颈椎椎体CT值在颈椎退行性疾病手术病人术前骨质量评估中的应用研究

Application of CT value of cervical vertebral body in preoperative bone quality assessment of patients with cervical degenerative diseases

目的研究颈椎椎体CT值在颈椎退行性疾病术前骨质量评估中的应用价值。方法回顾性分析2015年1月至2017年12月在北京大学第三医院骨科颈椎专业组接受颈椎手术治疗的939例颈椎退行性疾病病人,其中男484例,女455例,平均年龄为59岁。在PACS系统上测量C2~C7椎体中横断面的CT值,通过双能X线吸收法(dual-energy X-ray absorptiometry, DXA)获得L1~L4总的骨密度T 值。分析C2~C7椎体CT值的变化规律、颈椎椎体CT值与L1~L4总的骨密度T 值的相关性,并分别计算-2.5<T 值<-1、T 值≤-2.5时,C2~C7椎体CT均值的临界值。结果C2~C7椎体的CT值分别为(363.43±92.52)HU、(340.44±80.73)HU、(338.37±86.92)HU、(333.43±87.49)HU、(289.98±76.60)HU、(259.43±62.59)HU,依次递减;C2~C7椎体CT值为(322.52±89.27)HU。L1~L4总的骨密度T 值平均值为-0.73。C2~C7椎体的CT值与L1~L4总的骨密度T 值呈正相关(r=0.487,P<0.001)。-2.5<T 值<-1时,C2~C7椎体CT均值的临界值为327HU,采用该临界值筛查骨质减少的灵敏度为75.7%,特异度为59.8%。T值≤-2.5时,C2~C7椎体CT均值的临界值为269 HU,采用该临界值筛查骨质疏松的灵敏度为63.8%,特异度为80.8%。结论颈椎退行性疾病手术病人的颈椎CT值自C2至C7递减;颈椎椎体CT值与DXA检查的骨密度T 值呈正相关,有助于术前临床评估病人的骨质量。

Objective To study the application of CT value of cervical vertebral body in preoperative bone quality assessment of patients with cervical degenerative diseases. Methods A retrospective analysis was made on 939 patients with cervical degenerative diseases who underwent cervical spine surgery from January 2015 to December 2017 in the Cervical Spine Specialty Group of Orthopaedic Department of the Third Hospital of Peking University, including 484 males and 455 females, with an average age of 59 years. The CT value of C2-C7 vertebral body in sagittal reconstruction of cervical spine was measured on PACS system. The total T value of L1-L4 was obtained by dual-energy X-ray absorptiometry (DXA). To analyze the regularity of CT value of C2-C7 cervical vertebral, the correlation between CT value of cervical vertebral and T value measured by DXA, and the critical value of CT value of cervical vertebral when -2.5<T value<-1.0 and T value≤-2.5. Results The CT values of C2-C7 vertebral body in sagittal reconstruction of cervical spine on PACS system were (363.43±92.52),(340.44±80.73),(338.37±86.92),(333.43±87.49),(289.98±76.60), and (259.43±62.59) HU respectively, with an average of (322.52±89.27) HU. The average of T value by DXA was -0.73 in all patients included in the study. The CT value of C2-C7 vertebral body was positively correlated with the T value of DXA (r=0.487, P<0.001). While -2.5<T value<-1.0, the mean CT value of C2-C7 vertebral body was 327 HU, the sensitivity and specificity of using the mean CT value to screen osteopenia were 75.7% and 59.8% respectively. While T≤- 2.5, the mean CT value of C2- C7 vertebral body was 269 HU, the sensitivity and specificity of using the mean CT value to screen osteoporosis were 63.8% and 80.8% respectively. Conclusion The CT value of cervical spine in patients with cervical degenerative diseases decreased gradually from C2 to C7. The CT value of cervical spine was positively correlated with the T value of DXA, which would be helpful to evaluate the bone quality of patients before operation.