Clinical Application Value Of Susceptibility Weighted Angiography In Prognosis Evaluation Of Acute Cerebral Infarction

Part One Sensitivity of SWAN in detecting cerebral microhemorrhage and its clinical value in evaluating prognosis of acute cerebral infarctionObjective:To compare the sensitivity of susceptibility weighted angiography(SWAN)and gradient-echo T2*-weighted imaging(GRE-T2*WI)in detecting cerebral microbleeds(CMBs)in patients with acute cerebral infarction,and to explore the value of SWAN in evaluating the prognosis of acute cerebral infarction,so as to provide theoretical basis for clinical treatment of cerebral infarction.Methods:Forty-seven patients with acute cerebral infarction within 6-72 hours without thrombolytic therapy were scanned by computed tomography(CT),magnetic resonance imaging(MRI),Gradient-echo T2*-weighted imaging(GRE-T2*WI),SWAN sequence.The number of cerebral microbleeds(CMBs)was counted and graded.The difference in the overall detection rate of CMBs in the GRE-T2*WI sequence and SWAN sequence was compared.The prognosis of the patients was followed up for 3 months.Logistic regression was used to analyze the risk factors affecting the prognosis of the patients.Results: 115 and 185 CMBs were detected by GRE-T2*WI and SWAN respectively.The detection rate of CMBs by SWAN was higher than that of GRE-T2*WI.The difference of detection rate between the two was statistically significant(Z =-4.673,P <0.05).Age,NIHSS score and CMBs grade were related to prognosis in prognostic univariate analysis.In multivariate analysis,NISHH score and multiple CMBs(>10)were independent risk factors for prognosis(OR= 1.503,%95CI 1.065~2.122,P= 0.021;(OR= 26.662,%95CI 1.949-364.664,P= 0.014).Conclusion: The sensitivity of SWAN in detecting CMBs is higher than GRE-T2*WI.CMBs is significantly related to the prognosis of patients with acute cerebral infarction.The presence and quantity of CMBs affect the recovery of patients with acute cerebral infarction at 3 months.The detection of CMBs by SWAN has guiding value in the formulation of clinical treatment and prognosis evaluation of patients with cerebral infarction.It can be used as a routine examination sequence of patients with acute cerebral infarction.Part Two Clinical value of SWAN in guiding thrombolytic therapy and evaluating prognosis of acute cerebral infarctionObjective: To investigate the clinical value of asymmetrical cortical vein sign(ACVS)on susceptibility weighted angiography(SWAN)in guiding thrombolysis and evaluating prognosis of acute cerebral infarction.Methods: Sixty-five patients with acute cerebral infarction within 6 hours of onset in our hospital were enrolled.All patients underwent routine MRI and SWAN scan before treatment.According to the presence or absence of ACVS,the patients were divided into ACVS group and ACVS-negative group.There were 11 patients with ACVS from onset to thrombolysis time less than 4.5 hours,9 patients with 4.5-6h thrombolytic therapy,15 patients with non-thrombolytic therapy,and ACVS negative group had 9 patients with thrombolytic time <4.5h,7 patients with 4.5-6h thrombolysis,and 14 patients with non-thrombolytic therapy.The Modfied Rankin Scale(m RS)was used to compare the prognosis of the two groups at 3 months after onset under different thrombolysis times and non-thrombolytic therapy.Results:There was no significant difference in the prognosis between the two groups at <4.5h thrombolytic therapy(P= 1.0>0.05).The prognosis of the ACVS group was better than that of the ACVS negative group at 4.5-6h thrombolysis,and the difference was statistically significant.(P= 0.041<0.05).In the non-thrombolytic therapy,the prognosis of the ACVS group was worse than that of the ACVS-negative group,and the difference was statistically significant(P= 0.016<0.05).There was no significant differencein prognosis between ACVS patients treated with <4.5h thrombolysis and 4.5-6h thrombolysis(P= 0.566> 0.0125).Patients with negative ACVS had better prognosis under <4.5 h thrombolysis than those under 4.5-6h thrombolysis(P= 0.009<0.0125).Conclusion: Patients with acute cerebral infarction can benefit from thrombolysis with or without ACVS within 4.5 hours of onset,patients with ACVS within 4.5 hours to 6 hours of onset can benefit more from thrombolysis than patients with ACVS negative,patients with ACVS within 6 hours of onset have worse prognosis than patients with ACVS negative under non-thrombolytic therapy,and patients with ACVS within 6 hours of onset had better prognosis after thrombolytic therapy than those without thrombolytic therapy.Using SWAN technique to display ACVS in acute cerebral infarction can identify the ischemic state of brain tissue in early stage,and provide theoretical basis for thrombolytic therapy and prognosis evaluation.