both benign and malignant. A benign hepatic hemangioma is the most common entity encountered, but in patients with atypical findings or risk for malignancy, other entities must be considered.
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.
Hypertriglyceridemia-induced pancreatitis is an uncommon form of acute pancreatitis caused by high levels of circulating triglycerides in the blood.
Hypertriglyceridemia-induced pancreatitis accounts for around 1-4% of cases of acute pancreatitis and is the third most common cause...
Hypertrophy of the caudate lobe is seen in a number of conditions, including:
cirrhosis: most common
primary sclerosing cholangitis (end stage)
congenital hepatic fibrosis
cavernous transformation of the portal vein
The caudate-right lobe ratio m...
Hypervascular liver lesions may be caused by primary liver pathology or metastatic disease.
hepatocellular carcinoma (HCC)
most common hypervascular primary liver malignancy
early arterial phase enhancement and then rapid wash out
rim enhancement of c...
IgG4-related disease (IgG4-RD) is a systemic disease that is characterized by extensive IgG4-positive plasma cells and T-lymphocyte infiltration of various organs.
This condition has been known by many other names in the past, such as IgG4-related sclerosing disease, IgG4-related s...
IgG4-related sclerosing cholangitis, also known as autoimmune cholangiopathy, is part of the spectrum of IgG4-related disease but can also occur in isolation. It is a separate entity to primary sclerosing cholangitis.
The pathogenesis is poorly understood. The disease is characteriz...
Imaging in liver transplantation is aimed to evaluate donor and recipient for successful transplantation and its outcome.
volume of liver
parenchymal disease (diffuse or focal)
Increased splenic density can be due to a number of processes. The density may be due to calcification (most common) or other compounds (iron, Thorotrast), and can be seen (often incidentally) on abdominal radiographs and CT. On CT the usual splenic attenuation is 35-55 HU or ~10 HU 6 lower than...
Infantile hepatic hemangiomas (IHH) are liver lesions composed of large endothelial-lined vascular channels seen in fetuses and neonates. Not to be confused with hepatic epithelioid hemangioendothelioma, which occurs in older patients.
These benign tumors were previously referred t...
The inferior pancreaticoduodenal artery is the first branch of the superior mesenteric artery (SMA), though it often arises from the first jejunal branch.
It anastomoses with branches of the superior pancreaticoduodenal artery (from the gastroduodenal artery) and it supplies the head of the pan...
Inferior vena cava (IVC) webs are an uncommon condition characterized by obstruction of the hepatic segment of the inferior vena cava by a membrane or fibrous band. This is often associated with occlusion of one or more of the hepatic veins.
If there is hepatic vein invol...
Infiltrative hepatocellular carcinoma (HCC), also known as diffuse hepatocellular carcinoma, is an infrequent subtype of HCC, which has particular imaging characteristics. Because of these characteristics, it has been called cirrhotomimetic-HCC or cirrhosis-like HCC.
Inflammatory hepatic adenomas are a genetic and pathological subtype of hepatic adenoma. Their appearance and prognosis is different than other subtypes and has the highest incidence of hemorrhage amongst hepatic adenoma subtypes.
Most common subtype of hepatic adenoma (40-50%). O...
Inflammatory myofibroblastic tumors (IMT), also known as plasma cell granulomas, are rare neoplasms that have a diverse spectrum of biological behavior.
These tumors were previously referred as inflammatory pseudotumor.
They can occur at any age and there is curre...
Insulinomas are the most common sporadic endocrine tumor of the pancreas.
On imaging, they usually present as small well-defined hypervascular tumors that may be found anywhere along the pancreas.
Account for 40% of syndromic pancreatic endocrine tumors. The overall incidence is...
Interstitial edematous pancreatitis is one of the two subtypes of acute pancreatitis. It is normally referred to as "acute pancreatitis" or "uncomplicated pancreatitis" in day-to-day use. Please refer to the article on acute pancreatitis for further details.
Intrabiliary rupture of hepatic hydatid cyst is a common complication associated with hepatic hydatid cysts. It is important to appreciate the direct and indirect signs of this condition.
The radiological features of intrabiliary rupture of a hepatic hydatid cyst can be c...
Intracholecystic papillary neoplasms (ICPN), also known as intracholecystic papillary-tubular neoplasms, are rare, recently described, preinvasive neoplasms of the gallbladder.
On imaging, these lesions resemble adenomas of the gallbladder or have features suspicious for gallbladder carcinoma, ...
The intraductal neoplasms of the bile ducts are divided into those lesions that are a precursor to adenocarcinoma of the bile ducts, also referred to as preinvasive lesions, and the invasive tumors, which are cholangiocarcinomas of intraductal growing type.
