Liver, Biliary tree and gallbladder Flashcards
current method of choice for most hepatic imaging
dynamic bolus contrast-enhanced MDCT
imaging used to characterize cavernous hemangiomas and focal nodular hyperplasia
radionuclide imaging
2/3 of hepatic blood supply comes from
portal vein
maximum enhancement of the liver parenchyma occurs at
60 to 120 seconds following hepatic arterial enhancement
2 major classes of gadolinium used in hepatic imaging
extracellular agents such as gadopentetate dimeglumine (magnevist) and liver specific contrast agent such as gadoxetate disodium (eovist)
imaging that is very useful for definitive diagnosis of cavernous hemangioma
radionuclide blood pool imaging
3 longitudinal plane landmarks of surgical liver segments
middle hepatic vein, IVC, gallbladder fossa
divides the right liver lobe in anterior and posterior segments
right hepatic vein
anterior segments of right liver lobe
segment 5 and 8
posterior segments of right liver lobe
segment 6 and 7
divides the left liver lobe into medial and lateral segments
left hepatic vein
divides the left liver lobe into superior and inferior segments
left portal vein
divides the right liver lobe into superior and inferior segments
right portal vein
segment 1 of liver is the _____ which extends between the fissuer of the ligamentum venosum and IVC
caudate lobe
hepatic venous drainage from caudate lobe is directly into the
IVC via small veins
difference of THADs or THIDs (transient hepatic attenuation differences) from true parenchymal abnormality
no associated mass effect, vessels traverse them without distortion, underlying liver parenchyma is preserved
“third inflow” of portal venous flow are from systemic veins in the
pericholecystic, parabiliary, epigastric-paraumbilical venous systems
hepatic arterial flow may be increased by
hypervascular tumors, arterioportal shunting, inflammation of adjacent orgas, aberrants hepatic arterial supply
normal liver length
15.5 cm
liver length is measured in
midclavicular line
normal variant of hepatic shape found most in women. refers to an elongated inferior tip of right liver lobe
Reidel lobe
most common abnormality demonstrated by hepatic imaging
fatty liver
includes a continuum of liver disease that extends from simple fatty liver through nonalcoholic steatohepatitis to cirrhosis
nonalcoholic fatty liver disease
at risk for NASH include
those with type 2 DM, metabolic syndrome
reliable US findings of fatty liver include
liver echogenicity greater than that of the renal cortex, loss of visualization of normal echogenic portal triads in the periphery of the liver, poor sound penetration with loss of definition of the diaphragm
on unenhanced CT, fatty liver is diagnosed when the liver is ___ HU less than the spleen attenuation or when the liver is less than ____ HU
10 HU less than the spleen or less than 40 HU
MR sequence most sensitive to diganosis of fatty liver
GRE
potential pitfall in MR diagnosis of fatty liver in patients with cirrhosis
Iron deposition, which also cause a loss of signal in our-of-phase MR imaging
characteristic feature of fatty liver deposition on all modalities include
lack of mass effect, angulated geometric boundaries between involved and uninvolved parenchyma
fatty changes can develop within ___ weeks of hepatocyte insult and may resolve within ____ days of removing the insult
3 weeks, 6 days
focal fatty infiltration is most common in what parts of the liver
adjacent to falciform ligament, GB fossa, porta hepatis
fat-spared area is most commonly in what segment
segment 4
used to quantify liver fat
MR spectroscopy
type of fatty liver distribution that is only associated with renal failure on peritoneal dialysis and only when insulin is added to the dialysate
subcapsular fatty liver
characterized pathologically by portal and perilobular inflammation and fibrosis
chronic hepatitis
causes of chronic hepatitis
chronic viral infection and hepatitis B and C
characterized pathologically by diffuse parenchymal destruction, fibrosis with alteration of hepatic architecture and innumerable regenerative nodules that replace normal liver parenchyma
cirrhosis
causes of cirrhosis
hepatic toxins (alcohol, drugs, aflatoxin from a grain fungus), infections, biliary obstruction and heredity (Wilson disease)
In asia and africa, most cases of cirrhosis are due to
chronic active hepatitis
morphologic alterations seen in cirrhosis
