From the *Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich; †Department of Radiology, University of Basel, Basel; and ‡Siemens Healthcare AG, Zurich, Switzerland.
Invest Radiol. 2017 Aug;52(8):482-487. doi: 10.1097/RLI.0000000000000363.
The aim of this study was to evaluate the reproducibility of 3 T magnetic resonance imaging diffusion tensor imaging (DTI) of the brachial plexus in healthy subjects.
Ten healthy volunteers were included, and morphological and DTI sequences of the nerve roots of the brachial plexus from C5 to T1 of both sides were repeatedly acquired on a 3 T magnetic resonance system (MAGNETOM Skyra; Siemens Healthcare, Erlangen, Germany). A prototype diffusion-weighted single-shot echo-planar imaging sequence-enabling slice-specific shim adjustments was performed with b-values of 0 and 800 s/mm in 30 gradient directions, resulting in an acquisition time of about 6 minutes each in axial orientation. Between scans, subjects were moved and repositioned in the scanner, coils were reinserted, and new localizers were acquired. Image analysis was performed using MITK Diffusion software toolkit. Two independent readers performed diffusion data postprocessing, and regions of interest (ROIs) were set on the proximal postganglionic trunk at each spinal level, bilaterally to obtain values for fractional anisotropy (FA) and mean diffusivity (MD). Interreader and intrareader agreement as well as test-retest reproducibility of DTI metrics were assessed.
Intraclass correlation coefficients (ICCs) for interreader and intrareader agreement did not differ significantly between measurements for FA and MD. In particular, ICCs for interreader agreement of FA ranged from 0.741 to 0.961 and that of MD ranged from 0.802 to 0.998, and ICCs for intrareader agreement of FA ranged from 0.759 to 0.949 and that of MD ranged from 0.796 to 0.998. The test-retest reproducibility of DTI metrics showed an overall moderate to strong correlation (r > 0.707), with few minor exceptions, for both FA and MD values.
Diffusion tensor imaging metrics in the brachial plexus are reproducible. Future applications of DTI for a possible clinical use should be further investigated.
本研究旨在评估健康受试者 3T 磁共振成像弥散张量成像（DTI）对臂丛的可重复性。
纳入 10 名健康志愿者，在 3T 磁共振系统（MAGNETOM Skyra；西门子医疗，德国埃尔兰根）上对双侧 C5 至 T1 的神经根进行形态学和 DTI 序列重复采集。采用原型弥散加权单次激发回波平面成像序列，在 30 个梯度方向上施加 b 值为 0 和 800 s/mm，在轴位方向上采集时间约为 6 分钟。扫描之间，受试者在扫描仪中移动和重新定位，重新插入线圈，并采集新的定位器。使用 MITK Diffusion 软件工具包进行图像分析。两位独立的读者进行弥散数据后处理，并在每个脊柱水平的近端节后干双侧设置感兴趣区（ROI），以获得各向异性分数（FA）和平均弥散度（MD）的值。评估 DTI 指标的读者间和读者内一致性以及测试-重测可重复性。
FA 和 MD 的测量值的读者间和读者内一致性的组内相关系数（ICC）无显著差异。特别是 FA 的读者间一致性 ICC 范围为 0.741 至 0.961，MD 的 ICC 范围为 0.802 至 0.998，FA 的读者内一致性 ICC 范围为 0.759 至 0.949，MD 的 ICC 范围为 0.796 至 0.998。FA 和 MD 值的测试-重测可重复性总体上呈中度至高度相关（r＞0.707），只有少数例外。
臂丛的弥散张量成像指标具有可重复性。未来对 DTI 进行可能的临床应用的研究应进一步开展。
