The Radiomic Analysis Of Intracranial Atherosclerotic Plaque In Vivo And In Vitro Based On High-resolution Magnetic Resonance Imaging

Part 1 Study on the morphological and radiomic characteristics of intracranial atherosclerotic plaques in vivoPurpose: Intracranial atherosclerotic disease(ICAD)is a major cause of ischemic cerebrovascular events worldwide.High-resolution magnetic resonance imaging(HR-MRI)has been used to characterize intracranial plaque.This study aims to evaluate a quantitative radiomic approach based on HR-MRI to differentiate symptomatic intracranial artery plaque from asymptomatic plaque.Methods: This study retrospectively analyzed 158 patients with middle cerebral artery and basilar artery stenosis underwent HR-MRI between September 2013 and October 2016.Patients were scanned with T1 and T2 weighted imaging,and T1 imaging following Gd contrast injection(CE-T1).The stenosis value,plaque area/burden,lumen area,intraplaque hemorrhage(IPH),contrast enhancement ratio and 109 quantitative radiomic features were extracted and compared between symptomatic and asymptomatic patients.Multi-variate logistic analysis and a random forest model were used to evaluate the diagnostic performance.Results: According to the result of the clinical and morphological features,smoking(odds ratio [OR]=2.724;95%CI,1.200-6.183),IPH(OR=11.340;95%CI,1.441-89.221)and enhancement ratio(OR=6.865;95%CI,1.052-44.802)were independently associated with symptomatic plaques.The combined smoking,IPH and enhancement ratio had an area under the curve(AUC)of 0.714 for identifying symptomatic plaques.Radiomic features in T2 WI,T1WI and CE-T1 WI images were associated with symptomatic plaques,whose AUC respectively are 0.801,0.835 and 0.846.The combined all radiomic approach had a significantly higher AUC of 0.953.Combination of all features reached an AUC of 0.976,with accuracy of 87.4%.Conclusion: Radiomic analysis of intracranial artery plaque on HR-MRI accurately distinguished between plaques in patients who were symptomatic and plaques in patients who were asymptomatic.The highest accuracy was achieved by combining radiomic features with traditional assessment of clinical and morphological features.Part 2 An Initial Study on the radiomic characteristics of intracranial atherosclerotic plaques in vitroPurpose: The study aims to evaluate the stability of intracranial atherosclerotic plaque in vitro and further analyze the radiomic features of the unstable plaque using the vessel wall imaging on 3.0 T magnetic resonance imaging(MRI)on the basis of pathological classification.Methods: 40 atherosclerotic arteries from 14 cases(8 males and 6 females,average age 79.14±10.34 years old)were collected on the department of pathology in the university and the hospital from January 2013 to June 2015.3.0T MRI was performed on the lesion.After the image scanning was completed,the vascular pathological specimen should be processed,and the plaque on MRI should be matched with the one on the pathology level.According to the pathological classification criteria,the plaques were classified into stable plaque and unstable one.3D-slice software was used to manually sketch the plaques on MRI to extract the radiomic characteristics.Statistical analysis was carried out by random forest method.Results: There are 49 stable plaques and 56 unstable ones by the pathological classification.The radiomic model of intracranial atherosclerotic plaques on the two sequences(T1WI,T2WI)had a better performance on discriminating the stability of the plaques.In addition,the accuracy on T1 WI and T2 WI were 0.832,0.813,and AUC value was 0.897 and 0.920,respectively.When combined with all the radiomic features,the accuracy was up to 0.861 and the AUC value was 0.945.Conclusion: The radiomics based on the vessel wall imaging of 3.0T high-resolution MRI can quantitatively and accurately assess the stability of the intracranial plaques in vitro.The radiomic features of unstable plaques have different performances in the two sequences(T1WI and T2WI).Combining all the radiomic features can predict the stability of the ex-vivo plaque more accurately.Part 3 A comparative study on the radiomic characteristics of intracranial atherosclerotic plaques between in vitro and in vivoPurpose: This study was based on the previous researches on the radiomic analysis of intracranial atherosclerotic plaque in vitro and in vivo,and analyzed the correlation between the radiomic characteristics of the intracranial atherosclerotic plaque in vitro and vivo.The difference between the classification by clinical symptoms and pathological criteria was judged,and the consistency on the symptomatic atherosclerotic plaque and the unstable plaques was assessed.Methods: The radiomic measurement on the plaque in vitro and in vivo was shown in the first part and the second part.According to the radiomic characteristics of the plaques in vitro,the same radiomic characteristics were found out on the same sequences.And based on the pathological classification criteria,intracranial atherosclerotic plaques in vivo were divided into stability plaques and unstable ones with the same radiomic characteristics.Cohen's kappa(?)value was used to identify the consistency between the classification by clinical symptoms and pathological criteria.Results: There were two same radiomic characteristics on T2 WI and T1 WI,respectively.After the consistency analysis,kappa values by the four radiomic features which could discriminate the stability of the plaque through two classification method were 0.084,0.107,0.076 and 0.084 respectively,and the test had no statistical difference(p > 0.05).The symptomatic plaques which should be the unstable plaque on the pathological classification had a relatively low sensitivity and a relatively high specificity.The average positive predictive value was 0.475,and the negative predictive value was 0.608.Conclusion: The radiomic analysis can be used to distinguish the nature of the intracranial atherosclerotic plaques both in vitro and in vivo.But the consistency between the symptomatic classification and pathological classification was poor.Symptomatic atherosclerotic plaques were low positive predictive values for unstable plaques,and asymptomatic plaques were more likely to stabilize plaques.