(18)F-FDG PET/CT performed immediately after percutaneous ablation to evaluate outcomes of the procedure: preliminary results

OBJECTIVE: To determine whether (18)F-fluorodeoxyglucose positron emission tomography/computed tomography performed immediately after percutaneous ablation ((iPA)(18)F-FDG PET/CT) is useful in evaluating the outcomes of the procedure. MATERIALS AND METHODS: This was a retrospective study of 20 patients (13 males, 7 females; mean age, 65.8 ± 12.1 years) submitted to percutaneous ablation of metastases. All of the lesions treated had shown focal uptake on a (18)F-FDG PET/CT scan obtained at baseline. The primary tumors were mainly colorectal cancer (in 45%) or lung cancer (in 40%). (iPA)(18)F-FDG PET/CT was performed to identify any residual viable tumor cells. The treatment was considered a success (no viable tumor cells present) if no uptake of (18)F-FDG was noted on the (iPA)(18)F-FDG PET/CT scan. RESULTS: Twenty-six lesions were submitted to percutaneous ablation with either cryoablation (n = 7) or radiofrequency ablation (n = 19). The mean lesion diameter was 2.52 ± 1.49 cm. For the detection of viable tumor cells, (iPA)(18)F-FDG PET/CT had a sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 66.7%, 95%, 88.5%, 80%, and 90.5%, respectively. There was a significant correlation between the (iPA)(18)F-FDG PET/CT findings and the results of the follow-up studies (kappa = 0.66; p < 0.01). CONCLUSION: (iPA)(18)F-FDG PET/CT studies appear to constitute a useful means of evaluating the outcomes of percutaneous ablation. By detecting residual viable tumor cells, this strategy might allow early re-intervention, thus reducing morbidity. Studies involving larger numbers of patients are needed in order to confirm our findings.