Diffusion-weighted imaging of the pericholecystic hepatic parenchyma for distinguishing acute and chronic cholecystitis.

ABSTRACT

PURPOSE: The purpose of this study is to measure the performance of restricted diffusion of the pericholecystic hepatic parenchyma for distinguishing between acute and chronic cholecystitis. METHODS: The institutional review board approved this HIPAA-compliant retrospective study. Two hundred sixty-six patients presenting with acute right upper quadrant pain between 10/3/2010 and 11/28/2012 undergoing MR within 48 h of equivocal utility of ultrasound (US) were included. Diffusion-weighted imaging (DWI) sequences (b = 0, 600 s/mm2, apparent diffusion coefficient (ADC) maps) were reviewed and graded in a blinded fashion by two abdominal fellowship-trained radiologists for the presence of restricted diffusion in the pericholecystic hepatic parenchyma and the gallbladder wall. Sensitivity, specificity, and inter-observer agreement for individual imaging signs were calculated using surgical pathology as the reference standard for acute cholecystitis. RESULTS: Of the 266 patients, 113 were treated conservatively and 153 underwent cholecystectomy. Restricted diffusion of the pericholecystic hepatic parenchyma showed low sensitivity (reviewer 1, 40%; reviewer 2, 30%) and moderately high specificity (reviewer 1, 84%; reviewer 2, 75%) for distinguishing acute and chronic cholecystitis. Restricted diffusion in the gallbladder wall showed low sensitivity (reviewer 1, 30%; reviewer 2, 7%) and high specificity (reviewer 1, 93%; reviewer 2, 97%) for distinguishing acute and chronic cholecystitis. CONCLUSION: Diffusion-weighted imaging of the pericholecystic hepatic parenchyma shows moderately high specificity for distinguishing between acute and chronic cholecystitis.