Volume模式下低管电压低对比剂量在头颅CTA中的应用价值  

作　　者：唐婷 王世威[1] 徐志超[1] 

机构地区：[1]浙江中医药大学附属第一医院,310006

出　　处：《浙江临床医学》2021年第5期732-733,736,共3页Zhejiang Clinical Medical Journal

摘　　要：目的探讨在volume模式下低管电压及低对比剂用量在头颅CTA检查中的应用价值。方法60例拟行头颅CTA检查的患者(BMI在18.5~25 kg/m^(2))随机分为观察组和对照组,各30例。观察组与对照组管电压分别采用100 kVp和120 kVp;管电流250 mA,对比剂量35 ml,两组一致。记录两组CT容积剂量指数(CTDIvol)及剂量长度乘积(DLP),由2名高年资影像医师以5分制对两组图像进行主观评价。采用CTA血管分析软件(Vitrea Extend Version6.7.3)得到后处理图像,计算得到颈内动脉(后膝段)、大脑中动脉(眶后段)、椎动脉(颅内段)、大脑浅静脉(上矢状窦)、脑组织(半卵圆中心脑白质)的信噪比(SNR)、对比噪声比(CNR)。采用独立样本t检验比较两组一般资料及各兴趣区CT值差异,采用McNemar卡方检验评价两组主观图像质量评分的一致性,采用秩和检验比较两组辐射剂量及两组间SNR和CNR差异。结果观察组显示较好的主观图像质量(评分优良56例、合格4例,优良率93.3%),与对照组(优良60例,优良率100%)比较差异有统计学意义(kappa=0.905,P<0.001)。观察组和对照组CTDIvol分别为16.4(14.6,16.8)和25.2(23.3,25.8)差异有统计学意义(Z=-6.436,P<0.001);观察组和对照组学DLP分别为229.3(204.4,268.4)mGy·cm和373.1(352.3,412.5)mGy·cm,差异有统计学意义(Z=-6.720,P<0.001);观察组大脑中动脉的SNR值为9.57(7.84,17.97),CNR值为8.17(6.97,15.97);对照组大脑中动脉SNR值为10.07(7.94,14.33),CNR值为8.94(6.9,12.52),两组SNR、CNR差异无统计学意义(P>0.05)。结论在volume模式下进行头颅CTA检查,降低管电压及低对比剂用量方法可行,同时在不影响图像质量的前提下可大幅度降低患者所接受的辐射剂量及对比剂量。Objective To study the value of low tube voltage and low contrast medium dosage in intracranial CTA examination with volume mode.Method 60 patients scheduled for CTA(BMI 18.5~25 kg/m^(2))were randomly divided into experimental group and control group,with 30 cases in each group.The experimental group and the control group were used in the tube voltage 100kVp and 120kVp respectively;tube current 250 mA and the contrast medium dose 35 ml was same in two groups.The CTDIvol and the dose length product(DLP)of the two groups were recorded.The image quality were evaluated by two senior doctors with a five-point scale subjectively.Post-processing images were obtained using CTA vessel analysis software(Vitrea Extend Version 6.7.3).The signal to noise ratio(SNR)and the contrast to noise ratio(CNR)was calculated in five region of interests(ROIs):carotid artery(posterior knee segment),middle cerebral artery(posterior segment),vertebral artery(intracranial segment)of the veins(superior sagittal sinus),brain tssue(semiotid center white matter).The general information and the CT value of the five ROIs in two groups were compared by independent-samplesT test and the consistency of subjective image quality scores was evaluated by using McNemar's Chi-square test.The difference of the radiation dose,SNR and CNR were compared by the rank sum test.Result The experimental group showed a good subjective image quality score of 56 cases,4 cases qualified,good rate of 93.3%,while 60 cases were excellent with the control group,excellent and good rate of 100%,The difference was not significant in good rate between 2 groups(kappa=0.905,P<0.001).The CTDIvol of the experimental group and control group were 16.4(14.6,16.8)and 25.2(23.3,25.8)respectively(Z=-6.436,P<0.001).The DLP of the experimental group and the control group were 229.3(204.4,268.4)mGy·cm and 373.1(352.3,412.5)mGy·cm,respetively,the diference was significant(Z=-6.720,P<0.001).There was no significant difference in SNR and CNR between two groups in five ROIs(P>0.05).Conclusion

关 键 词：X线计算机体层摄影 辐射剂量 容积扫描 

分 类 号：R81[医药卫生—放射医学]