Preliminary Study On The Application Value Of ZTE Sequence In Calcified Plaques Of Intracranial Arterial Wall

Objective:Atherosclerosis(AS)is a common chronic vascular disease caused by multiple factors,in which calcification has a high incidence and may affect the stability of AS.At present,High resolution Magnetic Resonance Vessel Wall Imaging(HR-VWI)is the best magnetic resonance sequence for displaying vascular walls and evaluating plaque components.However,it does not display calcification well and needs to be analyzed in conjunction with Computed Tomography(CT).Therefore,this article envisions the use of Zero Echo Time(ZTE)imaging technology to demonstrate the ability of structures with low hydrogen proton content such as bone cortex,cartilage,and periosteum,and to preliminarily explore the effectiveness of ZTE technology in displaying calcified plaques on the wall of intracranial arteries.Methods:Thirty three patients with intracranial atherosclerosis and multiple calcium plaques diagnosed by computed tomography angiography(CTA)in our hospital were collected in the study,and accepted the ZTE and HR-VMI scans of intracranial vessels.The interval between CT and MRI scans for all patients didn’t exceed a month.Firstly,two experienced imaging physicians were requested to score CT and ZTE images in terms of significance and contrast of calcified plaques,diagnostic confidence,and image quality,in a double-blind method.A 5-point scale was used to evaluate the differences in the display quality of calcified plaques between CT and ZTE images,and analyzed by Wilcoxon paired coincidence rank sum test;Using the Weight Kappa test to analyze the consistency between evaluators;Then,a comparative analysis was conducted on the distribution and quantity of calcified plaques among CT,ZTE original and post-processing images,and HR-VWI;Using Mc Nemar paired sample test to compare the sensitivity and specificity of various methods for detecting calcified plaques;And ICC was used to analyze the consistency for detecting calcified plaques among CT and ZTE original and post-processing images,as well as HR-VMI;Secondly,the calcification plaque’s maximum diameter that perpendicular to the arterial wall was measured in the CT and ZTE original,post-processing,and HR-VMI images,respectively.And using the Bland-Altman plot to compare the consistency of calcified plaque diameter in different images.Then,the correlation of calcification diameter between ZTE and CT was evaluate by linear regression.Finally,the Weight Kappa test was used to analyze the consistency between ZTE and CTA in evaluating the degree of vascular stenosis.Results:1.In terms of the significance and contrast of CT and ZTE imaging on calcified plaques,there was no statistically significant difference(p>0.05)in the scores of the two physicians,and there was good consistency(Kappa=0.784);In terms of diagnostic confidence,two physicians scored lower on a few ZTE images compared to CT,with a statistically significant difference(p<0.05).There was good consistency between evaluators(Kappa=0.678).In terms of image quality,one physician scored lower on ZTE,with a statistically significant difference(p<0.05).There was good consistency between evaluators(Kappa=0.522).2.Using CT as the reference standard,the sensitivity of HR-VMI for detecting intracranial arterial wall calcification was 95.42%,96.15%,67.65%,and the specificity was 89.58%,78.44%,and 52.82%,respectively,using ZTE raw data and post-processing images.In terms of sensitivity in detecting calcified plaques,there were significant differences(p<0.001)between HR-VMI and ZTE original images,as well as between HR-VMI and ZTE post-processed images,while there was no significant difference(p>0.05)between ZTE original images and ZTE post-processed images.In terms of specificity in detecting calcified plaques,there were significant differences(p<0.001)between HR-VMI and ZTE original images,as well as between HR-VMI and ZTE post-processed images,and there were also differences(p<0.05)between ZTE original images and ZTE post-processed images.In addition,the ICC analysis results showed strong consistency between ZTE and CT(ICC>0.9).The consistency between HR-VMI and CT was low(ICC>0.752),and the differences were statistically significant(p<0.05).3.According to the Bland Altman plot,there is high consistency in the diameter measurement of calcified plaques on CT and ZTE images,with almost all points within the 95%consistency interval.The mean difference between ZTE raw and post-processed images and CT images is 0.255mm and 0.382mm,respectively.However,the consistency of diameter measurement results between HR-VMI and CT images is poor,and the average difference between the two is 0.905mm.Linear regression analysis showed that both ZTE images had a strong correlation with CT(R~2=0.8764,0.8555),while the correlation between HR-VMI and CT was weaker than ZTE(R~2=0.5955).4.The consistency between CTA and ZTE in evaluating the degree of vascular stenosis is good(Kappa=0.779).Conclusion:ZTE imaging technology can not only obtain the similar display efficiency of vascular wall calcification with CT,and also display the vascular lumen well.It make up for the deficiency of conventional magnetic resonance imaging technology in displaying calcified plaque of intracranial artery wall,and may became an effective examination method for clinical risk stratification of vascular diseases.