hepatomegaly, atrophy or hypertrophy of hepatic segments, coarsening of hepatic parenchymal texture, nodularity of the parenchyma, hypertrophy of caudate lobe and left lobe with shrinkage of right lobe, regenerating nodules, enlargement of hilar periportal space (>10 mm) reflecting parenchymal atrophy
extrahepatic signs of cirrhosis
presence of portosystemic collaterals as evidence of portal hypertension, splenomegaly and ascites
effective treatment for portal hypertension and long-term control of esophageal variceal bleeding
transjugular intrahepatic portosystemic shunts (TIPS)
well established effective treatment for end-stage liver disease
liver transplantation
mimics of cirrhosis include
diffuse hepatic nodularity or portal hypertension including pseuocirrhosis of treated breast cancer metastases, miliary metastases, sarcoidosis, schistosomiasis, Budd-Chiari syndrome, nodular regenerative hyperplasia, idiopathic portal hypertension, portal vein obstruction, biliary obstruction
constant feature of cirrhosis
nodules
causes of nodules in a cirrhotic liver
regenerative nodules, dysplastic nodules, HCC, confluent fibrosis, focal fat infiltration, focal fat sparing, metastases
micronodular pattern of cirrhosis include small RN with sizes of
< 3mm
macronodular pattern of cirrhosis include RN size of
> 3mm
regenerative nodules are supplied by
portal vein
describe cirrhotic nodules that are high in iron content and appear as low signal nodules on both T1 and T2
siderotic nodules
siderotic nodules may be considered benign when they are
< 20 mm in diameter, homogeneous on all image sequences, isoenhance compared to background cirrhotic nodules in all phases
most often involved part of the liver in confluent fibrosis
central portion of right hepatic lobe
appearance of acute liver fibrosis on MRI
bright on T2 due to high fluid content
chronic cirrhosis appears what on MRI
low in fluid content and appears dark on T2
pathologic increase in portal venous pressure that results in the formation of portosystemic collateral vessels that divert blood flow away from the liver into the systemic circulation
portal hypertension
causes of portal hypertension
progressive vascular fibrosis associated with chronic liver disease, portal vein thrombosis or compression and parasitic infections
complications of portal hypertension
hemorrhage from varices and hepatic encephalopathy
Signs of portal hypertension include
visualization of portosystemic collaterals, increased portal vein diameter, increased SMV and splenic vein diameters, portal vein thrombosis, calcifications in the portal and mesenteric veins, edem in the mesentery, omentum and retroperitoneum, splenomegaly, ascites, reversal of flow in any portion of the portal venous system
normal diameter of portal vein
<13mm
normal diameter of SMV and splenic vein
< 10mm
portosystemic collaterals
coronary, gastroesophageal, splenorenal, paraumbilical, hemorrhoidal and retroperitoneal
causes of portal vein thrombosis
as complication of cirrhosis, portal vein invasion or compression by tumor, hypercoagulable states or inflammation (pancreatitis)
refer to a group of disorders characterized by obstruction to hepatic venous outflow involving one or more hepatic veins
Budd-Chiari syndrome
causes of Budd-Chiari syndrome include
coagulation disorder, membranous webs, obstructing hepatic veins or IVC and malignant tumor invasion of the hepatic veins
in Budd-Chiari syndrome, caudate lobe is spared because
it has a separate venous drainage which the IVC
characteristic appearance of Budd-Chiari syndrome
early phase CT images show the markeldy heterogeneous liver with prominent central and weak peripheral enhancement
common complication of congestive heart failure and constrictive pericarditis wherein the hepatic venous drainage is impaired and the liver becomes engorged and swollen
passive hepatic congestion
radiographic findings of passive hepatic congestion
distention of hepatic veins and IVC, reflux of IV contrast into the hepatic veins and IVC, increased pulsatility of portal vein, and inhomogeneous contrast enhancement of the liver
this condition may primary resulting from a hereditary disorder that increases dietary iron absorption, or secondary due to excessive iron intake usually from multiple blood transfusions or chronic diseases including cirrhosis, myelodysplastic syndrome and certain anemias
hemochromatosis
reticuloendothelial pattern of iron deposition is seen in
secondary hemochromatosis with iron overload cause by blood transfusions
renal pattern of iron deposition appears
loss of renal cortical signal on T1 and T2, reversing the normal corticomedullary differentiation pattern
excess iron increases hepatic parenhcymal attenuation of ___ on noncontrast images
above 72 HU
an omnious imaging sign associated with bowel ischemia in adults and necrotizing enterocolitis in infants
gas in portal venous system
portal venous gas presents as
air-density tubular structures extending to the periphery of liver
pneumobilia presents as
central and does not extend into the peripheral 2 cm of the liver
LI-RADS category: definitely benign ; hemangioma, cyst, cystic biliary hamartoma, focal fat deposition or sparing, perfusion alteration, vascular anomalies, definite confluent fibrosis, hypertrophic pseudomass
LR-1
LI-RADS category: findings are less certain than for LR-1, persistent perfusion alteration, probable confluent fibrosis, pseudomass, cirrhosis-associated nodule, focal scars
LR-2
LI-RADS category: intermediate probability for HCC
LR-3
LI-RADS category: probably HCC
LR-4
LI-RADS category: Definitely HCC
LR-5
LI-RADS category: definitely tumor invading vein
LR-TIV
LI-RADS category: Treated posttreatment observation
LR-5 treated posttreatment observation
LI-RADS category: other malignancy which include cholangiocarcinoma, lymphoma, metastases
OM
Management of LR 1 and 2
Continued routine surveillance, as appropriate
management of LR-3
variable follow-up (depends on clinical consideration)
management of LR-4
Additional imaging, biopsy, treatment or close follow-up
management of LR-5 and LR-TIV
Treat without biopsy. Radiologic TNM staging
management of LR-5 treated posttreatment observation
close follow-up to asses treatment response. Retreat if needed
management of other malignancies
biopsy, additional imaging, treatment or close follow-up
In normal liver parenchyma, most common hypervascular lesions are
hemangiomas, FNH, hepatic adenoma and hypervascular metastases
In fibrotic liver and cirrhosis, the most hypervascular lesions are
HCC and dysplastic nodules
hepatic metastases most commonly originate from
GI, breast or lung
most characteristic of hepatic metastases
band-like peripheral enhancement creating a “target-lesion” on postcontrast CT and MR
true or false: metastases are extremely rare in cirrhotioc liver
true
most common hypovascular metastases
colorectal, lung, prostate, gastric and uroepithelial carcinomas
hypervascular metastases are
associated with primary neuroendocrine tumors (pancreatic islet cell tumors, carcinoid tumor, pheochromocytoma), RCC, thyroid carcinoma, melanoma, some sarcomas and choriocarcinoma
most common liver neoplasm that is common in women
cavernous hemangioma
tumor that consists of large, thin-walled, blood-filled vascular spaces separated by fibrous septa
cavernous hemangioma
giant hemangiomas meaures
> 5 cm
gian hemangiomas occassionally cause symptoms by
mass effect, hemorrhage or AV shunting
true or false: no doppler signal is obtained from most cavernous hemangiomas because the flow is too low
true
characteristic pattern of enhancement of hemangioma
discontinuous nodular enhancement from the periphery of the lesion that gradually becomes isodense or hyperdense compared to the liver parenchyma
contrast enhancement of hemangioma persists for up to how many minutes
20 to 30 minutes
most common primary malignancy of liver
HCC
risk factors for HCC
cirrhosis, chronic hepatitis, variety of carcinogens (sex hormones, aflatoxin and thorotrast)
tumor marker for HCC
serum AFP
3 major growth patterns that affect imaging appearance of HCC
solitary massive, multinodular, diffuse infiltrative
essential characteristic for diagnosis of HCC
arterial phase enhancement reflects neoangiogenesis with supply from hepatic artery
benign solid mass consisting of abnormally arranged hepatocytes, bile ducts, and Kupffer cells
Focal nodular hyperplasia
these lesions are solitary, less than 5 cm in diameter, hypervascular, with central fibrous scar containing thick-walled blood vessels. lack a capsule
FNH
treatment for FNH
do not require tx
finding that is highly indicative of FNH
show normal or increased radionuclide activity on technetium-99m sulfur colloid liver-spleen scans because of the presence of Kupffer cells
rare, benign tumors that carry a risk of life threatening hemorrhage and potential for malignant degeneration
hepatic adenomas
found most commonly in woman on long-term oral contraceptives
hepatic adenomas
this tumor consists of sheets and cords of benign hepatocytes without a distinct acinar architecture
hepatic adenomas
appearance of hepatic adenomas on technetium sulfur colloid radionuclide scans
appear as cold defects due to the presence of some nonfunctional Kupffer cells
treatment for hepatic adenomas
surgical removal
characteristic feature of hepatic adenoma that makes it prone to hemorrhage
poor connective tissue support
most of this tumors are solitary, smooth and encapsulated. they do not have central scars. tumor size is commonly 8-15 cm but may be up to 30 cm in size. areas of necrosis, hemorrhage and fibrosis are common
hepatic adenomas
this tumors is usually heterogeneous in appearance depending on presence of fat, necrosis, hemorrhage or rarely calcification
hepatic adenomas
presence of multiple adenomas (>10) in an otherwise normal liver in patients, usually young women without risk factors for hepatic adenomas
Liver adenomatosis
a hepatocellular malignancy with clinical and pathologic features that are distinct from HCC. tumors present as large liver mass in an adoloscent or young adult (mean age 23) with none of the risk factors for HCC, and without elevation of AFP. cords of tumor are surrounded by prominent fibrous bands that emanate from a central fibrotic scar. characteristic appearance is a large, lobulated hepatic mass with central scar and calcifications
fibrolamellar carcinoma
lymphoma involving the liver usually appears
it is diffusely infiltrative and undetectable by imaging methods
an autosomal dominant disorder of fibrovascular dysplasia resulting in multiple telangiectasias and AVM
hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)
thin walled dilated vascular channels that appear on the skin and mucous membranes as well as throughout the body in multiple organs
telangiectasias
patients present with epistaxis and intestinal bleeding, about 30% of patients have diffuse telangiectasias and multiple AV fistuals in the liver. these can result in pain, jaundice, portal hypertension and high-output cardiac failure
hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)
nodular transformation of the liver parenchyma without fibrosis occurs in this condition and is called pseudocirrhosis
hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)
rare disorder associated with chronic wasting from cancer or tuberculosis, or associated with use of oral contraceptives or anabolic steroids. cystic dilatation of the hepatic sinusoids and multiple small (1 to 3 mm) blood-filled spaces characterize the lesions
Peliosis hepatis
small benign neoplasms consisting of dilated cystic branching bile ducts embedded within fibrous tissue. they appear as multiple, tiny (<1 cm) cystic lesions throughout the liver, best recognized in MR
bile duct hamartomas
rare cystic neoplasm of biliary epithelium. they are premalignant and on continuum of disease with cystadenocarcinomas. tumors typically contain mucin and appear as large (up to 35 cm) multiloculated cystic mass
biliary cystadenoma/cystadenocarcinoma
presence of thick, coarse, calcifications in biliary cystadenoma suggests
malignancy
pyogenic liver abscess is usually caused by
E.coli, S. aureus, streptococcus or anaerobic bacteria
liver abscess that may present as a solitary cavity or a tight group of individual loculated abscesses
pyogenic
liver abscess that presents as solitary with thick nodular walls
amebic abscess
hydatid cyst is caused by
Echinococcus granulosus or E. multilocularis tapeworm
most common organ affected by hydatid cyst
liver
tx for amebic abscess
metronidazole or tinidazole
tx for hydatid cyst
mebendazole or surgical excision
preferred screening method for biliary obstruction
US
mainly used to guide therapy when the biliary tree cannot be accessed endoscopically
percutaneous transhepatic cholangiography
has the greates sensitivity for early biliary tree obstruction
scintigraphy
CT cholangiography is performed using what contrast agent
iopanoic acid
hepatobiliary agents for MRCP are utilized for
contrast-enhanced cholangiogram, bile leak, suspected gallbladder obstruction, and hepaticojejunostomy evaluations
more anteriorly located bile ducts
left
right and left hepatic ducts combine to form
common hepatic duct
cystic duct coarses posteriorly and inferiorly from the GB to join the ___ and form the ___
joint the common hepatic duct to form the common bile duct
CBD and pancreatic duct share a common orifice in how many percent of individuals
60%
considered as extrahepatic bile ducts
CHD and CBD
normal intrahepatic bile ducts has diameter of
