Coarsened hepatic echotexture is a sonographic descriptor where there uniform smooth hepatic echotexture of the liver is lost. This can occur due to number of reasons which include:
conditions that cause hepatic fibrosis 1
various types of hepatitis 3
Coeliac artery (also known as the coeliac axis or trunk) is a major visceral artery in the abdominal cavity.
Arises anteriorly from abdominal aorta at the T12 level, behind the median arcuate ligament, just as the aorta enters the abdomen.
It is typically a sho...
The common bile duct (CBD), which is sometimes simply known as the bile duct, is formed by the union of the cystic duct and common hepatic duct.
The CBD is approximately 8 cm long and usually <6 mm wide in diameter but this can be dependent on a number of factors including age a...
The common hepatic artery (CHA) is a terminal branch of the coeliac artery.
Origin and course
The CHA is a terminal branch of the coeliac artery, it passes to the right in the lesser sac, and enters the lesser omentum to pass slightly upwards towards the porta hepatis. It gives ...
Confluent hepatic fibrosis is a possible result of chronic injury to the liver, most commonly from cirrhosis or hepatic vascular injury.
Confluent hepatic fibrosis is a cause of wedge-shaped or concave-marginated abnormalities in the cirrhotic liver: It occurs more freque...
Congestive hepatopathy includes a spectrum of hepatic derangements that can occur in the setting of right-sided heart failure (and its underlying causes). If there is subsequent hepatic fibrosis the term cardiac cirrhosis may be used. The condition can rarely occur as a result of non-cardiac cau...
Contrast-enhanced ultrasound (CEUS) involves the administration of intravenous contrast agents containing microbubbles of perfluorocarbon or nitrogen gas. The bubbles greatly affect ultrasound backscatter and increase vascular contrast in a similar manner to intravenous contrast agents used in C...
The cottage loaf sign occurs as a result of a right-sided diaphragmatic rupture with partial herniation of the liver through the diaphragmatic defect. The herniated component is separated by a waist at the diaphragm from the larger intra-abdominal component. This shape is reminiscent of a cottag...
The Couinaud classification (pronounced kwee-NO) is currently the most widely used system to describe functional liver anatomy. It is the preferred anatomy classification system as it divides the liver into eight independent functional units (termed segments) rather than relying on the tradition...
Pauli et al published a "handy" way to remember the Couinaud classification of hepatic segments 1.
Make a fist with your right hand. The fingers should be wrapped around the flexed thumb and the fist should face you. The segments are represented by the following:
segment I (caudate): the thumb...
Courvoisier sign or Courvoisier-Terrier sign states that in a patient with painless jaundice and an enlarged gallbladder (or right upper quadrant mass), the cause is unlikely to be gallstones and therefore presumes the cause to be an obstructing pancreatic or biliary neoplasm until proven otherw...
CT cholangiography is a technique of imaging the biliary tree with the usage of hepatobiliary excreted contrast. It is useful in delineating biliary anatomy, identifying a bile leak or looking for retained gallstones within the biliary system.
Second-line test (after ultrasound) wh...
CT polytrauma/multitrauma (also called trauma CT) is an increasingly used test in the patient with multiple injuries sustained after significant trauma.
There is some evidence that trauma patients who undergo whole body CT (WBCT) / panscan have better survival than patients who undergo selectiv...
The CT severity index (CTSI) is based on findings from a CT scan with intravenous contrast to assess the severity of acute pancreatitis. The severity of computed tomography findings have been found to correlate well with clinical indices of severity.
The CTSI sums two scores:
A cyst is an abnormal fluid filled structure which is lined by epithelium. This distinguishes it from a pseudocyst with lacks an epithelial lining and instead has a vascular and fibrotic capsule
Cysts are extremely common and found in many organs. Examples include:
The cystic artery represents the main blood supply to the gallbladder. It most commonly arises from the right hepatic artery within Calots triangle 1.
The cystic artery passes posterior to the cystic duct to reach the neck of the gallbladder. At this point, it gives off two-to-fo...
