青少年急性单纯膝关节软骨骨折的MRI表现

MRI findings of juvenile acute pure cartilage fracture of the knee joint

目的分析青少年急性单纯膝关节软骨骨折的 MRI 表现,以提高对 MRI 表现的认识。方法回顾性分析经关节镜手术证实的26例27处急性单纯膝关节软骨骨折的 MRI 表现,重点观察软骨、软骨下低信号线和软骨下骨髓的改变。26例均采用矢状面和冠状面扫描,矢状面应用快速小角度激发成像序列 T_1WI 加脂肪抑制(FLASH-FS-T_1WI)、SE-T_1WI 和三维稳态进动快速成像序列T_2WI 加脂肪抑制(FISP-3D-FS-LWI)序列,冠状面应用多回波数据结合成像序列 T_2WI(ME-T_2WI)和SE-T_1WI,有5例还加扫了横轴面 ME-T_2WI。结果 26例27处软骨骨折中髌骨8处,股骨内髁7处,股骨外髁11处,胫骨平台1处。单纯软骨骨折有3种类型,软骨全层缺损(7处,其中髌骨3处、股骨内髁2处、股骨外髁1处、胫骨平台外后髁1处)、裂隙状软骨骨折(3处,其中股骨内髁2处、股骨外髁1处)、软骨部分缺损(17处,其中髌骨5处、股骨内髁3处、股骨外髁9处)。关节镜手术发现21例有关节内软骨游离体,而 MRI 仅发现3例。全部患者软骨骨折附近均有骨髓挫伤,软骨下低信号线形态、信号均正常。结论膝关节股骨和胫骨平台软骨骨折采用矢状面 FLASH-FS-T_1WI、SE-T_1WI 和FISP-3D-FS-T_2WI 序列及冠状面 ME-T_2WI、SE-T_1 WI,髌骨软骨骨折加扫横轴面 ME-T_2WI 序列可显示急性单纯膝关节软骨骨折的部位、范围和类型,是软骨骨折最好的无创性检查方法。

Objective To study the MRI manifestation of juvenile acute pure cartilage fracture of the knee joint. Methods The MRI changes of cartilage, subcartilage low signal line and subcartilage bone were analysed retrospectively in 26 juvenile patients with acute pure cartilage fracture confirmed by arthroscopy. Sagittal and coronal MRI scanning were performed in 26 patients. Using fast low angle shot fat saturation T, -weighted image （ FLASH-FS-T1WI） sequences, spin echo T, -weighted image （ SE-T, WI） and fast imaging with steady-state precession three dimensional fat saturation T2-weighted image（ FISP-3D -FS- T2WI ）sequences in sagittal plane, SE-T1WI and multi echo data image combination T2-weighted imaging （MEDIC or ME-T2WI） in coronal plane. Using ME-T2WI sequence, axial plane MRI scanning in 5 patients. Results Twenty-seven sites of 26 patients include 8 patella , 7 femoral medial condyle, 11 femoral lateral condyle and ltibial plateau. Three types pure cartilage fracture were observed, totally defect of the cartilage in 7 sites （include 3 patella, 2 femoral medial condyle, 1 femoral lateral condyle and 1 tibial plateau）, fissuring fracture in 3 sites （include 2 femoral medial and 1 femoral lateral condyles）, superficial defect of the cartilage in 17 sites （include 5 patella, 3 femoral medial and 9 femoral lateral condyle）. Corpus liberum was found in 21 patients＇ knee joints by arthroscopy, but only 3 cases by MRI. Bone bruise was detected, and subcartilage low signal lines were normal. Conclusion Using FLASH-FS- T1WI,SE-T1WI,FISP-3D-FS-T2WI and ME-T2WI sequences, sagittal and coronal MRI scanning in femoral and tibial plateau pure cartilage fractures ,and using ME-T2WI sequence axial scanning in patella r cartilage fractures may show the position, extension and types of the acute pure cartilage fracture of the knee joint. MRI is the best non-invasive method for studying cartilage fracture.