Department of Radiology, University Hospital and University of Zurich, Zurich, Switzerland; origin of work: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
J Magn Reson Imaging. 2019 Jan;49(1):109-117. doi: 10.1002/jmri.26223. Epub 2018 Oct 6.
Quantitative MRI allows assessment of shoulder rotator cuff (RC) muscles by Dixon MR sequences with calculation of fractional fat content (FF%) maps and diffusion tensor imaging (DTI) including tractography.
To compare FF% and DTI derived parameters among visually intact RC muscles, to compare 2D with 3D DTI measurements and to establish normative values.
Prospective.
Forty patients aged >18 years undergoing shoulder MR arthrography were included.
FIELD STRENGTH/SEQUENCE: MR arthrography of the shoulder including 3D multiecho Dixon and 3D echo-planar DTI sequences (15 gradient encoding directions, b-value 600 s/mm ) was performed at 3.0T.
Muscles affected by RC tears or fatty infiltration of Goutallier grade ≥1 were excluded. Two independent radiologists measured FF%, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) by region-of-interest (ROI) placements at the Y-position of the scapula and 3D tractography of each muscle with qualitative evaluation was performed.
Intraclass correlation coefficients (ICCs) and Cohen's kappa were used for interreader agreement and Pearson correlation coefficient to correlate quantitative measures with each other and age, independent-samples t-test, one-way analysis of variance (ANOVA), and Kruskal-Wallis test were performed to investigate differences between genders and muscles.
Qualitative and quantitative measurements showed moderate (κ = 0.41-0.56) to almost perfect (ICC = 0.75-0.99) agreement. There were weak but significant positive correlations of FF% with age (r = 0.273, P < 0.05) and FA-2D (r = 0.319-0.383, P < 0.05). Significant differences were found among RC muscles for ADC, radial diffusivity (RD), and tract homogeneity (all P < 0.05) but not between genders (all P ≥ 0.05). High correlations of 2D with 3D measurements for ADC (r = 0.639, P < 0.001) and FA (r = 0.628, P < 0.001) were seen.
Quantitative MRI with estimation of FF% and DTI parameters shows significant age-associated changes and differences among visually intact RC muscles. High reproducibility and correlations of 2D with 3D DTI measurements can be expected.
2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:109-117.
定量 MRI 通过 Dixon MR 序列评估肩袖（RC）肌肉，计算部分脂肪含量（FF%）图谱和扩散张量成像（DTI），包括轨迹图。
比较视觉上完整的 RC 肌肉之间的 FF%和 DTI 衍生参数，比较 2D 与 3D DTI 测量值并建立正常值。
前瞻性。
40 名年龄> 18 岁的接受肩部磁共振关节造影术的患者。
磁场强度/序列：在 3.0T 上进行包括 3D 多回波 Dixon 和 3D 回波平面 DTI 序列（15 个梯度编码方向，b 值为 600 s/mm ）的肩部磁共振关节造影术。
排除受 RC 撕裂或 Goutallier 分级≥1 的脂肪浸润影响的肌肉。两位独立的放射科医生通过在肩胛骨的 Y 位置进行 ROI 定位来测量 FF%、表观扩散系数（ADC）和各肌肉的分数各向异性（FA），并进行定性评估。
采用组内相关系数（ICC）和 Cohen's kappa 评估两位观察者之间的一致性，Pearson 相关系数评估定量测量值之间以及与年龄之间的相关性，采用独立样本 t 检验、单因素方差分析（ANOVA）和 Kruskal-Wallis 检验比较性别和肌肉之间的差异。
定性和定量测量值之间的一致性为中等（κ=0.41-0.56）到几乎完美（ICC=0.75-0.99）。FF%与年龄（r=0.273，P<0.05）和 FA-2D（r=0.319-0.383，P<0.05）呈弱但有统计学意义的正相关。RC 肌肉之间的 ADC、径向扩散系数（RD）和轨迹同质性（均 P<0.05）存在显著差异，但性别之间无差异（均 P≥0.05）。ADC（r=0.639，P<0.001）和 FA（r=0.628，P<0.001）的 2D 与 3D 测量值之间存在高度相关性。
通过估计 FF%和 DTI 参数的定量 MRI 显示出与年龄相关的显著变化和视觉上完整的 RC 肌肉之间的差异。可以预期 2D 与 3D DTI 测量值之间具有高度的可重复性和相关性。
2 技术功效：第 2 阶段 J. Magn. Reson. Imaging 2019;49:109-117.