Cystic hepatic metastases are included in the differential for new cystic liver lesions. The internal cystic component may represent necrosis as the tumor outgrows its hepatic blood supply, or it may represent a mucinous component, similar to the primary tumor.
The liver and lungs are the most ...
Cystic lesions of liver carry a broad differential diagnosis. These include:
simple hepatic cyst
adult polycystic liver disease
infectious: inflammatory conditions
pyogenic hepatic abscess
amoebic hepatic abscess
The differential for cystic lesions of the pancreas includes:
intraductal papillary mucinous neoplasms (IPMN)
serous cystadenoma uncommonly uni/macrolocular
pancreatic cysts occur in association with
von Hippel Lindau syndrome
autosomal dominant polycysti...
A gas filled focal collection in the right upper upper quadrant on plain film can occur from a number of pathologies. Things to consider are
entero biliary fistula : common types include cholecysto-duodenal fistula and cholecysto-colic fistula and. Can occur with
gallstone ileus (majority of ...
Diffuse thickening of the gallbladder wall can occur in a number of situations.
gallbladder empyema 7
postprandial physiological state (pseudothickening)
Diffuse hepatic steatosis, also known as fatty liver, is a common imaging finding and can lead to difficulties assessing the liver appearances, especially when associated with focal fatty sparing.
Diffuse hepatic steatosis is common, affecting ~25% of the population.
Grading of diffuse hepatic steatosis on ultrasound has been used to communicate to the clinician about the extent of fatty changes in the liver.
grade I: increased hepatic echogenicity with visible periportal and diaphragmatic echogenicity
grade II: increased hepatic echogenicity wit...
Double barrel sign is an imaging appearance of two lumens adjacent to each other.
It can be seen in:
dilated bile duct adjacent to portal vein
double barrel aorta: aortic dissection
double barrel oesophagus: oesophageal dissection
The double duct sign refers to the presence of simultaneous dilatation of the common bile and pancreatic ducts. Being an anatomical sign it can be seen on all modalities that can visualise the region, including: MRI, CT, ultrasound and endoscopic retrograde cholangiopancreatography (ERCP).
The double target sign is a characteristic imaging feature of liver abscess demonstrated on contrast enhanced CT scans, in which a central, fluid-filled low attenuation lesion is surrounded by a high attenuation inner rim and a low attenuation outer ring 1,2.
The inner ring (abscess membrane) d...
The duct penetrating sign is a radiographic sign which can be useful in differentiating between focal pancreatitis (inflammatory pancreatic mass) from pancreatic carcinoma.
A positive sign is when a mass is penetrated by an unobstructed pancreatic duct; this makes focal pancreatitis the most li...
Dysplastic liver nodules are focal nodular regions (≥ 1 mm) without definite evidence of malignancy.
They have been found in cirrhotic patients with a prevalence of 14% (size >1.0 cm) to 37% (size >0.5 cm) 2.
increased fat or glyco...
Ectopic intracaval liver is a rare congenital abnormality of the liver in which a part of the liver invaginates the inferior vena cava (IVC). Lobar or segmental agenesis, Riedel lobe, and ectopic hepatic lobes have been described as congenital abnormalities 1. The term ectopic intracaval may be ...
Ectopic pancreatic tissue (or heterotopic pancreatic tissue) refers to the situation where rests of pancreatic tissue lie outside and separate to the pancreatic gland. Most patients are completely asymptomatic.
It is reportedly relatively common, affecting ~5% (range 1-10%) 1 of p...
Emphysematous cholecystitis is a rare form of acute cholecystitis where gallbladder wall necrosis causes gas formation in the lumen or wall. It is a surgical emergency, due to the high mortality from gallbladder gangrene and perforation.
Men are affected twice as commonly as women...
Endocrine tumours of the pancreas arise from the pancreatic islet cells and include some distinct tumours that match the cell type of origin.
Pancreatic endocrine tumours have commonly been referred to as "islet cell tumours", referring to the islets of Langerhans, from which they...
