S Yamada1,2,3, H Ito4, M Ishikawa5, K Yamamoto2, M Yamaguchi2, M Oshima3, K Nozaki6. 1. From the Department of Neurosurgery (S.Y., K.N.), Shiga University of Medical Science, Shiga, Japan shigekiyamada39@gmail.com. 2. Department of Neurosurgery and Normal Pressure Hydrocephalus Center (S.Y., K.Y., M.Y.), Rakuwakai Otowa Hospital, Kyoto, Japan. 3. Interfaculty Initiative in Information Studies/Institute of Industrial Science (S.Y., M.O.), The University of Tokyo, Tokyo, Japan. 4. Medical System Research and Development Center (H.I.), Fujifilm Corporation, Tokyo, Japan. 5. Rakuwa Villa Ilios (M.I.), Kyoto, Japan. 6. From the Department of Neurosurgery (S.Y., K.N.), Shiga University of Medical Science, Shiga, Japan.
Abstract
BACKGROUND AND PURPOSE: Oscillatory shear stress could not be directly measured in consideration of direction, although cerebrospinal fluid has repetitive movements synchronized with heartbeat. Our aim was to evaluate the important of oscillatory shear stress in the cerebral aqueduct and foramen magnum in idiopathic normal pressure hydrocephalus by comparing it with wall shear stress and the oscillatory shear index in patients with idiopathic normal pressure hydrocephalus. MATERIALS AND METHODS: By means of the 4D flow application, oscillatory shear stress, wall shear stress, and the oscillatory shear index were measured in 41 patients with idiopathic normal pressure hydrocephalus, 23 with co-occurrence of idiopathic normal pressure hydrocephalus and Alzheimer-type dementia, and 9 age-matched controls. These shear stress parameters at the cerebral aqueduct were compared with apertures and stroke volumes at the foramen of Magendie and cerebral aqueduct. RESULTS: Two wall shear stress magnitude peaks during a heartbeat were changed to periodic oscillation by converting oscillatory shear stress. The mean oscillatory shear stress amplitude and time-averaged wall shear stress values at the dorsal and ventral regions of the cerebral aqueduct in the idiopathic normal pressure hydrocephalus groups were significantly higher than those in controls. Furthermore, those at the ventral region of the cerebral aqueduct in the idiopathic normal pressure hydrocephalus group were also significantly higher than those in the co-occurrence of idiopathic normal pressure hydrocephalus with Alzheimer-type dementia group. The oscillatory shear stress amplitude at the dorsal region of the cerebral aqueduct was significantly associated with foramen of Magendie diameters, whereas it was strongly associated with the stroke volume at the upper end of the cerebral aqueduct rather than that at the foramen of Magendie. CONCLUSIONS: Oscillatory shear stress, which reflects wall shear stress vector changes better than the conventional wall shear stress magnitude and the oscillatory shear index, can be directly measured on 4D flow MR imaging. Oscillatory shear stress at the cerebral aqueduct was considerably higher in patients with idiopathic normal pressure hydrocephalus.
BACKGROUND AND PURPOSE: Oscillatory shear stress could not be directly measured in consideration of direction, although cerebrospinal fluid has repetitive movements synchronized with heartbeat. Our aim was to evaluate the important of oscillatory shear stress in the cerebral aqueduct and foramen magnum in idiopathic normal pressure hydrocephalus by comparing it with wall shear stress and the oscillatory shear index in patients with idiopathic normal pressure hydrocephalus. MATERIALS AND METHODS: By means of the 4D flow application, oscillatory shear stress, wall shear stress, and the oscillatory shear index were measured in 41 patients with idiopathic normal pressure hydrocephalus, 23 with co-occurrence of idiopathic normal pressure hydrocephalus and Alzheimer-type dementia, and 9 age-matched controls. These shear stress parameters at the cerebral aqueduct were compared with apertures and stroke volumes at the foramen of Magendie and cerebral aqueduct. RESULTS: Two wall shear stress magnitude peaks during a heartbeat were changed to periodic oscillation by converting oscillatory shear stress. The mean oscillatory shear stress amplitude and time-averaged wall shear stress values at the dorsal and ventral regions of the cerebral aqueduct in the idiopathic normal pressure hydrocephalus groups were significantly higher than those in controls. Furthermore, those at the ventral region of the cerebral aqueduct in the idiopathic normal pressure hydrocephalus group were also significantly higher than those in the co-occurrence of idiopathic normal pressure hydrocephalus with Alzheimer-type dementia group. The oscillatory shear stress amplitude at the dorsal region of the cerebral aqueduct was significantly associated with foramen of Magendie diameters, whereas it was strongly associated with the stroke volume at the upper end of the cerebral aqueduct rather than that at the foramen of Magendie. CONCLUSIONS: Oscillatory shear stress, which reflects wall shear stress vector changes better than the conventional wall shear stress magnitude and the oscillatory shear index, can be directly measured on 4D flow MR imaging. Oscillatory shear stress at the cerebral aqueduct was considerably higher in patients with idiopathic normal pressure hydrocephalus.
Authors: Jae-Eun Kang; Miranda M Lim; Randall J Bateman; James J Lee; Liam P Smyth; John R Cirrito; Nobuhiro Fujiki; Seiji Nishino; David M Holtzman Journal: Science Date: 2009-09-24 Impact factor: 47.728
Authors: Brett A Shook; Jessica B Lennington; Rebecca L Acabchuk; Meredith Halling; Ye Sun; John Peters; Qian Wu; Amit Mahajan; Douglas W Fellows; Joanne C Conover Journal: Aging Cell Date: 2013-12-17 Impact factor: 9.304