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Biliary System: Imaging Approach and Differential Diagnosis

Imaging Indications and Protocols Oral and IV cholangiography have been supplanted by newer cross-sectional imaging and cholescintigraphy. MR hepatobiliary IV contrast agents may be used to supplement CT or MR cholangiography. Cholescintigraphy is a nuclear medicine study used to evaluate the morphology and function of the biliary tree. In a " HIDA scan ," the patient receives an IV administration of Tc-99m iminodiacetic acid compound, an…

Hepatic Metastases and Lymphoma

KEY FACTS Imaging Multiphasic CT or MR are 1st-line tests Accuracy: Helical CT (~ 80%), MR and PET (~ 90%) Hepatic lymphoma Diffuse low density on CT may mimic steatosis – Easily distinguished from steatosis on MR Multiple well-defined, homogeneous, low-density (CECT) or high-intensity (T2WI) masses Liver metastases Hypovascular metastases: Low-density center with peripheral rim or target-like enhancement Hypervascular metastases: Hyperdense (intense) on arterial-phase CECT or…

Hepatocellular Carcinoma

KEY FACTS Imaging Patients with chronic liver disease must be in surveillance program (clinical & imaging) Small, curable hepatocellular carcinomas (HCCs) can be diagnosed by CT & MR Criteria for HCC are often specific enough to guide therapy without tissue confirmation Multiphasic contrast-enhanced CT or MR is definitive imaging study Key imaging features Hypervascular mass on arterial phase (CT or MR) with "washout" on venous &…

Hepatic Inflammatory Pseudotumor

KEY FACTS Terminology Heterogeneous group of lesions occurring in liver and bile ducts (among other organs) characterized by fibroblastic and myofibroblastic proliferation with inflammatory infiltrate You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

Hepatic Adenoma

KEY FACTS Imaging Key features (not always present): Hypervascular, fat-containing, hemorrhagic, encapsulated MR shows some elements better than CT (lipid & hemorrhage) T1WI: Mass: Heterogeneous signal intensity – Increased signal intensity (due to fat or recent hemorrhage) – Decreased signal intensity (necrosis, calcification, old hemorrhage) T2WI: Mass: Heterogeneous signal intensity – Increased signal intensity (old hemorrhage, necrosis) – Decreased signal intensity (fat, recent hemorrhage) Gadoxetate-enhanced MR…

Hepatic Transplantation

KEY FACTS Terminology Orthotopic liver transplantation (OLT) Imaging Allograft rejection No reliable imaging findings to suggest or confirm diagnosis Biliary leak From entry of T-tube: Easily treated From biliary anastomosis: Requires revision From intrahepatic ducts: Biliary necrosis; catastrophic Biliary obstruction Responds to balloon dilation & stenting Hepatic artery (HA) stenosis US: Damped waveform in HA distal to stenosis: Slow systolic upstroke; decreased resistive index (RI) (<…

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

KEY FACTS Terminology Shunt between main portal vein and hepatic vein created with balloon-expandable metallic stent Imaging US is primary imaging tool following transjugular intrahepatic portocaval shunt (TIPS) Goal of US: Detect stenosis before shunt occludes or symptoms recur Echogenic stent is easily seen on US but does not block sound transmission Color Doppler shows patency and flow direction within TIPS, portal vein, hepatic veins, and…