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...
Intraductal papillary neoplasm of the bile duct (IPNB) is a pre-invasive biliary tree neoplasm considered to be a precursor of cholangiocarcinoma.
Biliary papillary adenoma and non-invasive papillary carcinoma of the biliary tract were terms used to refer to localized low-grade an...
Intraductal tubulopapillary neoplasms of the bile ducts are rare intraluminal mass forming pre-invasive biliary neoplasms with no mucin production.
ITPNs of the bile ducts are rare tumors of unknown incidence, found more frequently in women at their 60s 1,2.
Intrahepatic arterioportal shunts represent abnormal flow between the portal venous system and a hepatic arterial system within the liver. They can be a reversible cause of portal hypertension.
Clinical features will depend on the size and other underlying pathology. Smal...
Intrahepatic arteriovenous shunts, also referred to as intrahepatic arteriovenous malformations (AVMs) or hepatic arteriosystemic venous shunts, represent a spectrum of abnormal communications between the hepatic arterial system and the hepatic veins.
Please note that arterioportal shunts, whi...
The American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) introduced a unique staging system for the intrahepatic cholangiocarcinoma in their 7th edition in 2010. They further refined the staging system in the 8th edition.
T: primary tumor
Irreversible electroporation (IRE), also known as non-thermal irreversible electroporation (NTIRE), is a non-invasive soft-tissue ablation technique used for tumor ablation in regions that require very high precision and preservation of surrounding collagenous structures (vessels and ducts) and ...
Jaundice refers to a clinical sign of hyperbilirubinemia (serum bilirubin >2.5 mg/dL) which has many causes. It is often a clue to a diagnosis. It can be largely divided into two types:
non-obstructive, i.e. prehepatic and hepatic causes
obstructive, i.e. posthepatic causes
Imaging has a majo...
Kasai classification is used to describe the three main anatomical types of biliary atresia.
type I: obliteration of common bile duct (patent cystic and common hepatic duct)
IIa: obliteration of common hepatic duct (patent cystic and common bile duct), sometimes with a...
Klatskin tumor is a term that was traditionally given to a hilar cholangiocarcinoma, occurring at the bifurcation of the common hepatic duct. Typically, these tumors are small, poorly differentiated, exhibit aggressive biologic behavior, and tend to obstruct the intrahepatic bile ducts.
Komi classification of bile duct cysts, as stated by Komi et al, divides anomalous union of the pancreatico-bile ducts (AUPBD) into 3 types based on the angle of union of the ducts 1.
type I: union of the ducts at a right angle to each other
type Ia: without dilatation or
KRAS (shortened name for the gene Kirsten RAt Sarcoma viral oncogene homolog) mutations are associated in a number of malignancies including:
certain adenocarcinomas of the lung
colorectal carcinoma 1
pancreatic ductal adenocarcinoma
Several germline KRAS mutations have also been found to b...
The Krenning score is a proposed semi-quantitative method of assessing the degree of tracer uptake on octreotide scintigraphy.
Initially designed for assessment of 111In-DTPA on planar imaging, the Krenning score is applicable to SPECT or SPECT/CT using various radiopharmaceuticals....
This article lists a series of labeled imaging anatomy cases by system and modality.
CT head: non-contrast axial
CT head: non-contrast coronal
CT head: non-contrast sagittal
CT head: angiogram axial
CT head: angiogram coronal
CT head: angiogram sagittal
CT head: venogram axial
The term lamellated (or laminated which means the same thing) is a radiopathological term used to describe the layered appearance of many calculi, including those of the renal tract, the salivary glands, and the biliary tree. The internal structure of these calculi has been likened to that of an...
The left hepatic artery (LHA) is formed when the proper hepatic artery (PHA) bifurcates. The hepatic arteries provide 25% of the blood supply and 50% of the oxygen supply to the liver.
The PHA bifurcates into the left and right hepatic arteries at or before reaching the porta hep...
The left triangular ligament is a peritoneal suspensory ligament of the liver. It is formed by the fusion of the superior and inferior reflections of the coronary ligament.
It is shorter than the right triangular ligament and does not separate the left subphrenic space from the subhepatic space.
Lemmel syndrome is defined as an obstructive jaundice caused by a periampullary duodenal diverticulum compressing the intrapancreatic common bile duct with resultant bile duct dilatation.
Patients may present with recurrent episodes of jaundice, pancreatitis and/or cholan...
Leptospirosis results from infection of the zoonoses Leptospira spp. The condition can have multiorgan manifestations. Commonly affected organs include:
lung: pulmonary leptospirosis
liver: hepatic leptospirosis
central nervous system: CNS leptospirosis
skeletal muscle: muscular leptospirosi...
