Syphilis is the result of infection with the gram negative spirochete Treponema pallidum, subspecies pallidum. It results in a heterogeneous spectrum of disease with many systems that can potentially be involved, which are discussed separately.
Despite the discovery of penicillin...
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.
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.
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 ...
Ascites is defined as an abnormal amount of intraperitoneal fluid.
Patients with a large volume of ascites can present with abdominal distension (which may be painful), nausea, vomiting, dyspnoea and peripheral oedema 7, 9.
Ascitic fluid is traditionally chara...
Portal biliopathy or portal ductopathy refers to biliary obstruction that is associated with cavernous transformation of the portal vein due to portal vein thrombosis 1.2.
Portal bilopathy may present as jaundice, cholangitis due to bile duct obstruction, or rarely as hae...
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...
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...
A periampullary diverticulum is a location-specific type of duodenal diverticulum.
The incidence is reported to increase with age with reported rates as high as 27%.
It is located close to the region of the duodenum often involving the D2 segment.
Acute cholecystitis refers to the acute inflammation of the gallbladder. It is the primary complication of cholelithiasis and the most common cause of acute pain in the right upper quadrant (RUQ).
Constant right upper quadrant pain that can radiate to the right shoulder. ...
Wirsungocele refers to a cystic dilatation of the pancreatic duct of Wirsung, which is the portion of ventral duct between the dorsal-ventral junction and major duodenal papilla. It is believed to be analogous to choledochocele and santorinicele.
It may be an incidental f...
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...
The abdomen, when looking from in front, is divided into nine regions by imaginary planes (two vertical and two horizontal) forming abdominal surface anatomy. The nine regions are of clinical importance when examining and describing pathologies related to the abdomen. The horizontal planes are o...
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.
Choledochal cysts represent congenital cystic dilatations of the biliary tree. Diagnosis relies on the exclusion of other conditions (e.g. tumour, gallstone, inflammation) as a cause of biliary duct dilatation.
Choledochal cysts are rare, with an incidence of 1:100,000-150,000. Al...
There is a wide range of liver and biliary interventional procedures, both diagnostic and therapeutic, most commonly using CT-guidance or ultrasound-guidance.
Percutaneous transhepatic biliary interventions
percutaneous transhepatic cholangiography (PTC)
percutaneous transhepatic biliary dr...
Pancreatic ductal adenocarcinoma makes up the vast majority (~90%) of all pancreatic neoplasms and remains a disease with a very poor prognosis and high morbidity.
On imaging, it usually presents as a hypodense mass on CT that is poorly marginated, which may encase vessels and the common biliar...
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...
Primary biliary cholangitis (PBC) is a chronic progressive cholestatic liver disease that is the cause of 1-2% of deaths from cirrhosis and constitutes the third most common indication for liver transplantation in adults.
The name of this disease was changed from primary biliary ci...
Ciliated hepatic foregut cyst is 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...
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...
In the gallbladder, the Mercedes-Benz sign describes a star-shaped pattern of gas-fissuring within gallstones initially described on an abdominal radiograph 2.
Fissures, usually fluid-filled, are present in close to 50% of gallstones. Less than half of these fissured gallstones contain some amo...
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. Main duct type (see below) appears to present a decade or so earlier on average than bran...
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 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....
Pancreatic pseudocysts are common sequelae of acute pancreatitis or chronic pancreatitis, and the most common cystic lesion of the pancreas. They are important both in terms of management and differentiation from other cystic processes or masses in this region.
The following are th...
Budd-Chiari syndrome refers to the clinical picture that occurs when there is partial or complete hepatic venous outflow obstruction. It is characterised on imaging by ascites, caudate hypertrophy, peripheral atrophy, and prominent collateral veins.
Budd-Chiari syndrome is rare. ...
Hepatic haemangiomatosis is a situation when the are multiple haemangiomas affecting the liver. When the lesions are spread throughout the liver, then this is termed diffuse hepatic haemangiomatosis (the latter situation typically occurs in infants 1).
In CT imaging, the presence of phleboliths...
The 1994 revision of the AAST (American Association for the Surgery of Trauma) liver injury scale is the most widely used liver injury grading system at the time of writing (late 2016).
haematoma: subcapsular, <10% surface area
laceration: capsular tear, <1 cm parenc...
The term ampullary tumour generally refers to either benign or malignant neoplasms that arise from the glandular epithelium of the ampulla of Vater, including 1:
ampullary adenoma (adenoma of ampulla of Vater)
ampullary carcinoma (carcinoma of ampulla of Vater)
According to some authors, ampu...
The hepatic veins have a characteristic spectral Doppler waveform. Alterations in the normal hepatic vein waveform may reveal or confirm abnormalities in the heart or liver.
The key factor in the shape of the hepatic vein spectral Doppler waveform is the motion of the heart. Multip...
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.
Portal vein thrombosis may be seen in a variety of clinical contexts, and when acute can be a life-threatening condition. It is a major cause of non-cirrhotic presinusoidal portal hypertension. Portal vein thrombus may be either bland and/or malignant (i.e. tumour thrombus), and it is a critical...
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...
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 ...
Acute pancreatitis is an acute inflammation of the pancreas and is a potentially life-threatening condition.
The diagnosis of acute pancreatitis is made by fulfilling two of the following three criteria 8:
acute onset of persistent, severe epigastric pain (i.e. pain consistent with acute pancr...
The pancreas is uncommonly injured in blunt trauma. However, pancreatic trauma has a high morbidity and mortality. Imaging features range between subtle to obvious.
The pancreas is injured in ~7.5% (range 2-13%) of blunt trauma cases 1,3. Motor vehicle accidents account for the va...
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...
The PRETEXT system proposed by the International Childhood Liver Tumours Strategy Group (previously called Société Internationale d’Oncologie Pédiatrique - Epithelial Liver Tumour Study Group - SIOPEL) aims for staging and risk stratification of liver tumours at diagnosis.
It is used to descri...
The term epidermoid cyst can refer to a:
epidermal inclusion cyst
intracranial epidermoid cyst
splenic epidermoid cyst
spinal epidermoid cyst
testicular epidermoid cyst
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...
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...
Schistosomiasis hepatic manifestations are a chronic result of the deposition of eggs into small portal venules leading to periportal fibrosis and liver cirrhosis.
For a general view over this trematode infection, please refer to the main article on schistosomiasis.
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...
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.
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...
Periportal hypoechogenicity can result from many causes:
orthotopic liver transplant rejection
malignant lymphatic obstruction
Periampullary tumours are those that arise within 2 cm of the ampulla of Vater in the duodenum.
Tumours that fall under this group include four main types of tumours 1,4:
pancreatic head / uncinate process tumours: includes pancreatic ductal adenocarcinoma involving head and uncinate process o...
Non-neoplastic solid lesions of the pancreas (NNSLP) are conditions which may mimic pancreatic neoplasms on imaging. They include:
intrapancreatic accessory spleen
congenital anomalies, such as prominent pancreatic lobulations and bifid pancr...
A mucocele simply refers to accumulation and expansion of a structure by mucus. It occurs in a variety of locations which are discussed separately:
paranasal sinus mucocele
oral cavity e.g. ranula, mucous retention cysts
mucocele of the appendix 1
mucocele of the gallbladder
mucocele of the...
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
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...
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)
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 ...
Thickening of the bile duct wall can stem from a variety of aetiologies.
bile duct wall thickening
bile duct walls are typically not visible when normal
possible narrowing of the ducts with obstruction
possible secondary signs of cholangitis, including debr...
Paediatric benign liver tumours are a relatively rare, but important group of conditions. Importantly, the commonest cause of a benign liver tumour is specific to the paediatric population. The list in descending order of frequency is:
infantile hepatic hemangioma (previously haemangioendotheli...
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
Diffuse thickening of the gallbladder wall can occur in a number of situations.
gallbladder empyema 7
postprandial physiological state (pseudothickening)
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...
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...
Milk of calcium (MOC) is a term given to dependent, sedimented calcification within a cystic structure or hollow organ. This sort of colloidal calcium suspension layering can occur in various regions:
renal cysts: milk of calcium in renal cyst (most common)
breast cysts: milk of calcium in bre...
The 2001 World Health Organization (WHO) classification of hepatic hydatid cysts is used to assess the stage of hepatic hydatid cyst on ultrasound and is useful in deciding the appropriate management for it depending on the stage of the cyst. This classification was proposed by WHO in 2001 and a...
The liver is one of the most frequently damaged organs in blunt trauma, and liver trauma is associated with a significant mortality rate.
In blunt abdominal trauma, the liver is injured ~5% (range 1-10%) of the time 1,3.
Patients can present with right uppe...
Retained gallstones are common during a laparoscopic cholecystectomy, with a reported incidence of 0.1–20%, and occur when gallstones are inadvertently spilled into the peritoneal cavity.
When recognised intraoperatively spilled stones should be retrieved to avoid potential complications includ...
Splenomegaly is a term which refers to enlargement of the spleen. The normal adult splenic length upper limit is usually around 12-15 cm. Also one should know how to calculate splenic index, volume and mass by CT and MR techniques. Massive splenomegaly is a term used when the spleen weighs >1000...
