80KV低剂量在头颈部CT血管成像的初步研究

A Preliminary Study in Cerebral and Neck CT Angiography with 80KV and Low Contrast Agent Dose

目的探讨"双低"血管成像技术-低千伏、低对比剂用量应用于临床头颈部血管成像的可行性。方法采用35ml的低对比剂用量用于头颈部CT血管成像,将20例临床疑似头颈部血管疾病患者随机分为2组,实验组10例采用80KV进行头颈部血管成像扫描,对照组10例采用常规120KV,两组的对比剂用量均为35ml,注射速率为5ml/s,注射完毕后同等速率注入生理盐水40ml;均采用自动管电流调节技术(Caredose 4D),迭代算法(SAFIRE)重建,根据原始图像及最大密度投影像(MIP),比较不同千伏血管强化程度,不同KV下的辐射剂量、脑实质的密度及信号噪声比(SNR)、对比噪声比(CNR)、噪声等,并对其进行统计学分析。结果实验组和对照组图像质量评分分别为5.833±0.100和5.856±0.133,P=0.694>0.05;图像噪声分别为2.261±0.026和2.522±0.031(P=0.000<0.05),噪声明显增加;辐射剂量分别为412.4±49.2和101.8±11.6,P=0.000<0.05,辐射剂量显著下降。结论采用"双低"技术进行头颈部CT血管造影,所得图像能满足影像诊断,且大为减少辐射剂量和对比剂用量,可望用于头颈部CT血管成像筛查和治疗后复查,值得临床进一步深入研究和推广应用。

Objective To assess the feasibility of the ＂double- low＂ CT angiography- low-kilovolt and low contrast agent dose in cerebral and neck angiography. Methods In this study, low contrast agent dose-35 ml would be used in cerebral and neck CT angiography. Twenty patients, clinically suspected the insufficiency of head-and-neck artery, were divided into two groups. One group（10 patients）took the conventional tube voltage-120 KV,while the other group（10 patients）took the 80 KV tube voltage, both the amount of contrast agent were 35 ml, and the injection rate was 5ml/s, then injected 40 ml saline with the same rate. Both of two groups take auto- Care dose 4D and Safire reconstruction, according to the original images and Maximum intensity projection（MIP）, comparing the display of the vessels in cerebral and neck, calculating the radiation dose, and the density, noise, signal-to-noise ratio, contrast-to-noise ratio of the parenchymal with different kilovolts, then take statistical analysis. Results Results The qualities of the images to both of the groups respectively are 5.833±0.100 and 5.856±0.133, P=0.694〉0.05; Noise of the images respectively is 2.261±0.026 and 2.522±0.031,P=0.000〈0.05, the noise is markedly increased; The radiation doses are 412.4±49.2 and 101.8±11.6, P=0.000〈0.05, the radiation doses are dramatic declined. Conclusion With the use of ＂double-low＂ in dual-energy CT in cerebral and neck angiography, not only ensuring the images could be used to the clinical diagnose, but also reducing the radiation dose and the contrast agent dosage; In cerebral and neck angiography, it is hopefully used in the screening and reexamination during therapy, and it is worthy of further study and application.