360 degrees open-ended and navigated magnetic resonance-guided microwave ablation for hepatic tumors in risk areas

Context: Image-guided local ablation has becoming a promising treatment option for patients unsuitable for surgical resection. Currently, magnetic resonance (MR) imaging has been used as guidance for ablation due to its good soft-tissue contrast, high image quality and absence of ionizing radiation. However, the limited operating space and interrupted and delayed imaging of the conventional MR equipment increased the difficulty of puncture during operation. Therefore, we utilized an easy-to-use optical navigation system with a 0.4 T 360 degrees open MR system to perform MR-guided microwave ablation (MWA) to treat liver tumor patients in risk areas. Aim: To evaluate the safety and efficacy of MR-guided MWA in treating liver tumors using a 0.4 T open and navigated MR system. Materials and Methods: A retrospective analysis was performed on 19 liver tumor patients who underwent MR-guided MWA between August 2014 and August 2017. The complications, complete ablation, and long-term outcomes were analyzed and evaluated. Results: It was found that navigated MRI guidance allowed for precise needle placement in the targeted tumor, and ablation was successfully performed in all patients without serious intraoperative complications and death. Additionally, complete ablation was reached at 94.74% (18/19), with only one patient discovered with residual tumor, and therefore received another MWA session within three months. Conclusion: 360 degrees open MR system combined with navigation systems conveniently enhanced the operation of MR-guided ablation, producing effective outcomes. Therefore, this option may be a safe and effective therapy for liver tumors in patients, especially for those situated in risk areas and those not visible to identify by ultrasound or computerized tomography.