Leukemic infiltration of the liver can occur with several forms of leukemia inclusive of acute myeloid leukemia (AML), acute lymphoid leukemia (ALL) and chronic myeloid leukemia (CML).
Described features are non-specific but include:
periportal low att...
The ligamentum venosum is a fibrous remnant which travels superiorly from the porta hepatis of the liver to the inferior vena cava. It is often obliterated in adults.
In the fetus, it is patent and known as the ductus venosus which shunts blood returning from the placenta in the umbilical vein...
The light bulb sign of a hepatic hemangioma is a feature than can be seen on MRI imaging with a classic hepatic hemangioma. This refers to marked hyperintensity seen on heavily T2 weighted sequences that has been likened to a glowing light bulb.
light bulb sign - shoulder
light bulb ...
Limy bile stands for the presence of a viscous substance in the dependent parts of the gallbladder and/or bile ducts, almost entirely composed of calcium carbonate, and therefore highly radiopaque.
The terms limy bile and calcium milk gallbladder can be used interchangeably for inc...
Lipase, more specifically pancreatic lipase, is an enzyme produced in the pancreas and is responsible for the digestion of fat molecules. It may be raised (hyperlipasemia) in numerous pancreatic, hepatobiliary and other diseases but is most commonly associated with acute pancreatitis.
Lipomatous pseudohypertrophy of the pancreas is a rare, benign entity characterized by focal or diffuse enlargement of the pancreas due to the replacement of exocrine parenchyma with adipose tissue.
Arguably lipomatous pseudohypertrophy may be considered a distinct clinicopathologi...
Liquefactive necrosis is a form of necrosis where there is transformation of the tissue into a liquid viscous mass.
In liquefactive necrosis, the affected cell is completely digested by hydrolytic enzymes leading to a soft, circumscribed lesion which can consist of fluid with remains...
Liver Imaging Reporting and Data System (LI-RADS) is both a set of standardized terminology and a classification system for imaging findings in liver lesions. The LI-RADS score for a liver lesion is an indication of its relative risk for hepatocellular carcinoma (HCC).
The classification system...
Littoral cell angioma of the spleen is a rare, benign primary vascular tumor of the spleen.
Littoral cell angiomas may occur at any age and have no gender predilection.
Littoral cell angiomas have been diagnosed in association with various malignancies outside the s...
The liver is the largest abdominal organ that plays a major role in metabolism and has a number of functions, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, hormone production, and detoxification. It is one of the very few organs that has the ability to r...
There is a wide range of liver and biliary interventional procedures, both diagnostic and therapeutic, most commonly using CT-guidance or ultrasound-guidance.
transjugular intrahepatic portosystemic shunt (TIPS)
transjugular liver biopsy (TJLB)
Percutaneous liver biopsy, utilizing either ultrasound or CT guidance, allows for an accurate and reliable method of acquiring hepatic tissue for histopathological assessment. It is divided into two types:
non-focal or non-targeted liver biopsy (used in the assessment and staging of the parench...
Transjugular liver biopsy (TJLB) is an alternative to a percutaneous liver biopsy in patients with diffuse liver disease, coagulopathy and ascites.
It is sometimes done in combination with a transjugular intrahepatic portosystemic shunt (TIPSS) or venography.
Barcelona clinic liver cancer (BCLC) staging uses a set of criteria to guide management of patients with hepatocellular carcinoma (HCC).
The classification takes the following variables into account 1,2:
performance status (PS)
radiologic tumor extent
Liver lesions represent a heterogeneous group of pathology ranging from solitary benign lesions to multiple metastases from a variety of primary tumors.
Liver lesions may be infiltrative or have mass-effect, be solitary or multiple, benign or malignant.
Assessment of liver lesions takes into c...
Pediatric liver lesions are a heterogeneous group that includes infiltrative lesions and those that demonstrate mass-effect. Moreover, they may be solitary or multiple, benign or malignant:
benign liver tumors
malignant liver tumors
There are differing frequencies of both benign...
Liver lobules are the basic functional units of the liver. They are classically described ('classic lobules') as hexagonal structures made of six vertically aligned portal canals with a central vein. However, microscopic evaluation of the liver usually shows a lack of classic liver lobule as a w...
Examination of the liver with MRI requires numerous sequences and imaging at multiple times after the administration of gadolinium. Many variations exist, but a typical protocol would include:
T2 fat sat
T1 weighted gradient echo in and out of phase
T1 2D or 3D gradient ech...
Liver sinusoids are a type of fenestrated/porous blood vessel which compose the 'capillary bed' of the liver parenchyma. They receive terminal branches of the oxygen-rich hepatic artery (terminal hepatic arterioles) and nutrient-rich portal vein (terminal portal venules). They facilitate vascula...
