Real Time US 18FDG PET/CT Image Fusion for Guidance of Thermal Ablation of 18FDG PET Positive Liver Metastases: The Added Value of Contrast Enhancement
PurposeTo assess the feasibility of US 18FDG PET/CT fusion guided microwave ablation of liver metastases either poorly visible or totally undetectable with US, CEUS and CT, but visualized by PET imaging.Materials and MethodsTwenty three patients with 58 liver metastases underwent microwave ablation guided by image fusion system that combines US with 18FDG PET/CT images. In 28/58 tumors, 18FDG PET/CT with contrast medium (PET/CECT) was used. The registration technical feasibility, registration time, rates of correct targeting, technical success at 24 h, final result at 1 year and complications were analyzed and compared between the PET/CT and PET/CECT groups.ResultsRegistration was successfully performed in all cases with a mean time of 7.8 1.7 min (mean standard deviation) (4.6 1.5 min for PET/CECT group versus 10.9 1.8 min for PET/CT group, P 0.01) In total, 46/58 (79.3% tumors were correctly targeted, while 3/28 (10.7% and 9/30 (30% were incorrectly targeted in PET/CT and PET/CECT group, respectively (P 0.05) Complete ablation was obtained at 24 h in 70.0% of cases (n 40 tumors) 23/28 (82.1% in the PET/CECT group and 17/30 (56.7% in the PET/CT group (P 0.037) Fourteen tumors underwent local retreatment (11 ablations, 2 with resection and 1 with stereotactic body radiation therapy) while 4 tumors could not be retreated because of distant disease progression and underwent systemic therapy. Finally, 54/58 (93.1% tumors were completely treated at 1 year. One major complication occurred, a gastrointestinal hemorrhage which required surgical repair.ConclusionsPercutaneous ablation of 18FDG PET positive liver metastases using fusion imaging of real time US and pre acquired 18FDG PET/CT images is feasible, safe and effective. Contrast enhanced PET/CT improves overall ablation accuracy and shortens procedural duration time.
CardioVascular and Interventional Radiology