ISSN 1004-4140
CN 11-3017/P

颅内动脉瘤栓塞术后能谱CTA联合MAR的临床研究

Clinical Value of Spectral Imaging Combined with MAR for CTA after Embolization of Intracranial Aneurysms

  • 摘要: 目的:评价颅内动脉瘤栓塞术后能谱CTA联合去金属伪影技术(MAR)的应用价值。方法:收集37例颅内动脉瘤栓塞术后需行能谱头颈CTA检查患者的CT原始数据,分别重建出70~140 keV单能级图像、120 kVp-like混合能量图像及70~140 keV MAR处理图像和120kVp-like MAR图像;感兴趣区(ROI)放置在伪影最严重层面的线圈附近,测量CT值及标准差(SD),计算伪影指数(AI)及信噪比(SNR);在主观分析方面,由两名诊断医生采用Likert 5分量表法对所有图像的伪影程度和血管显示能力进行评估;比较MAR组和非MAR组图像的主观评分和客观参数。采用Wilcoxon秩和检验、配对样本t检验及独立样本t检验比较各组图像之间的差异。结果:8组单能量图像上,MAR图像的AI明显低于非MAR图像;在80~110 keV条件下,MAR图像SNR高于非MAR组,差异具有统计学意义;相同keV下,与非MAR组相比,MAR组图像的伪影评分及周围血管显示主观评分得分均更高。对于非MAR处理图像,AI值与周围血管显示评分在植入不同直径弹簧圈的患者图像上没有统计学差;对于MAR图像,较大直径弹簧圈组(>8.79 mm)患者图像的AI值明显高于常规直径组,而周围血管显示主观评分明显低于常规直径组。结论:能谱CTA成像联合MAR可有效减少颅内动脉瘤栓塞植入物伪影,改善周围血管显示,对于小直径的弹簧圈MAR减少伪影效果最为显著。

     

    Abstract: Objective: To evaluate the application value of combining spectral imaging and metal artifact reduction (MAR) in head and neck CTA after the embolization of intracranial aneurysms. Methods: We collected 37 patients who experienced embolization of intracranial aneurysms then received spectral imaging of head and neck CTA. Monochromatic images with energy ranging from 70~140 keV, 120 kVp-like mixed energic images, 70~140 keV MAR images, and 120 kVp-like MAR images were generated. The region of interest was placed on the area near the coil and with the most serious metal artifact. CT attenuation and standard deviation were measured, and artifact index (AI) and signal-noise ratio (SNR) were calculated. Two radiologists independently subjectively evaluated the metal artifact and the display of surrounding vessels using Likert 5 scales. The subjective scores and objective parameters between MAR and non-MAR images were compared. The Wilcoxon ranking test, paired sample t test, and independent sample t test were utilized to compare parameters between the groups. Results: MAR images had significantly lower AI than did non-MAR images for all eight monochromatic energies. When energies ranged from 80~110 keV, SNR was higher for MAR images than for non-MAR images, and the difference was statistically significant. With same energies, MAR images had higher artifact and vessel display scores than did non-MAR images. For non-MAR images, the different coil diameters did not make a statistical difference in AI and vessel display scores. For MAR images, a larger coil diameter (>8.79 mm) led to higher AI and lower vessel display scores than did normal diameters (≤8.79 mm). Conclusion: The combination of spectral imaging and MAR could effectively reduce the metal artifact of implants for the embolization of intracranial aneurysms and improve the surrounding vessel display. Moreover, the metal artifact reduction effect was more significant for the coils with smaller diameters.

     

/

返回文章
返回