Endoscopic retrograde cholangiopancreatography (ERCP) is a diagnostic and interventional procedure technique using both endoscopy and fluoroscopy for examination and intervention of the biliary tree and pancreatic ducts. It is typically performed by doctors with endoscopic qualifications (e.g. g...
The term epidermoid cyst can refer to a:
epidermal inclusion cyst
intracranial epidermoid cyst
splenic epidermoid cyst
spinal epidermoid cyst
testicular epidermoid cyst
Exophytic hepatic mass or tumour is a lesion which predominantly lies outside the margins of liver but originates from within the liver.
Causes include 1:
focal nodular hyperplasia
Extra-hepatic portal vein obstruction is the most common cause of noncirrhotic portal hypertension in children and young adults in developing countries. It may or may not extend into intrahepatic portal veins.
It usually occurs in children and young adults, presenting as ...
Extramedullary haematopoiesis is a response to failure of erythropoiesis in the bone marrow.
chronic myelogenous leukaemia
myelofibrosis with myeloid metaplasia
sickle cell disease
Extrapulmonary tuberculosis (TB) refers to the haematogenous spread of Mycobacterium tuberculosis.
Extrapulmonary tubercuosis can occur as a primary form of the disease, i.e. direct infection of an extrapulmonary organ without the presence of primary pulmonary tuberculosis or it can ...
The falciform ligament is a broad and thin peritoneal ligament. It is sickle-shaped (Latin: "falciform") and a remnant of the ventral mesentery of the fetus.
It is situated in an anteroposterior plane but lies obliquely so that one surface faces forward and is in contact with the peritoneum beh...
A variety of benign and malignant liver lesions may contain macroscopic and/or intracytoplasmic fat in sufficient quantities enabling characterization on imaging studies. Most fat containing liver lesions (80%) in patients with cirrhosis are malignant, most of which are hepatocellular carcinoma ...
Fetal hepatomegaly (or more simply an enlarged fetal liver) can occur in number of situations. It can occur with or without fetal splenomegaly.
in utero infections
fetal parvovirus B19 infection
fetal cytomegalovirus infection 3
transient abnormal myelopoiesis (TAM) associate...
Fetal intrahepatic calcification can be a relatively common finding. Calcifications in the liver can be single or multiple and in most cases in which isolated hepatic calcific deposits are detected, there is usually no underlying abnormality.
The presence of isolated intrahepatic calcification ...
Fibrolamellar hepatocellular carcinoma is a distinct variant of generic hepatocellular carcinoma (HCC), with different demographics and risk factors (see epidemiology).
Typically these tumours occur in young adults (20 to 40 years of age) without gender predilection. Unlike HCCs t...
Flash filling hepatic venous malformations, also known as flash filling hepatic haemangiomas, are a type of atypical hepatic venous malformation (haemangioma), which due to its imaging features often raises the concern of a malignant process rather than a benign one.
It is importa...
Focal fatty sparing of the liver is a localised absence of fatty change in a liver otherwise, affects with fatty change (diffuse hepatic steatosis). Recognition of this finding is useful to prevent falsely thinking the region is a mass.
To be added
Similar to its inver...
Focal gallbladder wall thickening is an imaging finding that includes both benign and malignant etiologies.
gallbladder carcinoma: look for infiltration into adjacent organs, metastases, lymphadenopathy, bile duct dil...
The focal hepatic hot spot sign can be seen on technetium 99m sulfur colloid scans of the liver and spleen.
It occurs as a focal area of increased radiopharmaceutical uptake in the medial segment of the left hepatic lobe (segment IV) due to superior vena cava obstruction ...
Focal hepatic steatosis (focal fat infiltration of the liver) is common and seen in a number of clinical settings, essentially the same as those that contribute to diffuse hepatic steatosis:
drugs (amiodarone, methotrexate, chemothe...
