title: Regional MRI Diffusion, White-Matter Hyperintensities, and Cognitive Function in Alzheimer's Disease and Vascular Dementia.
abstract: OBJECTIVE
  An increase in brain water diffusivity as measured using magnetic resonance imaging (MRI) has been recently reported in normal-appearing white matter (NAWM) in patients affected by cognitive impairment. However, it remains to be clarified if this reflects an overt neuronal tissue disruption that leads to degenerative or microvascular lesions. This question was addressed by comparing the regional MRI apparent diffusion coefficients (ADCs) of NAWM in patients affected by Alzheimer's disease (AD) or vascular dementia (VaD). The relationships of ADCs with the white-matter hyperintensity (WMH) burden, carotid atherosclerosis, and cognitive performance were also investigated.
  
  
  METHODS
  Forty-nine AD and 31 VaD patients underwent brain MRI to assess the WMH volume and regional NAWM ADCs, neuropsychological evaluations, and carotid ultrasound to assess the plaque severity and intima-media thickness (IMT).
  
  
  RESULTS
  Regional ADCs in NAWM did not differ between VaD and AD patients, while the WMH volume was greater in VaD than in AD patients. The ADC in the anterior corpus callosum was related to the WMH volume, while a greater carotid IMT was positively correlated with the temporal ADC and WMH volume. The memory performance was worse in patients with higher temporal ADCs. Constructional praxis scores were related to ADCs in the frontal, and occipital lobes, in the anterior and posterior corpus callosum as well as to the WMH volume. Abstract reasoning was related to frontal, parietal, and temporal ADCs.
  
  
  CONCLUSIONS
  Our data show that higher regional ADCs in NAWM are associated with microcirculatory impairment, as depicted by the WMH volume. Moreover, regional ADCs in NAWM are differently associated with the neuropsychological performances in memory, constructional praxia, and abstract reasoning domains.
authors.affiliation: Neurology Unit, Campus Bio-Medico University, Rome, Italy. c.altamura@unicampus.it.
authors.forename: Claudia
authors.initials: C
authors.lastname: Altamura
authors.affiliation: Neurology Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Scrascia
authors.affiliation: Radiology Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Carlo Cosimo
authors.initials: CC
authors.lastname: Quattrocchi
authors.affiliation: Radiology Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Errante
authors.affiliation: Radiology Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Emma
authors.initials: E
authors.lastname: Gangemi
authors.affiliation: Clinical Medicine Department, Public Health, Life and Environment Scinces, University of L'Aquila, Italy.|IRCCS S. Raffaele, Rome - S.Raffaele Clinic, Cassino (FR), Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Curcio
authors.affiliation: Neurology Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Ursini
authors.affiliation: Neurology Clinic, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Silvestrini
authors.affiliation: Neurology Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Maggio
authors.affiliation: Radiology Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Beomonte Zobel
authors.affiliation: Neurology Clinic, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Paolo Maria
authors.initials: PM
authors.lastname: Rossini
authors.affiliation: Associazione Fatebenefratelli per la ricerca-AFAR, Rome, Italy.
authors.forename: Patrizio
authors.initials: P
authors.lastname: Pasqualetti
authors.affiliation: Internal and Subintensive Medicine, Ospedali Riuniti Ancona, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Falsetti
authors.affiliation: Neurology Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Vernieri
keywords: Alzheimer's disease; atherosclerosis; diffusion magnetic resonance imaging; leukoaraiosis; vascular dementia