MRI信号强度及临床表现对判断颈椎后纵韧带骨化症预后的作用

The role of MR T2 image signal intensity and clinical manifestations in predicting prognosis for cervical ossification of the posterior longitudinal ligament

目的探讨MRI T2信号强度及临床表现在判断颈椎后纵韧带骨化症（ossification of the posterior longitudinal ligament, OPLL）预后方面的作用。方法1999年2月至2007年7月，58例接受后路手术治疗的OPLL患者随访超过1年，最长7年，平均16．7个月。术前所有患者均行高分辨率1．5TMR检查。于矢状面R加权像脊髓受压信号增高最明显部位测量信号强度值，取兴趣区面积为0．05cm^2；再于C7T。椎体水平脊髓信号正常部位测量信号强度值，取兴趣区面积为0．3cm^2；如T2加权像脊髓信号无明显改变，则取脊髓受压最严重部位0．05cm^2为兴趣区测量信号强度值，计算两者比值。比值数据按大小通过聚类分析法分为三组。结合临床表现判断与预后之间的关系。结果经成组设计方差分析，各组间年龄差异有统计学意义。经卡方检验，三组间性别差异无统计学意义，而Babinski征、踝阵挛阳性率差异有统计学意义。经秩和检验，三组间病程、术前JOA评分、术后JOA评分及改善率差异均有统计学意义。通过多元回归方析，改善率的78．6％可以由信号强度比值、术前JOA评分、年龄、病程、Babinski征及踝阵挛来解释。结论T2加权像低信号强度比值组OPLL患者，年龄相对较小，病程相对较短，Babinski征出现概率较小，减压术后效果较好。反之，信号强度高且伴随锥体束征则提示预后较差。

Objective To investigate whether the signal intensity ratio on MRI and clinical manifestations can reflect prognosis in patients with cervical ossification of the posterior longitudinal ligament （OPLL）. Methods From February 1999 to July 2007, 58 patients with cervical OPLL were prospectively enrolled. They were treated with posterior decompression and followed up 1 to 7 years. 1.5 T MRI was performed in all patients before surgery. T2 weighted images （T2WI） of sagittal signal intensity on the cervical severe com- pression cord were obtained, and the regions of interest （ROIs） were taken by 0.05 cm^2. T2WI of sagittal normal cord signal on the cervical between C7T1 disc levels were obtained, and the ROIs were taken by 0.3 cm^2. Signal value was measured by computer and the signal ratio between regions of the 0.05 cm^2 and 0.3 cm^2 had been calculated. All of 58 patients have been divided into three groups with signal intensity ratio. Statistical analyses were performed. Results There were significant differences between three groups at the recovery rate, age, duration of disease, Babinski sign, ankle clonus, preoperative JOA score and postoperative JOA score. There was no significant differences at gender in three groups. And multiple linear regression showed that the recovery rate was correlated with age, Babinski sign, duration of disease and ankle clonus. Conclusion Patients with low signal intensity ratio change on T2WI experienced a good surgical outcome. However, with the increase of signal intensity ratio and the occurrence of pyramidal sign, a poor prognosis after surgery will appear.