Application Of Susceptibility Weighted Imaging On Hemorrhagic Transformation Of Ischemic Stroke

Objective To investigate the diagnostic utility and predictable value of susceptibility weighted imaging (SWI) in a cohort of patients with hemorrhagic transformation (HT) of ischemic stroke, and to alalyze the outcome of ischemic stroke.Materials and methods48patients with ischemic stroke to be in Tianjin Union Medicine Centre from June2011to February2012were studied. Inclusion criterias were as follows:①2days within symptom onset;②absence of stroke history or without obvious squela after stroke;③exclusion of the lucunar infarction. The conventional MR and DWI,3D TOF MRA, SWI sequences were performed on all patients and follow-up examinations were obtained after about14days. All patients did not undergo thrombolysis therapy and the modified Rankin Scale (mRS) scores were assessed at3. months after stroke onset. To observe the presence and features of the HT on each sequence, as well as the cerebral microbleeds(CMB), abnormal visibility of microveins on SWI sequence. The correlation between the imaging finding and HT were analyzed. Also, whether the the outcome of patients after3months were associated with the infarct size, types of HT and distended veins surrounding the infarction region were analyzed.Results48patients with ischemic stroke were recruited, and were divided into two groups according to the infarcted size. Among the48patients,19cases(39.6%) had HT, with15cases of hemorrahagic infract (HI) and4cases of parenchymal hematoma (PH).14in19cases of the HT were mainly hyperintense on SWI phase imagings, while3cases of calcifications most were hypointense. The sensibility of T1WI, DWI, SWI in detecting HT were68.4%,36.8%,100%.15cases (31.3%) were found with CMB. The group with CMB were not more easily have HT than the other group(P=0.189), but3cases among the4cases with multiple CMB had HT. The cases of HT in large and small lesion area groups separately were13(54.2%) and6(26.0%), and the cases of worse outcome in the two groups separately were17(70.8%) and8(33.3%). The difference between the two groups were statistical significance (both P<0.05). The MRA imagings of the the19cases of HT demonstrated occlusion or various degree of stenosis in the main intracranial vessels.42patients on SWI, the rate of HT’was69.2%(9/13) in the group with increased microvessels within the infarction region, which was higher than the13.8%(4/29) in the remain group (P=0.039). Among the24patients with large lesion area, the difference of outcome between the HT group and Not HT group, as well as the simple infarction group and HI group, was not statistical significance(both P>0.05). However, the outcome of2cases of PH were not good and the distended veins surrounding the infarction region were associated with worse outcome.Conclusion The application of SWI sequence can detect and distinguish ICH and intracranial calcifications. HT are associated with the large lesion area, occlusion or various degree of stenosis in the main intracranial vessels, multiple CMBs, increased microvessels within the infarction region. The lesion area, PH and the distended veins surrounding the infarction region are probably associated with worse outcome of ischemic stroke. SWI may predict HT and outcome of acute ischemic stroke.