颅内动脉瘤夹闭术后瘤夹对CTA图像质量的影响研究

Effect of aneurysm clip on CTA of intracranial aneurysms after clipping

目的:探讨颅内动脉瘤夹闭术后动脉瘤夹对计算机断层血管造影(computed tomography angiography,CTA)图像的影响。方法:对62例颅内动脉瘤夹闭术后病人行同步CTA检查,运用容积再现(volume rendering,VR)及多平面重组(multiplanar reconstruction,MPR)方法,观察动脉瘤夹对CTA图像的影响,比较VR、MPR对动脉瘤夹闭术后载瘤动脉是否狭窄及狭窄程度。结果:CTA可清楚体现瘤夹与载瘤动脉的关系。使用Kappa系数分析,常规VR与MPR对比K=0.452,P=0.000;常规MPR与减影VR对比K=0.132,P=0.019,P<0.05。即常规VR与MPR评价血管狭窄有一定一致性,而常规MPR与减影VR一致性差。瘤夹伪影分为3个等级:Ⅰ级49例(79.0%),Ⅱ级11例(17.7%),3Ⅲ级2例(3.2%)。瘤夹数量与瘤夹伪影等级秩和检验P>0.05。结论:CTA图像质量受金属伪影及瘤夹减影不全的影响,减影CTA需要结合的多种图像重组方法提高对动脉瘤夹闭术后疗效评价的可靠性。

Objective：To investigate the effect of the aneurysm clip on the CTA image after clipping of intracranial aneurysm. Methods：Arteries of ruptured aneurysms and aneurysm clips imaging from 62 patients undergoing head subtraction CTA examination were retrospectively reconstructed, and the volume rendering（VR）and multiplanar reconstruction（MPR）were used to evaluate the effect of aneurysm clips and the accuracy of VR and MPR in the patients with aneurysm clipped,as well as to observe the residual aneurysms after clip. Results：CTA can clearly show the relationship between the aneurysm clip and the carrying vessel. Kappa index of agreement：K=0.452 was used for the conventional VR and the MPR（P=0.000）and K=0.132 for the MPR and the subtraction VR（P=0.019）.Consistency was observed between conventional VR,MPR and vascular stenosis evaluation while poor consistency was observed between MPR and the subtraction VR. Aneurysm clip artifact was divided into 3 grades：type a 49 cases（79.0%）,type b 11 cases（17.7%）,type c 2 cases（3.2%）. The rank sum test of the number of clips and clip artifact contrast show that the results were not statistically different（P 〉0.05）. Conclusion： CTA image quality is affected by the metal artifact and the shadow of the clip. We should combine subtraction CTA with multi type image reconstruction methods to improve the accuracy of the treatment for patients after aneurysm clipping.