Annals of nuclear medicine
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The aim of this study was to clarify the regional differences in cerebral blood flow (CBF) change during hyperventilation by using H2(15)O and positron emission tomography (PET). Eight healthy volunteers (age: 63.0 +/- 8.9 yr.) were studied. Regional CBF was measured by the H2(15)O autoradiographic method and PET. ⋯ The SPM revealed that primary motor and premotor cortices were significantly activated by hyperventilation. In these areas absolute CBF values were significantly higher than those in the temporal, occipital and parietal lobes in the hypocapnic state, but there were no significant regional differences in the normocapnic state. In the hypocapnic state induced by hyperventilation, the primary motor and premotor CBF shows combined changes with vasoreaction to hypocapnia and increase in activation due to hyperventilation.