Use of dynamic CT attenuation value for diagnosis of acute gangrenous cholecystitis

Abstract

Objective: To determine if the increase in transient focal enhancement of the liver adjacent to the gallbladder seen on dynamic computed tomography (CT) is greater in gangrenous cholecystitis than in nongangrenous cholecystitis by determining the CT attenuation value.

Methods: We retrospectively reviewed the medical records of 57 patients who underwent emergency cholecystectomy for acute cholecystitis and preoperative dynamic CT scans between March 2011 and April 2016. Based on the pathology findings, patients were assigned to a gangrenous group or a nongangrenous group. The CT attenuation ratio (AR) was defined as the ratio of the maximum CT attenuation value in the region of interest in segment 5 (liver parenchyma adjacent to the gallbladder) and that in the control region of interest in segment 8. The patient characteristics and CT findings were compared between the groups. The appropriate AR of the arterial phase (ARAP) cutoff value for a diagnosis of gangrenous cholecystitis was determined using receiver operating characteristic curve analysis.

Results: The ARAP was significantly higher in the gangrenous group than in the nongangrenous group (P < .001); the area under the receiver operating characteristic curve was 0.849. The ARAP cutoff value of 1.46 had a sensitivity and specificity of 84.6% and 83.9%, respectively (odds ratio, 21.17; 95% confidence interval, 4.90-118.91), and ARAP ≥1.46 was significantly correlated with a diagnosis of gangrenous cholecystitis (P < .001).

Conclusions: The increase in transient focal enhancement of the liver adjacent to the gallbladder during the arterial phase of dynamic CT was greater in gangrenous cholecystitis than in nongangrenous cholecystitis.