Benign Nonphysiologic Lesions with Increased 18F-FDG Uptake on PET/CT: Characterization and Incidence

Abstract
OBJECTIVE. The objective of our study was to characterize benign lesions showing increased 18F-FDG uptake and to determine their incidence on whole-body FDG PET/CT performed in oncologic patients. In addition, the performance of PET alone and PET/CT in characterizing lesions as benign was compared.MATERIALS AND METHODS. A retrospective review of 1,134 consecutive reports of PET/CT studies performed in patients with proven or suspected malignancy over a 6-month period yielded 289 patients with 313 lesions that showed increased FDG uptake but were suspected to be benign (nonphysiologic) or indeterminate. Lesions were subjectively categorized on the basis of the intensity of FDG uptake (mild, moderate, or marked) as compared with background activity. For each lesion, a decision was made as to whether a benign diagnosis could be obtained by the CT part of the study, the PET pattern, or clinical correlation, or whether histologic sampling was necessary. The performance of PET alone and PET/CT for characterizin...