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Objective:To explore the value of 3.0 T high resolution MRI (HR-MRI) in the follow-up of drug treatment in acute and non-acute ischemic stroke caused by middle cerebral artery (MCA) plaque.Methods:The perspective study enrolled patients with ischemic stroke caused by MCA stenosis from October 2012 to October 2015 in the department of Neurology and Neurosurgery of Changhai Hospital Affiliated to Naval Medical University. All the patients underwent HR-MRI and then were divided into acute and non-acute stroke groups according to the intervels of the last symptom onset to the time of HR-MRI examination. All patients were informed consent to receive antiplatelet drug and intensive lipid therapy and followed up with HR-MRI. The HR-MRI sequence including T 2WI, T 1WI and contrast-enhanced T 1WI of vessel wall, and T 2WI and DWI of brain were routinely performed. T-test of paired samples was used to evaluate the changes of stenosis rate of vascular lumen, plaque enhancement degree, plaque volume and plaque burden on HR-MRI, and the NIHSS score of nervous system and blood biochemical indicators of the patients before and after treatment. Chi square test was used to compare the difference in ischemic event recurrcence between the acute and the non-acute stroke group. Results:A total of 31 acute stroke patients and 20 non-acute stroke patients were enrolled in the study. The mean follow-up time of acute stroke group was (671.71±522.86) days. Compare with the baseline, the stenosis rate of vascular lumen ( P=0.039), plaque enhancement degree ( P<0.001), plaque volume ( P=0.024) and plaque burden ( P=0.031) were all improved after the drug treatment, the NIHSS score of nervous system was also significantly improved, and the levels of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) in 12 patients were significantly decreased. The mean follow-up time of patients with non-acute stroke was (695.35±555.90) days. The stenosis rate of vascular lumen, plaque enhancement degree, plaque volume and plaque burden were slightly improved, but without statistical significance ( P>0.05). There were no significant changes in NIHSS score of nervous system, TC, triglyceride (TG) and LDL-C ( P>0.05), however the high density lipoprotein cholesterol (HDL-C) was significantly increased than that in the baseline ( P=0.02). During the follow-up period, no new cerebral infarction was found in the DWI images of the two groups. Six patients had transient ischemic attack (TIA) recurrence in the acute stroke group and 5 patients in the non-acute stroke group, there was no significant difference between both groups(χ 2=0.229, P= 0.632). Conclusion:HR-MRI can be used as an important evaluation method for the follow-up of MCA atherosclerotic plaque therapy. After antiplatelet therapy and intensive lipid-lowering therapy, the plaque volume and burden of MCA offending plaque, and plaque enhancement decreased in acute stroke patients but there was no significant change in non-acute patients.
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Objective To investigate the ability of quantitative radiomic method based on highresolution magnetic resonance imaging (HR-MRI) to distinguish between culprit plaques and non-culprit plaques of intracranial atherosclerosis.Methods Patients with middle cerebral artery and basilar artery stenosis underwent HR-MRI in Changhai Hospital Affiliated to the Naval Medical University from September 2013 to October 2016 were analyzed retrospectively.The minimum lumen area,plaque burden,severity of luminal stenosis,intraplaque hemorrhage (IPH),enhancement rate,and 109quantitative radiomic characteristics of the culprit and non-culprit plaques were measured.For clinical features and traditional plaque morphology,multivariate logistic regression models were used to determine independent risk factors for culprit plaque.A random forest-supervised machine learning method was used to determine the radiomic characteristics of distinguishing between symptomatic plaques and asymptomatic plaques.The receiver operating characteristic (ROC) curve was constructed,and the diagnostic efficacy was described by the area under the curve (AUC).Results During the study,158 subjects were enrolled,and they aged (59.42± 11.62) years.The plaques of 75 patients were located in middle cerebral artery,and the plaques of 83 patients were located in basilar artery.There were 111 symptomatic patients and 47 asymptomatic patients.Multivariate logistic regression analysis showed that smoking (odds ratio [OR] 2.724,95％ confidence interval [CI] 1.200-6.183),IPH (OR 11.340,95％ CI 1.441-89.221),and enhancement rate (OR 6.865,95％ CI 1.052-44.802) were the independent risk factors for culprit plaques.The AUC of these three characteristics for predicting symptomatic plaques were 0.605,0.584,and 0.590,respectively.The combination of the three cloud improve the test efficacy for the intracranial atherosclerotic culprit plaques,AUC could reached 0.714.Radiomic analysis showed that 22 radiomic characteristics extracted from T-2 weighted imaging,T1 weighted imaging,and contrast-enhanced T1 weighted imaging were associated with the culprit plaques.Their AUCs were 0.801,0.835,and 0.846,respectively.After the combination of all morphological and radiomic characteristics,AUC could reach 0.976,the accuracy rate was 87.4％.However,the difference was not statistically significant compared to the combined AUC of all radiomic characteristics (0.953) (P=0.275).Conclusion Radiomic analysis could accurately distinguish between the culprit plaques and non-culprit plaques of intracranial atherosclerosis,and is superior to the traditional morphological methods.
