title: Do brain T2/FLAIR white matter hyperintensities correspond to myelin loss in normal aging? A radiologic-neuropathologic correlation study.
abstract: BACKGROUND
  White matter hyperintensities (WMH) lesions on T2/FLAIR brain MRI are frequently seen in healthy elderly people. Whether these radiological lesions correspond to irreversible histological changes is still a matter of debate. We report the radiologic-histopathologic concordance between T2/FLAIR WMHs and neuropathologically confirmed demyelination in the periventricular, perivascular and deep white matter (WM) areas.
  
  
  RESULTS
  Inter-rater reliability was substantial-almost perfect between neuropathologists (kappa 0.71 - 0.79) and fair-moderate between radiologists (kappa 0.34 - 0.42). Discriminating low versus high lesion scores, radiologic compared to neuropathologic evaluation had sensitivity / specificity of 0.83 / 0.47 for periventricular and 0.44 / 0.88 for deep white matter lesions. T2/FLAIR WMHs overestimate neuropathologically confirmed demyelination in the periventricular (p < 0.001) areas but underestimates it in the deep WM (0 < 0.05). In a subset of 14 cases with prominent perivascular WMH, no corresponding demyelination was found in 12 cases.
  
  
  CONCLUSIONS
  MRI T2/FLAIR overestimates periventricular and perivascular lesions compared to histopathologically confirmed demyelination. The relatively high concentration of interstitial water in the periventricular / perivascular regions due to increasing blood-brain-barrier permeability and plasma leakage in brain aging may evoke T2/FLAIR WMH despite relatively mild demyelination.
authors.affiliation: Service neuro-diagnostique et neuro-interventionnel DISIM, University Hospitals of Geneva, rue Gabrielle Perret-Gentil 4,1211, Geneva 14, Switzerland. sven.haller@hcuge.ch.
authors.forename: Sven
authors.initials: S
authors.lastname: Haller
authors.forename: Enikö
authors.initials: E
authors.lastname: Kövari
authors.forename: François R
authors.initials: FR
authors.lastname: Herrmann
authors.forename: Victor
authors.initials: V
authors.lastname: Cuvinciuc
authors.forename: Ann-Marie
authors.initials: AM
authors.lastname: Tomm
authors.forename: Gilbert B
authors.initials: GB
authors.lastname: Zulian
authors.forename: Karl-Olof
authors.initials: KO
authors.lastname: Lovblad
authors.forename: Panteleimon
authors.initials: P
authors.lastname: Giannakopoulos
authors.forename: Constantin
authors.initials: C
authors.lastname: Bouras
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009186:Myelin Sheath / Q000473:pathology*; D066127:White Matter / Q000473:pathology*