新双源双能量CT单能谱成像技术在老年腰椎金属内固定术后的应用

Application of new dual-source monoenergetic imaging of dual energy CT in elderly patients with lumbar spinal metal internal fixation

目的探讨新双源双能量CT单能谱成像及后处理技术在老年腰椎金属内固定术后评估的临床应用价值。方法回顾性分析经浙江省立同德医院诊断治疗的48例老年腰椎压缩性骨折内固定的患者,经新双源双能量CT检测后,数据进行后处理获得50、80、110、140、170 keV不同能谱的图像,由2名副主任医师以上的放射科医师在后处理系统里采用双盲法对上述5组图像和120 kV融合图像的图像质量和伪影进行独立评估,并进行评分,评分采用4分制的评分标准,按照金属固定物外形、位置及相邻骨组织解剖细节显示清楚程度和有无伪影,从4分到1分逐渐递减。对不同的重建方法产生的图像质量和伪影大小的数据,采用kruskal-Wallis秩和检验对图像进行统计分析。结果两位医师评价图像质量进行一致性检验的结果显示,两位医师的一致性非常强(Kappa=0.872)。新双源双能量CT成像的单能量技术在80 keV条件以上均可提供较好的图像质量,特别110 keV时图像质量达到最佳效果,3分达36例,4分4例和8例2分,与其他keV条件下比较,差异有统计学意义(χ2=87.637,P=0.003)。结论新双源双能量CT单能谱成像技术在减少金属伪影并提高图像质量中有明显优势,能提高老年腰椎金属内固定术后的影像质量,在110 keV时图像效果最佳,对脊柱外科的临床工作有很好的指导作用,值得进一步推广。

Objective To explore the clinical value of new dual-source monoenergetic imaging of dual energy CT and post-processing technology in elderly patients with lumbar spinal metal internal fixation.Methods A total of 48 elderly patients with internal fixation of lumbar vertebral compression fractures diagnosed and treated in Litongde Hospital in Zhejiang Province were retrospectively analyzed.After detected by new dual-source monoenergetic imaging of dual energy CT,the data were processed to obtain 50,80,110,140,and 170 kev images of different energy spectrums.The quality and artifacts of the five groups of images and the 120 kV fusion image were independently evaluated and scored by two radiologists titled associate chief physician or above in the post-processing system using double-blind methods.The scoring system was based on the shape,location,clarity degree of anatomical details of the adjacent bone tissue and the presence or absence of artifacts and adopted a 4-point scale,which gradually decreased from 4 to 1 point.The kruskal-Wallis rank sum test was used to analyze the image quality.Results The consistency of the two physicians in evaluating the image quality was rather high(Kappa=0.872).The new dual-source monoenergetic imaging of dual energy CT can provide better image quality under the condition of above 80 keV,and the image quality reached the best at 110 keV;there were 36 cases with 3 points,4 cases with 4 points,and 8 cases with 2 points;compared with other keV conditions,the difference was statistically significant(χ2=87.637,P=0.003).Conclusion The new dual-source monoenergetic imaging of dual energy CT has significant advantages in reducing metal artifacts and improving image quality,and can improve the image quality of elderly lumbar spine after metal internal fixation.The image quality is best at 110 keV.It has a good guiding value on the clinical work of spine surgery and deserves further promotion.