The Value Of T2~*-Weighted Gradient-echo Imaging On Hemorrhagic Transformation Of Acute Ischemic Stroke

BACKGROUND AND OBJECTIVEStroke is a kind of brain blood circulation disorder, Which is caused by brain artery stenosis, occlusion or rupture. It showed a transient or permanent brain dysfunction in clinical practice. Stroke can be divided into ischemic stroke and hemorrhagic stroke, Among them ischemic stroke accounts for about80%of all stroke. Stroke is a common and frequently-occurring disease, bring serious injurious to human life and health, also brought a heavy burden to social and family. The incidence of stroke is rising in recent years, now it has become the leading cause of death in Chinese population.Ischemic stroke, also known as hemorrhagic transformation after the merger cerebral hemorrhagic transformation (HT), it refers to the secondary hemorrhage or infarct area after infarction infarct vascular distribution occurs, some scholars believe that HT is cerebral complications caused more by thrombolysis, anticoagulation therapy, However,some scholars believe that it is the natural course of cerebral infarction in one stage. If infarction patients with hemorrhagic transformation happened once, it will be made to change the treatment plan and it will become more difficult, so to discover these patients is particularly important clinically. we all know that the most important examination of cerebral hemorrhage is brain CT, but the CT examination for find micro bleeding is insensitive, there are a lot of limitations, in recent years, the development and application of new MRI sequences for the diagnosis of cerebrovascular disease provide more reference value. GRE-T2*WI sequence is highly sensitive to hemorrhagic focus, It can detected bleeding at an early stage.Our aim is to investigate the diagnostic value of T2*-weighted sequences on patients with hemorrhagic transformation of ischemic stroke and to analysis its risk factors,At the same time, we track its short-term prognosis.Materials and MethodsThe patients with acute ischemic stroke in Second Hospital of Shandong University from December2013to July2014are included in the study. All the patients with acute ischemic stroke underwent conventional MRI and T2*WI, and to check the detection rate between conventional MR sequences and T2*WI (gradient echo sequence) for HT. we observed the signal characteristics of the bleeding site, size, number, shape, and analysis the relevance of stems infarct size, infarct location and occurred in patients with underlying diseases with HT.and evaluate the prognosis of patients followed up the line. We record the mRS score which is after two months,0-1minutes as a good outcome,2-6minutes as a poor prognosis, while analysis of the correlation between the infarct size and the prognosis, as well as the HT sub-type and prognosis.ResultsThe conventional MR detected4cases from45cases of acute ischemic stroke patients, T2*WI detected15cases, The sensitivity of conventional MRI and T2*WI in detecting HT separately were8.8%,33.3%. The difference between the two sequence were statistical significance (P<0.05).According to the type of bleeding, HI type accounted for11cases(73.3%), PH type accounted for4cases (26.7%).45patients with ischemic stroke were recruited, and were divided into three groups according to the infarcted size, and the cases of the group were10,28,7. The cases of HT in lacunar, small and large lesion area groups separately were2,8,5. According to the presence or absence of hypertension, it divided into hypertension group and non-hypertensive group, the number of cases which occurred HT were12and3separately. Between the two groups, the difference was not statistically significant.Two months later, HT group had3cases of worse prognosis(20%); non-HT Group had5cases of bad prognosis(16.7%), there were no statistical significant difference between the two groups(P>0.05).The poor prognosis in PH type and HI were3cases and0cases, the difference was statistically significant (P <0.05).lacunar infarction with poor prognosis group is0cases; small infarcts have3cases of adverse outcomes; large infarcts have5cases of adverse outcomes, the large area of infarction group compared with the other two groups, the difference is statistically significant.ConclusionGradient-echoT2*-Weighted MRI has a higher detection rate for HT when compared with conventional MR imaging sequences.it can find the bleeding in the infarction area early and accurately, especially micro-bleeding, and This has important implications for patients with acute ischemic stroke who have merged bleeding in the early stages. HT is closely related to the occurrence of infarct size, infarct location, and no clear correlation with the blood pressure. The difference of outcome between the HT group and non-HT group were not statistical significance (P>0.05), With different HT group, there are different prognosis. PH patients often have worse outcome compared with purely ischemic stroke, while HI type although have hemorrhage, but the prognosis is relatively no significant difference with the patients have purely ischemic stroke.With different infarct size,there are different prognosis, the greater the infarction, the prognosis may be poor. The occurrence of HT related to the infarction size, the location of the infarction.