The Cytoscan (TM) model E-II, a new reflectance microscope for intravital microscopy: Comparison with the standard fluorescence method

The Cytoscan(TM) Model E-II (Cytometrics Inc., Philadelphia, Pa., USA) is a newly developed instrument which functions as an intravital microscope and is small and easily portable. Through the use of orthogonal polarization s pectral (OPS) imaging, the Cytoscan Model E-II delivers images of the micro circulation which are comparable to those achieved with intravital fluoresc ence videomicroscopy (IFM), but without the use of fluorescent dyes. The pu rpose of this study was to validate the Cytoscan Model E-II instrument agai nst IFM. The experiments were carried out on striated muscle in the dorsal skinfold chamber of the awake Syrian hamster. The following parameters were measured in identical regions of interest in the same animal under baselin e conditions and 0.5 and 2 h after a 4-hour period of pressure-induced isch emia: arteriolar diameter, venular diameter and venular red blood cell velo city. Bland-Altman plots showed good agreement between the two techniques f or venular red blood cell velocity. As expected, arteriolar and venular dia meters as measured by the Cytoscan were on average 5 mum smaller than the v alues from IFM, since the Cytoscan measures the red blood cell column width and IFM measures luminal diameter. Thus, OPS imaging can be used to make v alid measurements of microvascular diameter and red blood cell velocity in tissues. Copyright (C) 2000 S. Karger AG, Basel.