| Background and purposeIn recent years,with the emergence of multi slice spiral CT and the application of advanced postprocessing techniques,CT angiography(CTA)is widely used in the diagnosis of vascular disease,CTA has simple and rapid imaging,high spatial resolution,non-invasive,multi angle repeated observation and analysis,low cost and high rate of correct diagnosis.Advantages of lesions therefore,CTA is often used as the preferred method in the clinical diagnosis of vascular diseases.At the same time,during the process of CTA examination,the radiation and the harm of iodine contrast agent to the whole body are attracting more and more attention,especially in elderly patients with renal insufficiency."Double low"technology is one of the most popular topics in the field at present,that is,the technology to reduce the radiation measurement of X-ray and the harm of contrast agent at the same time.Literature has shown that"double low"technology in the heart of coronary arteries,cranial vessels and other areas of more exploration,and the renal angiogenic image is relatively scarce.Kidney CTA examination abdominal pelvic organs and glands are more,so the application of double low technology in the kidney of CTA test in the major.The purpose of this experiment is to explore the application of 80kVp tube voltage and50ml isotonic contrast agent(270mgi/ml)in renal CTA examination of 60 elderly patients,while ensuring image quality,while minimizing X-ray radiation and the harm caused by contrast agents.Materials and methodsFrom 2016 08 to 2017 06 months in the CT room of the Second Affiliated Hospital of Zhengzhou University underwent renal artery or abdominal aortic CTA was examined in 160 patients,male 86 cases,female 74 cases,age 60-91 years,average(73.7+9.7),BMI(18.0~26.0kg/m~2),there were no differences between groups in gender,age,BMI(P>0.05).They were randomly divided into routine group:tube voltage 120kVp,tube current 120 mAs,contrast agent 70 ml(40 cases);tube voltage(80K Vp)and contrast agent(50ml)double low patients were divided into two low(150m As)group,double low(180m As)group,double low(210m As)group(40 cases)according to the tube current intensity.Were measured by SAFIRE iterative reconstruction after the measured renal artery,renal artery and abdominal aortic bifurcation branches of the CT value,image noise and calculate the SNR,CNR,effective radiation dose ED,the incidence of adverse reactions was analyzed by using5 score methods;two deputy director for information of radiologists independently assessed image quality.The statistical method was compared,and the test level was0.05.If P<0.05,the difference was statistically significant.ResultsThe CT values of the 4 groups were all greater than that of 300Hu,and the degree of vascular enhancement in the double low 3 groups was higher than that of the conventional group(P<0.05)with two low 3 groups(all P>0.05).bilateral renal artery and 4 small branches were clearly,vascular edge,renal artery score was 5;double low(150 m As)photos like particles slightly rough,noise slightly larger,abdominal aorta,bilateral renal arteries and 2 branches showed clear renal artery score was 3;double low(180m As)photos like noise is slightly big,abdominal aorta,bilateral renal arteries and 3 bilateral renal artery 4 small branches were clearly,vascular edge,renal artery score was 5.The image noise of the two low 3 groups was higher than that of the conventional group(all P<0.05).Compared with the routine group and the double low(210 m As)group,there was no significant difference in the difference between SNR and CNR(P>0.05),and the difference of SNR and CNR between the other groups was statistically significant(P<0.05).The effective radiation of double low(150 m As),double low(180 m As)group and double low(210m As)group decreased by 63.3%,56.2%and 48.8%compared with the conventional group,respectively,and the average image scores of all groups were all higher than 3 points.The average score of4.3 points in the conventional group,4.2 points in the double low(210m As)group was higher than that in the double low(180m As)group 3.4.There was no significant difference in the score between group 150m and group As(3.1 210m).There was no significant difference between the two groups(P>0.05),and the difference between the other groups was statistically significant(P<0.05).The difference between the two groups was not statistically significant(P>0.05).There was no significant difference between the two groups(P>0.05).The difference between the other groups was statistically significant(P<0.05).In the routine group,4cases of mild contrast reaction were found,and both of the two low groups did not appear.ConclusionsUnder the condition of 80Kv tube voltage and 50ml low concentration contrast agent,increasing the tube current(210mAs)appropriately,combined with the iterative reconstruction technology,can not only ensure the image quality,but also reduce the harm caused by the radiation dose and contrast agent,which has great clinical application value. |
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