Fluid-Attenuated Inversion Recovery Hyperintensity Correlates With Matrix Metalloproteinase-9 Level and Hemorrhagic Transformation in Acute Ischemic Stroke

Abstract

Background and Purpose— Matrix metalloproteinase-9 (MMP-9) is elevated in patients with acute stroke who later develop hemorrhagic transformation (HT). It is controversial whether early fluid-attenuated inversion recovery (FLAIR) hyperintensity on brain MRI predicts hemorrhagic transformation (HT). We assessed whether FLAIR hyperintensity was associated with MMP-9 and HT. Methods— We analyzed a prospectively collected cohort of acute stroke subjects with acute brain MRI images and MMP-9 values within the first 12 hours after stroke onset. FLAIR hyperintensity was measured using a signal intensity ratio between the stroke lesion and corresponding normal contralateral hemisphere. MMP-9 was measured using enzyme-linked immunosorbent assay. The relationships between FLAIR ratio (FR), MMP-9, and HT were evaluated. Results— A total of 180 subjects were available for analysis. Patients were imaged with brain MRI at 5.6±4.3 hours from last seen well time. MMP-9 blood samples were drawn within 7.7±4.0 hours from last seen well time. The time to MRI ( r =0.17, P =0.027) and MMP-9 level ( r =0.29, P <0.001) were each associated with FR. The association between MMP-9 and FR remained significant after multivariable adjustment ( P <0.001). FR was also associated with HT and symptomatic hemorrhage ( P =0.012). Conclusions— FR correlates with both MMP-9 level and risk of hemorrhage. FLAIR changes in the acute phase of stroke may predict hemorrhagic transformation, possibly as a reflection of altered blood–brain barrier integrity.