< or = to 3mm
normal extrahepatic bile duct measures
< 7 mm
increased CBD diameter has also been attributed with
aging and previous cholecystectomy
right hepatic duct drains what segments
5 and 8
right posterior duct drains what segments
6 and 7
left hepatic duct drains what segments
2,3 and 4
caudate lobe drainage
either right or left hepatic duct
variations of biliary tree
drainage of right posterior duct into left hepatic duct (13 to 19%), triple confluence with the right posterior, right anterior and left hepatic ducts uniting at a single position (11%), and anomalies of the cystic duct including low insertion on the CBD, long parallel coarse with CHD and insertion on the medial rather than lateral side of CBD
presence of biliary obstruction has what laboratory findings
elevated alkaline phosphatase and direct hyperbilirubinemia
true or false: not all patients with clinical evidence of biliary obstruction have biliary dilatation
true
gallbladder hydrops has a diameter of
> 5 cm
“double duct” sign refers to
dilatation of both common bile duct and pancreatic duct in the head of the pancreas
dilataton of both the CBD and pancreatic duct are usually due to
tumor at the ampulla
abrupt termination of a dilated common duct is characteristic of
malignant process
warranted therapy prior to biliary interventional procedures in obstructed patient
IV antibiotics
MRCP may miss stones smaller than ___ because they are lost within high signal fluid
3 mm
75% of biliary tract obstruction are
benign
primary sclerosing cholangitis is associated with ____ 50 to 70% of cases
ulcerative colitis
key diagnostic finding in primary sclerosing cholangitis
alternating dilation and stenosis produce a characteristic beaded pattern of intrahepatic ducts
complications of primary sclerosing cholangitis
biliary cirrhosis and cholangiocarcinoma
characterized by thickening of walls of the bile ducts and GB due to inflammation and edema. caused by CMV and cryptosporidium
HIV-associated cholangitis
occurs in the setting of biliary obstruction and is life-threatening with mortality as high as 65%
acute bacterial cholangitis
charcot triad of acute bacterial cholangitis
fever, pain, jaundice
previously been called oriental cholangiohepatitis because it is endemic in SE asia
recurrent pyogenic cholangitis
recurrent pyogenic cholangitis is associated with parasitic infection, namely
clonorchis sinensis, ascaris lumbricoided
findings in recurrent pyogenic cholangitis
intraductal stones, severe extrahepatic biliary dilation, focal strictures, pneumobilia, and straightening and rigidity of intrahepatic ducts
uncommon congenital anomaly of the biliary tree characterized by saccular ectasia of the IHBD without biliary obstruction
Caroli disease
enhancing fibrovascular bundles are seen centrally within many of the dilated bile ducts producing the characteristic central dot sign
caroli disease
caroli disease is associated with
medullary sponge kidney and autosomal recessive polycystic kidney disease
choledochal cysts are more common in what gender
females
most common type of choledochal cysts
type 1
type of choledochal cyst that is confined to the EHBD and appear as fusiform or saccular dilatation
type 1
type of choledochal cyst that are diverticula of CBD attached by a narrow stalk
type 2
type of choledochal cyst that are termed choledochoceles and are focal dilatations of the intaduodenal portion of the CBD, closely resembling ureteroceles
type 3
type of choledochal cysts that are defined as multiple focal dilatations of the IHBD and EHBD usually with a focal large cystic dilatation of the CBD
type 4
caroli disease from todani classification is
type 5
most common primary tumors associated with intraluminal biliary metastases
colorectal cancers
findings that favor biliary metastases from cholangiocarcinoma
contiguous parenchymal mass and expansion of the duct at the site of intraluminal mass in a patient with known colorectal cancer
second most common malignant primary hepatic tumor
cholangiocarcinoma
cholangiocarcinomas are usually
adenocarcinomas
growth patterns of cholangiocarcinoma include
mass-forming, periductal infiltrating and intraductal polypoid
findings which favor cholangiocarcinoma over HCC include
arterial phase target enhancement, portal venous and delayed phase central enhancement, retraction of the liver surface, biliary obstruction disproportionate to the size of the mass and elevated CA 19-9 and CEA
