低管电压技术在腹主动脉及下肢动脉CT成像中的可行性研究  

Feasibility of Low Tube Voltage CTA in Abdominal Aorta and Lower Extremity Artery

作　　者：王敏[1] 李剑[1] 

机构地区：[1]山东省济宁市第一人民医院CT室

出　　处：《中国医学计算机成像杂志》2014年第1期68-71,共4页Chinese Computed Medical Imaging

摘　　要：目的:比较128层CT低管电压(80 kV)和标准管电压(120 kV)腹主动脉及下肢动脉成像(CTA)的辐射剂量和图像质量,探讨低管电压扫描的可行性。方法:48例行腹主动脉及下肢动脉CTA的患者随机分为A(120 kV、120 mAs)、B(80 kV、120mAs)两组,每组24例。2名研究者分别对图像质量进行定量和定性分析。测定血管内CT值、血管内噪声N,计算信噪比CNR。采用4分法评价图像质量。记录剂量长度乘积DLP。对两组间各值的差异进行统计学分析。结果:B组各节段血管CT值均高于A组,差异有统计学意义(P<0.05)。B组血管噪声(57.95±19.23)高于A组(22.78±6.15),差异有统计学意义(P<0.05),但A、B两组CNR无统计学差异(15.69±5.39 vs.14.85±5.61,P﹥0.05)。A、B两组各节段血管图像质量主观评分无统计学差异(P﹥0.05)。B组DLP明显低于A组(274.96±20.72 mGy·cm vs.1025.50±64.15 mGy·cm),差异有统计学意义(P<0.05)。结论:低管电压腹主动脉及下肢动脉CTA可以在较低辐射剂量下获得满足诊断要求的图像质量。Purpose： To compare the radiation dose and image quality of abdominal aorta and lower extremity artery CTA by using 80 kV and 120 kV tube voltage on a 128-slice CT and to evaluate the feasibility of low tube voltage technique. Methods： Forty-eight patients who underwent abdominal aorta and lower extremity artery CTA were randomly assigned to two different protocols in this trial： group A （n=24） was examined with 120- kV protocol and group B （n=24） was examined with 80-kV protocol. Objective indices such as vascular attenuation, image noise （N） and contrast-to-noise ratio （CNR） were analyzed. Subjective image quality was assessed by two observers in consensus using a four-point scale. Dose length product （DLP） was recorded. Image quality and radiation dose were compared with t test between the two groups. Results： Vessel attenuation was significantly higher in group B than that in group A （P〈0.05）. Noise was significantly higher in group B than that in group A （57.95±19.23HU vs. 22.78±6.15HU, P〈0.05）, however, there was no significant difference of CNR between them （15.69±5.39 vs.14.85±5.61, P〉 0.05）. Subjective image quality was rated similar in both groups （p〈0.05）. The effective dose of group B was significantly lower than that of group A （DLP：274.96±20.72 mGy.cm vs. 1025.50±64.15 mGy-cm, P〈0.05）. Conclusion： Eighty kV tube voltage is feasible for abdominal aorta and lower extremity artery CTA, the radiation dose can be significantly reduced and the image quality can meet [he diagnostic] request.

关 键 词：体层摄影术 X线计算机 血管造影术 辐射剂量 

分 类 号：R816.2[医药卫生—放射医学]