Focal hypodense hepatic lesions on a non-contrast CT scan can result from a number of pathological entities, including:
biliary hamartoma: von Meyenberg complexes 2
hepatoma/hepatocellular carcinoma (HCC)
Focal nodular hyperplasia (FNH) is a regenerative mass lesion of the liver and the second most common benign liver lesion (most common is cavernous haemangioma). Many FNHs have characteristic radiographic features in multimodality imaging, but some lesions may be atypical in appearance. FNHs are...
Focussed Assessment with Sonography for Trauma (FAST) scan is a point-of-care ultrasound examination performed at the time of presentation of a trauma patient.
It is invariably performed by a clinician, who should be formally trained, and is considered as an 'extension' of the trauma clinical ...
Gadoxetate disodium (also known by the tradenames PrimovistTM and EovistTM) is a hepatospecific paramagnetic gadolinium-based contrast agent, used exclusively in MRI liver imaging. Its chief use is in hepatic lesion characterisation, i.e. assessing focal liver lesions identified on other imaging...
The gallbladder is a pear-shaped musculomembranous sac, lodged in a fossa on the undersurface of the right lobe of the liver, and extending from near the right extremity of the porta hepatis to the anterior border of the liver.
It typically measures from 7 to 10 cm in length and...
Agenesis of the gallbladder is a rare congenital anomaly.
The incidence is <0.1% (range 0.04-0.1%). There is strong female predominance present among the symptomatic cases.
Most patients with agenesis of the gallbladder are asymptomatic. Although some patie...
Gallbladder carcinomas are usually asymptomatic until they reach an incurable stage. As such, early incidental detection is important, if the occasional patient is to be successfully treated. The majority (90%) are adenocarcinomas, and the remainder are squamous cell carcinomas.
Gallbladder duplication is a rare anatomic anomaly characterised by the presence of an accessory gallbladder. There is no increased risk for malignancy or calculi compared to a single gallbladder.
Prevalence is estimated at 1 in 3000.
Boyden's classification divi...
Gallbladder dysfunction, or functional gallbladder disorder, refers to biliary pain due to motility disturbance of the gallbladder without gallstones, biliary sludge, microlithiasis or microcrystals. The disorder has previous been known by several other names, including gallbladder dyskinesia, g...
Gallbladder empyema (suppurative cholecystitis1) is an uncommon complication of cholecystitis and refers to a situation where the gallbladder lumen is filled and distended by purulent material (pus).
There is an increased incidence in those with diabetes 2 and/or advanced atherosc...
Gallbladder ghost triad is a term used on ultrasound studies when there is a combination of three gallbladder features on biliary atresia:
atretic gallbladder, length less than 19 mm
irregular or lobular contour
lack of smooth/complete echogenic mucosal lining with an indistinct wall
Gallbladder hydrops refers to marked dilatation of the gallbladder due to chronic obstruction of the cystic duct results in accumulation of the sterile non-pigmented mucin.
Abdominal pain with palpable gallbladder without any signs of infection. In an asymptomatic patient...
Gallbladder perforations are a relatively rare complication that can occur in some situations but occurs most frequently as a result of acute cholecystitis. It can carry a relatively high mortality rate. It can also occur during laparoscopic cholecystectomies with the incidence of gallbladder pe...
Gallbladder polyps are elevated lesions on the mucosal surface of the gallbladder. The vast majority are benign, but malignant entities are possible. Gallbladder polyps may be detected on ultrasound, CT, or MRI, but are usually best characterized on ultrasound.
Gallbladder polyps ...
Gallbladder sludge (also known as biliary sand, biliary sediment, or thick bile) is a mixture of particulate matter and bile, normally seen as a liquid-liquid level in the gallbladder on ultrasound, corresponding to the precipitate of bile solutes 1.
These precipitates consist of cholesterol ...
Gallbladder triplication is an extremely rare anomaly. There are three types of gallbladder triplication are described according to the number of cystic duct and their insertion:
Three gallbladders and three cystic ducts which unite to form a common cystic duct before joining the common bile du...
Gallbladder volvulus is a relatively rare condition in which there is a rotation of the gallbladder around the axis of the cystic duct and artery.
