Zanetti M, Gerber C, Hodler J
Department of Radiology, Orthopedic University Clinic Balgrist, Switzerland.
Invest Radiol. 1998 Mar;33(3):163-70. doi: 10.1097/00004424-199803000-00006.
The purpose of this study was to establish a magnetic resonance (MR) imaging standard for quantification of the muscles of the rotator cuff.
Parasagittal T1-weighted turbo spin-echo images of the shoulder were obtained in 70 asymptomatic subjects (35 women, 35 men; age range: 21-70 years, mean: 45 years). Standardized cross-sectional areas (rotator cuff muscle areas divided by the area of the supraspinatus fossa) and standardized signal intensities (related to signal intensities of the teres major muscle) were measured and compared with 30 patients with different stages of rotator cuff tears and 10 patients with glenohumeral instability. In addition, a so-called tangent sign was evaluated with the hypothesis that a healthy supraspinatus muscle crosses a line (tangent) drawn through the superior borders of the scapular spine and the superior margin of the coracoid.
Cross-sectional areas of the muscles of the rotator cuff were variable in asymptomatic subjects. Cross-sectional areas (but not signal intensities) did discriminate patients with different stages of rotator cuff tears from asymptomatic subjects. The tangent sign was negative in all asymptomatic subjects but positive in four and nine of 10 patients with medium and large rotator cuff tears, respectively.
A method for quantification of the muscles of the rotator cuff using MR imaging is presented. Cross-sectional areas can be used for quantification of the muscles of the rotator cuff. The tangent sign is a useful MR sign for atrophy of the supraspinatus muscle.
本研究的目的是建立用于定量评估肩袖肌肉的磁共振（MR）成像标准。
对70名无症状受试者（35名女性，35名男性；年龄范围：21 - 70岁，平均45岁）进行肩部矢状旁位T1加权快速自旋回波成像。测量标准化横截面积（肩袖肌肉面积除以冈上肌窝面积）和标准化信号强度（与大圆肌信号强度相关），并与30例不同阶段肩袖撕裂患者及10例肩肱关节不稳患者进行比较。此外，评估一种所谓的切线征，其假设为健康的冈上肌穿过一条通过肩胛冈上缘和喙突上缘绘制的线（切线）。
无症状受试者的肩袖肌肉横截面积存在差异。横截面积（而非信号强度）能够区分不同阶段肩袖撕裂患者与无症状受试者。在所有无症状受试者中切线征为阴性，但在10例中、大型肩袖撕裂患者中分别有4例和9例为阳性。
提出了一种使用MR成像定量评估肩袖肌肉的方法。横截面积可用于肩袖肌肉的定量评估。切线征是评估冈上肌萎缩的有用MR征象。
