三维延迟增强MRI对髋关节发育不良中退变软骨的诊断价值

Assessment of the degenerative cartilage of hip dysplasia with three dimensional delayed enhanced MRI of cartilage

目的应用3D延迟增强MR成像（dGEMRIC）检测软骨内成分改变，探讨dGEMRIC评估成年髋关节发育不良软骨退行性病变的可行性。方法对X线摄片证实的20例髋关节发育不良成年患者（35个髋关节）进行疼痛问卷调查、3D-dGEMRIC及常规MR序列扫描。在x线片上测量外侧中心一边缘角，结合X线片和MRI对35个髋关节进行骨性关节炎（OA）的TSnnis分级（1-3级）。将Tonnis1级的髋关节归为早期OA组，将无临床疼痛症状且TSnnis0级的髋关节归为形态正常组。用1．5TMR扫描仪完成髋关节3D-dGEMRIC数据采集，行放射状（或日射状）重组，选取髋关节6个位置，分别为前部、前上部、上前部、上部、上后部与后上部，测量软骨的dGEMRIC指数。组间同一位置dGEMRIC指数的比较采用Kruskal-Wallis检验与Mann-Whitney检验，形态正常组与早期OA组各自不同位置间dGEMRIC指数的比较采用Wilcoxon检验。结果6个位置的dGEMRIC指数中位数TSnnis0级为579ms，1级为500ms，2级（包括3级1例）为439ms。Tsnnis2级组低于TSnnis1级组（Z=-1．990，P=0．047），Tonnis1级组低于TSnnis0级组（Z=-2．149，P=0．032）。前部、前上部、上前部、上部软骨的dGEMRIC指数在早期OA组低于形态正常组（Z=-2．333--2．041，P值均小于0．05）。形态正常组关节上前部的dGEMRIC指数低于上部区域（Z=一2．201，P=0．028），早期OA组上前部的dGEMRIC指数低于除前上部外的其他区域（Z=-3．041--2．277，P〈0．05）。结论dGEMRIC指数有助于髋关节发育不良退行性变的早期诊断与分期。3D放射状重组技术提示髋关节前部至上部区域的软骨为OA的早期及主要累及部位，其中上前部可能是OA的最早累及部位。

Objective To evaluate the feasibility of assessing osteoarthritis （OA） in hip dysplasia using 3D delayed gadolinium-enhanced MRI of cartilage （dGEMRIC）. Methods Thirty-five hips in 20 patients with radiographic evidence of hip dysplasia underwent 3D-dGEMRIC scanning. Clinical symptoms were assessed with the Western Ontario and MeMaster Universities Osteoarthritis （ WOMAC ） questionnaire. Radiographic measurement of lateral center-edge angle and Tonnis grading were performed on the X-rays. Hips of T6nnis grade 1 were included in the group of hips with early OA, while the hips with no evidence of OA and without pain symptom were included in the group of hips with normal morphology. The 3D-dGEMRC scans were completed on a 1.5 T MR scanner. The data of 3D-dGEMRIC was reconstructed radically. The dGEMRIC indices were measured on six sites of periphery zones of hip cartilage on reconstructed images. The dGEMRIC indices among different groups were analyzed by non-parametric tests. The differences of dGEMRIC indices among six sites in the group of early OA or the group of normal morphology were analyzed by Wilcoxon test. Results The mean dGEMRIC indices of six sites were lower in group of Tbnnis grade 1 than in group of Tbnnis grade 0 （Z = -2. 149,P =0. 032） , and lower in group of Ttinnis grade 2 than in group of Tonnis grade 1 （ Z = - 1. 990, P = 0. 047 ）. The dGEMRIC indices of theanterior site, anterosuperior site, superior-anterior site, and superior site were significantly different between the group of hips with early OA and the group of hips with normal morphology （Z = -2. 333---2. 041 ,all of the P values were lower than 0. 05 ）. in the group of hips with normal morphology, the dGEMRIC indices of superior-anterior site of hip were lower than superior site（ P = 0. 028 ）. In the group of hips with early OA, the dGEMRIC indices of superior-anterior site were lower than the other sites except for anterior-superior site （ Z = - 3. 041--- 2. 277, all of the P values were lower than 0. 05 ）. Conclusions 3D-dGEMRIC might be a sensitive technique for detection of glyeosaminoglycans alteration in early OA and staging of OA in hip dysplasia. Radial reconstruction could provide an accurate assessment of OA, and the results demonstrated that early cartilage alteration could be detected in the anterior to superior sites of hips, and the earliest cartilage alteration may occur in the superior-anterior site of hips.