title: Diffusional Kurtosis Imaging in Idiopathic Normal Pressure Hydrocephalus: Correlation with Severity of Cognitive Impairment.
abstract: OBJECTIVE
  Diffusional kurtosis imaging (DKI) is an emerging technique that describes diffusion of water molecules in terms of deviation from Gaussian distribution. This study investigated correlations between DKI metrics and cognitive function in patients with idiopathic normal pressure hydrocephalus (iNPH).
  
  
  METHODS
  DKI was performed in 29 iNPH patients and 14 age-matched controls. Mini-mental state examination (MMSE), frontal assessment battery (FAB), and trail making test A (TMT-A) were used as cognitive measures. Tract-based spatial statistics (TBSS) analyses were performed to investigate the between-group differences and correlations with the cognitive measures of the diffusion metrics, including mean kurtosis (MK), fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD).
  
  
  RESULTS
  In iNPH patients, FA and MK identified positive correlations with cognitive function in similar regions, predominantly in the frontal lobes (P < 0.05, corrected for multiple comparisons). The frontoparietal subcortical white matter showed significant correlations with FAB and TMT-A across more extensive areas in MK analyses than in FA. ADC, AD, and RD analyses showed no significant correlations with MMSE and FAB, while negative correlation with TMT-A was observed in the limited portion of the frontal deep white matter.
  
  
  CONCLUSIONS
  Both FA and MK correlated well with cognitive impairment in iNPH. The observed differences between FA and MK results suggest DKI may play a complementary role to conventional FA and ADC analyses, especially for evaluation of the subcortical white matter.
authors: Department of Radiology, Graduate School of Medicine, University of Tokyo.
authors: Kouhei
authors: K
authors: Kamiya
authors: Koji
authors: K
authors: Kamagata
authors: Masakazu
authors: M
authors: Miyajima
authors: Madoka
authors: M
authors: Nakajima
authors: Masaaki
authors: M
authors: Hori
authors: Kohei
authors: K
authors: Tsuruta
authors: Harushi
authors: H
authors: Mori
authors: Akira
authors: A
authors: Kunimatsu
authors: Hajime
authors: H
authors: Arai
authors: Shigeki
authors: S
authors: Aoki
authors: Kuni
authors: K
authors: Ohtomo
mesh_terms: D000368:Aged; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D003704:Dementia / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D016011:Normal Distribution; D066127:White Matter / Q000503:physiopathology*