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Objective To explore the remodeling modes and the plaque distribution of atherosclerotic BA at 3.0T high resolution MRI.Methods 90 symptomatic patients with atherosclerotic stenosis of BA on digital subtraction angiography (DSA) (50 ％-99 ％) were recruited consecutively.Luminal area,vessel area of maximal narrow sites and the reference sites were measured.The differences of involved imaging parameters between negative group and positive group were analyzed.Results 51 patients with required imaging quality were enrolled finally.Among the 51 patients,the rate of positive remodeling cases was 72.5％ (37/51) and negative remodeling took over 27.5％ (14/51).Compared with the negative remodeling group,the positive remodeling group had greater plaque size,larger plaque burden percentage,and higher maximal wall thickness at maximal lumen narrowing sites.The plaques were mainly located at ventral wall of the vessel.Conclusion 3.0T high-resolution MR imaging could be applied in assessing the remodeling modes and plaque distribution of BA stenosis.
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Objective To observe diffusion changes of epiphysis of femoral head with ischemia of difference phases by line-scan diffusion weighted imaging(LSDWI),and determine whether LSDWI can provide temporal information and severity about ischemia of epiphysis.Methods lschemia was surgically induced in one hip of each piglet(n=25)and the other hip served as a normal control.Piglets were imaged before surgery and at 3 hours,72 hours and 1,3 and 6 weeks after surgery by using LSDWI.Apparent difrusion coefficients(A DC)in epiphysis of the femoral heads were calculated.Significant difierences in ADC values between ischemia group and control group were found by using paired t-test.After scan at individual time points,5 piglets were sacrificed for histological study each time.Results The ADC value in the ischemic femoral heads f(1.22±0.37)×10-3 mm2/s]decreased significantiy at 3 hours after surgery (t=3.914,P＜0.01),compared to that in control[(1.73±0.33)×10-3mm2/s},and increased at 72 hours[(2.15±0.32)×10-3mm2/s versus(1.70±0.22)×10-3 mm2/s](t=3.348,P＜0.01).Then ADC valne kept increasing until 6 weeks after surgery[(1.61±0.27)×10-3mm2/s in ischemia side vs (1.11±0.45)×10-3mm2/s in the control](t=4.136,P＜0.01).rrhe percentage change of the ADC value significandy increased at 3 hours,72 hours,1 and 3 week(s)after the surgery(P＜0.01),compared to that at the prior neighboring time point.No significant increase in the percentage change of ADC value was found between the 3rd week and the 6th week after the surgery(t=2.29.P＞0.05).Histological examinations revealed abnormal thickening within epiphyseal cartilage,and cartilaginous islands within ossified tissues.Growth disturbante wag found in form of focal growth plate disruption.Conclusions Dynamic changes of ADC values were found with the prolonged ischemia of the femoral head by LSDWI.It could serve as a useful marker for evaluating duration and extent of ischemic epiphyseal disruption.