The liver is one of the most frequently damaged organs in blunt trauma, and liver trauma is associated with a significant mortality rate.
In blunt abdominal trauma, the liver is injured ~5% (range 1-10%) of the time 1,3.
Patients can present with right uppe...
Liver tumors, like tumors of any organ, can be classified as primary or secondary.
Liver metastases are by far the most common hepatic malignancy, with many of the most common primaries readily seeding to the liver. This is especially the case with gastrointestinal tract tumors, due...
The lollipop sign is seen in hepatic epithelioid hemangioendothelioma (HEHE). It represents hepatic/portal vein and/or their tributaries/branches tapering and terminating at or just within the edge of a well defined peripherally enhancing (or non-enhancing) lesion with an avascular core on CT or...
Low phospholipid-associated cholelithiasis (LPAC) syndrome is one of the syndromes associated with ABCB4/MDR3 mutation. Characteristics of this syndrome include 1,2:
symptomatic cholesterol stones with early onset (<40 years)
recurrent symptoms post cholecys...
LR2 cirrhosis-associated nodules are defined as "probably benign" according to the LI-RADS classification system. They are a common finding in a cirrhotic liver and do not need to be mentioned in the report.
The nodule must demonstrate all of the following:
Macroamylasemia is the presence of serum amylase of a large molecular size, seen in both otherwise healthy individuals, and also in various diseases. Amylase seems to be able to self-polymerize and/or form complexes with other blood proteins, e.g. immunoglobulins.
Macrolipasemia is the presence of serum lipase of a large molecular size, seen occasionally in otherwise healthy individuals, but more commonly in various diseases. Lipase is able to self-polymerize and/or form complexes with other blood proteins e.g. immunoglobulins.
Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive imaging technique to visualize the intra and extrahepatic biliary tree and pancreatic ductal system.
It can provide the diagnostic range equivalent to the ERCP and so it can replace the ERCP in high risk patients to avoid sign...
This is a basic article for medical students and other non-radiologists
Malignant biliary tract obstruction (MBTO) represents a group of conditions that cause obstructive jaundice. While most examples are the result of pancreatic head cancers, other malignancies may be causative.
Pediatric malignant liver tumors are rare, some of which occur only in children but that are similar to those that occur in adults.
Malignant liver tumors account for ~1% of pediatric malignancies 2.
Broadly, any malignant liver mass can be defined as a metastasis or p...
Mallory bodies are cytoplasmic eosinophylic 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 cirrhosis (PBC)
Mass-forming intrahepatic cholangiocarcinomas (MF-ICC), also referred as peripheral cholangiocarcinomas, compromise one of the three recognized growth patterns of intrahepatic cholangiocarcinomas.
On imaging, these tumors usually present as large and relatively well-defined hepatic masses with...
Mastocytosis is characterized by excessive accumulation of mast cells in one or more organs. According to the World Health Organization classification, three clinical entities fall under the mastocytosis umbrella: cutaneous mastocytosis, systemic mastocytosis (with or without cutaneous manifesta...
Meandering main pancreatic duct (MMPD) comprises of a reverse Z-type and loop-type of pancreatic ducts.
These ductal variants are found in ERCP and MRCP studies. The exact incidence is not known.
Increased incidence of meandering pancreatic duct has been reported in patients with idiopathic re...
Medical devices in the abdomen and pelvis are important to be recognized, just like medical devices of the chest. Often we ignore these devices, considering them to be incidental and non-pathological, however it is essential to be aware of potential complications.
Meglumine iotroxate (BiliscopinTM) is an iodinated, intravenous contrast agent that is preferentially excreted into the biliary tree and is used in CT intravenous cholangiography.
The typical dose is 100 mL Biliscopin (105 mg meglumine iotroxate/mL; 5.0 g iodine), which is administered via slow...
The MELD score (Model for End-stage Liver Disease) is a classification used to grade liver dysfunction in preparation for liver transplantation. It is an estimate of 3 month mortality.
The components of the score are:
serum creatinine (mg/dl)
if dialysis twice in last week, then bilirubin is ...
Melioidosis is an infectious disease caused by the bacterium Burkholderia pseudomallei (previously known as Pseudomonas pseudomallei) and is a multisystem disorder which may affect the lungs, brain, visceral organs, or musculoskeletal system.
Melioidosis is a disease of the monsoo...
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...
The METAVIR scoring system is a system used to assess the extent of inflammation and fibrosis by histopathological evaluation in a liver biopsy of patients with hepatitis C. The grade indicates the activity or degree of inflammation while the stage represents the amount of fibrosis or scarring....