CT evaluation of intracholecystic bile

Computed tomography (CT) has been used to detect a variety of gallbladder abnormalities, but the accuracy of routine abdominal CT in evaluating intracholecystic bile has not been established. Forty-six patients were identified in whom abdominal CT and sonography were performed within 1 week of each other. Using sonographic results as the standard, sensitivity, specificity, and accuracy of CT gallbladder evaluation were calculated; both initial CT interpretations and retrospective review of scans were used for this analysis. In the retrospective review, visual interpretation of gallbladder images and measurement of intracholecystic bile attenuation (greater than or equal to 25 H, abnormal) were analyzed. The overall sensitivity of CT in detecting abnormal gallbladder contents ranged from 44% (bile attenuation greater than or equal to 25 H) to 63% (retrospective CT interpretation), while specificity ranged from 77% to 93%. The most common cause of high-attenuation bile in the series was sludge, a cause not previously reported. It was concluded that intracholecystic bile is poorly evaluated on routine abdominal CT, particularly because of low sensitivity in disease detection.