Aubé Christophe, Schmidt Diethard, Brieger Jens, Schenk Martin, Helmberger Thomas, Koenig Claudius W, Schick Fritz, Claussen Claus D, Pereira Philippe L
Department of Radiology, University Hospital of Angers, Angers, France.
J Vasc Interv Radiol. 2004 Apr;15(4):385-92. doi: 10.1097/01.rvi.0000121408.46920.f1.
To evaluate and compare visibility and artifacts in magnetic resonance (MR) compatible radiofrequency (RF) electrodes for MR-guided RF ablation.
Six different MR compatible electrodes for RF ablation including two internally cooled single needles, one internally cooled cluster needle, two expandable needles and one perfused needle were tested in a phantom study at 0.2 Tesla and at 1.5 Tesla field strength. Fluoroscopic, T1- and T2-weighted fast spin echo (FSE) and gradient echo (GE) sequences, which are usually used for MR-guided interventions, were evaluated. Qualitative and quantitative evaluations were performed. Length, width, noise, tip artifacts, global artifacts and global visualization of the RF electrodes that showed all sequences at different angles.
Qualitative analysis showed that electrodes were well visualized at all angles and sequences and on both MR imagers. Quantitative analysis showed that artifact-induced widening of the shaft was increased in all electrodes by: a). use of fluoroscopic sequences, GE sequences, and fat saturation, b). increasing the angle between the needle and main magnetic field, and c). high field strength (1.5 T). Expandable needles produced fewer tip artifacts but broader signal voids along the shaft compared to nonexpandable needles. Cluster electrodes produced less widening than the other electrodes.
Visibility and artifacts in all six MR compatible RF electrodes are satisfactory and these electrodes could be used for MR-guided radiofrequency ablation procedures.
评估和比较用于磁共振（MR）引导下射频消融的MR兼容射频（RF）电极的可视性和伪影。
在体模研究中，于0.2特斯拉和1.5特斯拉场强下，对六种不同的用于射频消融的MR兼容电极进行测试，包括两根内部冷却的单针、一根内部冷却的集束针、两根可扩张针和一根灌注针。对通常用于MR引导介入的荧光透视、T1加权和T2加权快速自旋回波（FSE）以及梯度回波（GE）序列进行评估。进行了定性和定量评估。测量了在不同角度下显示所有序列的RF电极的长度、宽度、噪声、尖端伪影、整体伪影和整体可视性。
定性分析表明，在所有角度、序列以及两台MR成像仪上，电极均能清晰显示。定量分析表明，所有电极的伪影导致的针杆增宽因以下因素而增加：a）使用荧光透视序列、GE序列和脂肪饱和；b）增大针与主磁场之间的夹角；c）高场强（1.5 T）。与不可扩张针相比，可扩张针产生的尖端伪影较少，但针杆沿线的信号空洞更宽。集束电极产生的增宽比其他电极少。
所有六种MR兼容RF电极的可视性和伪影均令人满意，这些电极可用于MR引导下的射频消融手术。
