title: Neurite orientation dispersion and density imaging for evaluation of corticospinal tract in idiopathic normal pressure hydrocephalus.
abstract: OBJECTIVE
  To evaluate diffusional changes of the corticospinal tract (CST) in patients with idiopathic normal pressure hydrocephalus (iNPH) by neurite orientation dispersion and density imaging (NODDI).
  
  
  METHODS
  Nineteen patients with iNPH and 12 healthy controls were included. Diffusion MRI data for NODDI were acquired with a 3-T system, using 32 motion-probing gradient directions with six b-values (from 0 to 2500 s/mm2). The orientation dispersion index (ODI), intra-cellular volume fraction (Vic), and isotropic volume fraction (Viso) of the CST were calculated by tract-specific analysis in patients and controls. We also measured the fractional anisotropy (FA) and apparent diffusion coefficient (ADC).
  
  
  RESULTS
  The ODI of the CST (0.087 ± 0.024 vs. 0.183 ± 0.051, P < 0.01, Mann-Whitney U test) and Vic of the CST (0.551 ± 0.061 vs. 0.628 ± 0.038, P < 0.01, Mann-Whitney U test) were significantly lower in iNPH patients than in healthy controls. In receiver-operating characteristic analysis, the area under the curve (AUC) of the ODI and FA were not significantly different (Fig. 4a, 0.987 vs. 0.904, P = 0.061), and the AUC of the Vic and ADC also showed no significant difference (Fig. 4b, 0.864 vs. 0.912, P = 0.194).
  
  
  CONCLUSIONS
  The NODDI can effectively evaluate the condition of neurites in the CST of iNPH patients, and the ODI could be clinically useful in the diagnosis of iNPH.
authors: Department of Radiology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. ririe@juntendo.ac.jp.
authors: Ryusuke
authors: http://orcid.org/0000-0001-7402-3983
authors: R
authors: Irie
authors: Department of Radiological Sciences, Tokyo Metropolitan University Graduate School of Human Health Sciences, Tokyo, Japan.
authors: Kohei
authors: K
authors: Tsuruta
authors: Department of Radiology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors: Masaaki
authors: M
authors: Hori
authors: Department of Radiology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors: Michimasa
authors: M
authors: Suzuki
authors: Department of Radiology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors: Koji
authors: K
authors: Kamagata
authors: Department of Radiology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors: Atsushi
authors: A
authors: Nakanishi
authors: Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors: Kouhei
authors: K
authors: Kamiya
authors: Department of Neurosurgery, Juntendo University School of Medicine, Tokyo, Japan.
authors: Madoka
authors: M
authors: Nakajima
authors: Department of Neurosurgery, Juntendo University School of Medicine, Tokyo, Japan.
authors: Masakazu
authors: M
authors: Miyajima
authors: Department of Neurosurgery, Juntendo University School of Medicine, Tokyo, Japan.
authors: Hajime
authors: H
authors: Arai
authors: Department of Radiology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors: Shigeki
authors: S
authors: Aoki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D016022:Case-Control Studies; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D016501:Neurites; D011712:Pyramidal Tracts / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D012189:Retrospective Studies
keywords: Diffusion MRI; Idiopathic normal pressure hydrocephalus; Neurite orientation dispersion and density imaging; Tract-specific analysis