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

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.