In vitro artefact assessment of a new MR-compatible microwave antenna and a standard MR-compatible radiofrequency ablation electrode for tumour ablation

Abstract

MW applicator's artefact appearance is independent of angulation to main magnetic field. MW applicator's prominent distal artefact may increase visibility under MR-guidance. RF and MW applicator's artefacts are precise concerning tip depiction. Largest artefact diameters are measured with T1-weighted fast low angle shot sequence.

Preclinical evaluation of an MR-compatible microwave ablation system and comparison with a standard microwave ablation system in an ex vivo bovine liver model

“…Most common guidance modalities for thermo-applicator placement are computed tomography (CT) and ultrasound; however, magnetic resonance imaging (MRI) offers several advantages such as near real-time fluoroscopic sequences [11], free selection of imaging planes [12], higher sensitivity in depicting small parenchymal lesions [13], assessment of the ablation zone without application of contrast agent and absence of ionising radiation [14]. A recent pre-clinical study has addressed the MR artefact configuration of a MRcompatible prototype microwave applicator [15]. The authors stated that the microwave applicator's artefacts are precise regarding the tip depiction and that the artefact appearance is independent from the angulation to the main magnetic field.…”

Experimental assessment of microwave ablation computational modeling with MR thermometry

“…magnitude) images acquired by FLASH sequence. 42 This may decrease the accuracy of locating the MWA applicator tip, which was used as a reference for temperature comparison between experimental and simulated temperatures. This may also be a source of discrepancy between MR-measured and simulated temperatures at different ROIs or radially measured temperatures especially in the proximity of the applicator (Figs.…”

“…We note that the presence of the MWA applicator may cause an artifact in the anatomical (i.e. magnitude) images acquired by FLASH sequence 42 . This may decrease the accuracy of locating the MWA applicator tip, which was used as a reference for temperature comparison between experimental and simulated temperatures.…”

Real-time qualitative MR monitoring of microwave ablation in ex vivo livers

“…Because of the better soft tissue resolution and lack of radiation exposure, MR guidance might be able to overcome the disadvantages of the other techniques. While MRI has been proven to provide effective guidance for diagnostic interventions [20,21] and thermal ablations [22], its use in association with MWA and RFA was, until recently, restricted by the lack of MR-compatible systems [16,23].…”

“…Nevertheless, the challenge of MR-guided MW ablations relies on using fast sequences that are able to depict heatingrelated changes that can accurately predict tissue necrosis without being affected by major electric field-induced interference artefacts. Recently, a new MR-compatible MWA system combining the advantages of both techniques became commercially available [16].…”