Explore The Application Of Dual-source CT Dual-energy Technique In Evaluating Renal Perfusion Level In Aortic Dissection

Background and ObjectiveAortic dissection(AD)refers to the intimal rupture of the aorta due to various reasons.The intraluminal blood enters the medial membrane through the ruptured intimal port,forming a true and false double cavity,and extends along the long axis of the aorta.AD is an acute and severe disease in the clinic.If it is not diagnosed and treated properly,hypoperfusion and various complications caused by AD or dissection surgery will further damage the human body.Acute kidney injury(AKI)is one of its common complications.In recent years,the diagnosis of arterial dissection using CT has gradually become mainstream.Due to the characteristics of AD,if the renal perfusion level can be effectively evaluated at the same time as the diagnosis or review by aortic imaging(CTA),the renal injury can be predicted early and the prognosis improved.Dual-source CT(DSCT)has two sets of tube-detector systems that can perform high-and low-energy ray scanning at the same time.According to the different attenuation characteristics of substances with different densities under two energy rays,material composition separation can be achieved.The density image of the extracted iodine material is the iodine map,which can sensitively show the difference in the distribution of iodine ions in organs.The purpose of this study was to compare the differences between hypoperfusion kidneys and normal kidney parameters in AD patients by using dual-source CT dual-energy scanning and post-processing techniques,so as to explore whether the dual-energy CT technology was accurate in evaluating renal insufficiency in AD.Materials and methodsForty patients with AD or AD stent implantation were collected from January 2019 to August 2019.Six patients with primary renal disease were excluded,and the remaining had 22 males,aged 44 to 66,with an average age at 55.6±6.6 years old.Twenty-eight cases were reviewed after AD,and 6 cases were new AD.The 34 patients underwent DSCTA and then performed dual-source CT dual-energy scanning.The images were uploaded to a workstation and processed by image post-processing software to obtain the MIP,MPR,VR,and dual-energy scan post-processed images(virtual plain scan images of renal perfusion and iodine maps).Senior diagnostic imaging doctors evaluated DSCTA post-processed images and divided the resulting kidney images into normal group and hypoperfusion group,and then the ROI technique was used to determine the CT value,iodine concentration,contrast enhancement rate and lipid content of normal group and hypoperfusion group.SPSS 22.0 software was used for statistical analysis.The data was expressed as mean±standard deviation(x±s).A paired t-test was used to analyze whether the values in the abnormal perfusion area of the dual-energy kidney and the normal control side were different(CT value,iodine concentration,contrast enhancement rate,lipid content).The difference was statistically significant with P<0.05.ResultsAmong the 34 patients with DSCTA results,30 cases were found to have renal hypoperfusion,all of which were unilateral renal impairment.Among them,28 cases were postoperative,and 2 cases were newly developed.Another patient was found to have a round-like suspected hyperperfusion zone in the kidney,which was judged to be a stone.Virtual plain scan of renal perfusion and iodine map revealed that renal perfusion was reduced in 26 cases,renal perfusion defect in 4 cases,and intra-renal stones in 1 case,which were consistent with DSCTA results.The ROI of the renal perfusion reduction area and the normal control side were set and the corresponding data was measured.Statistical analysis showed that the CT value,iodine concentration and rate of contrast enhancement in renal hypoperfusion group were lower than those in control group(t=9.71,P<0.05;t=9.04,P<0.05;t=8.01,P<0.05).There was no statistical significant difference in lipid content between the renal hypoperfusion group and control group(t=1.43,P=0.164).ConclusionsUsing dual-source CT dual-energy technology can more effectively evaluate renal perfusion in patients with AD,detect renal perfusion abnormalities and prompt renal injury in time.