Choledochocoeles refer to a specific type of choledochal cyst (type III under the Todani classification system). In this type, there is dilatation of the intramural portion of the distal common bile duct within the duodenal wall. Its precise etiology is not clear 3. Patients are usually adolesce...
Choledocholithiasis denotes the presence of gallstones within the bile ducts (common hepatic duct / common bile duct).
Choledocholithiasis is relatively common, seen in in 6-12% of patients who undergo cholecystectomy 2.
Stones within the bile duct are ofte...
Cholescintigraphy is the use of radiotracers to assess the anatomy and function of the biliary system (and the liver indirectly). Currently, this is most commonly performed with Tc99m-IDA analogs, and "h"epatic "IDA" imaging gave rise to the more common term "HIDA scan."
After intravenous injec...
Chronic cholecystitis refers to prolonged inflammatory condition that affects the gallbladder. It is almost always seen in the setting of cholelithiasis (95%), caused by intermittent obstruction of the cystic duct or infundibulum or dysmotility.
Patients may have a histor...
Chronic pancreatitis represents the end result of a continuous, prolonged, inflammatory and fibrosing process that affects the pancreas. This results in irreversible morphologic changes and permanent endocrine and exocrine pancreatic dysfunction.
The most common cause of chronic p...
Ciliated hepatic foregut cysts are a very rare type of hepatic cyst, with nonspecific radiological features. Less than a hundred of cases have been reported yet 1. They are usually benign, but rare cases of malignant degeneration (in squamous cell carcinoma) have also been reported 1-4.
Cirrhosis is the common endpoint of a wide variety of chronic liver disease processes which cause hepatocellular necrosis. Cirrhosis can be diagnosed with ultrasound, CT, and MRI, and these imaging modalities can also be used to evaluate for possible complications of cirrhosis, such as portal hy...
Clonorchiasis is a trematodiasis caused by chronic infestation by Clonorchis sinensis, and can lead to recurrent pyogenic cholangitis, biliary strictures and cholangiocarcinoma.
Infection with Clonorchis sinensis occurs in endemic areas, mainly east China. Over 85 million people ...
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
Celiac artery, also known as the celiac axis or celiac trunk, is a major visceral artery in the abdominal cavity supplying the foregut. It arises from the abdominal aorta and commonly gives rise to three branches: left gastric artery, splenic artery, and common hepatic artery.
The coeliacomesenteric trunk represents an uncommon vascular anatomical variant where both the celiac trunk and the superior mesenteric artery have a common origin from the abdominal aorta as a single trunk. Its frequency has been reported to occur in about 1.5% of the population 1,2.
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 celiac artery.
Origin and course
The CHA is a terminal branch of the celiac artery, it passes over the top of pancreas, and downwards to the right in the lesser sac towards the first part of duodenum. It gives off the r...
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...
Copper (chemical symbol Cu) is one of the trace elements. It has an important biological role as a redox agent and as a cofactor in cuproproteins, facilitating many vital metabolic reactions.
Copper has the atomic number 29 with an atomic weight of 63.54 g/mol. It is...
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 thum...
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, whole body CT (WBCT) or panscan, is an increasingly used investigation in patients with multiple injuries sustained after significant trauma.
Clinical assessment and mechanism of injury may underestimate injury severity by 30% 8. There is some e...
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; with one exception: lung cysts contain gas, not fluid. By contradistinction, a pseudocyst lacks an epithelial lining and instead has a vascular and fibrotic capsule.
Cysts are extremely common and found in most organs. E...
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
ciliated hepatic foregut duplication cyst 6
infectious: inflammatory conditions
pyogenic hepatic ...
The differential for cystic lesions of the pancreas includes:
intraductal papillary mucinous neoplasm (IPMN)
serous cystadenoma uncommonly uni/macrolocular
simple pancreatic cyst
pancreatic cysts occur in association with
von Hippel Lindau syndrome
A Denver shunt, or peritoneovenous shunt, is a device used to shunt ascites to the superior vena cava in patients with refractory ascites.
The proximal end is located in the peritoneal cavity and the distal end in the superior vena cava, with a subcutaneous course in the anterior chest wall. It...
Diabetes mellitus, often referred to simply as diabetes, is a group of metabolic conditions characterized by hyperglycemia.
These conditions should not be confused with diabetes insipidus which is clinically distinct and not related to hyperglycemia.
Symptoms/signs of h...
Diabetic ketoacidosis (DKA) is an acute, life threatening complication that usually occurs in new onset and established type 1 diabetic patients due to a state of severe insulin deficiency. This condition is characterized by hyperglycemia, ketoacidosis and ketonuria.
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
xanthogranulomatous cholecystitis 11
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.
The term 'fatty infiltration of the liver' is often erroneously used to describe live...
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: diffusely increased hepatic echogenicity but periportal and diaphragmatic echogenicity is still appreciable
grade II: diffusely in...
The dorsal pancreatic artery is a branch of the splenic artery that supplies the pancreas. It arises from the proximal splenic artery and descends a short distance to run along the posterior margin of the pancreas where it divides in to left and right branches.
the right branches pass either an...
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 esophagus: esophageal 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 visualize 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.
