MRI Manifestations Of Posterior Cerebral Circulation Ischemia And Evaluation Before And After Interventional Therapy

Background and purpose:Stroke is a common disease that threatens peopleundefineds health.(posterior circulation ischemia,PCI(posterior circulation ischemia)refers to cerebral ischemia caused by vertebrobasilar artery stenosis.By 2015,the number of deaths due to cerebrovascular disease in the world has reached six million three hundred and twenty six thousand one hundred,ranking second in the cause of death in human beings.In 2016,the Lancet magazine published a worldwide analysis of causes of death,and the average number of deaths due to cerebrovascular disease will increase by about 30.000 per year.Among 188 countries or regions in the world,China is the top country in the list of stroke risk factors.In all stroke cases,posterior circulation stroke accounted for about 20% of ischemic stroke,and vertebrobasilar artery stenosis accounted for 10.9% of stroke.The clinical observation noted that the mortality of stroke patients caused by severe stenosis or occlusion of basilar artery could exceed 70% without prompt treatment.Compared with anterior circulation ischemia,the clinical manifestations of posterior circulation ischemia are complicated,difficult to diagnose,poor therapeutic effect,high mortality and serious harm to human body.Therefore,the early prevention and diagnosis of post-circulatory ischemia can prevent the disability caused by the disease and save the lives of patients.Since Mr imaging can be multimodal,multi-directional,and without any radiation to the body,it is possible to detect it early with MRI imaging.Early diagnosis of posterior circulation ischemia.The most common cause of vertebrobasilar stenosis in clinical work is atherosclerotic plaques,and the nature of plaques(no plaque,stable plaque,unstable plaque)and the patientundefineds condition,The incidence and prognosis of posterior circulation cerebral infarction were closely related.With the development of interventional therapy,severe stenosis of vertebrobasilar artery and nearly occlusive lesion can improve the prognosis of patients by endovascular recanalization.However,large samples of evidence-based medicine are needed to support the safety and effectiveness of recanalization therapy.In the same way,individual treatment should be made according to the patientsundefined basic diseases,clinical symptoms and personal wishes,so the imaging manifestations play a key role in the choice of the therapeutic regimen,and so on,it is necessary to make individual treatment according to the patientsundefined basic diseases,clinical symptoms and personal wishes.Therefore,the purpose of this study is to evaluate the characteristics of MRI images in patients with post-circulatory ischemia,and to evaluate the improvement and imaging features before and after interventional therapy for the diagnosis of post-circulatory ischemia,and to evaluate the short-term follow-up of some of the patients undergoing interventional therapy.And reasonable treatment to provide scientific basis.Part1: MRI manifestation of cerebral posterior circulation ischemiaObject:To explore the characteristics of MRI in cerebral posterior circulation ischemia,and to provide scientific and reasonable basis for clinical treatment.Methods:From September 2017 to May 2018,75 patients with PCI diagnosed by digital subtraction angiography(DSA)in the interventional cerebral vascular disease area of Zhengzhou University People's Hospital were collected as the pathological group,including 45 males and 30 females,aged 46 to 82.The average age of(64 ±9)years was(64 ±9)years old.All patients underwent conventional plain scan,DWI,MRA,SWI,3D-ASL and DSC-PWI sequences with Siemens Prisma3.0T,and 25 patients underwent high resolution magnetic resonance imaging(high-resolution magnetic resonance imaging,)of cerebral vessels.HR-MRI)scanning.The ischemic lesions and the proportion of abnormal signal cases in each sequence of MRI in the lesion group were counted,and the stenosis of the vessels was analyzed on the original images of MRA.The mean values of CBF in each brain area were calculated by 3D-ASL,including bilateral frontal and parietal blood flow of anterior circulation,bilateral occipital lobe and cerebellar blood flow of posterior circulation.The