title: Fluid-attenuated inversion recovery hyperintensity correlates with matrix metalloproteinase-9 level and hemorrhagic transformation in acute ischemic stroke.
abstract: OBJECTIVE
  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.
authors.affiliation: From the Department of Neurology, Massachusetts General Hospital, Boston, MA (R.J., T.W.K.B., L.P., W.T.K.); Department of Neurology and Psychiatry, Policlinico Umberto I Hospital, Sapienza University of Rome, Rome, Italy (S.L.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (K.L.F.); and Department of Neurology, Yale New Haven Hospital, New Haven, CT (K.N.S.).
authors.forename: Ruchira
authors.initials: R
authors.lastname: Jha
authors.forename: Thomas W K
authors.initials: TW
authors.lastname: Battey
authors.forename: Ly
authors.initials: L
authors.lastname: Pham
authors.forename: Svetlana
authors.initials: S
authors.lastname: Lorenzano
authors.forename: Karen L
authors.initials: KL
authors.lastname: Furie
authors.forename: Kevin N
authors.initials: KN
authors.lastname: Sheth
authors.forename: W Taylor
authors.initials: WT
authors.lastname: Kimberly
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001812:Blood-Brain Barrier / Q000378:metabolism; D001929:Brain Edema / Q000453:epidemiology / Q000378:metabolism; D002545:Brain Ischemia / Q000453:epidemiology / Q000378:metabolism*; D002543:Cerebral Hemorrhage / Q000453:epidemiology / Q000378:metabolism*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology / Q000378:metabolism*
chemical_list: C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9
keywords: brain edema; brain ischemia; hemorrhage; magnetic resonance imaging; matrix metalloproteinases; stroke