Desiree Deandreis MD, Presenter: Nothing to Disclose

Sophie Leboulleux, Abstract Co-Author: Nothing to Disclose

Clarisse Dromain MD, Abstract Co-Author: Nothing to Disclose

Anne Auperin MD, Abstract Co-Author: Nothing to Disclose

Martin Schlumberger, Abstract Co-Author: Nothing to Disclose

Thierry J. De Baere MD, Abstract Co-Author: Speaker, Boston Scientific Corporation

PURPOSE: to study the usefulness of FDG-PET/CT in the evaluation of lung radiofrequency ablation (RFA)

MATERIALS AND METHODS: Patients planned for lung RFA between February 2004 and March 2007 underwent FDG PET/CT before RFA (pre-RFA PET) and if FDG uptake was present  at 24 hours, 1 month (M1) and 3 months (M3) after RFA. Suspicious uptakes of incomplete treatment or recurrence on FDG PET/CT were investigated by biopsy or followed up on subsequent chest CT scan and/or FDG PET/CT. Thirty four patients (22 males, 12 females; mean age: 64 years) were included: 29 patients with lung metastases from either colorectal cancer (n: 16), head and neck cancer (n: 3), bile duct cancer (n: 2), adrenocortical carcinoma (n: 2), other origins (n: 6) and 5 patients with primary lung squamous carcinoma.

RESULTS: In 11 patients pre-RFA PET detected unexpected lesions leading to treatment changes in 9 patients (28%) (cancellation of RFA in 4 cases, increasing the number of lung metastases treated with RFA in 4 cases and association of thyroid surgery in 1 case). In 2 patients, FDG uptake at pre-RFA PET was absent and FDG-PET/CT follow-up was not performed. In the others 21 patients FDG uptake was present only in the lesions planned for RFA. Overall, 52 lesions in 28 patients were RF ablated and followed up by FDG-PET/CT. FDG-PET/CT diagnosed complete treatment in 36 lesions, local recurrent/persistent disease in 12 lesions (2 at day 1, 4 at M1 and 6 at M3), and was equivocal in 4 lesions at M1. FDG/PET was falsely positive in 6 lesions, truly positive in 10 lesions and truly negative in 36 lesions. Sensitivity for the diagnosis of relapse was 100% and specificity was 86%. Inflammatory mediastinal lymph node with FDG uptake was observed in 12 patients (37%) in at least 1 of the 3 FDG-PET/CT and FDG uptake at RFA puncture point was also detected in 11 patients in at least 1 of the 3 FDG-PET/CT (34%).  

CONCLUSIONS: FDG PET/CT is useful for the early diagnosis of relapse after RFA. The appearance of FDG uptake in mediastinal lymph nodes or at the site of the needle path used for RFA may occur and should not be considered pathological uptakes.

FDG-PET/CT can be an usefull tool to follow up patients with lung lesions treated by radiofrequency ablation .

Deandreis, D, Leboulleux, S, Dromain, C, Auperin, A, Schlumberger, M, De Baere, T, Role of FDG PET/CT in the Follow-up of Lung Lesions Treated with Radiofrequency Ablation.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/7120787.html