Simplified Protocol for Fdg-Pet in Patients with Suspected Cholecystitis: Technical Aspects

2514 Objectives Ultrasound and HIDA studies have become the tests of choice in the evaluation of patients (pts) with abdominal pain and suspected cholecystitis. FDG-PET has demonstrated high sensitivity in dection of infection/inflammation. The purpose of this study is to evaluate the effectiveness of FDG-PET in the evaluation of abdominal pain and suspected cholecystitis and to develop a protocol which delivers minimum radiation and can be performed rapidly with minimum pt discomfort. Methods Pts are restricted from carbohydrates for 3hrs prior to injection of FDG. This includes no dextrose drip (1/2 Normal Saline is requested). This includes no dextrose drip with antibiotic or heparin. A low dose PET-CT was performed using a 5mCi dose of FDG and a 20-30 MAS (low-dose) CT scan begun 45-60 minutes post injection. Depending on the PET-CT used, a 2-4 bed position scan was performed from the top of the liver to the upper pelvis (includes gallbladder and appendix). Bed position time was 2-5 minutes depending on PET-CT system used. 19 pts with suspected cholecystitis were studied along with 40 control subjects. All studies were read by at least one nuclear medicine physician. A positive study was defined as detection of activity in the gallbladder wall. Results Using this low-dose protocol, scan time range from 4-20 minutes depending on choice of PET-CT system. Total body radiation was 0.75-1 rads. 10 pts tested positive for cholecystitis. 9 out of 10 underwent cholecystectomy with pathologic confirmation of cholecystitis. Of 9 pts with negative PET-CT, 6 were managed conservatively, and 3 had cholecystectomy performed. Of the 3, 2 were negative for cholecystitis and 1 had a 1mm focus of inflammation (CT, HIDA and ultrasound were negative). Conclusions A simplified low-dose PET-CT protocol is highly sensitive and specific in the evaluation of suspected cholecystitis. Rapid scan times give minimal pt discomfort and total body radiation is less than 1rad