Investigation Of The Prognostic Evaluation Of Cerebral Infarction Treated With Venous Thrombolysis Through SWI Venous Analysis

Part I Correlation between asymmetrical cortical vein sign and prognosis of cerebral infarction treated with intravenous thrombolysisBackground and Objective:Intracranial vascular conditions are usually assessed by imaging techniques before and after intravenous thrombolytic therapy.Compared to CTA,MRA and other traditional inspection techniques,Susceptibility weighted imaging(SWI)sequences have an irreplaceable value in the development and analysis of veins.The intracranial venous system plays an important regulatory role in the development of ischemic lesions in the brain tissue,mainly as a decrease in venous blood oxygen content and an increase in the proportion of deoxyhemoglobin.Since the structure of deoxyhemoglobin contains 4 unpaired electrons,the susceptibility changes significantly when its content changes,thus the signal changes presented in the SWI imaging sequence can be easily observed.Previous studies have indicated that ischemic events in the middle cerebral artery supply area are often accompanied by special venous imaging signs,asymmetrical cortical venous signs(ACVS).ACVS is an imaging marker that reflects the metabolism of brain tissue.This study was performed on patients with middle cerebral artery ischemic infarction after intravenous thrombolysis.The characteristics of ACVS in these patients were described.The related factors of ACVS were analyzed,and the correlation between the signs and clinical prognosis was discussed.Methods:Patients with acute ischemic stroke who were admitted to the First Hospital of Jilin University within year 2016 to 2018 for intravenous thrombolysis were retrospectively enrolled.A multimodal magnetic examination containing SWI sequences was performed within 72 hours after receiving intravenous thrombolytic therapy,and the lesion was located in a unilateral middle cerebral artery blood supply area.The clinical and imaging data of the patients were collected,and the clinical data were masked to descriptively record and score the imaging data of each patient.According to the presence and absence of ACVS,patients were divided into two groups.The clinical data and other imaging parameters of the two groups were compared.According to different types of ACVS grouping,the clinical and other imaging features of patients with various signs were compared and analyzed.According to the early improvement and long-term prognosis,single factor and multi-factor analysis were used to determine whether the ACVS sign was the influential factor and independent predictor of poor early improvement and unfavorable outcomes of thrombolytic therapy.Results:Of the 100 patients included in the analysis,36 patients had ACVS after thrombolysis,including 15 cases of asymmetrical prominent cortical vein sign(APCVS)and 12 cases of simple asymmetrical faded cortical vein sign(AFCVS)and 9 cases of APCVS combined with AFCVS.Compared with patients with ACVS and patients without ACVS,the Alberta Stroke Program Early CT Score(ASPECTS)based on Diffusion Weighted Imaging(DWI),the degree of stenosis,the NIHSS score within the hospital,early improvement of thrombolytic therapy and long-term prognosis were all different,and the difference was statistically significant(P<0.05).The main result was that patients with ACVS had lower ASPECTS scores,higher rates of arterial strict stenosis,higher NIHSS scores,lower early improvement,and higher proportion of poor prognosis.Patients were divided into three groups according to different ACVS phenotypes.The proportion of unfavorable outcomes between the three groups of patients,the degree of middle cerebral artery stenosis and the size of infarct size were statistically significant(P<0.05).By pairwise comparison,the APCVS+AFCVS group had a higher incidence of unfavorable outcomes than the other two groups(P<0.008),and the degree of middle cerebral artery stenosis was more severe(P<0.045).The incidence of poor prognosis was lowest in the simple AFCV group compared with the other two groups(P<0.045).Patients in the APCVS group had smaller ischemic lesions than the other two groups(P < 0.007).Analysis of the influencing factors of poor prognosis found that early improvement was poor,severe stenosis of the middle artery,high NIHSS score,large lesion area and present of ACVS were related factors leading to poor prognosis.Among them,early improvement of thrombolytic therapy is poor,and severe middle cerebral artery stenosis is an independent predictor of unfavorable outcome after 3 months of onset of stroke.Conclusion:Three