FLUORODEOXYGLUCOSE PET OF ABDOMINAL AND PELVIC NEOPLASMS - POTENTIAL ROLE IN ONCOLOGIC IMAGING

Fluorine-18-fluoro-2-deoxyglucose (FDG) positron emission tomography ( PET) was used to image 38 patients with known or suspected malignant p rocesses involving the abdomen or pelvis (including primary [n = 2] an d secondary [n = 19] fiver tumors, recurrent colon carcinoma [n = 1], lymphoma [n = 15], and cavernous hemangioma [n = 1]). PET results were compared with those from concurrent computed tomographic (CI) studies . Conspicuity of metastatic liver lesions on PET images often exceeded that of lesions on CT scans. Two well-differentiated primary liver tu mors failed to show increased FDG uptake. Thirteen of the 15 patients with lymphoma had active disease, as determined with CT or clinical fi ndings; 12 of 13 had increased FDG uptake on PET images. The false-neg ative result occurred a patient with a low-grade lymphoma. The recurre nt colorectal lesion was well demonstrated by PET, but further study i s needed to determine whether it can be used to distinguish recurrent disease from radiation-induced changes. PET may be useful in determini ng the response to oncologic therapy, but PET does not reliably allow exclusion of low-grade lymphoma or well-differentiated hepatic lesions . Clinical correlation is always required in evaluating the significan ce of PET findings, as inflammatory conditions can also result in incr eased FDG uptake.