Abstract

Near infrared spectroscopy using either broad band reflectance spectrophotometry or monochromatic illumination has been carried out to monitor non invasively the changes of the concentrations of chromophores in rat brain induced by the intravenous injection of various contrast agents (indocyamne green, ultrasmall magnetic particles suspension, albumine, dextran, or saline solution alone). Depending of the wavelength and of the absorption spectrum of the injected compound the bolus can be seen either by a decrease or an increase of the transmitted light, this latter due to induced dilution of the blood by the bolus. We suggest that this could be used to determine the arterial input function the contrast agent needed to perform absolute cerebral blood flow imaging by nuclear magnetic resonance.

© 2001 OSA/SPIE