Neurite orientation dispersion and density imaging for evaluation of corticospinal tract in idiopathic normal pressure hydrocephalus

• Published in: Japanese journal of radiology Vol. 35; no. 1; pp. 25 - 30
• Main Authors: Irie, Ryusuke, Tsuruta, Kohei, Hori, Masaaki, Suzuki, Michimasa, Kamagata, Koji, Nakanishi, Atsushi, Kamiya, Kouhei, Nakajima, Madoka, Miyajima, Masakazu, Arai, Hajime, Aoki, Shigeki
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01-01-2017; Springer Nature B.V
• Subjects: Aged; Aged, 80 and over; Anisotropy; Case-Control Studies; Diffusion Magnetic Resonance Imaging; Female; Humans; Hydrocephalus, Normal Pressure - diagnostic imaging; Hydrocephalus, Normal Pressure - physiopathology; Imaging; Male; Medicine; Medicine & Public Health; Neurites; Nuclear Medicine; Original Article; Pyramidal Tracts - diagnostic imaging; Pyramidal Tracts - physiopathology; Radiology; Radiotherapy; Retrospective Studies; Diffusion MRI; Neurite orientation dispersion and density imaging; Tract-specific analysis; Idiopathic normal pressure hydrocephalus
• ISSN: 1867-1071; 1867-108X
• DOI: 10.1007/s11604-016-0594-7

Purpose
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).
Materials and 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/mm
2
). 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. 
4
a, 0.987 vs. 0.904,
P
 = 0.061), and the AUC of the Vic and ADC also showed no significant difference (Fig. 
4
b, 0.864 vs. 0.912,
P
 = 0.194).
Conclusion
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.