The Imaging Evaluation of Cholelithiasis in the Obese Patient—Ultrasound vs CT Cholecystography: Our Experience with the Bariatric Surgery Population

The purpose of this study was to compare computed tomography (CT) cholecystography and ultrasound for gallstone detection in preoperative bariatric surgery patients.

The study included 16 asymptomatic prebariatric surgery patients. On the same day, each patient underwent abdominal CT 4 h after IV cholecystograffin injection, and gallbladder ultrasound. CT and ultrasounds were reviewed by two independent, blinded radiologists, and scored as follows: no gallstones, possible gallstones, definite gallstones, indeterminate. CT and ultrasound results were compared.

Ultrasound detected definite gallstones in three patients, possible gallstones in one patient, and no gallstones in ten patients. Two scans were considered indeterminate. CT cholecystography detected definite gallstones in six patients, possible gallstones in zero patients, and no gallstones in nine patients, and was indeterminate in one patient. All three patients with gallstones seen sonographically had definite gallstones on CT. The patient with possible gallstones detected sonographically had definite stones detected at CT. One of the two patients with indeterminate ultrasounds had gallstones detected at CT. The other patient had both studies indeterminate. One patient with no gallstones sonographically had definite gallstones at CT. No patients with a negative CT had gallstones seen on ultrasound. Nine patients had no gallstones on either modality.

CT cholecystography is more sensitive and specific for the detection of gallstones in the obese population. CT cholecystography should be considered in place of ultrasound in the preoperative workup of these patients.