Swami Vimarsha Gopal, Cheng-Baron June, Hui Catherine, Thompson Richard B, Jaremko Jacob Lester
Department of Radiology and Diagnostic Imaging, University of Alberta, 2A2.41 WC Mackenzie Health Sciences Centre, 8440-112 Street, Edmonton, AB, T6G 2B7, Canada,
Knee Surg Sports Traumatol Arthrosc. 2015 Apr;23(4):1206-14. doi: 10.1007/s00167-014-2948-y. Epub 2014 Mar 21.
Anatomic placement of anterior cruciate ligament (ACL) grafts at arthroscopic reconstruction can be challenging. Localising ACL attachments on magnetic resonance imaging (MRI) sequences pre-operatively could aid with planning for anatomic graft placement. Though ACL attachments can be identified on two-dimensional (2D) MRI, slice thickness theoretically limits out-of-plane accuracy and a 3D MRI base sequence with smaller isotropic voxels may improve observer reliability in localising ACL attachment locations. The purpose of this study was to test whether a high-resolution 3D sequence improved inter- and intra-observer reliability of ACL attachment localisation compared with conventional 2D MRI for this application.
Twenty paediatric knees were retrospectively scanned at 1.5 Tesla with multi-planar 2D proton density (slice thickness 3-4 mm) and T2-weighted 3D multiple-echo data image combination gradient echo (isotropic 0.8 mm voxels) sequences. Two observers blinded to each others' findings identified ACL attachments on MRI slices, and 3D reconstructions showing ACL attachments were produced. ACL attachment centre locations and areas were calculated, and reliability assessed.
Inter-observer variation of centre locations of ACL attachments identified on 3D versus 2D sequences was not significantly different (mean ± SD): 1.8 ± 0.6 versus 1.5 ± 0.7 mm at femoral attachments, 1.7 ± 0.7 versus 1.5 ± 0.8 mm at tibial attachments (p > 0.05). The 95 % confidence interval for centre locations was <4.0 mm in all cases. Inter-observer reliability of attachment areas was not higher for 3D sequences.
ACL attachment centres were localised with high and similar inter- and intra-observer reliability on a high-resolution 3D and multi-planar conventional 2D sequences. Using this technique, MRI could potentially be used for planning and intra-operative guidance of anatomic ACL reconstruction, whether from 2D or 3D base sequences. Surgeons in clinical practice need not order a lengthy dedicated 3D MRI to localise ligament attachments, but can confidently use a standard 2D MRI for this application.
III.
在关节镜重建术中，前交叉韧带（ACL）移植物的解剖学放置具有挑战性。术前在磁共振成像（MRI）序列上定位ACL附着点有助于规划解剖学移植物的放置。虽然可以在二维（2D）MRI上识别ACL附着点，但切片厚度理论上限制了平面外的准确性，具有较小各向同性体素的三维（3D）MRI基础序列可能会提高观察者在定位ACL附着位置时的可靠性。本研究的目的是测试与传统2D MRI相比，高分辨率3D序列是否能提高观察者间和观察者内对ACL附着定位的可靠性。
对20个儿童膝关节进行回顾性扫描，使用多平面2D质子密度（切片厚度3 - 4毫米）和T2加权3D多回波数据图像组合梯度回波（各向同性体素0.8毫米）序列，在1.5特斯拉磁场下进行扫描。两名对彼此结果不知情的观察者在MRI切片上识别ACL附着点，并生成显示ACL附着点的3D重建图像。计算ACL附着中心位置和面积，并评估可靠性。
在3D序列和2D序列上识别的ACL附着中心位置的观察者间差异无显著统计学意义（平均值±标准差）：股骨附着点处分别为1.8±0.6毫米和1.5±0.7毫米，胫骨附着点处分别为1.7±0.7毫米和1.5±0.8毫米（p>0.05）。所有情况下，中心位置的95%置信区间均<4.0毫米。3D序列的附着面积观察者间可靠性并不更高。
在高分辨率3D序列和多平面传统2D序列上，ACL附着中心的定位在观察者间和观察者内具有较高且相似的可靠性。使用该技术，MRI可能可用于解剖学ACL重建的规划和术中指导，无论是基于2D还是3D基础序列。临床实践中的外科医生无需订购冗长的专用3D MRI来定位韧带附着点，而是可以放心地使用标准2D MRI进行此应用。
III级。
