Fluid-Attenuated Inversion Recovery Hyperintensity Is Associated with Hemorrhagic Transformation following Reperfusion Therapy.

BACKGROUND: It is still controversial whether early fluid-attenuated inversion recovery (FLAIR) hyperintensity within acute ischemic lesions carries the risk of hemorrhagic transformation (HT) after reperfusion therapy. Furthermore, the association between the location of FLAIR hyperintensity and HT has not been investigated. METHODS: We retrospectively reviewed patients who underwent reperfusion therapy within 6 hours of stroke onset and magnetic resonance imaging including a FLAIR sequence before completing reperfusion therapy. FLAIR hyperintensity within the diffusion-weighted imaging (DWI) lesion was rated qualitatively, and HT was assessed on follow-up gradient echo imaging. The location of the FLAIR change and HT was classified as subcortical, cortical, or cortico-subcortical. RESULTS: Of 134 patients with acute ischemic stroke included in this study, early FLAIR changes within DWI lesions were identified in 56 (41.8%) patients, and HT was noted in 51 (38.1%) patients. FLAIR change was independently associated with HT (odds ratio: 4.37, 95% confidence interval: 1.72-11.12). Geographically, 48.2% of the patients with a FLAIR change developed a matched HT (restricted to the region with the FLAIR change), and the risk of HT was further increased in patients with a FLAIR change in the cortico-subcortical region (68.8%). CONCLUSIONS: In patients in the acute stage of stroke, an early FLAIR change is associated with the risk of HT following reperfusion therapy with a highly matched geographic relationship and common risk factors. Thus, identification of FLAIR change may be a useful surrogate marker to assess the likelihood of subsequent HT in patients treated with reperfusion therapy.