title: Whole brain apparent diffusion coefficient histogram: a new tool for evaluation of leukoaraiosis.
abstract: OBJECTIVE
  To test whole brain apparent diffusion coefficient histogram analysis as an alternative approach to visual score for the assessment of leukoaraiosis (LA).
  
  
  METHODS
  T2 and diffusion weighted images were obtained in 15 elderly patients. LA extension was assessed on T2 weighted images by two observers using a semiquantitative visual score. Apparent diffusion coefficient (ADC) maps of the entire brain were generated and, after exclusion of the skull with manual tracing and of the cerebrospinal fluid (CSF) by application of a threshold value, whole brain (WB)-ADC histogram was obtained. Moreover, a brain volume index (BVI) was calculated on ADC maps as (intracranial volume - CSF volume) /intracranial volume.
  
  
  RESULTS
  The kappa inter-observer agreement for LA scoring was 0.69. Manual segmentation of the skull showed a mean inter-operator coefficient of variation below 3%. The median value of whole brain ADC histogram directly correlated with LA extension (P = 0.013). Moreover a significant inverse correlation (P = 0.002) was found between WB-ADC median value and BVI.
  
  
  CONCLUSIONS
  WB-ADC histogram is a reproducible alternative tool for assessing LA extension and severity.
authors.affiliation: Radiodiagnostica, Dipartimento di Fisiopatologia Clinica, Università di Firenze, Firenze, Italy. m.mascalchi@dfc.unifi.it
authors.forename: Mario
authors.initials: M
authors.lastname: Mascalchi
authors.forename: Carlo
authors.initials: C
authors.lastname: Tessa
authors.forename: Marco
authors.initials: M
authors.lastname: Moretti
authors.forename: Riccardo
authors.initials: R
authors.lastname: Della Nave
authors.forename: Vieri
authors.initials: V
authors.lastname: Boddi
authors.forename: Sara
authors.initials: S
authors.lastname: Martini
authors.forename: Domenico
authors.initials: D
authors.lastname: Inzitari
authors.forename: Natale
authors.initials: N
authors.lastname: Villari
mesh_terms: D000368:Aged; D001834:Body Water / Q000502:physiology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D004058:Diffusion; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012044:Regression Analysis; D020521:Stroke / Q000473:pathology* / Q000503:physiopathology