单次对比增强双源双能量CT血管成像评估颅内出血及其原因

Evaluation of intracranial hemorrhage and its causes by single-contrast-enhanced dual-source dual-energy CT angiography

目的随着双源CT在临床的推广应用,双源CT双能量成像已成为研究热点。文中探讨单次对比增强的双源双能量CT血管血管成像(CT angiography,CTA)对评估颅内出血及其原因的应用价值。方法对43例蛛网膜下腔出血患者进行双源CT头颅常规平扫(conventional nonenhanced CT,CNCT)及对比增强双能量CT扫描(80 kV/400 mA和140 kV/95mA)。利用Liver VNC软件进行对比增强双能量CT数据处理得到虚拟平扫(virtual nonenhanced CT,VNCT)数据,与CNCT检出的蛛网膜下腔出血比较,分析CNCT和VNCT的图像质量、辐射剂量、平均CT值、信噪比、对比噪声比及病灶检出率的差异。利用双能量CTA判断颅内血管异常,并与数字减影血管造影(digital subtraction angiography,DSA)所检出的病变比较诊断符合率。结果双能量VNCT的图像质量低于常规平扫(Z值=-6.576,P<0.01),但可满足临床诊断要求。VNCT的正常脑组织及出血区CT值、信号噪声比(signal-to-noise ratio,SNR)及对比噪声比(contrast-to-noise ratio,CNR)低于CNCT(P<0.01)。VNCT和CNCT对病灶的检出结果相似。在43例临床疑有脑血管病变的患者中,双能量CTA检出25例患者为动脉瘤,4例为动静脉畸形,3例为烟雾病,11例为阴性,与DSA或手术证实结果完全一致。双能量CTA患者接受的辐射剂量明显低于常规DSA(P<0.01)。结论从双源双能量CT中获得VNCT平扫图像可用于诊断颅内出血,图像质量可满足临床诊断需要。双能量CTA与DSA的诊断符合率很高。应用该技术可减少每次平扫所接受的辐射剂量,具有潜在的临床应用价值。

Objective Dual-source dual-energy CT imaging is becoming a focus of research with its wide clinical application.This study aimed to investigate intracranial hemorrhage and its causes by single contrast-enhanced dual-source dual-energy CT angiography（CTA）.Methods Forty-three patients suspected of subarachnoid hemorrhage underwent head conventional nonenhanced CT（CNCT） and contrast-enhanced dual-energy CT scan（80 kV/400 mA and 140 kV/95 mA）.The dedicated software of Liver VNC was used to reformat virtual nonenhanced CT（VNCT）.Image quality,radiation dose,average CT value,signal to noise ratio（SNR）,contrast-to-noise ratio（CNR） and lesion detectability were compared between VNCT and CNCT.Prevalence lesions detected were compared between dual-energy CTA and digital subtraction angiography（DSA）.Results The image quality of dual-energy VNCT could satisfy the diagnostic requirements,though lower than that of conventional nonenhanced CT（Z=-6.576,P0.01）.The average CT value of the brain tissue and bleeding area,SNR and CNR of VNCT were lower than those of CNCT（P0.01）,while VNCT and CNCT showed a similar performance in detecting intracranial bleeding.Of the 43 cases,25 were diagnosed as intracranial aneurysm,4 as arteriovenous malformation（AVM）,3 as moyamoya′s disease,and 11 with negative results,which were concordant with the results of digital subtraction angiography（DSA）.There was no significant difference for the size and diameter of aneurysm between dual-energy CT angiography and DSA,and had a good relationship.Radiation exposure in dual-energy CTA was significantly lower than that in conventional DSA（P0.01）.Conclusion VNCT images from dual-source dual-energy CT scan can be used for the diagnosis of intracranial hemorrhage,and the image quality can meet the requirements of clinical diagnosis.Single contrast-enhanced dual-source dual-energy CTA has a potential value of clinical application for is high rate of correct diagnosis and low-dose radiation.