Ga-67 scan to detect intra-abdominal infection in patients after colorectal surgery

Purpose: Intra-abdominal infection is still an important issue in colorecta l surgery. The Ga-67 scan is relatively inexpensive, but the delay in diagn osis and the intense physiologic bowel activity are considerable drawbacks to its use in abdominal investigations. In this study, the authors performe d 24-hour Ga-67 scans and read the images with the surgeon to detect abdomi nal infection in patients who underwent colorectal surgery. Methods: Sixty-one patients who underwent colorectal surgery were enrolled in this study. Ga-67 scintigraphy was performed 24 hours, and later as need ed, after the injection of 111 MBq (3 mCi) Ga-67 citrate. All scans were in terpreted together by a nuclear medicine specialist and the surgeon. The in tensity of Ga-67 uptake was recorded as grade 0: no uptake; grade 1: less t han liver uptake; grade 2: equal to liver uptake; or grade 3: greater than liver uptake. When the intensity of Ga-67 uptake was equal to or greater th an grade 2, the pattern of Ga-67 uptake was classified as changing or uncha nging. A positive Ga-67 scan was defined as having an intensity of grade 2 or 3 with an unchanging pattern. Results: Nineteen abdominal infections were diagnosed, all by Ga-67 scans, for a diagnostic sensitivity rate of 100%. Of the 42 patients with no intra -abdominal infection, only 2 had positive Ga-67 scans. This resulted in a s pecificity rate of 95.2%. The overall accuracy of the Ga-67 scan in the det ection of intra-abdominal infection after colorectal surgery was 96.7%. Conclusions: The Ga-67 scan is useful for detecting intra-abdominal infecti on after colorectal surgery. Reading the images with the surgeon and using a lateral view can decrease the false-positive rate. A negative Ga-67 scan can rule out intra-abdominal infection, whereas a positive Ga-67 scan indic ates the need for further patient evaluation after colorectal surgery.