磁共振成像在盘状半月板中的应用价值

The application value of magnetic resonance imaging in discoid meniscus

目的探讨膝关节盘状半月板磁共振成像(MRI)影像学表现及与损伤程度和分型的关系,分析MRI应用价值。方法四川省骨科医院接受膝关节关节镜检查及MRI检查的136例(147膝)盘状半月板患者,对其临床资料和MRI图像进行回顾性分析,观察关节镜下及MRI图像表现,评估并比较半月板损伤程度和分型,对照关节镜下表现(金标准),对MRI诊断撕裂的效能进行评价。结果136例147膝盘状半月板经关节镜、MRI检查一致证实外侧盘状半月板145膝,内侧盘状半月板2膝;关节镜证实盘状半月板伴半月板损伤131膝,其中退变42膝、撕裂89膝;盘状半月板MRI表现为半月板增大、增宽、增厚,矢状位均可见≥3层“领结样”改变;147膝盘状半月板经MRI评估损伤130膝,包括Ⅰ级13膝、Ⅱ级29膝、Ⅲ级88膝;对照关节镜检查结果,MRI对盘状半月板撕裂的诊断敏感度97.75%、特异度98.26%,准确率97.96%;147膝MRI分型占比为板型65.31%、楔型23.81%、肥角型10.88%,以板型居多,对应三型半月板撕裂率分为别61.46%、42.86%、93.75%,以肥角型撕裂率最高。MRI相对形态学参数外侧半月板宽度/股骨外侧髁宽度(WDLM/WLFC)、游离缘高度/体部高度(HF/HM)、外侧半月板宽度/胫骨平台宽度(板面比)由大到小依次为撕裂、退变、正常膝,关节囊缘高度体部高度/(HP/HM)由大到小依次为正常、退变、撕裂膝(P<0.05);WDLM/WLFC、HF/HM、HP/HM、板面比诊断盘状半月板损伤的曲线下面积分别为0.806、0.833、0.764、0.901,其中板面比诊断效能最高(P<0.05)。结论MRI可清晰显示盘状半月板的形态、信号变化情况,准确判断损伤程度及分型。

Objective To explore the manifestations of magnetic resonance imaging(MRI)of discoid meniscus of knee joint and the relationship between the MRI manifestation and the injury degree and classification in order to analyze the application value of MRI.Methods One hundred and thirty-six patients with discoid meniscus injury(147 knees)who underwent knee arthroscopy and MRI examination in our hospital were selected.Their clinical data and MRI images were retrospectively analyzed.The image manifestations of arthroscopy and MRI were observed.The degree and classification of meniscus injury were evaluated and compared.The performance of MRI in the diagnosis of tear injury was evaluated by comparing the arthroscopy findings(the gold standard).Results Among the 147 knees of the 136 patients with discoid meniscus injury,lateral discoid meniscus injury in 145 knees and medial discoid meniscus injury in 2 knees were confirmed by both arthroscopy and MRI.Arthroscopy confirmed discoid meniscus with meniscal injury in 131 knees,including degeneration in 42 knees and tear in 89 knees.MRI findings of discoid meniscus injury showed meniscus enlargement,widening and thickening,and≥3 layers of"tie-like"changes in sagittal position,Injury was evaluated by MRI in 130 knees among the 147 knees of discoid meniscus,including 13 knees of grade Ⅰ,29 knees of grade Ⅱ and 88 knees of grade Ⅲ.Compare with the results of arthroscopy,the sensitivity of MRI was 97.75%,the specificity was 98.26%and the accuracy rate was 97.96%in the diagnosis of discoid meniscus tear.The MRI classification of 147 knees accounted for 65.31%of the slab type,23.81%of the wedge type,and 10.88%of the hypertrophied-horn type,with the majority of the slab type.The meniscus tear rates of the corresponding three types were 61.46%,42.86%,and 93.75%,respectively,with the highest hypertrophied-horn tear rate.The MRI relative morphological parameters included lateral discoid meniscus body width/lateral femoral condyle width(WDLM/WLFC),free border height/body height(HF/HM)and lateral meniscus width/tibial plateau width(plate-to-surface ratio).The order of these parameters from high to low was revealed tear,degeneration and normal knee,and the order of joint capsule edge height/body height(HP/HM)from large to small was normal knee,degeneration and tear knee(P<0.05).The areas under the ROC curves of WDLM/WLFC,HF/HM,HP/HM,and plate-to-surface ratio in the diagnosis of discoid meniscus injury were 0.806,0.833,0.764,and 0.901,respectively.Among those,the plate-to-surface ratio had the highest diagnostic efficiency(P<0.05).Conclusions MRI can clearly show the morphological and signal changes of discoid meniscus.It can also accurately judge the injury degree and classification.