能谱CT低剂量颅底区减影融合CTA技术与临床应用

Subtraction Fusion CTA Technique of Low-dose skull base with energy spectrum CT and clinical applications

目的:比较能谱CT颅底区减影融合CTA(BRSF-CTA)与数字减影CTA(DS-CTA)图像质量与辐射剂量,深入探讨BRSF-CTA技术参数,并评估其临床应用。方法:把临床怀疑脑血管病的144例者行头颈CTA联合成像,分成A组(DS-CTA)组和B组(BRSF-CTA)组,每组72例。对所有CTA检查均行VR、MIP、CPR分析后,比较两组技术的图像质量、辐射剂量。结果:两组在显示颈内动脉在颈段、颅底段、颅内段图像质量评分无统计学意义(P>0.05),图像均可满足诊断需求;而在颈内动脉颈段、大脑中动脉的CT值和其背景噪声(SD)、信噪比(SNR)、对比噪声比(CNR)有统计学意义(P<0.05)。两组的容积CT剂量指数、剂量长度乘积和有效剂量分别为7.81±0.86mGy、697.63±79.34mGy.cm、2.16±0.25mSv,6.16±0.59mGy、380.86±42.76mGy.cm、1.18±0.13mSv,辐射剂量降低了42.2%,统计学比较有显著差异性(P<0.05)。本研究中诊断35例颅内动脉瘤,其中颅底动脉瘤7例。BRSF-CTA技术可直观、形象、多角度显示颅底动脉瘤与前床突和载瘤动脉的位置关系,并优势展示1例颈动脉床突孔,2例瘤体近前床突小于5mm,1例后交通复杂动脉瘤并显示其瘤体的细小动脉分支。结论:BRSF-CTA技术降低了辐射剂量,图像质量满意,显示颅底骨质解剖、变异、动脉瘤和载瘤动脉的关系较DS-CTA清楚直观。BRSF-CTA实现细小目标结构显示,可弥补DS-CTA不能显示瘤体小分支的不足,为外科手术制定个性化方案提供依据。

Objective:In order to compare the image quality and radiation dosage between basicranial region subtraction fusion CTA(BRSF-CTA)and digital subtraction CTA(DS-CTA)with energy spectrum CT,the technical parameters of BRSF-CTA are analyzed and the clinical applications are evaluated.Methods:Head-neck CTA of 144 patients with suspected cerebrovascular disease were separated into two groups of 72 patients in each group:The groups are the conventional DS-CTA group and the BRSF-CTA group.All CTA were analyzed by VR,MIP and CPR.The image quality and radiation dosage were then compared.Results:There is no statistical significance on the scores of image quality,CT value,or noise,SNR,CNR in the segments of the cervical and intracranial between groups of BRSF-CTA and DS-CTA(P>0.05),and moreover all the images met the diagnostic needs.The volume CT dose index,dose length product and effective dose of DS-CTA and BRSF-CTA group are 7.81±0.86 mGy.cm,697.63±79.34 mGy.cm,2.16±0.25 mSv and 6.16±0.59 mGy,380.86±42.76 mGy.cm,1.18±0.13 mSv,respectively.Their radiation dose of BRSF-CTA group decreased by 42.2%and there is statistical significance between groups of DS-CTA and BRSF-CTA(P<0.05).In this group,35 cases of Intracranial aneurysms were found with BRSF-CTA,including 7 cases of Basicranial aneurysms.BRSF-CTA can visually and directly display the positional relationship between the parental artery and anterior clinoid process.This is an advantage over the DS-CTA display the variation of the carotico clinoid foramen in the case 1.In case 2,the distance between the tumor and the anterior clinoid process with less than 5 mm and the complex posterior communicating aneurysm with the branches of small arteries in the tumor.Conclusion:The BRSF-CTA technique can effectively reduce radiation doses and can also achieve satisfactory image quality.It shows the anatomy as well as the variation of the skull base.Also it shows the basicranial aneurysms and its parent artery more clearly and directly than that of DS-CTA.BRSF-CTA can realize the display of small target structure,which can make up for the lack of DS-CTA in displaying the small branches of an aneurysm body.It can also provide a basis for making personalized plans for surgery.