Measuring different oxygenation levels in a blood perfusion model simulating the human head using NIRS

Abstract

The oxygenation, perfusion and metabolism of the brain - segmented in both hemispheres - can be estimated from the oxygenation and hemoglobin levels of the venous blood in the cerebral efferent vessels.We present a phantom based model to simulate the anatomical target region which was connected to hemodynamic perfusion circuit to provide different oxygenation rates inside of the simulated target vessel (measurement cell) reproducible. A triple-wavelength (770, 808 and 850 nm) multi-distance NIRS sensor (6 photodiodes, linearly arranged, separated 6 mm each) was used to detect these different saturation levels.The results illustrate the capability to measure the optical property variation of hemoglobin due to oxygenation and deoxygenation processes in a specific vessel. Based on these first results a series of measurements is introduced to correlate the amount of reflected light to the actual oxygen saturation of the blood.

Calibration and evaluation of a continuous wave multi-distance NIRS system in simulated desaturation investigations

“…The equipped and former developed model setup (Layer 1: scalp; Layer 2: skull, Layer 3: target vessel, Layer 4: brain) with an integrated hemodynamic perfusion circuit is presented elsewhere [40,41] (figure 2).…”

“…A developed and previously presented [40,41] triple-wavelength (770, 808 and 850 nm, Series 330-1206, OSA Opto Light GmbH) CW MD-NIRS sensor (6 photodiodes, linearly arranged, separated 6 mm each, BP 104 S, OSRAM Opto Semiconductors GmbH) was equipped (figure 3) to detect the different saturation levels. The PD signals were digitalized (USB 6259, National Instruments, TX, USA) and further processed (Thinkpad, IBM, Software: Windows XP, LabVIEW 7.0).…”