Electromagnetic Navigation System-Guided Microwave Ablation of Hepatic Tumors: A Matched Cohort Study

• Published in: Cardiovascular and interventional radiology Vol. 44; no. 3; pp. 500 - 506
• Main Authors: Ringe, K. I., Pöhler, G. H., Rabeh, H., Wacker, F.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2021; Springer Nature B.V
• Subjects: Ablation; Accuracy; Antenna feeds; Antennas; Cardiology; Cohort analysis; Deviation; Exposure; Imaging; Liver; Liver cancer; Medicine; Medicine & Public Health; Metastases; Microwave ablation; Navigation systems; Non-Vascular Interventions; Nuclear Medicine; Placement; Radiation; Radiation effects; Radiology; Technical Note; Time measurement; Tumors; Ultrasound; Electromagnetic; Microwave ablation; Accuracy; Navigation; Computed tomography
• ISSN: 0174-1551; 1432-086X
• DOI: 10.1007/s00270-020-02761-6

Purpose To assess the accuracy and applicability of an electromagnetic navigation system (EMNS) for CT-guided microwave ablation (MWA) of hepatic tumors in comparison with conventional CT-guidance. Materials and Methods 34 patients ( m  = 20/ f  = 14, mean age 34 y) with 34 liver tumors (primary = 22, metastases = 14, mean size 20 mm) referred for CT-guided MWA were included in this IRB-approved study. Interventions were performed prospectively using an EMNS in 17 patients (navigation group), and results were compared to a matched historic cohort of 17 patients using conventional CT-guidance (control group, t -test, p  < 0.05 deemed significant). Primary outcome measurement: accuracy of antenna placement (deviation). Secondary outcome measurements: setup time, number of control scans, duration and radiation exposure for antenna placement. Results Ablations were performed using a single or a double-angulated approach. Application of the EMNS was feasible in 14 cases (82%). Mean total deviation of the antenna feed point in the navigation and control group was 2.4 mm (range 0.2–4.8 mm) and 3.9 mm (range 0.4–7.8 mm), p  < 0.05. Mean setup time for the EMNS was 6.75 ± 3.9 min (range 3–12 min). Mean number of control scans in the navigation and control group was 3 ± 0.9 (range 1–4) and 6 ± 1.3 (range 4–8), p  < 0.0001; mean time for antenna placement was 9 ± 7.3 min (range 1.4–25.9 min) and 11.45 ± 6.1 min (range 3.9–27.4 min), p  = 0.3164. Radiation exposure was significantly less in the navigation group. Conclusion Our experience in a limited number of patients suggests that EMNS enables intuitive CT-guided MWA of liver tumors with higher accuracy when compared to ablations performed without navigation and with fewer control scans needed.