Brandser E A, Riley M A, Berbaum K S, el-Khoury G Y, Bennett D L
Department of Radiology, University of Iowa College of Medicine, University of Iowa Hospitals and Clinics, Iowa City 52242, USA.
AJR Am J Roentgenol. 1996 Jul;167(1):121-6. doi: 10.2214/ajr.167.1.8659355.
The purpose of this blinded study was to test the value of primary and secondary signs, independent of each other, for diagnosis of a tear of the anterior cruciate ligament (ACL) by means of MR imaging.
MR images of the knee in 74 patients who had the status of the ACL confirmed arthroscopically were blindly reviewed for status of the ACL three times: with primary signs masked, with secondary signs masked, and with no signs masked. On the basis of the observed signs at each session, the status of the ACL was predicted and the confidence in that prediction was noted. The MR imaging predictions were compared with the arthroscopic findings. The results were analyzed with receiver operating characteristic curves and stepwise discriminant analysis.
We found no difference in diagnostic performance when only primary signs were used and when both primary and secondary signs were used. When using primary signs only, our observers performed significantly better than when using secondary signs alone. However, with secondary signs alone, our observers performed better than if left to chance for predicting ACL status. Of the secondary signs, our statistical analysis found bone contusion, anterior translation of the tibia, and an uncovered posterior horn of the lateral meniscus to be the most useful for diagnosis.
Secondary signs do have value for deciding ACL status independent of primary signs. However, our observers performed much better when using primary signs instead of secondary signs. In the clinical setting, secondary signs do not help significantly in the diagnosis of ACL tears by means of MR imaging.
本双盲研究旨在通过磁共振成像（MR成像）测试彼此独立的主要征象和次要征象对诊断前交叉韧带（ACL）撕裂的价值。
对74例经关节镜检查确诊ACL状况的患者的膝关节MR图像进行三次盲法评估，以确定ACL的状况：分别遮蔽主要征象、遮蔽次要征象以及不遮蔽任何征象。根据每次观察到的征象，预测ACL的状况并记录对该预测的信心程度。将MR成像的预测结果与关节镜检查结果进行比较。采用受试者工作特征曲线和逐步判别分析对结果进行分析。
我们发现仅使用主要征象时与同时使用主要征象和次要征象时的诊断性能没有差异。仅使用主要征象时，我们的观察者的表现明显优于仅使用次要征象时。然而，仅使用次要征象时，我们的观察者在预测ACL状况方面的表现也优于随机猜测。在次要征象中，我们的统计分析发现骨挫伤、胫骨前移和外侧半月板后角未覆盖是最有助于诊断的。
次要征象对于独立于主要征象来判定ACL状况确实具有价值。然而，我们的观察者使用主要征象时的表现比使用次要征象时要好得多。在临床环境中，次要征象对通过MR成像诊断ACL撕裂没有显著帮助。
