Eastlack Jason, Tenorio Lulu, Wadhwa Vibhor, Scott Kelly, Starr Adam, Chhabra Avneesh
1 Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
2 Department of Radiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Br J Radiol. 2017 Nov;90(1079):20170116. doi: 10.1259/bjr.20170116. Epub 2017 Aug 22.
To evaluate the frequency of sciatic neuromuscular variants on MR neurography and determine the interobserver variability.
A retrospective evaluation of 137 consecutive lumbosacral plexus magnetic resonance neurography examinations was performed. All examinations were performed using nerve selective 3D imaging and independently reviewed by two readers for the presence of sciatic neuromuscular variants and piriformis muscle asymmetry. Inter- and intraobserver performance were evaluated.
There were a total of 44/268 (16.4%) extremities with sciatic neuromuscular variants. The interobserver performance in the identification of sciatic nerve variants was excellent (kappa values from 0.8-0.9). There was a total of 45/134 (33.6%) patients with piriformis muscle asymmetry. Of these, 7/134 (5.2%) had piriformis muscle atrophy and 38/134 (28.4%) had piriformis muscle hypertrophy. The interobserver performance in the identification of piriformis muscle atrophy and hypertrophy was moderate to good (kappa values from 0.39-0.61). The intraobserver performance revealed kappa values of 0.735 and 0.821 on right and left, respectively.
Sciatic neuromuscular variants and piriformis muscle asymmetry are frequent on lumbosacral plexus MRN with moderate to excellent interobserver performance. Advances in knowledge: Sciatic neuromuscular variants and piriformis asymmetry on MR neurography are frequent and the prevalence is similar to cumulative prevalence from available scientific series. Interobserver performance for identification of sciatic neuromuscular variants is excellent, and moderate-good for piriformis muscle asymmetry.
评估坐骨神经肌肉变异在磁共振神经成像上的发生率，并确定观察者间的变异性。
对137例连续的腰骶丛磁共振神经成像检查进行回顾性评估。所有检查均采用神经选择性三维成像，并由两位阅片者独立评估是否存在坐骨神经肌肉变异及梨状肌不对称。评估观察者间及观察者内的表现。
共有44/268（16.4%）个肢体存在坐骨神经肌肉变异。观察者间在识别坐骨神经变异方面的表现极佳（kappa值为0.8 - 0.9）。共有45/134（33.6%）例患者存在梨状肌不对称。其中，7/134（5.2%）有梨状肌萎缩，38/134（28.4%）有梨状肌肥大。观察者间在识别梨状肌萎缩和肥大方面的表现为中等至良好（kappa值为0.39 - 0.61）。观察者内表现显示，右侧和左侧的kappa值分别为0.735和0.821。
腰骶丛磁共振神经成像上坐骨神经肌肉变异和梨状肌不对称较为常见，观察者间表现为中等至极佳。知识进展：磁共振神经成像上坐骨神经肌肉变异和梨状肌不对称较为常见，其患病率与现有科学系列的累积患病率相似。观察者间识别坐骨神经肌肉变异的表现极佳，而识别梨状肌不对称的表现为中等至良好。
