title: [Brain apparent diffusion coefficient: differences caused by age, sex, laterality, and distinct b value].
abstract: OBJECTIVE
  To analyze the effects of age, sex, and b value on the apparent diffusion coefficient (ADC) in brain areas affected by neurodegenerative diseases.
  
  
  METHODS
  We studied the ADC of the genu and splenium of the corpus callosum and of the hippocampus in normal patients using diffusion magnetic resonance imaging (dMRI) with b1,000 s/mm2 and b3,000 s/mm2. We calculated the differences between the ADC (diffusion differential [DD]) with b1,000 and with b3,000 for each region. Patients were classified into the following age groups (<or=30 years old, 31-60 years old, >60 years old). We used a Kruskal-Wallis one-way ANOVA and the Bonferroni correction to analyze the differences in ADC and DD between age groups and between sexes. Pearson's chi-square test was used to correlate the ADC and DD with age.
  
  
  RESULTS
  In the right hippocampus, we observed differences in ADC (b1,000, p=0.011; b3,000, p=0.024) and DD (p=0.006) with age. Differences in ADC were observed between the 31-60 year-old age group and the >60 year-old age group (p=0.009) for b1,000, and between the<30 year-old age group and the 31-60 year-old age group (p=0.036) for b3,000. The DD in the >60 year-old age group was different from the rest. In the corpus callosum, there were significant differences between sexes in the DD of the genu (p=0.016). The DD was correlated with age in the right hippocampus (r=0.321, p=0.023).
  
  
  CONCLUSIONS
  Our data indicate greater stability in mean ADC values with b3000 during aging. It might be useful to analyze the ADC with a higher b in patients with neurodegenerative diseases.
authors.affiliation: Area de Neurorradiología de Cabeza y Cuello, Servicio de Radiodiagnóstico, Hospital General Universitario Morales Meseguer, Murcia, Spain. josem.garcia11@carm.es
authors.forename: J M
authors.initials: JM
authors.lastname: García Santos
authors.forename: C
authors.initials: C
authors.lastname: Ordóñez González
authors.forename: S
authors.initials: S
authors.lastname: Torres del Río
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001921:Brain / Q000473:pathology*; D002648:Child; D003430:Cross-Sectional Studies; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000473:pathology*; D012189:Retrospective Studies; D012737:Sex Factors; D055815:Young Adult