@misc{oai:repo.qst.go.jp:00071154,
 author = {Ito, Hiroshi and Masanobu, Ibaraki and Takuwa, Hiroyuki and Kawaguchi, Hiroshi and Masamoto, Kazuto and Ikoma, Youko and Seki, Chie and Kanno, Iwao and 伊藤 浩 and 茨木 正信 and 田桑 弘之 and 川口 拓之 and 正本 和人 and 生駒 洋子 and 関 千江 and 菅野 巖},
 month = {Jun},
 note = {Objectives: According to a model for the regulation of cerebral oxygen delivery proposed by Hyder et al., the relation between cerebral blood flow (CBF) and cerebral oxygen extraction fraction (OEF) can be expressed using the effective diffusivity for oxygen in the capillary bed (D) as OEF=1-exp(-D/CBF). In this study, changes in D during neural activation and deactivation were estimated from changes in CBF and OEF measured by PET in humans during neural activation and deactivation observed in crossed cerebellar diaschisis (CCD) caused by contralateral supratentorial lesions.
Methods: CBF, cerebral blood volume (CBV), cerebral metabolic rate of oxygen (CMRO2) and OEF were measured in each of 7 healthy men at rest and during performance of a right hand motor task. D values were calculated for each condition. CBF, CBV, CMRO2 and OEF for CCD and unaffected sides were measured in 11 patients with cerebrovascular disease, and D values were calculated for both sides.
Results: Changes in CBF, CBV, CMRO2, OEF, and D during neural activation in the left precentral gyrus were 48+-23%, 14+-25%, 11+-13%, -24+-8%, and 5+-14%, respectively. Changes in CBF, CBV, CMRO2, OEF, and D in CCD side (neural deactivation) as compared to unaffected side were -27+-8%, -25+-32%, -20+-9%, 10+-6%, and -17+-10%, respectively.
Conclusions: The degree of changes in D during neural activation was smaller than during neural deactivation. Since the D value is proportional to capillary blood volume, the degree of changes in capillary blood volume during neural activation might be smaller than during neural deactivation, corresponding to smaller degree of changes in CBV during neural activation as compared with neural deactivation. Further studies to investigate changes in capillary blood volume during neural activation and deactivation using microscope in animals will be required., Society of Nuclear Medicine and Molecular Imaging 2013 Annual Meeting},
 title = {Changes in effective diffusivity for oxygen in the capillary bed during neural activation and deactivation measured by PET},
 year = {2013}
}