Epstein-Barr virus-associated smooth muscle tumors (EBV-SMT) are rare and encountered in immunocompromised individuals.
These tumors are generally exceedingly rare, and only seen with any frequency in the setting of immunosuppression, particularly in HIV/AIDS patients, but also po...
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, also known as heterotopic pancreatic tissue, refers to the presence of pancreatic tissue in the submucosal, muscularis or subserosal layers of the luminal gastrointestinal tract outside the normal confines of the pancreas and lacking any anatomic or vascular connection...
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 tumors of the pancreas arise from the pancreatic islet cells and include some distinct tumors that match the cell type of origin.
Pancreatic endocrine tumors have commonly been referred to as "islet cell tumors", referring to the islets of Langerhans, from which they wer...
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 tumor 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 hematopoiesis is a response to the failure of erythropoiesis in the bone marrow.
This article aims to a general approach on the condition, for a dedicated discussion for a particularly involved organ, please refer to the specific articles on:
extramedullary hematopoiesis in the...
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 artery, also known as the hepatic falciform artery (FHA) is an uncommon vascular anatomic variant that most commonly arises as the terminal branch of the middle hepatic artery which courses anteriorly through the falciform ligament into and supplying the supraumbilical anterior abd...
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) associated...
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 histological variant of hepatocellular carcinoma characterized on microscopy by laminated fibrous layers between the tumor cells. It is important as it has different demographics and risk factors compared to 'standard' hepatocellular carcinoma...
Fibropolycystic liver disease is a collective term for a group of congenital liver and biliary abnormalities resulting from abnormal development of the ductal plates. Disease in this group include:
congenital hepatic fibrosis
autosomal dominant polycystic disease
Flash filling hepatic venous malformations, also known as flash filling hepatic hemangiomas, are a type of atypical hepatic venous malformation (hemangioma), which due to its imaging features often raises the concern of a malignant process rather than a benign one.
It is important...
Focal fatty sparing of the liver is the localised absence of increased intracellular hepatic fat, in a liver otherwise fatty in appearance i.e. diffuse hepatic steatosis. Recognition of this finding is important to prevent the erroneous belief that the region of sparing is itself a mass.
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 is common and seen in a number of clinical settings, essentially the same as those that contribute to diffuse hepatic steatosis:
drugs (amiodarone, methotrexate, chemotherapy)
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 a hemangioma). Many FNHs have characteristic radiographic features on multimodality imaging, but some lesions may be atypical in appearance. FNHs are typicall...
Focused 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 a...
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 characterization, i.e. assessing focal liver lesions identified on other imaging...
The gallbladder is a pear-shaped musculomembranous sac located along the undersurface of the liver. It functions to accumulate and concentrate bile between meals.
The adult gallbladder measures from 7-10 cm in length and 3-4 cm in transverse diameter 6. The gallbladd...
Agenesis of the gallbladder is a rare congenital anomaly.
overall incidence is estimated <0.1% (range 0.04-0.1%)
reported 3:1 female predominance of symptomatic cases
equivalent gender distribution in autopsy cases
Most patients with agenesis of...
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 is squamous cell carcinomas.
The gallbladder cholecystoses are conditions characterized by the accumulation of cholesterol (and other fats) in the wall of the gallbladder. There are two main forms:
Gallbladder duplication is a rare anatomic anomaly characterized 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 resulting in accumulation of sterile non-pigmented mucin.
Abdominal pain with palpable gallbladder without any signs of infection. In an asymptomatic patient, ...
Gallbladder metastases are rare and usually represent an advanced and end-stage of malignancy.
They represent <5% of all gallbladder cancers 1.
Most patients with gallbladder metastases are asymptomatic, and the metastases are detected on surveillance or st...
Gallbladder perforations are a serious complication of acute cholecystitis and represent an advanced stage of the disease. They tend to occur in an elderly and/or comorbid demographic and carry higher rates of morbidity and mortality.
Symptoms and clinical signs are varia...
Gallbladder polyps are elevated lesions on the mucosal surface of the gallbladder. The vast majority are benign, but malignant forms are seen. Gallbladder polyps may be detected by ultrasound, CT, or MRI, but are usually best characterized on ultrasound.
Gallbladder polyps are rel...
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 cholecystosis, and results from accumulation of cholesterol esters and triglycerides in the macrophages within the gallbladder wall.
It may occur in two forms:
diffuse: strawberry gallbladder
Its prevalence may range around 4-8% ...
This is a basic article for medical students and other non-radiologists
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 centimeters. 90% ...
Gallstone ileus is an uncommon cause of a mechanical small bowel obstruction. It is a rare complication of chronic cholecystitis 7 and occurs when a gallstone passes through a fistula between the gallbladder and small bowel before becoming impacted at the ileocecal valve.
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 ischemia with necrosis of the gallbladder wall 4.
Gastrinomas are the second most common pancreatic endocrine tumor 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 general...
The gastroduodenal artery (GDA) is a terminal branch of the common hepatic artery which mainly supplies the pylorus of the stomach, proximal duodenum, and the head of the pancreas. Due to its proximity to the anterior wall of the first part of the duodenum, the gastroduodenal artery is one of th...
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