Causes of generalised reduction of liver echogenicity on ultrasound include:
diffuse malignant infiltration
generalised increase in liver echogenicity
hepatic attenuation on CT
Geographic appearance is a term used in imaging, and other clinical fields (e.g. histopathology) to describe lesions with a well-circumscribed margins with adjacent tissues. The term derives from the somewhat similar appearance of the outline of countries on a map or the clear demarcation forme...
Giant hepatic venous malformations (also known as giant hepatic hemangiomas) are relatively uncommon non-neoplastic vascular lesions of the liver, which can be strikingly large and mimic tumors.
It is important to note that according to newer nomenclature, these lesions are merely...
Gilbert syndrome is a hereditary condition which can result in jaundice.
It is results in intermittent unconjugated hyperbilirubinemia in the absence of hepatocellular disease or hemolysis. Uridine diphosphate-glucuronyl transferase activity is reduced resulting in indirect hyperbili...
Glisson's capsule is the external fibrous layer that envelops liver lobules.
Right upper quadrant pain can be caused by distension of Glisson's capsule 3. This can be caused by several processes, including a hematoma or a mass.
History and etymology
It is named after Franc...
Glucagonomas are pancreatic endocrine tumors that secrete glucagon. Most lesions are malignant.
They are very rare with an incidence of ~0.000005% or less than 1 case per 20 million. Equal incidence in middle-aged men and women.
Most patients present with ...
Glycogen storage disease (GSD) refers to a number of syndromes which are characterized by a defect in synthesis, metabolism or storage of glycogen.
There are many types of GSD:
type I: von Gierke disease
type II: Pompe disease
type III: Cori or Forbes disease
type IV: Andersen di...
Glycogen storage disease type II, also known as Pompe disease or acid maltase deficiency disease, is an inherited lysosomal disorder characterized by abnormal glycogen accumulation within lysosomes. It is a multi-system disorder involving the heart, skeletal muscle and liver. It is caused by the...
Granulomatous hepatitis refers to an inflammatory liver disease associated with granuloma formation in the liver. These can caseating or non-caseating.
It can be associated with a wide variety of conditions, which most commonly includes
sarcoidosis: hepatic manifestati...
The greater pancreatic artery, also known as the pancreatica magna artery, is a branch of the splenic artery that supplies the pancreatic tail and body.
It arises approximately two thirds the way along the splenic artery and descends a short distance to run to the left along the posterior margi...
Gullo syndrome, also known as benign pancreatic hyperenzymaemia, is characterized by the abnormal elevation of the serum levels of most or all of the pancreatic enzymes without any evidence of underlying pancreatic pathology. All other laboratory assays and imaging studies are unremarkable.
Abdominal complications of hematopoietic stem cell transplantation can occur early (0-100 days) or late (>100 days) post-transplant.
bacterial infections, e.g. pseudomembranous colitis
fungal infections, often affecting the esophagus or as hepatic/splenic microabscesses
Haemobilia refers to the presence of blood in the biliary tree.
The classical clinical triad, only seen in ~50% of cases, consists of:
melena (i.e. upper gastrointestinal bleeding)
iatrogenic: surgical or percutaneous proce...
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 in organ dysfunction.
This article focus on the general principles of he...
Hemorrhagic cholecystitis refers to an inflammatory process of the gallbladder, complicated by hemorrhage into the lumen.
The presenting features may mimic non-hemorrhagic acute cholecystitis, with right upper quadrant pain being a dominant feature. If the blood is passe...
Hemorrhagic pancreatitis is a possible uncommon complication that can occur with pancreatitis and is characterized by bleeding within or around the pancreas. It is usually considered a late sequela of acute pancreatitis.
Hemorrhage can occur in patients with severe necrotizing pancre...
HELLP syndrome is a pregnancy-related condition and is an abbreviation for:
elevated liver enzymes and
It is considered a severe and life-threatening form of pre-eclampsia although it can occur without co-existing pre-eclampsia.
The estimated inciden...
Hepascore is a biochemical severity scoring system based on liver function tests in predicting the extent of liver fibrosis/cirrhosis in patients with hepatitis C infection. Hepascore may also be applicable to other liver diseases and is being trialed for fatty liver disease and hepatitis B infe...
Hepatic abscesses, like abscesses elsewhere, are localised collections of necrotic inflammatory tissue caused by bacterial, parasitic or fungal agents.
The frequency of individual infective agents as causes of liver abscesses are intimately linked to the demographics of the affec...
