TY - GEN
T1 - Evaluation of NIRS data based on theoretical analysis of oxygen transport to cerebral tissue
AU - Oyama, Kazunori
AU - Kondo, Toshihiro
AU - Komatsu, Hidefumi
AU - Sugiura, Toshihiko
PY - 2009/12/1
Y1 - 2009/12/1
N2 - NIRS has been widely utilized for monitoring oxygen concentration of cerebral blood flow (CBF). However, meanings of signals measured by NIRS still have many unclear points. One of the factors is that the physiological mechanism of coupling between neuronal activity, metabolism and CBF is not clarified enough. In this study, we evaluate NIRS data based upon numerical simulation of oxygen transport to cerebral tissue. With a 2-dimensional mathematical model of oxygen transport from an arteriole to its surrounding tissue, we simulate the activity-dependent oxygenation changes. On the basis of calculated oxygen tension distribution, we derive quantities of two kinds of hemoglobin in the arteriole by using the oxygen dissociation curve, and theoretically decompose each hemoglobin change into its factors. This decomposition has revealed that NIRS data can reflect two types of physiological phenomena: a qualitative change caused by oxygen dissociation and a quantitative change caused by an increase of CBF. These results indicate that cellular oxygen consumption can be reflected more in the time courses of deoxygenated hemoglobin than those of oxygenated hemoglobin. It will be desirable to focus not only on oxygenated hemoglobin but also on deoxygenated hemoglobin when conducting evaluation of a brain function.
AB - NIRS has been widely utilized for monitoring oxygen concentration of cerebral blood flow (CBF). However, meanings of signals measured by NIRS still have many unclear points. One of the factors is that the physiological mechanism of coupling between neuronal activity, metabolism and CBF is not clarified enough. In this study, we evaluate NIRS data based upon numerical simulation of oxygen transport to cerebral tissue. With a 2-dimensional mathematical model of oxygen transport from an arteriole to its surrounding tissue, we simulate the activity-dependent oxygenation changes. On the basis of calculated oxygen tension distribution, we derive quantities of two kinds of hemoglobin in the arteriole by using the oxygen dissociation curve, and theoretically decompose each hemoglobin change into its factors. This decomposition has revealed that NIRS data can reflect two types of physiological phenomena: a qualitative change caused by oxygen dissociation and a quantitative change caused by an increase of CBF. These results indicate that cellular oxygen consumption can be reflected more in the time courses of deoxygenated hemoglobin than those of oxygenated hemoglobin. It will be desirable to focus not only on oxygenated hemoglobin but also on deoxygenated hemoglobin when conducting evaluation of a brain function.
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U2 - 10.1007/978-0-387-85998-9_28
DO - 10.1007/978-0-387-85998-9_28
M3 - Conference contribution
C2 - 19227469
AN - SCOPUS:61849129307
SN - 9780387859972
T3 - Advances in Experimental Medicine and Biology
SP - 181
EP - 186
BT - Oxygen Transport to Tissue XXX
A2 - Liss, Per
A2 - Hansell, Peter
A2 - Bruley, Duane
A2 - Harrison, David
ER -