Gallbladder carcinoma is the most common biliary malignancy and occurs predominantly in the sixth and seventh decade, with a slight female predominance.
Findings on MRI, which are suggestive of gallbladder carcinoma, are:
- a mass either protruding into the gallbladder lumen or replacing the lumen completely;
- focal or diffuse thickening of the gallbladder wall greater than 1 cm;
- soft tissue (tumor) invasion of adjacent organs such as the liver, duodenum, and pancreas, which occurs frequently.
On T1-weighted MR images, the tumor is hypoor isointense compared to adjacent liver.
On T2-weighted sequences, it is usually hyperintense relative to the liver and poorly delineated.
The tumor usually enhances on T1-weighted immediate post-gadolinium images in a heterogeneous fashion, which facilitates differentiation from chronic cholecystitis (Kelekis and Semelka 1996).