膝关节盘状半月板MRI表现

MRI manifestation of discoid meniscus of knee joint

目的探讨膝关节盘状半月板的MRI表现、分型特点及诊断标准，以提高对盘状半月板的认识及对损伤的正确诊断率。方法膝关节盘状半月板患者111例（117个膝关节），均行MRI检查，测量盘状半月板宽度及胫骨平台宽度，记录“领结样”改变层数，计算盘状半月板宽度与胫骨平台宽度比值（板面比）；记录盘状半月板分型及损伤分级，计算盘状半月板损伤率，并比较不同年龄、分型患者盘状半月板损伤率。结果111例（117个膝关节）盘状半月板宽度14．6-29．4（21．60±3．42）mm，胫骨平台宽度56．9-83．3（70．36±5．70）mm，板面比为0．218-0．492（0.308±0．050），矢状位“领结样”改变均≥3层；板型25个，楔型79个，肥角型13个；正常半月板26个，Ⅰ级损伤10个，Ⅱ级损伤67个，Ⅲ级损伤14个，损伤率为69．23％；〉50岁组盘状半月板损伤率（87．30％）高于≤50岁组（48．15％）（P〈0.05）；板型、楔形盘状半月板损伤率（76．00％、75．95％）均高于肥角型（15．38％）（P〈0.05）。结论MRI检查可较好显示盘状半月板，准确对盘状半月板进行分型以及变性（损伤）分级，盘状半月板损伤率与年龄、盘状半月板类型有关。

Objective To investigate the MRI performance, classification features and diagnostic criteria of the discoid meniscus of knee joint to improve the understanding of the discoid meniscus and the correct diagnosis rate of injury. Methods A total of 111 patients （117 knees） of the knee meniscus were examined by MRI to measure the width of discoid meniscus and tibial plateau width. The layer numbers of bowtie change were recorded. The ratio of discoid meniscus width to tibial plateau width was calculated. The discoid meniscus injury type and classification were recorded, and discoid meniscus injury rate was calculated. The injury rates were compared among different ages and classifications of discoid meniscus. Results The width of discoid meniscus of 117 knee joints from 111 patients was from 14. 6 to 29.4 （21.60±3.42） mm, and the width of tibial plateau was from 56.9 to 83.3 （70.36±5.70） ram. The ratio of discoid meniscus width to tibial plateau width was from 0. 218 to 0. 492 （0. 308±0. 050）. The layers number of sagittal Bowtie change was more than 3 layers. There were 25 knee joints of slab types, 79 wedge types and 13 hypertrophied horn types, grade I injury in 10 joint knees, grade Ⅱ injury in 67 and grade Ⅲ injury in 14, with the injury rate of 69. 230/00. The injury rate of 〉50-year-old patients （87. 30%） was significantly higher than that of ≤ 50-year-old patients （48.15%） （P〈0.05）. The injury rate was significantly higher in slab-type （76.00%） and wedge-type discoid meniscus （75.95%） than that in hypertrophied horn type （15.38 %） （P〈0.01）. Conclusion MRI examination can finely display the discoid meniscus, and can make a qualitative diagnosis of the type and injury of the discoid meniscus. The injury rate is correlated with the age and the classification of the discoid meniscus.