Hepatobiliary imaging

Abstract

A patient's clinical presentation should prompt an imaging evaluation that is cost effective for accurate diagnosis and leads to appropriate treatment of gallbladder inflammatory disease. In the setting of recurrent biliary colic, chronic cholecystitis is the main diagnostic consideration. Imaging hallmarks include gallstones and gallbladder wall thickening for which ultrasonography is uniquely suited. When a patient appears more toxic with right upper quadrant pain, one would more strongly consider acute cholecystitis. Because the morbidity and mortality of acute cholecystitis are reduced with early cholecystectomy, it is incumbent upon the clinician to make the diagnosis promptly and accurately. Hepatobiliary imaging with an IDA derivative has proven superior sensitivity, specificity, and accuracy for this condition. The examination has validity because it detects cystic duct obstruction, the primary pathophysiologic event responsible for most acute calculous and acalculous disease. Utilizing morphine augmentation when delayed filling is present has reduced the total examination time to less than 2 hours. Use of ancillary findings including gallbladder hyperemia and the "hot rim" sign help predict complicated cholecystitis, enabling more urgent intervention. The bulk of data presented in this review supports hepatobiliary imaging as the modality of first choice in the evaluation of acute cholecystitis. In the intensive care setting, where acalculous disease and atypical presentations are common, hepatobiliary imaging also plays a major role. We recommend liberal use of Sincalide pretreatment, morphine augmentation, and delayed images to promote gallbladder filling. If the gallbladder is nonvisualizing despite these maneuvers, sonography is often added as an aid to detect secondary signs of acute cholecystitis and help confirm the diagnosis with greater certainty prior to high-risk surgery.