In Vivo Cerebral Blood Flow and Volume Changes of Human Brain Studying by Time-Resolved Near-Infrared Oximeter

The measure theory of cerebral blood flow (CBF), and cerebral blood volume (CBV) with time-resolved Near-infrared spectroscopy (NIRs) has been introduced in this paper, and calculation equations of CBF and CBV are developed also. Then NIRs Oximeter is used to monitor real-time data of CBF and CBV, one research path for non-invasive measurement of CBF and CBV characteristics is obtained. CBF and CBV changes at foreheads of 15 volunteers are monitoring under three conditions (be awaked from sleeping state, visual stimulation, aural stimulation). All the experimental results show that brain activity has a close relationship with cerebral local oxygen metabolism and hemodynamic variables like CBF, CBV, oxygen saturation of hemoglobin (SO₂), de-oxygenated hemoglobin concentration ([Hb]) oxy-hemoglobin concentration ([HbO₂]) and total hemoglobin concentration ([Hb_T]). This noninvasive technique may be a powerful tool for brain functional research.