Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD..
Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD.
Curr Probl Diagn Radiol. 2021 Sep-Oct;50(5):629-636. doi: 10.1067/j.cpradiol.2020.06.007. Epub 2020 Jun 26.
The relationship of magnetic resonance imaging (MRI) measures of rotator cuff intramuscular fatty infiltration (FI) to shoulder range of motion (ROM) and strength are not well understood. Our purpose was to determine if supraspinatus quantitative Dixon fat fraction has superior correlation to shoulder ROM and strength as compared to semiquantitative Goutallier grade.
Thirty-seven study subjects received shoulder MRI; and measurement of ipsilateral shoulder forward flexion ROM, abduction ROM and abduction strength. Supraspinatus Dixon fat fraction was measured on 6-point Dixon MRI by 2 diagnostic radiology residents. Supraspinatus Goutallier grade was assessed on T1-weighted MRI by 2 musculoskeletal radiologists. Questionnaires recorded demographics. Based on characteristics, study subjects were divided into 3 groups: Group 1, neither shoulder pain nor full-thickness supraspinatus tendon (SST) tear (n = 17; mean age, 63.0 ± 10.1 years); Group 2, positive complaint of shoulder pain but without full-thickness SST tear (n = 7; mean age, 57.4 ± 9.9 years); Group 3, positive complaint of shoulder pain and full-thickness SST tear (n = 13; mean age, 63.6 ± 8.1 years). One-way analysis of variance compared groups. Spearman (rho) rank order correlation was performed to determine correlation of supraspinatus Dixon fat fraction, or Goutallier grade, with measures of ROM and strength for the study population. Reliability analyses were performed for Dixon fat fraction and Goutallier grade.
No significant differences were present among groups for age. Significant differences existed among groups for forward flexion ROM (P= 0.001), abduction ROM (P < 0.001), Dixon fat fraction (P = 0.004) and Goutallier grade (P = 0.012). Dixon fat fraction showed statistically significant inverse correlations with forward flexion ROM (rho = -0.47; P = 0.005), abduction ROM (rho = -0.35, P = 0.041), and abduction strength (rho = -0.42; P = 0.013). Goutallier grade demonstrated weak inverse correlation that lacked statistical significance (P > 0.05) for the same measures. Dixon fat fraction showed strong interobserver and intraobserver reliability with intraclass correlation coefficients of 0.956 and 0.999, respectively. Goutallier grade showed poor interobserver (kappa, 0.188) and moderate intraobserver (kappa, 0.608) reliability.
Supraspinatus Dixon fat fraction has superior correlation to shoulder ROM and strength relative to Goutallier grade on MRI.
磁共振成像（MRI）测量肩袖内肌脂肪浸润（FI）与肩活动范围（ROM）和力量的关系尚不清楚。我们的目的是确定与半定量 Goutallier 分级相比，肩胛下肌定量 Dixon 脂肪分数是否与肩 ROM 和力量具有更好的相关性。
37 名研究对象接受了肩部 MRI 检查；并测量了同侧肩部前屈 ROM、外展 ROM 和外展力量。两名诊断放射科医生通过 6 点 Dixon MRI 测量肩胛下肌 Dixon 脂肪分数。两名肌肉骨骼放射科医生通过 T1 加权 MRI 评估肩胛下肌 Goutallier 分级。问卷调查记录了人口统计学资料。根据特征，研究对象分为 3 组：第 1 组，肩部既无疼痛也无全层肩胛下肌腱（SST）撕裂（n=17；平均年龄 63.0±10.1 岁）；第 2 组，肩部有疼痛但无全层 SST 撕裂的阳性主诉（n=7；平均年龄 57.4±9.9 岁）；第 3 组，肩部有疼痛和全层 SST 撕裂的阳性主诉（n=13；平均年龄 63.6±8.1 岁）。采用单因素方差分析比较各组。Spearman（rho）秩相关用于确定肩胛下肌 Dixon 脂肪分数或 Goutallier 分级与研究人群的 ROM 和力量测量值的相关性。对 Dixon 脂肪分数和 Goutallier 分级进行可靠性分析。
各组间年龄无显著差异。组间前屈 ROM（P=0.001）、外展 ROM（P<0.001）、Dixon 脂肪分数（P=0.004）和 Goutallier 分级（P=0.012）存在显著差异。Dixon 脂肪分数与前屈 ROM（rho=-0.47；P=0.005）、外展 ROM（rho=-0.35，P=0.041）和外展力量（rho=-0.42；P=0.013）呈统计学显著负相关。Goutallier 分级与同一指标呈弱负相关，但无统计学意义（P>0.05）。Dixon 脂肪分数具有较强的观察者间和观察者内可靠性，组内相关系数分别为 0.956 和 0.999。Goutallier 分级的观察者间可靠性差（kappa 值为 0.188），观察者内可靠性中等（kappa 值为 0.608）。
与 MRI 上的 Goutallier 分级相比，肩胛下肌 Dixon 脂肪分数与肩 ROM 和力量的相关性更好。