hilar cholangiocarcinoma that occurs near the junction of right and left bile ducts is also called
Klatskin tumor
most common form of cholangiocarcinomas
extrahepatic
predisposing conditions for extrahepatic cholangiocarcinoma include
choledochal cyst, ulcerative colitis, Caroli disease, clonorchis sinensis infection and PSC
produce a large amount of mucin that markedly dilates the biliary tree and impaurs the flow of bile. the tumors are intraductal, polypoid and characterized by innumerable tiny frond-like papillary projections
intraductal papillary mucinous tumor
pneumobilia is most commonly encountered in
patient with a surgically created biliary-enteric anastomosis, or who has had sphincteroto,u to facilitate stone passage
most commonly due to erosison of a gallstone through the gallbladder and into the duodeunum
cholecystoduodenal fistula
choledochoduodenal fistula is caused by
penetrating peptic ulcer erording into the common bile duct
neck of GB is invariably positioned in
porta hepatis and major interlobar fissure
descriptive folding of the GB fundus which is a common normal variant
phrygian cap
small fold in the cystic duct
spiral valves of Heister
gallbladder less than how many cm is considered contracted
less than 2 cm
normal gallbladder wall does not exceed
3mm
gallbladder wall thickness is measured where
from GB lumen to liver parenchyma
85% of gallstones are
cholesterol
15% of gallstones are
bilirubin/pigment stones related to hemolytic anemia
gallstones are best detected on what modality
US
result from biliary stasis
sludge balls or tumefactive biliary sludge
common benign polypoid masses that result from accumulation of triglycerides and cholesterol in macrophages in GB wall
cholesterol polyps
polyps ___ mm and smaller are routinely dismissed as benign cholesterol polyps
5 mm
all polypoid GB cancers found on large series of cholecystectomy specimens are larger than
10 mm
recommended follow-up interval for GB polyps with size of 5-10 mm
6 to 12 months interval
true or false: adenomatous polyps are potentially premalignant
true
gallbladder polyps larger than __mm should be considered for surgical removal because of risk of cancer
10 mm
may be focal and presents as a polypoid mass fixed to the gallbladder wall
adenomyomatosis
acute inflammation of the GB is caused by _____ obstructing the cystic duct in 90% of cases
gallstones
confident US diganosis of acute cholecystitis requires the presence of these 3 findings
cholelithiases, edema of GB wall, positive sonographic murphy sign
acalculous cholecystitis may be due to
wall ischemia or direct bacterial infection
patients at risk for acalculous cholecystitis include
those with lack of oral intake, posttrauma, postburn. postsurgery, or on TPN
term used to describe the presence of thick particulate matter in highly concentrated bile
sludge
indicated presence of necrosis of GB wall
gangrenous cholecystitis
findings include mucosal irregularity, thickening of GB wall with multiple lucent layers, indicating mucosal ulceration and reactive edema
gangrenous cholecystitis
life threatening complication of gangrenous cholecystitis
perforation
results from infection of the GB with gas-forming organisms, usually E.coli or clostridium perfringens
emphysematous cholecystitis
refers to condition of biliary obstruction resulting from a gallstone in the cystic duct eroding into the adjacent CBD
Mirizzi syndrome
described the presence of dystrophic calcification in the wall of an obstructed and chronically inflamed GB
porcelain GB
uncommon variant of chronic cholecystitis characterized by nodule depositis of lipid-laden macrophages in DB wall and proliferative fibrosis
xanthogranulomatous cholecystitis
condition that is difficult to differentiated from GB carcinoma which include marked wall thickening (2 cm), fat density nodules in the wall and narrowing of lumen
xanhogranulomatous cholecystits
finding that favors xanthogranulomatous cholecystitis from GB carcinoma
preservaton of linear enhancement of the mucosa on postcontrast MR
benign condition of GB characterized by wall thickening caused by hyperplasia of the mucosa and smooth muscle
adenomyomatosis
appears on MRCP as “pearl necklace” appearance of GB wall caused by bright fluid within the sinuses. CT shows wall thickening with tiny cystic spaces
adenomyomatosis
thickening of GB wall is associated with
acute or chronic cholecystitis, hepatitis, portal venous hypertension. AIDS, hypoalbuminemia, GB carcinoma
GB carcinoma is a tumor of what age group
elderly women
