Study Of Clinical Application Of SWI In Intravenous Thrombolysis For Acute Ischemic Stroke

ObjectiveSWI examination was performed before and after intravenous thrombolysis in patients with acute ischemic stroke.To analyze the related factors affecting the susceptibility vessel sign,asymmetric cortical vascular sign,prognostic factors,and factors related to vascular recanalization after intravenous thrombolysis.To investigate the value of SWI in identifying the etiology,analyze thrombolytic therapy and prognosis of neurological function in patients with acute ischemic stroke.Materials and Methods1.200 patients with acute ischemic stroke who were treated with intravenous recombinant tissue plasminogen activator?rt-PA?in Linyi people's Hospital from January2016 to February 2017 were collected.All Patients were examined by MRI,MRA,SWI.Clinical NHISS score before intravenous thrombolytic therapy and a modified Rankin scale score after intravenous thrombolysis for 3 months were acquired.Screening through group criteria and exclusion criteria,a total of 50 patients were enrolled.2.MRI inspection methods:All the patients were conducted with a 3.0-tesla MR scanner?Siemens 3.0-tesla Magnetom Verio,Germany?.Use the standard 8 channel head coil,with conventional scanning in supine position,head of advanced.The routine MRI sequence:transverse T₁WI,T₂WI,DWI,T₂FLAIR;sagittal T₁WI;MRA:three dimensional time of flight?3D-TOF?scanningSWI inspection:Using the real-time technology,generate amplitude image and Phase image of SWI automatically,and get the minP image by minimum density Projection reconstruction.3.Image analysis:the conventional MR images and SWI images were analyzed by two senior radiologist.According to SVS of SWI images,the 50 patients were divided into SVS positive group and SVS negative group;According to the ACVS display of SWI minP images,50 patients were divided into ACVS positive group and ACVS negative group.According to the MRA images after thrombolysis,patients were divided into vascular recanalization group and nonrecanalization group.4.Statistical analysis:SPSS 20.0 was used for statistical analysis.We use independent sample t-test to compare measurement data,and the chi-square test for comparison of enumeration data.To analyze the differences between the atrial-fibrillation group and non-atrial-fibrillation group,SVS positive group and SVS negative group,ACVS positive group and ACVS negative group,vascular recanalization group and vascular nonrecanalization group,improvement group and deterioration group.The significant factors in the single factor analysis were included in multivariate logistic regression analysis,and the independent factors of SVS positive,ACVS positive,vascular recanalization and clinical prognosis were analyzed.The difference was statistically significant with P<0.05.Results1.A total of 50 patients with AIS who underwent intravenous thrombolytic therapy were recruited,including 34 male patients?68%?.The average age was?63.76±3.18?years old.Among them,SVS was found in 34 patients?54%?before intravenous thrombolytic therapy;and ACVS was found in 40 patients?80%?.Recanalization after thrombolysis succeeded in 26 cases?52%?.2.Compared with non-atrial-fibrillation group,the rate of SVS positive in atrial-fibrillation group was higher??²=11.167,P=0.001?;age of onset in atrial-fibrillation group was higher?t=2.080,P=0.043?.The SVS was an independent influencing factor of atrial fibrillation?P=0.013,OR=0.058,95%CI:0.006⁰.549?.3.Ratio of positive SVS with atrial-fibrillation patients was higher??²=11.167,P=0.001?;NIHSS score of SVS positive group were higher than SVS negative group?t=2.090,P=0.042?;SVS positive patients had higher rates of ACVS??²=8.295,P=0.007?.Atrial-fibrillation?P=0.011,OR=0.039,95%CI:0.003⁰.471?and ACVS?P=0.039,OR=0.080,95%CI:0.007⁰.884?were independent influencing factors associated with SVS positive.4.The occurrence rate of SVS in ACVS positive group was significantly higher than that in ACVS negative group??²=8.295,P=0.004?.There were no differences in age,gender and atrial fibrillation between ACVS positive and negative groups.SVS was associated with the presence of ACVS?P=0.005,OR=0.043,95%CI:0.005⁰.383?.Although atrial fibrillation was an independent factor for SVS,it was not an independent influencing factor for ACVS??²=0.521,P=0.470?.5.Patients with atrial-fibrillation had a higher recanalization rate??²=4.608,P=0.032?after thrombolysis;The recanalization rate was low??²=4.987,P=0.035?in patients with hypertension;Patients with SVS showed a higher rate of recanalization??²=6.872,P=0.015?.After multivariate analysis,only SVS was an independent influencing factor affecting vascular recanalization?P=0.019,OR=0.041,95%CI:0.003⁰.586?.6.The factors affecting the prognosis of the patient were NIHSS score?t=-0.895,P=0.027?before thrombolysis.But the presence or absence of SVS did not affect the clinical outcome??²=0.995,P=0.575?.However,the prognostic factors of patients with SVS positive group were affected by the location of SVS?poor prognosis in M1 segment,?²=6.125,P=0.002?.ConclusionsIn patients with AIS with severe stenosis or occlusion of one of the middle cerebral arteries,several points of view can be concluded as follows:?1?SVS can be an independent related factor of atrial fibrillation as a cause of cardiac stroke.SVS and ACVS are independent of each other,and the presence of ACVS is a compensation for the rapidly decreasing cerebral perfusion pressure.?2?SVS positive patients before treatment may indicate a high recanalization rate in patients with intravenous thrombolysis.?3?Neither SVS nor ACVS before treatment could significantly influence the prognosis of neurological function,but the location of SVS might affect the improvement of neurological function.