Department for Orthopedics and Trauma Surgery, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany.
MVZ Radiology Network NRW, Düsseldorf, Germany.
J Orthop Surg Res. 2022 Jul 30;17(1):370. doi: 10.1186/s13018-022-03256-5.
Femoroacetabular impingement (FAI) syndrome is an established pre-osteoarthritic condition. Diagnosis is based on both clinical and radiographic parameters. An abnormal manually calculated alpha angle in magnetic resonance imaging (MRI) is traditionally utilized to diagnose abnormal femoral head-neck offset. This pilot study aimed to assess the feasibility of automated alpha angle measurements in patients with FAI syndrome, and to compare automated with manual measurements data with regard to the time and effort needed in each method.
Alpha angles were measured with manual and automated techniques, using postprocessing software in nineteen hip MRIs of FAI syndrome patients. Two observers conducted manual measurements. Intra- and inter-observer reproducibility and correlation of manual and automated alpha angle measurements were calculated using intra-class correlation (ICC) analysis. Both techniques were compared regarding the time taken (in minutes) and effort required, measured as the amount of mouse button presses performed.
The first observer's intra-observer reproducibility was good (ICC 0.77; p < 0.001) while the second observer's was good-to-excellent (ICC 0.93; p < 0.001). Inter-observer reproducibility between both observers in the first (ICC 0.45; p < 0.001) and second (ICC 0.56; p < 0.001) manual alpha angle assessment was moderate. The intra-class correlation coefficients between manual and automated alpha angle measurements were ICC = 0.24 (p = 0.052; observer 1, 1st measurement), ICC = 0.32 (p = 0.015; observer 1, 2nd measurement), ICC = 0.50 (p < 0.001; observer 2, 1st measurement), and ICC = 0.45 (p < 0.001; observer 2, 2nd measurement). Average runtime for automatic processing of the image data for the automated assessment was 16.6 ± 1.9 min. Automatic alpha angle measurements took longer (time difference: 14.6 ± 3.9 min; p < 0.001) but required less effort (difference in button presses: 231 ± 23; p < 0.001). While the automatic processing is running, the user can perform other tasks.
This pilot study demonstrates that objective and reliable automated alpha angle measurement of MRIs in FAI syndrome hips is feasible. Trial registration The Ethics Committee of the University of Düsseldorf approved our study (Registry-ID: 2017084398).
股骨髋臼撞击综合征（FAI）是一种公认的前骨关节炎病症。其诊断基于临床和影像学参数。磁共振成像（MRI）中手动计算的异常α角传统上用于诊断异常股骨头颈偏移。本初步研究旨在评估在 FAI 综合征患者中自动测量α角的可行性，并比较自动与手动测量数据在每种方法中所需的时间和精力。
使用后处理软件在 19 例 FAI 综合征患者的髋关节 MRI 中进行手动和自动测量。两位观察者进行手动测量。使用组内相关系数（ICC）分析计算手动和自动α角测量的内部和观察者间可重复性以及相关性。通过测量执行的鼠标按钮点击次数来比较两种技术所需的时间（以分钟计）和精力。
第一观察者的内部观察者可重复性良好（ICC 0.77；p<0.001），而第二观察者的可重复性为良好至优秀（ICC 0.93；p<0.001）。两位观察者在第一次（ICC 0.45；p<0.001）和第二次（ICC 0.56；p<0.001）手动α角评估中的观察者间可重复性为中度。手动和自动α角测量之间的组内相关系数为 ICC=0.24（p=0.052；观察者 1，第一次测量）、ICC=0.32（p=0.015；观察者 1，第二次测量）、ICC=0.50（p<0.001；观察者 2，第一次测量）和 ICC=0.45（p<0.001；观察者 2，第二次测量）。自动处理图像数据进行自动评估的平均运行时间为 16.6±1.9 分钟。自动α角测量所需时间更长（时间差异：14.6±3.9 分钟；p<0.001），但所需精力更少（按钮点击差异：231±23；p<0.001）。在自动处理运行时，用户可以执行其他任务。
本初步研究表明，FAI 综合征髋关节 MRI 的客观可靠的自动α角测量是可行的。
杜塞尔多夫大学伦理委员会批准了我们的研究（注册号：2017084398）。
