低管电压对头部减影CTA图像质量和辐射剂量的影响

Low Tube Voltage Effect on Image Quality and Radiation Exposure at Cerebral Subtraction CT Angiography

目的评估低管电压设置对头部减影CT血管成像(CTA)图像质量的影响,以降低头部减影CTA的辐射剂量。资料与方法 52例患者分成两组,分别使用100kV和120kV管电压行头部减影CTA检查。比较两组图像质量和辐射剂量。结果 100kV组脑组织CT值、背景噪声、脑动脉CT值和强化对比度均明显高于120kV组(P<0.01),两组间脑动脉的信噪比(SNR)和强化噪声比(CNR)比较差异均无统计学意义(SNRt=0.389,P=0.699;CNRt=0.698,P=0.488),同时两组间背景噪声的影响程度及脑动脉显示效果比较差异均无统计学意义(背景噪声的影响程度Z=-0.761,P=0.446;脑动脉显示效果Z=-1.298,P=0.194),而100kV组比120kV组辐射剂量降低约36.3%(P<0.01)。结论运用100kV低管电压设置能明显降低头部减影CTA的辐射剂量,而图像质量保持良好。

Objective To evaluate the image quality of cerebral subtraction CT angiography（CTA） using low tube voltage setting,so as to reduce radiation exposure of cerebral subtraction CTA.Materials and Methods Fifty two patients who underwent cerebral subtraction CTA were divided to group 1 （using 100 kV ） and group 2 （using 120 kV）.Image quality and radiation dose were compared between two groups.Results CT attenuation of cerebral tissue and cerebral artery,background noise were higher in 100 kV group than in 120 kV group（P0.01）.There was no difference between two groups on SNR and CNR of cerebral artery（SNR,t=0.389,P=0.699;CNR t=0.698,P=0.488）.There was no difference between two groups on background noise effect and cerebral artery quality（background noise effect Z=-0.761,P=0.446;cerebral artery quality Z=-1.298,P=0.194）.The radiation exposure dose of 100 kV group was decreased 36.3% compared to 120 kV group （P0.01）.Conclusion The scan mode with 100 kV can reduce radiation exposure dose obviously,and keep good CTA image quality .