MR-Guided High-Power Microwave Ablation in Hepatic Malignancies: Initial Results in Clinical Routine

Abstract

Purpose Evaluation of technique effectiveness, patient safety and ablation parameters of MR-guided microwave ablation in hepatic malignancies using an MR-conditional high-power microwave ablation system. Materials and Methods Institutional review board approval and informed patient consent were obtained. Patients who underwent MR-guided microwave ablation of hepatic malignancies in a 1.5T wide-bore scanner using a perfusion-cooled high-power microwave ablation system with a maximum generator power of 150 W were included. Ablation parameters comprising procedure durations, net ablation duration, applicator positions and ablation zone dimensions were recorded. Adverse events were classified according to the CIRSE classification system. Technique effectiveness was assessed after 1 month. Follow-up was conducted with contrast-enhanced MRI and ranged from 1 to 20 months (mean: 6.1 ± 5.4 months). Results Twenty-one consecutive patients (age: 63.4 ± 10.5 years; 5 female) underwent 22 procedures for 28 tumours (9 hepatocellular carcinomas, 19 metastases) with a mean tumour diameter of 14.6 ± 5.4 mm (range: 6–24 mm). Technique effectiveness was achieved in all lesions. Tumours were treated using 1.7 ± 0.7 applicator positions (range: 1–3). Mean energy and ablation duration per tumour were 75.3 ± 35.4 kJ and 13.3 ± 6.2 min, respectively. Coagulation zone short- and long-axis diameters were 29.1 ± 6.4 mm and 39.9 ± 7.4 mm, respectively. Average procedure duration was 146.4 ± 26.2 min (range: 98–187 min). One minor complication was reported. Five patients developed new tumour manifestations in the untreated liver. Local tumour progression was not observed during initial follow-up. Conclusion MR-guided high-power microwave ablation provides safe and effective treatment of hepatic malignancies with short ablation times and within acceptable procedure durations.

The Role of Human U Three Protein 14a as a Predictor for Hepatocellular Carcinoma Recurrence After Microwave Ablation

“…The antenna was attached to the microwave generator (ECO-100E2, Nanjing ECO Medical Instrument Co, China). 21,22 It generated electromagnetic waves that agitate water molecules in the surrounding tissue, producing friction and heat, thus inducing cellular death by coagulative necrosis. A pre-set mode with output power of 55 to 80 W was used with duration of 5 to 15 minutes for each ablation.…”

“…A 20 cm thin microwave antenna (14.5 G) was then placed directly into the deepest part of the nodule, as shown in Figure 1. The antenna was attached to the microwave generator (ECO-100E2, Nanjing ECO Medical Instrument Co, China) 21,22. It generated electromagnetic waves that agitate water molecules in the surrounding tissue, producing friction and heat, thus inducing cellular death by coagulative necrosis.…”

Development of a novel MR‐conditional microwave needle for MR‐guided interventional microwave ablation at 1.5T

“…Recently, MR‐guided interventional microwave ablation (MWA) has been developed for the treatment of liver tumors 1–5 . MWA usually operates at 900–950 MHz or 2400–2450 MHz frequencies.…”

“…Recently, MR-guided interventional microwave ablation (MWA) has been developed for the treatment of liver tumors. [1][2][3][4][5] MWA usually operates at 900-950 MHz or 2400-2450 MHz frequencies. Although the lower frequency systems have longer wavelengths resulting in greater penetration, 6,7 the 2.45 GHz, an internationally Industrial Scientific Medical (ISM) frequency, is more widely used.…”

Artifact reduction of coaxial needles in magnetic resonance imaging-guided abdominal interventions at 1.5 T: a phantom study

“…Magnetic resonance imaging (MRI) demonstrates excellent characteristics for image guidance of interstitial interventional procedures, including the lack of ionizing radiation, high soft tissue contrast, and multiplanar needle guidance with simultaneous acquisition of axial, coronal, and sagittal image data sets in near real-time 1 – 8 . MRI-guided interventions are routinely performed in a broad range of organs, with a primary focus on body regions in which MRI is superior to computed tomography (CT) and ultrasound such as spine, prostate, and liver 1 , 9 – 13 . In particular, the combination of fast fluoroscopic T1-weighted gradient echo (GRE) sequences and hepatobiliary contrast agents has even enabled MRI-guided biopsy of small, CT-occult liver lesions with a diameter < 1 cm 14 .…”