The Clinical Utility of Rectal Gas Distension F-18 FDG PET/CT

The aim of this study was to evaluate the clinical value of rectal gas distension F-18 FDG PET/CT imaging for the differentiation of the rectal focal uptake lesions. Twenty four patients (M:F=11:13, Age 62.8±12.4 years) underwent rectal gas distension F-18 FDG PET/CT, prospectively: initial image at 50-60 min after the intravenous injection of F-18 FDG and rectal distension image after the infusion of air through the anus. Focally increased uptake lesions on initial images but disappeared on rectal distension images defined a physiological uptake. For the differential evaluation of persistent focal uptake lesions on rectal distension images, colonoscopy and histopathologic examination were performed. Among the 24 patients, 27 lesions of focal rectal uptake were detected on initial images of F-18 FDG PET/CT. Of these, 7 lesions were able to judge with physiological uptake because the focal increased uptake disappeared from rectal distension image. Remaining 3 lesions were non-rectal lesions (2 lesions: rectovesical space, 1 lesion: uterine myoma). Among 17 lesions which was showed persistent increased uptake in rectal distension image, 15 lesions were confirmed as the malignant tumor (SUVmax=15.9±6.8) and 2 lesions were confirmed as the benign lesions including adenoma and inflammatory disease. The rectal distension F-18 FDG PET/CT imaging could be an important noninvasive method for the differentiation of malignant and benign focal rectal uptake lesions including physiologic uptake