Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany.
J Vasc Interv Radiol. 2010 Mar;21(3):375-80. doi: 10.1016/j.jvir.2009.11.012.
To perform in vitro assessment of needle artifacts with an interactive three-dimensional (3D) near-real-time magnetic resonance (MR) fluoroscopy system for musculoskeletal interventions in a 1.5-T open-bore magnet.
One MR-compatible titanium needle, one MR-compatible Inconel (nickel-chromium superalloy) needle, and one MR-compatible carbon fiber needle were imaged with an interactive 3D MR sequence. Slice orientations, measurement parameters (fast low-angle shot, repetition time/echo time of 1,358/5 msec, flip angle of 15 degrees , bandwidth of 250 Hz/pixel; and true fast imaging with steady-state precession, repetition time/echo time of 770/2.2 msec, flip angle of 50 degrees , bandwidth of 558 Hz/pixel), phase encoding directions, and orientations to the main magnetic field (B(0)) were systematically varied. Artifact sizes, normalized artifact contrasts, and tip location errors were assessed for all variations of acquisition parameters and needles and compared with t tests.
Mean artifact sizes, normalized artifact contrast, and tip location errors were 22.9 mm, 96%, and 5.4 mm, respectively, for the Inconel needle; 6.1 mm, 70%, and 0.3 mm, respectively, for the titanium needle; and 2.8 mm, 38%, and -1.9 mm, respectively, for the carbon fiber needle. Artifact widths depended on needle materials and needle orientation to B(0), with significant differences on ttests. Artifact contrast did not depend on measurement parameters. No significant influence on artifact character was found for changes in phase encoding direction and slice orientation.
Because of its robustness in depicting needle artifacts, the interactive 3D MR fluoroscopy system appears to be suitable for MR-guided interventions. The titanium needle showed optimal artifacts with all combinations of measurement parameters. Artifacts with the other needles were too large (Inconel) or too small (carbon fiber).
在 1.5T 开放式磁体中使用交互式三维（3D）近实时磁共振（MR）透视系统对肌肉骨骼介入进行体外评估。
使用交互式 3D MR 序列对 1 根兼容 MR 的钛针、1 根兼容 MR 的因科镍合金（镍铬超合金）针和 1 根兼容 MR 的碳纤维针进行成像。系统地改变了切片取向、测量参数（快速小角度激发，重复时间/回波时间为 1358/5msec，翻转角为 15 度，带宽为 250Hz/像素；真正的快速稳态进动成像，重复时间/回波时间为 770/2.2msec，翻转角为 50 度，带宽为 558Hz/像素）、相位编码方向和相对于主磁场（B(0)）的方向。评估了所有采集参数和针的变化的伪影大小、归一化伪影对比度和尖端位置误差，并与 t 检验进行了比较。
因科镍合金针的平均伪影大小、归一化伪影对比度和尖端位置误差分别为 22.9mm、96%和 5.4mm；钛针分别为 6.1mm、70%和 0.3mm；碳纤维针分别为 2.8mm、38%和-1.9mm。伪影宽度取决于针的材料和针相对于 B(0)的方向，t 检验显示有显著差异。伪影对比不依赖于测量参数。相位编码方向和切片方向的变化对伪影特征没有显著影响。
由于交互式 3D MR 透视系统在描绘针伪影方面的稳健性，因此它似乎适合于 MR 引导的介入治疗。钛针在所有测量参数组合下均显示出最佳的伪影。其他针的伪影太大（因科镍合金）或太小（碳纤维）。