different forms of ACVS can be observed on SWI images of patients after intravenous thrombolysis.Among them,AFCVs alone may indicate good prognosis imaging,while AFCVS combined with APCVS may have poor prognosis.The ACVS signs were found in patients with poor thrombolytic therapy and poor prognosis,but not as independent predictors of poor prognosis.Part II Correlation between the changes of deep venous oxygen saturation on the affected side and the prognosis of patients with cerebral infarction after thrombolytic therapyBackground and Objective: Intracranial venous oxygen content in patients with ischemic stroke can reflect the activity and metabolism of local brain tissue.With the development of SWI imaging technology,the emergence of Susceptibility weighted imaging mapping(SWIM)has achieved quantitative analysis of venous magnetic susceptibility and venous oxygen saturation changes.Previous studies have only shown that intracranial venous oxygen saturation changes during ischemia may be related to collateral compensatory conditions.There is currently no correlation analysis between this magnitude change and other imaging parameters and clinical manifestations.The purpose of this study was to use the SWIM quantitative measurement method to measure the difference of bilateral cerebral hemispheric venous oxygen saturation in patients with ischemic stroke after thrombolytic therapy.Then explore the correlation between changes in this magnitude and changes in neurological function,intracranial lesion area,and long-term prognosis.Methods:The SWI images of 87 patients who were retrospectively collected and postprocessed to obtain SWIM images for measurement.The septum pellucidum vein(SPV)and thalamostriate vein(TSV)and the internal cerebral vein(ICV)of bilateral cerebral hemispheres were selected as the target vein of measurement.The measurement is performed by the open third-party software SPIN(Signal Process in Neuroimaging).According to the formula,the measured susceptibility value is converted into a difference rate,namely the deep vein susceptibility difference ratio(DVSDR).DVSDR is used to represent the deep venous oxygen saturation change for subsequent correlation analysis.Patients were grouped according to prognosis conditions.The DVSDR was compared between the two groups and then to test whether the value of DVSDR can be used to predict the outcome.We made Spearman tests between DVSDR and prognosis related factors such as early neurological function after thrombolysis,aiming to find out the correlation between neural functional improvement(NIHSS)and the size of lesion area(ASPECTS).Results:In patients with stroke after intravenous thrombolysis,the median value of the striatum venous susceptibility value was 165.320(145.010,187.430)ppb,the measured value of the contralateral side was 181.300(157.580,197.210)ppb,and the healthy side was higher than the affected side,the difference was statistically significant(p< 0.001).There was no significant difference in the susceptibility values between the bilateral septum and the intracerebral vein.Patients were grouped according to good prognosis and poor prognosis.In the comparative analysis,the prevalence of hypertension,the size of ischemic lesions(ASPECTS score),the 7-day NIHSS score,the proportion of severe middle cerebral artery stenosis,and the value of DVSDR were found with differences and the differences are statistically significant(p<0.05).Among them,DVSDR is small,that is,the patient's venous oxygen saturation is higher than that of the healthy side(p=0.003),which is an influential factor for poor prognosis,but it is not an independent predictor of poor prognosis.The Spearman correlation test found that DVSDR was positively correlated with NIHSS score change(p=0.042);DVSDR absolute value was negatively correlated with ASPECTS ischemic area score(p=0.002).Conclusion:The degree of changes in striatum venous oxygen saturation in the lateral thalamic striatum after intravenous thrombolysis can be used to reflect the difference in bilateral cerebral hemisphere metabolism.The deep venous oxygen saturation of the affected side is more likely to improve the neurological function than the healthy side,and the neurological function tends to worsen when the venous oxygen saturation of the affected side is higher than that of the healthy side.The greater the difference in deep venous oxygen saturation between the bilateral cerebral hemispheres,the larger the area of ischemic lesions.Deep venous oxygen saturation in the cerebral hemisphere of the affected side is a related factor for poor prognosis,but it is not an independent predictor of poor prognosis.