A method for monitoring of oxygen saturation changes in brain tissue using diffuse reflectance spectroscopy.
Continuous measurement of local brain oxygen saturation (SO2) can be used to monitor the status of brain trauma patients in the neurocritical care unit. Currently, micro-oxygen-electrodes are considered as the "gold standard" in measuring cerebral oxygen pressure (pO2), which is closely related to SO2through the oxygen dissociation curve (ODC) of hemoglobin, but with the drawback of slow in response time. The present study suggests estimation of SO2in brain tissue using diffuse reflectance spectroscopy (DRS) for finding an analytical relation between measured spectra and the SO2for different blood concentrations. The P3diffusion approximation is used to generate a set of spectra simulating brain tissue for various levels of blood concentrations in order to estimate SO2. The algorithm is evaluated on optical phantoms mimicking white brain matter (blood volume of 0.5-2%) where pO2and temperature is controlled and on clinical data collected during brain surgery. The suggested method is capable of estimating the blood fraction and oxygen saturation changes from the spectroscopic signal and the hemoglobin absorption profile.
Department of Biomedical Engineering, Linköping University, 581 83, LINKÖPING, Sweden.
Peter
P
Rejmstad
Department of Biomedical Engineering, Linköping University, 581 83, LINKÖPING, Sweden.
Johannes D
JD
Johansson
Department of Biomedical Engineering, Linköping University, 581 83, LINKÖPING, Sweden.
Neda
N
Haj-Hosseini
Department of Biomedical Engineering, Linköping University, 581 83, LINKÖPING, Sweden.
Karin
K
Wårdell
D000465:Algorithms; D001831:Body Temperature; D001921:Brain / Q000378:metabolism* / Q000601:surgery; D001932:Brain Neoplasms / Q000378:metabolism / Q000601:surgery; D002560:Cerebrovascular Circulation / Q000502:physiology; D000068456:Clinical Studies as Topic; D004058:Diffusion; D005336:Fiber Optic Technology; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D008959:Models, Neurological; D016343:Monitoring, Intraoperative; D010100:Oxygen / Q000378:metabolism*; D055420:Perfusion Imaging; D019047:Phantoms, Imaging; D012039:Regional Blood Flow / Q000502:physiology; D013057:Spectrum Analysis / Q000295:instrumentation; D066127:White Matter / Q000378:metabolism
D006454:Hemoglobins; D010100:Oxygen
diffuse reflectance spectroscopy; hemoglobin; human brain; optical phantom; oxygenation