[Validity of Near-infrared Spectroscopy].

Regional cerebral oxygen saturation measured by near-infrared spectroscopy has been used clinically. Its usefulness in cardiac surgery and neurosurgery was also reported. On the other hand, accuracy of rSO2 values has been supposed to be doubtful due to extra-cerebral contamination and unstable mean optical path-length. Therefore, we tried to review issues for accuracy of rSO2 values and clinical usefulness. Our aim is to clarify the issue and clinical usefulness of measuring regional cerebral oxygen saturation.