Positron emission tomography and breast lesions: low FDG activity in early phase imaging is not essentially benign

The frequency of malignancy with low FDG uptake is significant and often presents diagnostic challenges. The usefulness of dual-time point FDG-PET/CT imaging (including early "after 45 minutes" and delayed "after 100 minutes," phases after radionuclide administration) for detection of such tumors has been documented. The authors present 2 cases of pathologically proven breast cancer with minimally increased FDG uptake on the initial scan (maximum standardized uptake value; SUVmax <2.5). Detection was improved by performing a dynamic PET study with early and delayed scans. Patients with a poorly visualized breast lesion due to minimal FDG uptake on the initial FDG-PET images should not be considered as benign and deserves further delayed phase imaging.