Department of Diagnostic Radiology, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
Department of Quantitative Sciences, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
Skeletal Radiol. 2020 Jul;49(7):1073-1080. doi: 10.1007/s00256-020-03385-0. Epub 2020 Jan 29.
To determine whether a 3D magnetic resonance imaging (MRI) sequence with postprocessing applied to simulate computed tomography (CT) ("pseudo-CT") images can be used instead of CT to measure acetabular version and alpha angles and to plan for surgery in patients with femoroacetabular impingement (FAI).
Four readers retrospectively measured acetabular version and alpha angles on MRI and CT images of 40 hips from 20 consecutive patients (9 female patients, 11 male patients; mean age, 26.0 ± 6.5 years) with FAI. 3D models created from MRI and CT images were assessed by 2 orthopedic surgeons to determine the need for femoroplasty and/or acetabuloplasty. Interchangeability of MRI with CT was tested by comparing agreement between 2 readers using CT (intramodality) with agreement between 1 reader using CT and 1 using MRI (intermodality).
Intramodality and intermodality agreement values were nearly identical for acetabular version and alpha angle measurements and for surgical planning. Increases in inter-reader disagreement for acetabular version angle, alpha angle, and surgical planning when MRI was substituted for CT were - 2.1% (95% confidence interval [CI], - 7.7 to + 3.5%; p = 0.459), - 0.6% (95% CI, - 8.6 to + 7.3%; p = 0.878), and 0% (95% CI, - 15.1 to + 15.1%; p = 1.0), respectively, when an agreement criterion ≤ 5° was used for angle measurements.
Pseudo-CT MRI was interchangeable with CT for measuring acetabular version and highly favorable for interchangeability for measuring alpha angle and for surgical planning, suggesting that MRI could replace CT in assessing patients with FAI.
确定应用于模拟计算机断层扫描（CT）（“伪 CT”）图像的三维磁共振成像（MRI）序列是否可用于替代 CT 来测量髋臼版本和 alpha 角，并为患有髋关节撞击症（FAI）的患者计划手术。
4 名读者回顾性地测量了 20 例连续患者（9 名女性，11 名男性；平均年龄 26.0±6.5 岁）的 40 个髋关节的 MRI 和 CT 图像上的髋臼版本和 alpha 角。通过 2 名矫形外科医生评估从 MRI 和 CT 图像创建的 3D 模型，以确定是否需要股骨成形术和/或髋臼成形术。通过比较使用 CT（内模态）的 2 名读者之间的一致性与使用 CT 和 MRI 的 1 名读者之间的一致性（外模态），测试 MRI 与 CT 的可互换性。
髋臼版本和 alpha 角测量值以及手术计划的内模态和外模态之间的一致性值几乎相同。当使用 MRI 代替 CT 时，髋臼版本角、alpha 角和手术计划的读者间差异增加分别为 -2.1%（95%置信区间 [CI]，-7.7 至 +3.5%；p=0.459）、-0.6%（95% CI，-8.6 至 +7.3%；p=0.878）和 0%（95% CI，-15.1 至 +15.1%；p=1.0），当用于角度测量的一致性标准≤5°时。
用于模拟 CT 的伪 CT MRI 与 CT 可互换，非常适合用于测量 alpha 角和手术计划的互换性，这表明 MRI 可以替代 CT 来评估患有 FAI 的患者。
