title: Changes of fractional anisotropy and apparent diffusion coefficient in patients with idiopathic normal pressure hydrocephalus.
abstract: Since ventricular dilation and periventricular abnormal intensities are commonly seen in patients with idiopathic normal pressure hydrocephalus (INPH) on magnetic resonance imaging (MRI), dysfunction of white matter may have an important role in the mechanism causing symptoms of INPH. To clarify the pathophysiology of INPH, we analyzed axonal water dynamics using diffusion tensor MRI. Thirty-six patients with possible INPH were included. Regional fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured in several white matter regions before and 24 h after a cerebrospinal fluid tap test (CSF-TT). The patients were divided into two groups: patients who showed significant improvements in neurological status after the CSF-TT (positive, n = ;17) and those with no neurological improvement (negative, n = 19). After CSF-TT, ADC values were significantly decreased in the frontal periventricular region and the body of the corpus callosum in the positive group (p < 0.05), whereas no significant change was shown in the negative group. FA values were significantly increased in the body of the corpus callosum in both groups after CSF-TT (p < 0.05). After CSF-TT, water molecules at the extracellular space could move to the intraventricular space, resulting in decreased ADC values. This suggests that changes of water dynamics in white matter may have a role in the mechanism causing symptoms of INPH.
authors: Department of Neurosurgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Koichiro
authors: K
authors: Demura
authors: Mitsuhito
authors: M
authors: Mase
authors: Tosiaki
authors: T
authors: Miyati
authors: Tomoshi
authors: T
authors: Osawa
authors: Manabu
authors: M
authors: Hattori
authors: Harumasa
authors: H
authors: Kasai
authors: Masaki
authors: M
authors: Hara
authors: Yuta
authors: Y
authors: Shibamoto
authors: Kazuo
authors: K
authors: Yamada
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D002552:Cerebral Ventricles / Q000473:pathology; D003337:Corpus Callosum / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging