Detection of treated liver metastases using fluorine-18-fluordeoxyglucose (FDG) and positron emission tomography (PET)

The aim of the study was the evaluation of the detectability of heated live r metastases using one FDG-PET measurement The study includes 42 patients ( 80 lesions) from different primary tumours. Standardized Uptake Values (SUV ) as well as the tumour to liver Patio (T/L) were used for evaluation. A T/ L > 1.0 was considered to be pathological. Clinical follow-up data for at l east 6 months were used as a reference. The median value of the FDG-uptake was 2.9 SUV in all liver metastases. The sensitivity based on a T/L ratio e xceeding 1.0 was 82.5% (66/80 lesions). 25 of 80 (31%) lesions had a ratio T/L higher than 2.0 and were clearly visualized by PET. Negative results wi th a ratio T/L < 1.0 were raised in 14 of 80 treated metastatic lesions (17 .5%). Although these metastases were hypometabolic, they were correctly cla ssified due to the image correlation with computed tomography (CT) or magne tic resonance (MR) images or due to a baseline FDG-study prior to the onset of therapy. False positive results were not noted in this study. FDG-PET i s a reliable method for the evaluation of treated liver metastases. A basel ine FDG study prior to therapy is preferable for the interpretation.