基于腰椎MRI影像评估骨密度的新型评分方法

A new scoring system based on lumbar MRI image to assess bone mineral density

目的建立一个基于腰椎磁共振成像(MRI)的评分系统评估骨密度,并分析其与双能X线骨密度仪(DEXA)所测T值的相关性。方法回顾性分析2019年1月至2020年8月入住扬州大学临床医学院的诊断为腰椎退变性疾病且行手术治疗的82例患者的临床资料,根据DEXA检测的股骨颈和全髋骨密度T值中的较低值,分为骨量正常组(n=40)和骨量异常组(n=42)。通过MRI的T1加权像L1-4椎体的平均信号强度除以L3水平脑脊液的信号强度来计算患者的椎体骨质量(VBQ)评分,绘制受试者工作特征(ROC)曲线评估VBQ评分区分骨量正常与骨量异常的能力及预测骨量异常发生的准确性,并进一步通过回归分析确定VBQ评分和T值的相关性。结果骨量异常组DEXA所测T值最低值明显低于骨量正常组,VBQ评分明显高于骨量正常组(均P<0.001)。VBQ评分预测骨量异常的ROC曲线的曲线下面积(AUC)为0.930,截断值为2.98,灵敏度为81.6%,特异度为88.6%。VBQ评分与DEXA所测T值最低值呈负相关(r=-0.77)。结论VBQ评分可有效区分骨量正常与骨量异常,与DEXA所测T值最低值中度负相关。

Objective To establish a scoring system based on lumbar magnetic resonance imaging(MRI)images to evaluate bone mineral density and evaluate its correlation with T score of dual energy X-ray absorptiometry(DEXA).Methods The clinical data of 82 patients with lumbar degenerative diseases who were admitted to the Clinical Medical College of Yangzhou University from January 2019 to August 2020 were analyzed retrospectively.According to the lower value of T value of femoral neck and total hip bone mineral density detected by DEXA,they were divided into normal bone mass group(n=40)and abnormal bone mass group(n=42).The vertebral body bone mass(VBQ)score of the patient was calculated by dividing the average signal intensity of L1-4 vertebral body by the signal intensity of L3 level cerebrospinal fluid on T1 weighted image of MRI.The receiver operating characteristic(ROC)curve was drawn to evaluate the ability of VBQ score to distinguish between normal bone mass and abnormal bone mass and the accuracy of predicting the occurrence of abnormal bone mass.Further,the correlation between VBQ score and T value was determined by regression analysis.Results The lowest T value measured by DEXA in the abnormal bone mass group were significantly lower than those in the normal bone mass group,and the VBQ score was significantly higher than that in the normal bone mass group(all P<0.001).The area under curve(AUC)of VBQ score for predicting abnormal bone mass was 0.93,the cut-off value was 2.98,with sensitivity 81.6%,and specificity 88.6%.The VBQ score was corrected with the lowest T value measured by DEXA(r=-0.77).Conclusions VBQ score could effectively distinguish normal bone mass from abnormal bone mass and was negatively correlated with the lowest T value of DEXA.