双层探测器光谱CT钙抑制技术在急慢性胸腰椎压缩骨折中的诊断价值

The diagnostic value of dual-layer detector spectral CT calcium suppression technique in acute and chronic thoracolumbar compression fractures

目的评价光谱CT钙抑制(CaSupp)技术在急慢性胸腰椎压缩骨折中的诊断价值。方法回顾性收集2020年3月至10月就诊于山西医科大学第二医院的31例胸腰椎压缩骨折患者,对其行光谱CT和MR扫描。由医师A、B基于CaSupp图对急慢性椎体骨折进行诊断,采用Kappa检验评估二者诊断的一致性。在常规CT图及CaSupp图上分别测量骨折椎体及邻近正常椎体的常规CT值和CaSupp CT值,并计算两者的差值。以独立样本t检验比较急慢性骨折椎体间的常规CT值及CT值差值、CaSupp CT值及CT值差值的差异。以MRI为金标准,绘制ROC曲线评价医师主观诊断效能和各定量参数的诊断效能,并采用DeLong检验对各定量参数曲线下面积(AUC)进行两两比较。结果MRI诊断急、慢性压缩骨折椎体分别为48和11个。医师A、B的主观诊断急慢性椎体骨折的Kappa值为0.782,AUC、灵敏度、特异度分别为0.882和0.857、85.4%和89.6%、90.9%和81.8%。急、慢性压缩骨折间的常规CT值、CaSupp CT值、CaSupp CT值差值的差异均有统计学意义(P均<0.05)。常规CT值、CaSupp CT值、常规CT值差值、CaSupp CT值差值的AUC分别为0.824、0.930、0.706、0.934。两两比较显示CaSupp CT值及CaSupp CT值差值的AUC大于常规CT值差值,差异有统计学意义(Z=2.014、P=0.044,Z=2.028、P=0.043),余两两间AUC差异均无统计学意义(P均>0.05)。结论双层探测器光谱CT CaSupp技术对鉴别急慢性胸腰椎压缩骨折具有较高的价值,推荐使用CaSupp CT值和CaSupp CT值差值进行诊断。

Objective To evaluate the diagnostic value of spectral CT calcium suppression(CaSupp)technique in acute and chronic thoracolumbar compression fractures.Methods A total of 31 patients with thoracolumbar compression fractures were given spectral CT and MR scans from March to October 2020 in the Second Hospital of Shanxi Medical University.Acute and chronic vertebral fractures were diagnosed by doctor A and B based on CaSupp diagram,and the consistency between the two doctors was evaluated by Kappa test.CT values of fractured vertebra and adjacent normal vertebra were measured on conventional CT and CaSupp graphs respectively,and the CT value difference between fractured vertebra and adjacent vertebra was calculated.Independent sample t-test was used to compare the conventional CT value and CT value difference,CaSupp CT value and CT value difference between acute and chronic fractured vertebra.Using MRI as the gold standard,the ROC curves were drawn to evaluate the subjective diagnostic efficacy of physicians and the diagnostic efficacy of each quantitative parameter.DeLong test was used to compare the area under the curve(AUC)of each quantitative parameter in pairs.Results The number of vertebral bodies in acute and chronic compression fractures diagnosed by MRI was 48 and 11 respectively.The Kappa value of subjective diagnosis of acute and chronic vertebral fractures by doctors A and B was 0.782,and the AUC,sensitivity,specificity were 0.882 and 0.857,85.4%and 89.6%,90.9%and 81.8%,respectively.The differences of conventional CT value,CaSupp CT value and CaSupp CT value difference between acute and chronic compression fractures were statistically significant(all P<0.05),and the AUC values of conventional CT value,CaSupp CT value,conventional CT value difference and CaSupp CT value difference were 0.824,0.930,0.706 and 0.934,respectively.Pair comparison showed that the AUC of the CaSupp CT value and CaSupp CT value difference was greater than that of conventional CT value difference,with statistically significant differences(Z=2.014,P=0.044,Z=2.028,P=0.043),while there were no statistically significant differences between other AUC values(all P>0.05).Conclusion The dual-layer detector spectral CT CaSupp technique has high value in differentiating acute and chronic thoracolumbar compression fractures,and the CaSupp CT value and CaSupp CT value difference are recommended for diagnosis.