Hepatic adenomas, also referred as hepatocellular adenomas, are benign liver tumors generally hormone induced. The tumors are usually solitary, have a predilection for hemorrhage, and must be differentiated from other focal liver lesions.
The incidence of hepatic adenomas is unkno...
Hepatic adenomatosis is the presence of numerous, more than 10 and up to 50, hepatic adenomas. It is a rare disorder, best characterized with MRI.
Patients with hepatic adenomatosis do not necessarily have the classic risk factors associated with the development of hepatic adenoma...
A hepatic adrenal rest tumor (HART) (previously been termed primary hypernephroma of the liver or hypernephroid carcinoma of the liver) is a very rare liver tumor with histology similar to adrenocortical carcinoma
It tends to occur in younger patients and there is no recognised ge...
Hepatic amyloidosis is an uncommon manifestation of amyloidosis.
It can be primary or secondary and it typically occurs as diffuse infiltration 2.
There is amyloid deposition in liver parenchyma which occurs along the sinusoids within the space of Disse, or in blood vessel walls. He...
Hepatic angiomyolipoma (AML) is an uncommon benign hamartomatous hepatic mass lesion, containing blood vessel (angioid), smooth muscle (myoid) and mature fat (lipoid) components. There is an association with tuberous sclerosis, although this is less strong than for renal AMLs.
Hepatic angiosarcoma is a rare malignancy but is still the third most common primary liver tumor. They have a variable appearance on both CT and MRI reflecting the pleomorphic histological nature. Prognosis is very poor, with survival uncommon beyond one year from diagnosis.
The resistive index (RI) is the commonest Doppler parameter used for hepatic arterial evaluation. The usual range in normal, as well as post-transplant individuals, is between 0.55 and 0.8.
It is measured by:
RI = (peak systolic velocity - end diastolic velocity)/peak systolic velocity
The hepatic artery proper, also known as the proper hepatic artery, is the continuation of the common hepatic artery after it gives off the gastroduodenal artery.
The hepatic artery proper runs anteromedial to the portal vein and medial to the common bile duct to form the...
Hepatic attenuation on CT, reflected by Hounsfield values, depends on a combination of factors including the presence or absence, as well as the phase, of IV contrast administration.
Allowing for all these factors, the mean unenhanced attenuation value is around 55 HU 4.
Hepatic capsular retraction is an uncommon finding related to several benign and malignant pathologies and also intrinsic or extrinsic causes; a list of differential diagnoses is given below:
malignant tumor (primary or metastatic) - especially cholangiocarcinoma but hepatocellular carcinoma is...
The following mnemonics can be used as reminders of the causes of hepatic capsular retraction:
C: cholangiocarcinoma (intrahepatic)
T: treated hepatic metastasis or hepatocellular carcinoma
C: cirrhosis with confluent hepatic fibrosis
H: hemangioma (es...
Primary hepatic carcinoid is an extremely rare type of carcinoid tumor, with somewhere between 60-90 cases reported in the literature. Metastatic carcinoid tumor from the gastrointestinal tract to the liver is far more common.
Some patients present with carcinoid syndrome...
Hepatic carcinosarcoma is a very rare tumor that is defined by mixed histological features.
This tumor has also been referred to as malignant mixed tumor, spindle cell carcinoma, pseudosarcoma or sarcomatoid carcinoma 1,2.
Hepatic carcinocarcinoma contain a mixture of...
Hepatic encephalopathy, also known as portosystemic encephalopathy, refers to a spectrum of neuropsychiatric abnormalities occurring in patients with liver dysfunction and portal hypertension. It results from exposure of the brain to excessive amounts of ammonia.
Hepatic epithelioid hemangioendothelioma (HEHE) is a rare, low to intermediate grade malignant hepatic vascular tumor.
There may be a greater female incidence (with reported male-to-female ratio, 3:2), with peak incidence thought to be around 30-40 years old.
Hepatic hemangiomas are benign neoplastic vascular liver lesions. They are frequently diagnosed as an incidental finding on imaging, and most patients are asymptomatic. From a radiologic perspective, it is important to differentiate hemangiomas from hepatic malignancy.
Hepatic haemangiomatosis is a condition in which the are multiple hemangiomas affecting the liver.
When the lesions are spread throughout the liver, then this is termed diffuse hepatic haemangiomatosis.
giant liver hemangioma 2
Hepatic hemosiderosis refers to the deposition of hemosiderin in the liver.
Hepatic iron overload can be in the form of 7:
In the absence of genetic hemochromatosis and systemic...