CBV(cerebral blood volume),CBF(cerebral blood flow),MTT(mean transit time),TTP(time to peak)four groups of parameter values of ROI(region of interest)in the lesion group and the control group were measured by PWI.And 70 healthy adults with normal 3D-ASL and PWI perfusion in the same age group were selected as the control group,and the perfusion parameters were measured the same as before.Statistical analysis used SPSS 22.0 software to process the data,the counting data was expressed by n(%)and compared with X2 test.The Shapiro-Wilk-W test was used to determine whether the measurement data were in accordance with the normal distribution,the normal distribution was tested by T test,the value was expressed by x±s,the non-normal distribution was tested by Wicoxon rank sum test,and the value was expressed by median(quartile spacing).The difference was statistically significant(P < 0.05).Results:MRI multiple sequences of 75 patients with posterior circulation ischemia showed abnormal lesions in the posterior circulation region,including 15 in the left cerebellar hemisphere,18 in the right cerebellar hemisphere,35 in the bilateral cerebellar hemisphere,10 in the brainstem and 12 in the upper spinal cord.The MRI signal anomalies of different sequences are T1 WI sequence: 30.70%(23/75),T2 WI sequence: 60.0%(45/75),T2-flair sequence: 72.0%(54/75);DWI sequence: 90.60%(68/75);SWI sequence: 53.3%(40/75),PWI sequence: 86.6%)(65/75),PWI combined with DWI sequence: 96.0%(72/75),respectively.MRA sequence lesion group,and severe vertebrobasilar artery stenosis was found in 74 cases.The CBF value of anterior circulation in 3D-ASL sequence group was(65.4±3.6)ml/(100g.min),which was higher than that in posterior circulation(46.3±10.4)ml/(100g.min).The difference was statistically significant(P < 0.05).There was no significant difference in the anterior circulation(67.5±7.9)ml/(100g.min)compared with the posterior circulation(62.6±8.9)ml/(100g.min)in the control group(P >0.05).The CBF values of bilateral occipital lobe and cerebellum in the lesion group were lower than those in the control group,the difference was statistically significant.TTP in PWI lesion area of 75 patients with posterior circulation ischemia was(24.85±4.73)s,which was higher than that of TTP(21.94±4.47)s in the control group.There was a significant difference between the two groups(P < 0.05).The relative value of MTT(677.81±365.67)in the lesion group was higher than that in the control group MTT(590.35±288.08),and the relative value of CBV(683.96±202.70)?CBF(246.45±110.08)in the lesion group was lower than that in the control group CBV(750.56±256.96)?CBF(257.68±117.11),but there was no significant difference between the two groups(P > 0.05).In 25 patients with posterior circulation ischemia,the stenoses of the responsible vessels were found to be severe stenosis in the lumen and multiple plaques in the local area in the HR-MRI examination of the cerebral vessel wall in 25 patients with posterior circulation ischemia.Inflammatory cell infiltration was found in 64%(16/25)of unstable plaques.Conclusion:1.MRI is an important method for the diagnosis of cerebral posterior circulation.The positive rate of posterior circulation ischemia is different with different magnetic resonance imaging sequences.The diagnostic efficiency is SWI,PWI,T2-flair sequence,T2 WI sequence,SWI sequence and so on.2.The MRA manifestations of vertebral artery and vertebrobasilar artery in the patients with posterior circulation ischemia were mainly moderate or severe stenosis.SWI sequence could better guide the clinical use of drugs.3.3D-ASL sequence can be used to evaluate blood perfusion in patients with post-circulatory ischemia.The most sensitive parameter for diagnosis of PWI sequence is TTP.4.HR-MRI imaging of cerebral vascular wall has some value in evaluating pathological changes of cerebral vascular wall.Part2:Evaluation of MRI before and after interventional therapy for cerebral posterior circulation ischemiaObject:To evaluate the short-term effect of interventional therapy by observing the MRI manifestations before and after the interventional treatment in patients with post-circulatory ischemia.Methods:MRI images and clinical data of 36 patients with posterior circulation ischemia were prospectively collected from September 2017 to May 2018 in the