多层螺旋CT低剂量CTA评价大脑动脉的可行性

目的探讨64层MSCT 80 kV扫描使用低剂量对比剂的CTA评价大脑动脉的可行性。方法 2012年8月~2013年6月间住院拟做大脑动脉检查的患者62例,随机分成Ⅰ组(使用120 kV CT扫描和注射80ml碘海醇)和Ⅱ组(使用80 kV CT扫描和注射50 ml碘海醇加30 ml生理盐水)。其中I组31例(男17例,女14例,年龄37~76岁,中位年龄63岁,体重40~71 kg),Ⅱ组31例(男16例,女15例,年龄36~74岁,中位年龄59岁,体重38~73kg)。扫描后测量CTA图像中大脑中动脉M1段及基底动脉内的CT值、横轴位图像噪声及信噪比,并对大脑Willis环的VR三维图像进行3级评分;记录辐射剂量指标CTDI_(vol)和DLP。结果Ⅰ组大脑中动脉M1段和基底动脉的CT值为303.01和302.25和Ⅱ组大脑中动脉M1段和基底动脉的CT值为的307.19和306.38 HU,两组间具有显著的统计学差异(P0.05);I组图像的噪声大于Ⅱ组,但大脑Willis环的显示Ⅱ组稍优于I组。结论 64层MSCT80 kV扫描使用50 ml碘对比剂加30 ml生理盐水的CTA成像不仅能显著降低辐射剂量和碘对比剂用量同时可以保证大脑动脉的图像显示质量,对评价大脑动脉是可行的。

Feasibility of low-dose cerebral CT angiography

Objective To assess the feasibility of low-dose cerebral CT angiography（CTA）.Methods From August 2012 through June 2013,62 patients who underwent 64-detector-row CTA were randomly divided to two groups using conventional method of 120 kV and 80 mL of intravenous Iohexol（17 men,14 women,age range：37-76 years,median：63 years,body weight：40-71 kg）or low-dose method of 80 kV and 50 mL of intravenous Iohexol followed by 30 mL of normal saline（16 men,15 women,age range：36-74 years,median：59 years,body weight：38-73 kg）.The CT values of the M1 segments of the middle cerebral arteries（MCA）, basilar arteries,noise and signal-to-noise ratios on the axial images were determined.The quality of the circles of Willis on the 3 D volume rendered images was scored.The radiation dose indexes including CTDIvol and DLP were recorded.Results The CT values of the M1 segments of MCA and basilar arteries were significantly（P〈0.05）higher using the low-dose method（307.19,306.38）than those of conventional method（303.01,302.25）.The noise was lower and the image quality scores of the circles of Willis were higher with the low-dose method as well.Conclusion Low-dose cerebral CTA improves the image quality and significantly decrease the dose of radiation and iodinated contrast.