Roychowdhury S, Fitzgerald S W, Sonin A H, Peduto A J, Miller F H, Hoff F L
Department of Radiology, Northwestern University Medical School, Chicago, IL 60611, USA.
AJR Am J Roentgenol. 1997 Jun;168(6):1487-91. doi: 10.2214/ajr.168.6.9168712.
The purpose of this study was to determine the usefulness of axial MR imaging for diagnosing partial anterior cruciate ligament (ACL) tears and to determine if patients could be categorized as having stable or unstable partial ACL tears on the basis of criteria of axial MR imaging.
We reviewed 238 patients who, over a 2-year period, underwent both MR imaging of the knee and arthroscopic evaluation of the ACL. According to arthroscopic examination, these patients had 143 normal ACLs, 67 complete ACL tears, and 28 partial tears. The 28 partial tears included 20 stable tears (no ACL deficiency) and eight unstable partial tears having ACL deficiency or requiring ACL reconstructive surgery. The axial MR images were retrospectively reviewed by two interpreters who were unaware of the arthroscopic findings, and decisions were reached by consensus. The ACL was classified according to its axial configuration and continuity.
By axial MR imaging criteria, we found 109 elliptical ACLs, 45 attenuated ACLs, three ACLs with increased intrasubstance signal intensity, six isolated ACL bundle signs, 19 ACLs that could not be visualized, and 56 cloudlike mass signs. Arthroscopically normal ACLs and stable partial tears were difficult to distinguish reliably on axial MR images. Unstable partial ACL tears could not be distinguished from complete ACL tears. However, using axial MR imaging, our observers were able to segregate stable ACLs (normal ligaments and stable partial tears) from unstable ACLs (unstable partial tears and complete tears) with 100% sensitivity and 96% specificity.
Axial MR imaging of the ACL may provide important diagnostic information for patients who have ACL injury. On axial MR images, stable ACLs were elliptical, attenuated, or showed as areas of increased intrasubstance signal intensity. At arthroscopy, attenuated ACLs represented normal ACLs (76%) and stable partial tears (24%). On axial MR images, the configurations that indicated unstable ligaments were isolated ACL bundle, nonvisualized ACL, and cloudlike mass.
本研究的目的是确定轴向磁共振成像（MR成像）对诊断部分前交叉韧带（ACL）撕裂的有用性，并根据轴向MR成像标准确定患者是否可被归类为具有稳定或不稳定的部分ACL撕裂。
我们回顾了238例在2年期间接受了膝关节MR成像和ACL关节镜评估的患者。根据关节镜检查，这些患者中有143例ACL正常，67例ACL完全撕裂，28例部分撕裂。28例部分撕裂包括20例稳定撕裂（无ACL缺损）和8例不稳定部分撕裂，后者存在ACL缺损或需要进行ACL重建手术。两名不知道关节镜检查结果的解读人员对轴向MR图像进行了回顾性分析，并通过达成共识做出判断。根据ACL的轴向形态和连续性对其进行分类。
根据轴向MR成像标准，我们发现109例椭圆形ACL、45例ACL变细、3例ACL内信号强度增加、6例孤立的ACL束征、19例无法显示的ACL以及56例云状肿块征。在轴向MR图像上，关节镜检查正常的ACL和稳定的部分撕裂很难可靠地区分。不稳定的部分ACL撕裂与完全ACL撕裂无法区分。然而，使用轴向MR成像，我们的观察者能够以100%的敏感性和96%的特异性将稳定的ACL（正常韧带和稳定的部分撕裂）与不稳定的ACL（不稳定的部分撕裂和完全撕裂）区分开来。
ACL的轴向MR成像可能为患有ACL损伤的患者提供重要的诊断信息。在轴向MR图像上，稳定的ACL呈椭圆形、变细或表现为韧带内信号强度增加的区域。在关节镜检查中，变细的ACL代表正常ACL（76%）和稳定的部分撕裂（24%）。在轴向MR图像上，提示韧带不稳定的形态为孤立的ACL束、无法显示的ACL和云状肿块。
