CORE - GI Flashcards
Normal liver attenuation
40-60 HU; >75 HU = hyperattenuating; hypoattenuating = less than spleen on NECT or 25 HU less than spleen on CECT
Hot quadrate sign
SVC occlusion
Empty gallbladder fossa sign
hepatic parenchyma surrounding GB replaced by fat in early cirrhosis
Criteria for distended GB
> 4 cm
Porcelain GB
calcified GB wall; increased risk of gallbladder cancer
GB wall thickening
> 3 mm
Thoratrast complications (liver)
angiosarcoma, HCC, cholangiocarcinoma
Indications for gallbladder polyp removal
> 10 mm or >6 mm + suspicious features
Most common type of gallbladder polyp
cholesterol polyps
Transplant type with highest incidence of PTLD
small bowel > pancreas > heart & lung
Most common organ involved in PTLD
liver
Multiple hepatic adenomas
von Gierke disease or adenomatosis
Most common hepatitis virus to cause HCC worldwide
hepatitis B (can occur in acute or chronic HepB infection)
Light bulb sign
hemangioma - appears very T2 bright
Micronodular cirrhosis
<3 mm; assoc. with alcoholism
Macronodular cirrhosis
> 3 mm; assoc. with viral hepatitis
Starry sky pattern
periportal edema in the setting of hepatitis
Hydatid sand
echinococcal cyst; fine sediment caused by separation of membranes; may occur in liver or spleen
Water lily sign
echinococcal cyst; undulating membrane; may occur in liver or spleen
Daughter cysts
echinococcal cyst; may occur in liver or spleen
Hepatic candidiasis
multipe small “targetoid” or “bull’s eye” lesions
Hepatic PCP
punctate echogenic foci in liver +/- spleen; after inhaled pentamidine
Target sign
implies malignancy; hypoechoic halo surrounding a liver lesion
Double target sign (hypo-hyper-hypo)
pyogenic abscess; CT finding
Amebic abscess
Entamoeba histolytica; characteristic location is near dome of right lobe
Most common complication of amebic abscess
pleuropulmonary amebiasis (20-35%) > peritoneal, pericardial or renal amebiasis
Amebic abscess in the left hepatic lobe
may rupture into pericardium; emergent drainage necessary to avoid
Primary hemochromatosis
liver + pancreas; cirrhosis, diabetes, cardiomyopathy, arthritis, bronze skin; inherited; Tx phlebotomy
Secondary hemochromatosis
liver + spleen and bone marrow; due to chronic illness or multiple transfusions; Tx chelation
Scalloping of the liver
pseudomyxoma peritonei
Periportal hypoechoic infiltration
Kaposi’s sarcoma (in AIDS patient)
Increased liver signal on out-of-phase
hemochromatosis; liver is very T2 dark
Anti-mitochondrial antibodies
primary biliary cirrhosis
Mirizzi syndrome
stone in cystic duct causing obstruction of CHD; assoc. with GB carcinoma
Injury to bare area of the liver
retroperitoneal bleed
Falciform ligament location
divides segments 2/3 and 4; ligamentum teres runs within
Cantlie’s line
divides the liver into the functional left and right hepatic lobes; between segments 5/8 and 4
Most common hepatic vascular variant
replaced RHA
Most common biliary ductal variant
right posterior segmental branch draining into the left hepatic duct
T1 characteristics of liver-pancreas-spleen
pancreas (brightest) > liver > spleen (darkest)
Regenerative and dysplastic nodules
T2 iso/dark, no arterial enhancement; high grade dysplastic nodules may demonstrate arterial enhancement
Nodule within a nodule
HCC (T2 bright) within a regenerative/dysplastic nodule (T2 dark); suggests malignant transformation
Well-differentiated HCC
enhances during hepatobiliary phase with Eovist (normal HCC does not)
Massively dilated hepatic artery
HHT; multiple hepatic and pulmonic AVMs
Solitary pyogenic hepatic abscess
Klebsiella
Multiple pyogenic hepatic abscesses
E. coli
Gas in a hepatic abscess
suggests pyogenic etiology
Tortoise shell appearance of the liver
schistosomiasis
Hemangioma ultrasound characteristics (liver)
hyperechoic (unless liver is fatty), no internal flow, posterior acoustic enhancement
Most common benign liver neoplasm
hemangioma > FNH
T1 hyper- or isointense liver lesion DDx
HCC, FNH, hepatic adenoma
