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...
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 tumours generally hormone induced. The tumours are usually solitary, have a predilection for haemorrhage, and must be differentiated from other focal liver lesions.
The incidence of hepatic adenomas is un...
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 tumour (HART) (previously been termed primary hypernephroma of the liver or hypernephroid carcinoma of the liver) is a very rare liver tumour with histology similar to adrenocortical carcinoma
It tends to occur in younger patients and there is no recognised ...
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 tumour. 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 or the proper hepatic artery arises from the common hepatic artery as it divides into its two terminal branches, the hepatic artery proper and the gastroduodenal artery.
The hepatic artery proper runs to the right anterior to the portal vein and...
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 tumour (primary or metastatic) - especially cholangiocarcinoma but hepatocellular carcinoma i...
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: haemangioma (e...
Primary hepatic carcinoid is an extremely rare type of carcinoid tumour, with somewhere between 60-90 cases reported in the literature. Metastatic carcinoid tumour from the gastrointestinal tract to the liver is far more common.
Some patients present with carcinoid syndro...
Hepatic carcinosarcoma is a very rare tumour that is defined by mixed histological features.
This tumour has also been referred to as malignant mixed tumour, spindle cell carcinoma, pseudosarcoma or sarcomatoid carcinoma 1,2.
Hepatic carcinocarcinoma contain a mixture...
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 haemangioendothelioma (HEHE) is a rare, low to intermediate grade malignant hepatic vascular tumour.
There may be a greater female incidence (with reported male-to-female ratio, 3:2), with peak incidence thought to be around 30-40 year-old.
Hepatic haemangiomas 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 haemangiomas from hepatic neoplasms.
Hepatic haemangiomatosis is a condition in which the are multiple haemangiomas affecting the liver.
When the lesions are spread throughout the liver, then this is termed diffuse hepatic haemangiomatosis.
giant liver haemangioma 2
Hepatic haemosiderosis refers to the deposition of haemosiderin in the liver.
Hepatic iron overload can be in the form of 7:
In the absence of genetic haemochromatosis and syste...
Hepatic hydatid disease is a parasitic zoonosis caused by the Echinococcus tapeworm. In the liver, two agents are recognised as causing disease in the human:
For a general discussion, and for links to other system specific manifestations, p...
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 characterised 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.
Aetiology is unknown 7.
Hepatic IPT is often seen as a well-circumscribed, encapsulated inflammator...
Hepatic leiomyosarcomas are rare primary malignant tumours 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 tumour. 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. Ther...
Hepatic metastases are 18-40 times more common than primary liver tumours 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 ...
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 characterised 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 haemosiderosis. The nodules have an increased iron content compared with other regenerative nodules. They may be nondysplastic or dysplastic.
The reason why these nodules co...
Hepatic solitary fibrous tumours (hepatic SFTs) are rare mesenchymal tumours.
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 mischaracterised by both radiologists and sonographers as 'fatty infiltration' however the fat is in the hepatocytes and not the extracellular matrix. On imaging grounds, it can broadly be divided into two gr...
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...
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-visualisation 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 standardised 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) analogues: most commonly used tracer; used for evaluation of the biliary system (e.g....
Hepatobiliary MRI contrast agents are specialised 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 tumour in children under four years of age who usually present with painless abdominal mass and raised AFP. It is tumour of embryonic origin.
Most cases are seen during the first 18 months of life and diagnosis in adulthood...
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 paediatric liver tumours
not specific to hepatoblastoma; used in all paediatric liver tumours
Intergroup staging system
specific for hepatoblastoma (see below)
Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver. It is strongly associated with cirrhosis, from both alcohol and viral aetiologies. 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 recanalised 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)
hypoxaemia (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 haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterised 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 than 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
A hyalinised hepatic haemangioma (or sclerosing/sclerosed hepatic haemangioma) is a rare variant of hepatic haemangioma. Because of its unusual imaging features, it cannot be reliably differentiated from a malignant tumour without biopsy.
A hyalinised haemangioma differs from a typic...
A hyperattenuating gallbladder may occur from a number of different aetiologies:
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 haemangioma 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 (PSC) (end stage)
congenital hepatic fibrosis
cavernous transformation of the portal vein
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 characterised 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 haemangiomas (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 haemangioendothelioma, which occurs in older patients.
Those benign tumours were previous...
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 characterised 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, also known as diffuse hepatocellular carcinoma (HCC), 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 haemorrhage amongst hepatic adenoma subtypes.
Most common subtype of hepatic adenoma (40-50%). ...
Inflammatory myofibroblastic tumours (IMT), also known as plasma cell granulomas, are rare neoplasms that have a diverse spectrum of biological behaviour.
These tumours were previously referred as inflammatory pseudotumour.
They can occur at any age and there is c...
Inflammatory polyps of the gallbladder are a subtype of gallbladder polyps, representing ~10% of polyps.
Thought to develop from chronic inflammation, with deposition of cholesterol in the gallbladder wall and mucosal irritation, leading to a fibrous reaction 2.
There is no evidence...
In-phase (IP) and out-of-phase (OOP) sequences correspond to paired MRI gradient echo (GRE) sequences obtained with the same repetition time (TR) but with two different echo time (TE) values.
The main application of the IP-OOP sequences is to identify pathological (microsopic) fa...
Insulinomas are the most common sporadic endocrine tumour of the pancreas.
Account for 40% of syndromic pancreatic endocrine tumours. Overall incidence of ~0.0003%.
Typically insulinomas present with Whipple's triad consisting of:
fasting hypoglycaemia (<5...
Interstitial oedematous 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...
Intraductal papillary mucinous neoplasms or tumours (IPMNs or IMPTs) are cystic tumours of the pancreas.
These tumours are most frequently identified in older patients (50-60 years of age) 6, and thus are sometimes colloquially referred to as the "grandfather lesion". Main duct ty...
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 size and other underlying pathology. Small sh...
Irreversible electroporation (IRE), also known as non-thermal irreversible electroporation (NTIRE), is a non-invasive soft-tissue ablation technique used for tumour ablation in regions that require very high precision and preservation of surrounding structures.
In IRE electrodes are ...
Jaundice refers to a clinical sign of hyperbilirubinemia (>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. pre-hepatic and hepatic causes
obstructive, i.e. post-hepatic causes
Imaging has a major role in dete...
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 tumour is a term that was traditionally given to a hilar cholangiocarcinoma, occurring at the bifurcation of the common hepatic duct. Typically, these tumours are small, poorly differentiated, exhibit aggressive biologic behaviour, 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
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....
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 on reaching the porta hepatis. Thes...
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 (of the second part of the duodenum) compressing the intrapancreatic part of the common bile duct with resultant upstream dilatation of the extra- and intrahepatic bile ducts.