CCD imaging in cryospectrophotometric determination of microvascular oxyhemoglobin saturations.
A microspectrophotometric imaging method has been developed for localized measurements of intravascular oxyhemoglobin (HbO2) saturations in microvessels from sections of quick-frozen tissue. HbO2 saturation was calculated from the absorption spectrum of red blood cells measured at five selected wavelengths in the 520- to 570-nm range. We combined the use of narrow-bandwidth interference filters and a CCD camera mounted on a microscope to obtain one gray image of the sample at each wavelength. Each pixel is a quantitative measure of transmitted light intensity from the tissue sample at that location. A linear calibration curve for blood frozen in vitro (humans and mice) and in vivo (mice) was obtained using a multicomponent analysis. Oxy- and deoxyhemoglobin were assumed to be the only hemoglobin components present. A constant term compensates for light loss due to scattering on red blood cells and ice crystals. The standard error in single measurements of HbO2 saturation was 5%. The present method allows off-line analysis of the HbO2 saturation distribution within a microvessel network and offers new possibilities for comparative morphological studies.
Måseide
K
K
Institute for Cancer Research, Norwegian Radium Hospital, Montebello, Oslo, Norway.
Rofstad
E K
EK
D000818:Animals; D002138:Calibration; D005615:Freezing; D006321:Heart / Q000502:physiology; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008433:Mathematics; D051379:Mice; D008833:Microcirculation / Q000502:physiology*; D008954:Models, Biological; D010092:Oximetry / Q000295:instrumentation / Q000379:methods; D010108:Oxyhemoglobins / Q000032:analysis*; D012044:Regression Analysis; D013053:Spectrophotometry / Q000295:instrumentation / Q000379:methods
D006454:Hemoglobins; D010108:Oxyhemoglobins