自动管电流调制范围选择对头颈动脉CTA的辐射剂量及图像质量影响  

Effect of automatic tube current modulation range on radiation dose and image quality of head and neck CT angiography

作　　者：华海琴[1] 康德强[2] 徐晓娟[3] 李超[1] 刘冰[1] 刘明[1] 傅瑶[4] 王志群[1] 

机构地区：[1]北京中医药大学东方医院放射科,北京100078 [2]北京大学国际医院放射科,北京102206 [3]北京师范大学医院放射科,北京100088 [4]北京中医药大学东方医院人事科,北京100078

出　　处：《影像诊断与介入放射学》2017年第1期57-61,共5页Diagnostic Imaging & Interventional Radiology

摘　　要：目的探讨相同管电压和噪声指数(NI)条件下,自动毫安调制范围的选择对头颈动脉CTA辐射剂量及图像质量的影响。方法将29例患者随机分为2组,进行头颈动脉CTA检查。A组管电压为120 k V,管电流调制范围为150~600 m A;B组管电压为120 k V,管电流调制范围为150~400 m A。图像质量客观评价:测量主动脉弓、颈总动脉分叉部、基底动脉中部的CT值和噪声,并计算信噪比(SNR),图像质量主观评价:对血管后处理图像进行评分,包括容积再现(VR)、最大密度投影(MIP)及曲面重组(CPR)等。记录并统计辐射剂量参数,包括CTDIvol和DLP,同时记录主动脉弓、颈4椎体、齿状突、垂体窝水平层面管电流的值。结果两组主动脉弓、颈总动脉分叉部、基底动脉腔内信噪比无明显统计学差异。两组图像主观质量评分未见明显统计学差异。两组辐射剂量比较,A组CTDIvol、DLP显著大于B组。A、B组在主动脉弓水平组织较厚,管电流均保持为最大值;主动脉弓、颈4椎体水平、齿状突,A组管电流高于B组,差异具有统计学意义;两组垂体窝水平管电流差异无明显统计学意义。结论合理适当的选择管电流调节范围,有效利用管电流自动调节技术,有助于在保证图像质量的同时降低头颈CTA的辐射剂量。Objective To investigate the effects of automatic modulation range of m A on the radiation dose and image quality of head and neck CT angiography（CTA） at the same voltage and noise index.Methods 29 patients underwent head and neck CTA using 120 k V tube voltage were randomly divided into one group at 150-600 m A and another group at 150-400 m A tube current modulation.The CT densities and noise of aortic arch,common carotid artery bifurcation,and middle of the basilar artery were measured.The ratio of signal to noise was calculated.The blood vessel visualization was scored on volume rendering,maximum density projection,and surface reconstruction images.The radiation dose parameters including CTDIvoland DLP as well as the tube current of the aortic arch,4th cervical vertebra body,dentate process,and the horizontal plane of the pituitary fossa were recorded.Results There was no significant difference in the qualitative scores and ratios of signal to noise of the aortic arch,common carotid artery bifurcation,and basilar artery in both groups.The CTDIvoland DLP of the 150-600 m A group were significantly higher than that of the 150-400 m A group.In both groups,the tube current was maximal at the level of aortic arch.C4 whereas the tube current was significantly higher in the odontoid process and the pituitary fossa of the 150-600 m A group than that of the 150-400 m A group.There was no significant difference between the two groups in the horizontal tube current of the pituitary fossa.Conclusion Selecting the optimal range of the tube current and effectively using automatic tube current adjustment technology may help to improve image quality and reduce the radiation dose of head and neck CTA.

关 键 词：体层摄影术 X线计算机 头颈动脉CTA 自动管电流 低剂量 

分 类 号：R816.1[医药卫生—放射医学]