个体化低流速注射方案联合低管电压在低BMI受检者头颈部CTA成像的应用研究

Application of individualized low flow rate injection scheme combined with low tube voltage in head and neck CTA imaging of low BMI subject

目的探讨个体化低速率对比剂注射方案联合低管电压扫描在低体质量指数(body mass index,BMI)受检者头颈部CT血管成像的可行性。方法选取我科2020年1月—2020年11月低BMI受检者头颈部CTA检查90例进行研究,随机分成三组,每组30例。A组80 kV扫描,低流速、低总量注射方案;B组120 kV扫描,高流速、低总量注射方案;C组为120kV扫描条件,高流速、高总量注射方案。对比各组注射流速、注射总量、辐射剂量长度乘积(dose legth product,DLP),评价各组图像的主动脉弓、颈总动脉、基底动脉、胸锁乳突肌中段的CT值、信噪比及对比信噪比,由两名有经验的放射科医生对各组图像质量进行主观评价。结果图像质量主观评价A、B两组图像评分集中在4分段,C组图像评分集中在3分段,A、B组与C组主观评分比较差异有统计学意义(P<0.05)。A组对比剂注射流速和DLP比B、C组分别下降27.75%、47.10%;A、B组对比剂注射总量较C组下降39.87%,差异有统计学意义(P<0.05)。A组各血管CT值对应比B、C组数值稍高,除主动脉弓CT值外其余血管客观参数对比均有差异(P<0.05)。结论低BMI受检者头颈部CT血管个体化低流速精准对比剂注射方案联合低管电压扫描技术在获得满足诊断要求图像质量的前提下,既能降低受检者对比剂注射速率和注射风险,又能降低辐射剂量,值得推广应用。

Objective To explore the feasibility of individualized low rate contrast agent injection scheme combined with low tube voltage scanning in CTA imaging of low body mass index(BMI)subjects head and neck.Methods Ninety cases of head and neck CTA examination of low BMI subjects in our department from January 2020 to November 2020 were selected for the study,and randomly divided into three groups with 30 cases in each group.Group A applied 80 kV scanning,low flow rate and low total volume injection scheme.Group B applied 120 kV scanning,high flow rate,low total volume injection scheme.Group C applied 120 kV scanning,high flow rate and high total volume injection scheme.The injection velocity,injection volume,radiation dose length product(DLP)among three groups were compared.In each image of the aortic arch,common carotid artery,basilar artery and the central part of sternocleidomastoid,the CT value,the signal-to-noise ratio and contrast-to-noise ratio were evaluated.Two experienced radiologists performed image quality evaluation.Results Image quality in group A and B by subjective evaluation got 4 points out of 4,and group C got 3 points out of 4,and there was statistical difference between group A,B and C in subjective evaluation of image quality(P<0.05).The injection velocity and DLP of contrast agent in group A were 27.75%and 47.10%lower than those in group B and C,respectively.The total amount of contrast agent injection in groups A and B was decreased by 39.87%compared with group C,with statistical difference(P<0.05).The corresponding CT values of each vessel in group A were slightly higher than those in group B and C,and there were statistically significant differences in the objective parameters of other vessels except for aortic arch(P<0.05).Conclusion The combination of individualized low flow rate and precise contrast agent injection scheme with low tube voltage scanning technology for low BMI subject could not only reduce the injection rate and risk of contrast agent,but also reduce radiation dose,on the premise of meeting the diagnostic requirements of image quality.It is worthy of popularization and application.