Medical devices in the abdomen and pelvis are important to be recognised, just like medical devices of the chest. Often we ignore these devices, considering them to be incidental and non-pathological, however it is essential to be aware of potential complications.
Pseudocirrhosis is a complication of treated hepatic metastases, mainly those of breast cancer, which mimics liver cirrhosis radiologically. It has been reported in up to 50% of patients with breast cancer and liver metastases who underwent chemotherapy treatment 1. It is seen in the weeks or mo...
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...
Veins of Sappey are small veins around the falciform ligament that drain the venous blood from the anterior part of the abdominal wall directly into the liver. This flow dilutes the portal perfusion at these sites, causing hepatic pseudolesions.
The superior vein of Sappey drains...
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...
Thorotrast is a radioactive radiographic contrast agent containing thorium dioxide first produced in Germany in 1928 and was in use until the 1950s. It was used primarily for cerebral angiography, and 90% of the estimated 50,000-100,000 patients who received it were studied for this purpose.
Oriental cholangiohepatitis, or recurrent pyogenic cholangiohepatitis, is a condition essentially found in Southeast Asia and is characterised by intra and extrahepatic bile duct strictures and dilatation with intraductal pigmented stone formation.
Diagnosis is made after exclusion of more com...
In most instances predicting histology of a gallbladder polyp based purely on imaging is not possible. A number of features are however helpful in helping to decide management of a polypoid lesion of the gallbladder.
polyps that are less than 5 mm in size are almost alway...
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...
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...
Acute pancreatitis refers to acute inflammation of the pancreas and is a potentially life-threatening condition.
This is a summary article; read more in our article on acute pancreatitis.
epidemiology is dependent on the cause of pa...
Both endocrine and exocrine tumours of the pancreas are now staged by a single pancreatic staging system.
Staging of pancreatic ductal adenocarcinoma is with the TNM system, and as a majority of tumours are not-resectable, this is mostly achieved with imaging (typically CT scan) although laparo...
The caput medusae sign, refers to developmental venous anomalies of the brain, where a number of veins drain centrally towards a single drain vein. The appearance is reminiscent of Medusa, a gorgon of Greek mythology, who was encountered and defeated by Perseus.
The sign is seen on both CT and ...
Solid pseudopapillary tumours (SPT) of the pancreas are rare (usually benign) pancreatic tumours.
The tumour has been referred to with multiple different names, including:
solid pseudopapillary tumour (SPT) of the pancreas
solid pseudopapillary neoplasm (SPN)
Bunch of grapes sign refers to the ultrasound appearance of multiple cystic spaces or lesions and it has been described in a number of settings:
within the uterus as a result of hydropic swelling of trophoblastic villi within a hydatidiform mole
in bronchiectasis, where on a chest radiograph, ...
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)
The atoll sign in hepatic imaging has been described when a liver lesion shows a peripheral rim of high T2 signal intensity with the centre of the lesion appearing isointense to the background of non-cirrhotic liver on T2WI mimicking an atoll. It is considered a characteristic sign of an inflamm...
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 ~...
Low phospholipid-associated cholelithiasis (LPAC) syndrome is one of the syndromes associated with ABCB4/MDR3 mutation. Characteristics of this syndrome include 1,2:
symptomatic cholesterol stones with early onset (<40 years)
recurrent symptoms post cholecys...
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...
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.
Acute peripancreatic fluid collections (APFC) are an early complication of acute pancreatitis that usually develop in the first four weeks. After four weeks, the term pseudocysts is used. The absence of necrosis differentiates APFCs from acute necrotic collections (ANC), that is, APFCs occur in ...
Pancreatic atrophy is non-specific and is common in elderly patients, although in younger patients it can be a hallmark of pathology. Most commonly it is associated with aging, obesity and end-stage chronic pancreatitis.
It occurs principally with fatty replacement of the pancreas (pancreatic ...
Abscesses are focal confined collections of suppurative inflammatory material and can be thought of as having three components 1:
a central core consisting of necrotic inflammatory cells and local tissue
peripheral halo of viable neutrophils
surrounded by a 'capsule' with dilated blood vessel...
Portal venous gas is the accumulation of gas in the portal vein and its branches. It needs to be distinguished from pneumobilia, although this is usually not too problematic, when associated findings are taken into account along with the pattern of gas (i.e. peripheral in portal venous gas, cent...
The liver is the largest abdominal organ that plays a major role in metabolism and has a number of functions, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, hormone production, and detoxification. It is one of very few organs that has the ability to regen...
Cavernous transformation of the portal vein (CTPV) is a sequela of portal vein thrombosis and is the replacement of the normal single channel portal vein with numerous tortuous venous channels.
For a discussion of demographics and presentation, please refer to the article on portal vein thrombo...