title: Hypoperfusion and T1-hypointense lesions in white matter in multiple sclerosis.
abstract: BACKGROUND
  Longitudinal magnetic resonance imaging (MRI) studies show that a fraction of the multiple sclerosis (MS) T2-lesions contain T1-hypointense components that may persist to represent severe, irreversible tissue damage. It is not known why certain lesions convert to persistent T1-hypointense lesions.
  
  
  OBJECTIVE
  We hypothesized that the T1-hypointense lesions disproportionately distribute in the more hypoperfused areas of the brain. Here we investigated the association between hypoperfusion and T1-hypointense lesion distributions.
  
  
  METHODS
  MRI and cerebral blood flow (CBF) data were acquired on 45 multiple sclerosis (MS) patients and 20 healthy controls. CBF maps were generated using pseudo-continuous arterial spin labeling technique. The lesion probability distribution maps were superimposed on the CBF maps.
  
  
  RESULTS
  Two distinct CBF clusters were observed in the white matter (WM) both in healthy controls and MS patients. An overall reduction in CBF was observed in MS patients compared to healthy controls. The majority of the T1-hypointense lesions were concentrated almost exclusively in the WM regions with lower CBF. The T2-hyperintense lesions were more generally distributed in both higher and lower perfused WM.
  
  
  CONCLUSIONS
  This study suggests an association between hypoperfusion and T1-hypointense lesions.
authors.affiliation: Department of Diagnostic and Interventional Imaging, Texas, USA.
authors.forename: Ponnada A
authors.initials: PA
authors.lastname: Narayana
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Zhou
authors.forename: Khader M
authors.initials: KM
authors.lastname: Hasan
authors.forename: Sushmita
authors.initials: S
authors.lastname: Datta
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Sun
authors.forename: Jerry S
authors.initials: JS
authors.lastname: Wolinsky
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology* / Q000503:physiopathology; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D055815:Young Adult
keywords: Multiple sclerosis; T1-hypointense lesions; T2-hyperintense lesions; cerebral blood flow; magnetic resonance imaging