Monitoring physiological function by detection of exogenous fluorescent contrast agents

An invasive in vivo fluorescence detection scheme was employed to continuously monitor exogenous dye clearance from the vasculature. This invasive physiological monitoring technique was successfully demonstrated in a rabbit model. A commercially available catheter with embedded fiber optics was employed to transmit the excitation light and detect the emitted fluorescence. The clearance of indocyanine green, known to be exclusively cleared from the blood stream by the liver, was determined invasively. The clearance curves determined by this novel invasive method replicated the clearance curves in the same animals employing the non-invasive method established previously. Thus, the feasibility of a new invasive method for physiological function assessment was established.