Symptoms are non-specific, however right upper quadrant pain and vomiting are similar to biliary colic. Laboratory evaluation...
Gallbladder wall cholesterolosis is a situation that results from accumulation of cholesterol esters and triglycerides in the macrophages at gallbladder wall level.
It may occur in two forms:
diffuse: strawberry gallbladder
Its prevalence may range around 4-8% and th...
Gallstone disease represents a group of conditions that are linked to, or caused by, gallstones. These stones are formed from sludge in the gallbladder and may range from millimetres in diameter to several centimetres. 90% of gallstones are asymptomatic, but they may become impacted, causing pai...
Gallstone ileus is an uncommon cause of a mechanical small bowel obstruction (SBO). 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 ileocaecal valve.
Gallstone pancreatitis refers to pancreatitis caused by gallstones, specifically distal choledocholithiasis. Gallstones is the cause for 35-40% of acute pancreatitis but this number has a wide regional variance.
Gallstone pancreatitis has a higher incidence in women (compared to ...
Gallstones, also called cholelithiasis, are concretions that occur anywhere within the biliary system, most commonly within the gallbladder.
Gallstones (cholelithiasis) describes stone formation at any point along the biliary tree. Specific names can be given to gallstones dependi...
Gangrenous cholecystitis is the most common complication of acute cholecystitis, affecting ~15% (range 2-30%) of patients.
Gangrenous cholecystitis occurs as a result of ischaemia with necrosis of the gallbladder wall 4.
Gastrinomas are the second most common pancreatic endocrine tumour and the most common type in the setting of multiple endocrine neoplasia type I (MEN I).
Most gastrinomas are sporadic, although some are seen in the setting of multiple endocrine neoplasia type I (MEN I). In genera...
Causes of generalised increased liver echogenicity include:
diffuse fatty infiltration
cirrhosis: can be coarsened as well
chronic hepatitis 3: can be coarsened as well
diffuse infiltration or deposition
Causes of generalised reduction of liver echogenicity on ultrasound include:
diffuse malignant infiltration
generalised increase in liver echogenicity
hepatic attenuation on CT
Giant hepatic venous malformations (also known as giant hepatic haemangiomas) are relatively uncommon non-neoplastic vascular lesions of the liver, which can be strikingly large and mimic tumours.
It is important to note that according to newer nomenclature, these lesions are mere...
Glucagonomas are pancreatic endocrine tumours that secrete glucagon. Most lesions are malignant.
They are rare with an incidence of 0.000005%. Equal incidence in middle-aged men and women.
Most patients present with a necrolytic migratory rash and various ...
Glycogen storage disease (GSD) refers to a number of syndromes which are characterised 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...
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...
Abdominal complications of haematopoietic 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 oesophagus or as hepatic/splenic microabscesse...
Haemobilia refers to the presence of blood in the biliary tree.
The classical clinical triad, only seen in ~50% of cases, consists of:
melaena (i.e. upper gastrointestinal bleeding)
iatrogenic: surgical or percutaneous pro...
Haemochromatosis is an iron overload disorder characterised 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 h...
Haemorrhagic cholecystitis refers to an inflammatory process of the gallbladder, complicated by haemorrhage into the lumen.
The presenting features may mimic non-haemorrhagic acute cholecystitis, with right upper quadrant pain being a dominant feature. If the blood is pa...
Haemorrhagic pancreatitis is a possible uncommon complication that can occur with pancreatitis and is characterised by bleeding within or around the pancreas. It is usually considered a late sequela of acute pancreatitis.
Haemorrhage can occur in patients with severe necrotising panc...
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 adenoma is an uncommon benign liver tumour that is hormone induced. The tumours are usually solitary and have a predilection to haemorrhage and must be differentiated from other focal liver lesions.
It is the most frequent hepatic tumour in young women who are on the oral ...
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 development of hepatic adenoma, su...
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 regosnised...
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...
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 anterior to the portal vein and to the left ...