头颈部CTA两种扫描方式及其辐射剂量的比较分析

Comparison of the Image Quality and Radiation Exposure between Conventional and Subtractional CT Angiography of the Head and Neck with 64-slice Spiral CT

目的:优化头颈部CT增强扫描血管成像的扫描方式,减少其辐射危害。方法:回顾性地分析86例头颈部CT增强扫描血管成像的病例资料,其中行减影成像法及常规扫描成像法各43例,观察其成像质量,比较其单次扫描的CT剂量加权指数(CTDIvol)及剂量长度乘积(DLP)。结果:在扫描范围、扫描参数(kV、mAs、p、thin等)、对比剂注射流率和注射部位完全相同的情况下,常规扫描成像与减影成像法的图像质量相同,单次扫描CTDIvol相同,但DLP降低约48.26%左右。结论:常规扫描法能有效降低总曝光量和累计剂量长度乘积,可以有效地降低患者的辐射剂量,减少其辐射危害。

Objective：To compare the image quality and radiation exposure between conventional and subtractional CT angiography of the head and neck with 64-slice spiral CT.Methods：Patients were randomly assigned to a conventional or subtractional CTA protocol（n=43,respectively）.Contrast medium was injected automatically with bolus tracking.Other scanning parameters were kept constant.Effective dose was calculated on the basis of dose length product and volume CTdose index.Results：There was no significant difference in subjective image quality between protocols.Dose length product（DLP） for the conventional protocol was significantly reduced by about 48/26% as compared with the subtractional protocol（1992.35mGy/cm±5.51 vs 3850.76mGy/cm±5.56,P〈0.05）.Conclusion：Conventional scanning resulted in significant reduction of effective dose at head and neck CT angiography,without significant loss of objective or subjective image quality.