interventional cerebral vascular disease area of Zhengzhou University People's Hospital.All patients were confirmed by DSA(digital silhouette angiography)as vertebral artery or basilar artery stenosis > 70%.Among them,30 cases were reexamined within 3days after operation,and 15 cases were reexamined 6 months after operation.All the patients were examined by MRI before admission and 6 months after operation.All patients were performed routine plain scan,DWI,MRA,SWI,3D-ASL and DSC-PWI sequence scan by Siemens Prisma3.0T magnetic resonance instrument,and routine plain scan and DWI,MRA,were performed within 3 days after operation.SWI and 3D-ASL sequence scanning,the scanning data are transmitted to the supporting post-processing workstation for processing.The preoperative and postoperative imaging manifestations of conventional plain scan sequence and SWI sequence were observed in this group of patients undergoing PCI intervention.Changes of CBF in bilateral cerebellum and bilateral occipital lobe on3D-ASL sequence before and after operation,Improvement of vascular stenosis before and after interventional stent placement,Improvement of abnormal perfusion area of PWI,ASL sequence in ischemic area 3 days after operation and 6 months after operation compared with pre-operation.And the improvement of the stenosis rate on the original image of MRA sequence before and after operation(the ratio of the narrowest site to the adjacent normal artery),and the comparison of the preoperative MRA,DSA with the DSA at the 6th month after the operation.Statistical analysis used SPSS 22.0 software to process the data,the counting data was expressed by n(%),X2 test was used to compare the data,and Kappa test was used for consistency analysis.According to Wilcoxon rank sum test or pairing T test,the difference was statistically significant(P < 0.05).Results:In 36 patients with posterior circulation ischemia treated by interventional operation,13 patients were treated with simple vertebral artery stents,2 patients with bilateral vertebral artery and basilar artery stents,and 21 patients with simple basilar artery stents.The stenosis rate after stent implantation decreased from 90.7% ±2.5%to 12.3% ±1.9%(P < 0.05).Compared with pre-and post-operative images,there was no significant change in image quality in MRI routine sequence at 3 days after operation,but CBF values of bilateral occipital lobe and cerebellum in 3D-ASL sequence were higher than that before operation.The image quality of MRI was reduced to some extent compared with that before operation,but CBF value of bilateral occipital lobe and cerebellum were increased after operation.The difference was statistically significant(P < 0.05).At 6 months after operation,the clinical symptoms were improved in 10 cases,no significant change in 3 cases,and aggravation in 2 cases.Routine plain scan showed that the infarction focus was more than before,and the bleeding focus on SWI sequence was also slightly more than before,but there was no significant difference(P > 0.05).The abnormal perfusion area of PWI was decreased and the cerebral perfusion was improved.The restenosis in stent was found in 2 cases by DSA.Before operation and 6 months after MRA,the degree of stenosis was 83.3%(5 / 6),100%(6 / 6),Kappa,0.869,0.782),respectively.The basilar artery was 100%(10 / 10),100%(10 / 10),and the Kappa value was 0.853,0.855.There was no significant difference between pre-operation and 6-month follow-up(P > 0.05).Conclusion :1.Interventional stent placement of posterior circulation ischemia can effectively improve the stenosis of vertebral artery,vertebrobasilar artery and cerebral perfusion in ischemic area,and the clinical symptoms are improved obviously.2.Three days after the interventional treatment of posterior circulation ischemia,MRI showed that the symptoms of the patients were improved to some extent,but the conventional MRI findings did not change much,but ASL could reflect theimprovement of the condition.3.6 months after operation,cerebral blood perfusion in abnormal area of MRI was improved to some extent,suggesting that interventional therapy for post-circulatory ischemia has a definite therapeutic effect.4.6 months after operation,MRA can replace DSA to evaluate the improvement of cerebral artery,but the diagnosis of in-stent restenosis depends on DSA.