Gallbladder wall thickening: MR imaging and pathologic correlation with emphasis on layered pattern

The aim of this study was to correlate MR findings of gallbladder wall thickening with pathologic findings on the basis of the layered pattern and to evaluate the diagnostic value of MR imaging in gallbladder disease. We retrospectively evaluated the source images of HASTE sequences for MR cholangiography in 144 patients with gallbladder wall thickening. The layered pattern of thickened wall was classified into four patterns. Type 1 shows two layers with a thin hypointense inner layer and thick hyperintense outer layer. Type 2 has two layers of ill-defined margin. Type 3 shows multiple hyperintense cystic spaces in the wall. Type 4 shows diffuse nodular thickening without layering. MR findings of a layered pattern of thickened gallbladder were well correlated with histopathology. Chronic cholecystitis matched to type 1, acute cholecystitis corresponded to type 2, adenomyomatosis showed type 3, and the gallbladder carcinomas showed type 4. All four layered patterns were associated with PPV of 73% or greater, sensitivity of 92% or greater and specificity of 95% or greater. Our results indicate that MR findings of gallbladder wall thickening are characteristic in each entity and correlate well with pathologic findings. The classification of the layered pattern may be valuable for interpreting thickened gallbladder wall.