Threshold for hepatic adenoma resection
> 5 cm
Liver lesion with intralesional (microscopic) fat
HCC, hepatic adenoma
Non-enhancing T2 dark central scar
fibrolamellar HCC (gallium avid)
Late-enhancing T2 bright central scar
FNH (sulfur colloid avid, visible on HIDA)
Most common location for a hepatic adenoma
right hepatic lobe
Alternate name for Eovist
Gd-EOB-DTPA
Risk factors for cholangiocarcinoma
PSC, choledochal cysts, recurrent pyogenic cholangitis (chlonorchis senesis), FAP, thorotrast
Cholangiocarcinoma
delayed enhancement, ductal dilatation, capsular retraction
Risk factors for hepatic angiosarcoma
arsenic (25 year latent period), polyvinyl chloride exposure, radiation, thorotrast, hemochromatosis, NF1
Calcified liver mets
mucinous neoplasms (stomach, colon, ovary, breast)
Hypervascular liver mets
hemorrhagic mets + carcinoid, PNET
NASH
hepatic steatosis + abnormal LFTs
Budd-Chiari
most commonly: hypercoagulable state => hepatic vein thrombosis => nutmeg liver +/- multiple regenerative nodules
Nutmeg liver DDx
Budd-Chiari, hepatic veno-occlusive disease, right heart failure, constrictive pericarditis
Caudate lobe hypertrophy DDx
cirrhosis, Budd-Chiari, PSC, PBC
Causes of hepatic veno-occlusive disease
post-BMT, chemotherapy, Jamaican bush tea (alkaloids); occlusion of post-sinusoidal venules with patent hepatic veins; caudate lobe is NOT spared
Pseudocirrhosis
treated breast cancer mets; causes capsular retraction
Donor liver segments
right lobe (segments 5-8) in adults; segments 2/3 in peds
Indications for liver transplant
hepatitis C, alcoholic cirrhosis, HCC, PSC, cryptogenic cirrhosis (NASH)
Contraindications to liver transplant
extrahepatic malignancy, advanced cardiac or pulmonary disease, active substance abuse
Impending thrombosis post-liver transplant
days 3-10; normal waveform => loss of diastolic flow => tardus parvus arterial waveform + RI <0.5 => loss of hepatic artery waveform
“Central regenerative hypertrophy”
pattern in cirrhosis due to PSC
Dilated intrahepatic bile ducts in the setting of cirrhosis
PSC
Withered tree on MRCP
PSC
AIDS cholangiopathy
findings of PSC + papillary stenosis; classically due to cryptospordium infection (or CMV)
Malignant biliary strictures
long with shouldering (vs. benign strictures which are short and abrupt)
Charcot triad
fever, jaundice, RUQ pain; in ascending cholangitis
Recurrent pyogenic cholangitis
left lobe predominant disease burden
Primary biliary cirrhosis
autoimmune, middle-aged women, irregular intrahepatic ducts, normal extrahepatic ducts; increased risk of HCC
Most common type of choledochal cyst
type 1
Caroli’s disease associations
polycystic kidney disease, medullary sponge kidney
Complications of choledochal cysts
cholangiocarcinoma, bile duct stones, cirrhosis, cholangitis; Tx is resection
Duct of Luschka
accessory cystic duct; may cause bile leak after cholecystectomy
Multiple “halo” or “targetoid” liver masses
epitheloid hemangioendothelioma
Lace-like hepatic fibrosis
primary biliary cirrhosis
Cholesterolosis
cholesterol deposition within the gallbladder lamina propria; similar appearance to adenomyomatosis
Diffuse hepatic hypoattenuation
steatosis, amyloidosis (may also be focal)
Diffuse hepatic hyperattenuation
hemochromatosis, hemosiderosis, Wilson’s disease, amiodarone, methotrexate, gold, glycogen excess
Wilson’s disease
AR; hyperattenuating liver with multiple nodules; progresses to cirrhosis
Caudate-to-right lobe size ratio suggesting cirrhosis
> 0.65
von Meyenburg complexes
biliary hamartomas; small, irregular, non-communicating
Caroli syndrome
Caroli disease + hepatic fibrosis
Central dot sign (liver)
Caroli disease
Gallbladder wall thickening with intraluminal membranes
gangrenous cholecystitis; Tx emergent cholecystectomy (or -ostomy)
Most common islet cell tumor
insulinoma (almost always benign) > gastrinoma > glucagonoma
Gastrinoma
Zollinger-Ellison syndrome; assoc. with MEN1
Gastrinoma triangle
