高分辨C型臂CT评估颅内血流导向装置打开程度和贴壁情况的实验研究

An animal experimental study using high-resolution C-arm CT to evaluate the expansion degree and wall apposition of the intracranial blood flow diverter

目的探讨高分辨C型臂CT(简称C臂CT)技术在巴马小型猪颈动脉内血流导向装置(FD)置入术中对支架打开程度和贴壁评估中的应用价值。方法采用血管内治疗方式将Tubridge FD置入巴马小型猪颈动脉内。术后即刻行高分辨C臂CT扫描,对FD的打开程度及后处理图像的质量进行评估;然后对FD置入血管行三维数字减影血管造影(3D-DSA)扫描,通过后处理工作站,将高分辨C臂CT和3D-DSA图像信息采用双容积融合技术行二次重建并获得融合后图像(简称双容积重建法),并与行高分辨C臂CT扫描的同时持续注射稀释对比剂后获得的支架血管重建图像(简称稀释对比剂法)进行对比,并记录两种操作方法的射线曝光剂量,以评估其在FD贴壁评估中的准确性和安全性。观察FD置入术中和术后24h内不良事件的发生情况。结果9只巴马小型猪的左侧颈动脉内共置入9枚TubridgeFD。高分辨C臂CT平扫重建图像显示,8枚FD打开完全,1例FD远心端打开不良;图像质量为Ⅰ级8例,Ⅱ级1例。在支架贴壁方面,双容积重建法和稀释对比剂法均能较清晰展示FD的贴壁情况,其中8枚FD贴壁良好(贴壁评分为0分),1枚FD远心端贴壁不良(贴壁评分为1分,分类Ⅰa型),二者评估结果的一致率为100%。在射线曝光剂量方面,双容积重建法射线总曝光的剂量面积乘积明显高于稀释对比剂法[(906.89±44.49)μGym^(2)对比(725.44±42.17)μGym^(2),t=24.36,P<0.001]。2只巴马小型猪在应用稀释对比剂法中出现中度血管痉挛,所有动物术中及术后24 h内均未观察到血管夹层、血栓脱落等并发症的发生。结论高分辨C臂CT能清晰展示国产颅内FD的细微结构和完全打开情况,结合多种后处理技术能有效观察其贴壁情况。

Objective To explore the application value of high-resolution C-arm CT technology in the evaluation of stent opening and wall apposition during the placement of blood flow diverters(FD)in the carotid arteries of Bama miniature pigs.MethodsTubridge FD was inserted into the carotid artery of Bama miniature pigs using endovascular treatment.A high-resolution C-arm CT scan was performed immediately after the operation to evaluate the expansion degree of the FD and the quality of the post-processed images.Then a three-dimensional digital subtraction angiography(3D-DSA)scan of the FD-inserted blood vessel was performed.The post-processing workstation was used to have high-resolution C-arm CT and 3D-DSA image reconstructed using dual-volume fusion technology to obtain the fused image(referred to as the dual-volume reconstruction method),and diluted contrast agent was continuously injected while performing the high-resolution C-arm CT scan.The stent vascular reconstruction images obtained later(referred to as the diluted contrast medium method)were compared,and the radiation exposure doses of the two operating methods were documented to evaluate their accuracy and safety in FD apposition assessment.The occurrence of adverse events during surgery and within 24 hours after FD implantation was observed.Results A total of 9 Tubridge FDs were placed in the left carotid arteries of 9 Bama miniature pigs.High-resolution C-arm CT plain scan reconstructed images showed that 8 FDs had full expansion and 1 case of underexpansion of the distal end of the FD.The image quality was grade Ⅰ in 8 cases and grade Ⅱ in 1 case.In terms of stent apposition,both the double-volume reconstruction method and the diluted contrast agent method could clearly demonstrate the apposition of FDs.Among them,8 FDs showed good apposition(apposition score:O points),and 1 FD showed poor apposition at the distal end(apposition score:1 point,classified as type Ⅰa).The consistency rate of the two assessment results was 100%.In terms of radiation exposure dose,the dual-volume reconstruction method was significantly higher than the diluted contrast agent method(906.89±44.49μGym^(2) us.725.44±42.17μGym^(2),t=24.36,P<0.001).Two experimental pigs suffered from moderate vasospasm during the application of diluted contrast media.No complications such as vascular dissection or thrombus detachment were observed in all animals during the operation and within 24 hours after operation.Conclusion High-resolution C-arm CT can clearly display the fine structure and full expansion of the domestic intracranial blood flow diverters,and combined with a variety of post-processing techniques,its wall apposition can be effectively observed.