Observation Study Of 320-slice CT Perfusion Imaging In The Diagnosis Of Middle Cerebral Artery Stenosis

Objective Observational study of 320 rows of brain CT perfusion imaging combined with 4D-CTA in diagnosis of cerebral artery stenosis, observe the perfusion abnormalities in brain perfusion parameters of change and head and neck vascular stenosis, sum up the clinical value of CT perfusion.Methods and Materials From December 2013 to December 2015 at the Zhengzhou University Department of Radiology Department of CT Toshiba 640 slice CTP was examined in 300 patients.The whole brain CT perfusion scan was performed by using the 640 slice dynamic volume Aquilion of Toshiba one CT and the new model of whole cerebral perfusion.All patients were in intermittent period of onset within 24 hours of whole brain perfusion CT scanning and CTP before CT scan to determine the intracranial bleeding. Before the examination, all the patients and their families are required in reading written patient informed consent signed.6080 original image data of the whole brain CT dynamic volume image obtained by scanning were transmitted to thepost processing workstation, and the 19 volume dynamic scan data packets were imported into the Vitrea 6.3 post processing workstation of the Toshiba.Automatic generation of cerebral blood flow(CBF), cerebral blood volume(CBV), mean transit time(MTT), time to peak( TTP) and delay time(DLY) and other parameters.In the color perfusion map, the absolute value of the perfusion parameters of the corresponding ROI of the contralateral side was acquired automatically by means of the mirror measurement tool, and the average value of the 2 time was measured.The measurement results as the absolute value of the perfusion parameters, the absolute value of the perfusion parameters of the narrow side and the absolute value of each parameter, you will get the relative values of the perfusion parameters: r CBV, r TTP, r CBF and r MTT.Will import data Toshiba Vitrea 6.3 after processing workstation automatic subtraction angiography, the vessel analysis software can obtain volume rendering(VR), multi planar reformation(MPR) and maximum intensity projection(MIP) and image.Using 4D-CTA combined with head and neck Willis to observe the integrity of the development of CTA ring, and analyze the relationship between the parameters and perfusion parameters.The stenosis rate was calculated according to the North American symptomatic carotid artery intimal resection test(NASCET).By the two have 5 years imaging diagnosis experience of our hospital department of Radiology physician diagnosed in blind to the general information of patients and vascular stenosis severity, the image of measured data, then under different degree of stenosis of unilateral middle cerebral artery perfusion were compared to each perfusion parameters and the degree of MCA stenosis correlation analysis and evaluation.All data were used SPSS l9.0 were statistically analyzed and statistical data all with all numbers plus standard difference( sx �) said that each quantitative data for statistical analysis before should first normality and homogeneity of variance test, test the level of ?=0.05, P < 0.05 when difference was statistically significant.(1) Bilateral perfusion data were tested by paired sample t test, and the data between groups were compared by independent sample t-test.(2) Paired t-test was used to compare the data of different levels of stenosis and contralateral side of the group, and the relative value of the perfusion parameters in different degree of stenosis group was compared using single factor analysis of variance analysis.(3) Compare thecorrelation of MCA with different stenosis degree and the relative value of each perfusion parameters using Spearman correlation analysis.(4) Using 4D-CTA to observe the integrity of Willis ring development, analysis of the relationship between the 4D-CTA and perfusion parameters.(5) Severe stenosis and occlusion group in collateral circulation open and not open group between the perfusion parameters relative value was used to compare two independent samples t test, different collateral circulation compensatory pathways of hemodynamics in patients with statistical difference compared with the Wilcoxon rank sum test.Results 1.Comparison of absolute value of perfusion parameters in different degrees of MCA stenosis and contralateral side in different degree stenosis group:(1) in the mild stenosis group, there was no significant difference(P>0.05) compared with MTT, CBV and CBF, but the difference was statistically significant(P<0.05) compared with TTP.(2) in the moderate stenosis group, there was no significant difference between the two groups(P>0.05); the difference was statistically significant(P<0.05) between the two sides of the CBF, TTP, and MTT.(3) severe stenosis to occlusion group, compared to the two sides of CBV, the difference was not statistically significant(P>0.05); CBF, TTP, MTT was significantly increased, the difference was statistically significant(P<0.05) on both sides of the perfusion parameters. 2.Comparison of the relative values of various perfusion parameters in MCA stenosis and contralateral side of different degree stenosis group:(1) there were significant differences between r CBF and r MTT(P<0.05), while P>0.05 and r CBV did not show statistically significant differences(r TTP) between the three groups.After comparing the two groups, the difference of r CBF between the mild stenosis group and the severe stenosis and infarction group was statistically significant(P=0.004). With the increasing of the degree of stenosis, r CBF gradually became smaller, indicating that the more severe the CBF is, the lower it is.(2) the difference of r MTT between the three groups was statistically significant(P=0.001, P=0.02),and with ith the increase of the degree of stenosis, r MTT gradually increased,indicating that the more severe arterial stenosis, the greater the value of MTT.(3)Correlation analysis between the relative value of perfusion parameters and the degree of stenosis:The severity of stenosis was negatively correlated with the relative value of r CBF,and the greater the degree of stenosis, the smaller the absolute value of CBF, the relatively close relationship.The severity of stenosis was positively correlated with the relative value of r TTP.and the greater the degree of stenosis, the greater the absolute value of TTP, but the relative relationship is relatively weak.The severity of stenosis was positively correlated with the relative value of r MTT, that is, the greater the degree of stenosis, the greater the absolute value of MTT, the more closely related to the relationship between the degree of stenosis and the severity of the stenosis.There was no significant correlation between the degree of stenosis and the relative value of r CBV. 3.Comparison of the difference between the vascular side and the contralateral side of the value of the perfusion parameters of MCA bilateral stenosis or occlusion.Compared with the contralateral side, the CBV was slightly elevated, the difference was not statistically significant(P>0.05).While CBF was significantly reduced, MTT and TTP were slightly or significantly increased, and the differences between the three were statistically significant(P<0.05).CBF, MTT, TTP and non responsibility vascular side were compared, the difference was statistically significant(P values were 0.006,0.004,0.001 respectively). 4.Severe stenosis and occlusion group, 65 cases of the formation of collateral circulation, severe stenosis to occlusion group in perfusion abnormal collateral circulation open and not all perfusion parameters: collateral circulation open group and open group RTTP value differences were statistically significant(P<0.05). 5.Comparison of collateral circulation open group in different collateral circulation pathway between perfusion parameters, r TTP and r MTT differences between the two have statistical significance(P<0.05), shows that the different collateral circulation between TTP and MTT is differentiated, compensatory time is different.And the difference between the two kinds of collateral pathways between r CBF and r CBV have no statistical significance(P>0.05), and it shows that ndifference of different collateral pathways of cerebral blood flow and blood volume changes in local.Conclusions 320 row CT whole brain dynamic volume imaging combined the 4D-CTA examination can fully show the location of cerebral ischemia, scope, changes of cerebral blood flow perfusion parameters, corresponding head artery stenosis and collateral circulation compensation, for the early diagnosis and treatment of ischemic cerebrovascular disease provides image basis.