typical location; bounded by junction of cystic duct, CBD and duodenum inferiorly, and pancreas medially
Serous cystadenoma
grandmother tumor; benign; hypervascular, head most commonly, peripheral calcifications; assoc. with VHL; resection only if symptoms related to mass effect
Mucinous cystadenoma
mother tumor; pre-malignant; body and tail most commonly; Tx resection
Solid and papillary epithelial neoplasm (SPEN)
daughter tumor; tail most commonly; heterogenous, prone to hemorrhage; Tx resection (malignant potential)
Intraductal papillary mucinous neoplasm (IPMN)
grandfather tumor; main branch has higher malignant potential
Indications for IPMN resection
> 3 cm, mural nodularity, or ductal dilatation >10 mm
Lipase hypersecretion syndrome
syndrome related to acinar cell carcinoma (rare, aggressive, elderly males); subcutaneous fat necrosis, eosinophilia, bone infarcts=>polyarthralgias
Whipple triad
clinical symptoms of insulinoma: hypoglycemia, symptoms of hypoglycemia, alleviation with glucose administration
Crossing duct sign
pancreas divisum; CBD crosses the main pancreatic duct (which drains via minor papilla)
VHL associations (pancreas)
pancreatic cysts; increased risk of serous cystadenoma and PNETs
Sausage pancreas + associations
autoimmune pancreatitis; assoc. with IgG-4 and Sjogren’s
Wide duodenal sweep (fluoro)
mass effect from pancreatic cancer
Dorsal pancreatic agenesis
increased risk of diabetes; assoc. with polysplenia
Pancreatic lipomatosis DDx
CF, Schwachmann-Diamond, obesity, Cushing’s, chronic steroids, hyperlipidemia
Pancreatic agenesis
no duct present (vs. lipomatosis which still has a duct)
Next step in suspected pancreatic duct injury
MRCP or ERCP
Pancreas in CF
fibrosis, lipomatosis, or cystosis
Causes of acute pancreatitis
gallstones, EtOH, scorpion bite, ERCP, valproic acid, trauma, ascariasis
Pancreas hypoechoic relative to the liver
inflammation/edema
Most common anatomic variant of the pancreas
pancreas divisum; increased risk of pancreatitis
Complication(s) of chronic pancreatitis
increased risk of pancreatic cancer
Loss of T1 signal in the pancreas
suggests fibrosis (normally very T1 bright); chronic pancreatitis, CF
Capsule surrounding the pancreas
autoimmune pancreatitis; capsule may demonstrate delayed enhancement
Cause of groove pancreatitis
duodenal or biliary obstruction (stenosis or stricture)
Cystic change of duodenal wall
groove pancreatitis
Large pancreatic calcifications with ductal dilation
tropical pancreatitis; younger patients, assoc. with malnutrition; increased risk of pancreatic cancer
Most common cause of pancreatic pseudocyst
acute or chronic pancreatitis (inflammatory pseudocyst)
DDx for true pancreatic cysts (non-pseudocysts)
ADPKD, VHL, CF
Atrophic pancreas with dystrophic calcifications
chronic pancreatitis, IPMN
Strongest risk factor for pancreatic adenocarcinoma
smoking
Elevated CA-19-9
pancreatic adenocarcinoma
Syndromes assoc. with increased risk of pancreatic adenocarcinoma
HNPCC, BRCA, ataxia-telangiectasia, Peutz-Jeghers
Periampullary pancreatic cancer
originates within 2 cm of major papilla; increased incidence in Gardner syndrome
Unresectable pancreatic cancer
involvement of SMA or celiac axis
Large hyperenhancing pancreatic mass with calcifications
non-functional PNET; +/- necrosis
Whipple procedure
resection of pancreatic head, adjacent duodenum, and gastric antrum => attach CBD and pancreatic remnant to distal duodenum + gastrojejunostomy
Causes of pancreatic transplant failure
acute rejection > donor splenic vein thrombosis (usually within 6 weeks); both may demonstrate reversal of diastolic flow
Shrinking pancreas transplant
chronic rejection
Santorinicele
occurs in pancreas divisum; may cause obstruction => pancreatitis
Enhancing pancreatic mass
PNET, splenule, met (RCC most commonly), serous cystadenoma
Common channel syndrome
absent septum between distal CBD and pancreatic allowing reflux
Splenomegaly size criteria
> 14 cm; remember mono can cause this; volume >500 cc