Uneven fatty replacement of the pancreas: evaluation with CT.

PURPOSE: To determine the computed tomographic (CT) features of uneven fatty replacement of the pancreas and clarify their radiologic and clinical importance. MATERIALS AND METHODS: CT scans from 80 patients with uneven fatty replacement of the pancreas were reviewed. Uneven fatty replacement of the pancreas was classified into two types. In type 1, the posterior aspect of the head of the pancreas was spared from intense fatty replacement. In type 2, the focal area around the common bile duct (CBD) was spared from fatty replacement. Each type was divided into two subgroups on the basis of whether the body and tail of the pancreas showed intense fatty replacement (type a = negative for intense fatty replacement, type b = positive for intense fatty replacement). Findings from endoscopic retrograde cholangiopancreatography performed in five patients, histopathologic examination in one patient, and clinical examination in all 80 patients were also evaluated. RESULTS: Twenty-eight patients (35%) had type 1a replacement, 29 (36%) had type 1b replacement, nine (11%) had type 2a replacement, and 14 (18%) had type 2b replacement. In all patients, the anterior aspect of the head of the pancreas showed distinctly lower attenuation at CT. CONCLUSION: Fatty replacement is more severe in the anterior aspect of the head of the pancreas. The posterior aspect of the head of the pancreas and the area around the CBD tended to be spared.