Percutaneous electromagnetic navigation system for computed tomography (CT)-guided liver ablation: how far can we insert the antenna in the first scan?

Abstract

Aim: To evaluate technical/clinical success/efficacy of a commercially available electromagnetic navigation system in computed tomography (CT)-guided microwave ablation (MWA) of primary or metastatic liver tumours.

Materials and methods: This prospective observational study evaluated tumours treated with percutaneous CT-guided MWA using a commercially available electromagnetic navigation system under intravenous analgesia. Technical parameters evaluated included procedural duration and ratio of inserted probe length in first/final control scan. Inserted needle lengths were measured from the skin surface to the antenna tip at firstand final control scan. Clinical success was defined as lack of tumour remnant in 1st-month imaging follow-up. The Cardiovascular and Interventional Radiological Society of Europe (CIRSE) classification system was used for complications' reporting.

Results: A total of 64 patients (66.25 ± 8.87 years) and 80 tumours (2.69 ± 1.10 cm) were included in the study. Technical success was 98.75%. The mean duration of the procedure was 47.63 ± 19.88 min. The mean ratio of inserted antenna length between first and final scan was 70.92% (±15.86). Primary clinical success was 96.25% (tumour remnant at one-month followup in 3/80 tumours; all three cases retreated with ablation). Secondary clinical success was 100% (no tumour remnant in imaging follow-up). Recorded complications were Grade 1 (4 self-limited perihepatic haematomas requiring nothing but observation) and Grade 3 (1 hepatic abscess treated with percutaneous drainage).

Conclusion: The use of an electromagnetic navigation system for CT-guided MWA of malignant liver lesions can permit insertion of >70% of the required microwave antenna length to target lesion in the first pass, with satisfactory technical and clinical success and low complication rate.