title: Initial investigation of the blood-brain barrier in MS lesions at 7 tesla.
abstract: BACKGROUND
  We previously described two dynamics of contrast enhancement in scans of active multiple sclerosis lesions: Medium-sized, early lesions enhance centrifugally, whereas larger, slightly older lesions enhance centripetally. Due to technical limitations, our previous study did not characterize lesions < 5 mm in diameter, cortical enhancement, and anatomical structures within lesions.
  
  
  OBJECTIVE
  The objective of this paper is to obtain initial observations of these important aspects of lesion development on a 7 tesla scanner at high spatial resolution.
  
  
  METHODS
  We scanned eight patients, acquiring precontrast T2*-weighted scans, T1-weighted scans before and after contrast, and high-resolution dynamic contrast-enhanced scans during and up to 30 min after contrast.
  
  
  RESULTS
  We detected 15 enhancing lesions, obtaining dynamic data in 10: Five lesions < 4 mm enhanced centrifugally (initial central enhancement expanded outward), and five lesions > 4 mm enhanced centripetally (initial peripheral enhancement gradually filled the lesion). A leukocortical lesion initially showed enhancement in its white matter portion, which gradually spread into the cortex. Seventy-three percent of lesions were clearly perivenular.
  
  
  CONCLUSIONS
  Most active lesions are perivenular, and the smallest lesions enhance centrifugally. This supports the idea that lesions grow outward from a central vein.
authors.affiliation: Translational Neuroradiology Unit, Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: María I
authors.initials: MI
authors.lastname: Gaitán
authors.forename: Pascal
authors.initials: P
authors.lastname: Sati
authors.forename: Souheil J
authors.initials: SJ
authors.lastname: Inati
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Reich
mesh_terms: D000328:Adult; D001812:Blood-Brain Barrier / Q000473:pathology*; D001921:Brain / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology*