Validation of the multiple colored microsphere technique for regional blood flow measurements in newborn piglets

The use of multiple colored microspheres (CMS) for the measurement of regional blood flow (RBF) in almost all organs and tissues of newborn piglets was validated. For this purpose mixtures of different CMS and/or radio-labeled microspheres (RMS) were injected into the left ventricle of eight newborn piglets. Regional blood flows (RBF) were quantified using the reference sample method. Flow rates estimated by RMS and CMS were compared for each tissue sample. An excellent correlation (r = 0.995-0.999) between CMS and RMS flow rates was found even for organs with low perfusion and tissue samples containing 400-750 CMS. We conclude that the CMS technique is a valid alternative for RBF measurement in newborn piglets, and that all disadvantages arising from radioactive labeling are thereby avoided.