Hepatic hydatid disease a parasitic zoonosis caused by the Echinococcus tapeworm. In the liver, two agents are recognised as causing disease in humans:
For a general discussion, and for links to other system-specific manifestations, please ...
Hepatic hydrothorax (HH) is an uncommon manifestation of cirrhosis with ascites. It is one of the pulmonary complications of cirrhosis with portal hypertension.
It is characterized by formation of pleural effusions usually greater than 500 mL, in patients with portal hypertension without any o...
Hepatic infarction is an extremely rare situation because of the liver's dual blood supply by the hepatic artery and portal vein. Hepatic infarction can occur when there is both hepatic arterial and portal vein flow compromise but most cases are due to acute portal venous flow compromise 11.
Hepatic inflammatory pseudotumours (IPT) are rare benign hepatic lesions.
Most common in young adults with males affected more than females 7.
Etiology is unknown 7.
Hepatic IPT is often seen as a well-circumscribed, encapsulated inflammatory...
Hepatic leiomyosarcomas are rare primary malignant tumors derived from smooth muscle cells in the liver.
Hepatic leiomyosarcoma is rare 1. An equal sex distribution and a broad age range (5 months-66Y) has been reported. Some have suggested an associated with AIDS 2.
Hepatic lipomas are rare, usually asymptomatic, benign lesions of the liver.
They may be composed purely of fat cells, or they may be mixed with adenomatous, angiomatous or myomatous tissue, resulting in lesions such as adenolipoma, angiomyolipoma or myelolipoma 5.
A hepatic lymphangioma is a rare benign condition that corresponds to focally dilated lymphatic channels in the liver.
Most cases are asymptomatic.
A lymphangioma is a benign lesion that can occur at almost any location in the body. Hepatic involvement is les...
Hepatic lymphoma is a term given to any form of hepatic involvement with lymphoma. This can be broadly divided into:
secondary hepatic involvement with lymphoma: most common by far, many tend to be non-Hodgkin lymphoma (NHL) 1
primary hepatic lymphoma: extremely rare
Risk factors f...
Hepatic mesenchymal hamartoma is an uncommon benign hepatic tumor. Some authors even consider this to be a developmental anomaly rather than a cystic neoplasm 9,12.
It typically occurs in children and neonates, with most cases presenting within the first two years of life 3. There...
Hepatic metastases are 18-40 times more common than primary liver tumors 6. Ultrasound, CT, and MRI are all useful for detection of hepatic metastases and evaluation across multiple post-contrast CT series, or MRI pulse sequences are necessary.
The demographics of patients with l...
Hepatic myeloid sarcoma is a collection of immature myeloid cells than can present as a mass (or as masses) in the liver. It is a rare complication of haematologic disease.
Hepatic myeloid sarcoma is also referred to as "granulocytic sarcoma" or "chloroma".
Hepatic osteodystrophy is an often forgotten metabolic bone disease seen in patients with chronic liver disease, in particular cirrhosis, primary biliary cirrhosis, and primary sclerosing cholangitis. These patients have increased risk factors for developing osteoporosis such as hypogonadism, al...
Hepatic peliosis is a rare benign vascular condition characterized by dilatation of sinusoidal blood-filled spaces within the liver. There may be involvement of other organs, most commonly the spleen and bone marrow. It can be seen in a variety of settings and is important as appearances may m...
Hepatic pseudolesions near the falciform ligament show abnormal attenuation without mass effect. They may be seen on contrast-enhanced CT scans as either a region of high or low attenuation relative to the rest of the liver. They are typically located in the medial segment of the left lobe of th...
Hepatic siderotic nodules are a type of regenerative nodule formed in a cirrhotic liver. They occur in hepatic hemosiderosis. The nodules have an increased iron content compared with other regenerative nodules. They may be non-dysplastic or dysplastic.
The reason why these nodules co...
Hepatic solitary fibrous tumors (hepatic SFTs) are rare mesenchymal tumors.
Fewer than 60 cases have been reported in the literature. Female predominance (~70%). There is a mean age of 52 years at presentation, but a wide range of incidence (16-84 years).
Hepatic steatosis refers to an increase of intracellular fat in the liver. It is widely mischaracterized by both radiologists and sonographers as 'fatty infiltration' but the fat is in the hepatocytes and not in the extracellular matrix. On imaging grounds, it can broadly be divided into two gro...
The hepatic veins are three large intraparenchymal veins which drain the liver substance into the inferior vena cava (IVC), named the right hepatic vein, middle hepatic vein and left hepatic vein. The veins are important landmarks, running in between and hence defining the segments of the liver....
Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), is a condition arising from occlusion of hepatic venules.
right upper quadrant pain
abnormal liver function tests
Toxic injury to liver s...
Hepatic venous pressure gradient measurement is a safe and minimally invasive method to indirectly measure portal vein pressure in chronic liver disease patients suspected of developing portal vein hypertension.
diagnosis of liver fibrosis and risk stratification
Hepatisation of the gallbladder is a sonographic entity in which the gallbladder lumen is entirely filled with tumefactive sludge giving the gallbladder a similar appearance to liver parenchyma. It is one of the causes of non-visualization of the gallbladder on sonography.
In the set...
Hepatitis B virus (HBV) is a circular DNA virus endemic in many parts of the world. It is a risk factor for the development of hepatocellular carcinoma (HCC).
Acute HBV infection is most often subclinical and asymptomatic. Symptomatic patients (~33%) may experience fever,...
Hepatitis C virus (HCV) is an RNA virus and a member of the Flaviviridae family. It is a risk factor for the development of hepatocellular carcinoma (HCC).
Route of transmission
The most common route of transmission is through blood products and contaminated needles. Unprotected sex...
LI-RADS (Liver Imaging Reporting and Data System) 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 ...
Hepatobiliary imaging in nuclear medicine can be accomplished with multiple different radiotracers. The choice of tracer depends on the clinical question.
Common tracers include
Tc99m-IDA (iminodiacetic acid) analogs: most commonly used tracer; used for evaluation of the biliary system (e.g. H...
Hepatobiliary MRI contrast agents are specialized agents used to aid diagnosis in MRI.
They are separated into three categories: gadolinium-based agents, manganese-based agents and superparamagnetic iron oxide particles.
Gadolinium (Gd) based contrast agents are class...
The hepatobiliary system consists of the:
biliary tree (both intra- and extra-hepatic)
The pancreas is included by some.
Hepatoblastoma is the most common primary malignant liver tumor in children under four years of age who usually present with painless abdominal mass and raised AFP. It is tumor of embryonic origin.
Most cases are seen during the first 18 months of life and diagnosis in adulthood i...
Although hepatoblastomas can be histologically classified into a variety of sub types, it is important to remember that with the possible exception of small cell undifferentiated sub type, prognosis is independent of histology when adjusted for stage gender and age 1.
As expected there are a number of different staging systems for hepatoblastoma.
PRETEXT grouping system of pediatric liver tumors
not specific to hepatoblastoma; used in all pediatric liver tumors
Intergroup staging system
specific for hepatoblastoma (see below)
Intergroup staging ...
Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver. It is strongly associated with cirrhosis, from both alcohol and viral etiologies. HCC constitutes approximately 5% of all cancers partly due to the high endemic rates of hepatitis B infection 1.
Hepatocellular carcinoma staging classifications supersede the typical TNM staging system seen in most other epithelial cancers, as the TNM staging system has been found to not be as prognostically useful for stratification of patients with hepatocellular carcinoma. Several substitute staging sy...
Hepatocellular carcinoma surveillance programs have been adopted by some health systems in attempts to effect an early diagnosis of hepatocellular carcinoma in high-risk populations.
The idea behind hepatocellular carcinoma screening, as with any screening program, is to detect clin...
Hepatoduodenal ligament is the peritoneal ligament of lesser omentum, which attaches the duodenum to the liver.
Hepatoduodenal ligament contains:
common hepatic duct
part of cystic duct
Hepatoduodenal ligament is a rout of spread of diseases of pancratic head t...
Hepatofugal or non-forward portal flow (NFPF) is an abnormal flow pattern where 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 ...
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.
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,...
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 is type of biliary bypass procedure, It is a form of Roux-en-Y
choledo chojejunostomy that is fixed to the
abdominal wall. It is usually performed to facilitate subsequent retrograde extraction of
residual or recurrent
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 a risk for malignancy, other entities must be considered.
Hypertriglyceridaemia-induced pancreatitis is an uncommon form of acute pancreatitis caused by high levels of circulating triglycerides in the blood.
Hypertriglyceridaemia-induced pancreatitis accounts for around 1-4% of cases of acute pancreatitis and is the third most common cau...
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...
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 a liver lesion composed of large endothelial-lined vascular channels seen in fetuses and neonates. It should not be confused with a hepatic epithelioid hemangioendothelioma, which occurs in older patients.
Those benign tumors were previously ...
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.