低管电压CTA对颅内微小动脉瘤的诊断价值

目的 探讨100 kV低管电压脑CT血管成像（CT angiography,CTA）对颅内微小动脉瘤的诊断价值.方法 回顾分析100 kV低管电压CTA（L-CTA）和120 kV常规管电压CTA（C-CTA）两组中经3D-DSA或手术证实瘤体最大径≤3 mm微小动脉瘤,就两组CTA对微小动脉瘤的显现及其血管密度、形态、边缘、小动脉显示进行客观和主观评价,并对辐射剂量和相关图像噪声进行评价.结果 与C-CTA组相比,L-CTA组CTDIvol降低了35.65%,剂量长度乘积（DLP）及有效剂量（ED）也明显下降.虽然L-CTA组图像噪声显著增加,但L-CTA、C-CTA两组各血管间CNR、SNR差异及主观质量差异均无统计学意义（P＞0.05）.C-CTA、L-CTA诊断动脉瘤的灵敏度为93.88%和92.16%,两组之间差异无统计学意义（P＞0.05）.结论 L-CTA扫描在降低辐射剂量的同时,其图像质量和对微小动脉瘤的诊断并不受影响,是一种行之有效的低剂量扫描方法.

The value of cerebral CT angiography with low tube voltage in diagnosis of intracranial micro-aneurysms

Objective to investigate the value of cerebral CT angiography （CTA） with 100 kV lower tube voltage in diagnosis of intracranial micro-aneurysms. Methods In group CTA with 100 kV low tube voltage （L-CTA） and group CTA with 120 kV conventional tube voltage（C-CTA）,patients with micro-aneurysms（the biggest diameter 〈3 mm） identified by 3D-DSA or surgical were retrospective analyzed. The diagnostic value and image qualities including vas- cular attenuation value,vascular morphology and margin, depiction of small arterial details were compared between two groups. The radiation dose and image noise of the two groups were also compared respectively. Results Compared with group C-CTA, the CTDIvol of group L-CTA reduced 35.65%, dose length product（DLP）, effective dose（ED） also reduced significantly.Although the noise level was markedly higher at group L-CTA,the calculated CNRs,SNRs as well as subjective image quality showed no differences between the two groups （P 〉 0.05）. With the results of 3D- DSA as ＂gold standard＂ ,the sensitivity,of C-CTA and L-CTA in diagnosis of micro-aneurysms were 93.88% and 92.16%. There were no significant difference in sensitivity between the C-CTA and L-CTA groups （P 〉 0.05）. Con- clusion The value of cerebral CTA with 100 kV low tube voltage in detection of intracranial micro-aneurysms is sig- nificant, and it should be recommended as a routine scan method.