Geometrical characterization of healthy red blood cells using digital holographic microscopy and parametric shape models for biophysical studies and diagnostic applications

Abstract

Modeling of the red blood cell (RBC) shape is an integral part of the experimental and computer simulation investigations of light scattering by these cells for fundamental studies as well as diagnostic applications in the techniques like cytometry. In the present work, a comprehensive study of the geometrical characterization of healthy human RBCs using the digital holographic microscopy (DHM) and six frequently employed parametric shape models is reported. It is shown that the comparison of the optical phase profiles, the thickness profiles given by the models with the DHM results gives a better judgement of the appropriateness of the parametric shape models. Results of geometrical characterization of 500 healthy RBCs in terms of volume, surface area and sphericity index lead to the classification of the parametric models in two categories based on the nature of variation of these quantities with the cell diameter. In light of the variability of the healthy RBC shapes, our findings suggest that the parametric models exhibiting a negative correlation between the sphericity index and the cell diameter would provide more reliable estimates of the RBC parameters in diagnostic applications. Statistical distributions and descriptive statistics of the RBC volume, surface area and sphericity index serve as a guide for the assessment of the capability of the studied parametric models to give a reliable account of the variability of the healthy RBC shape and size.Comment: 25 pages, 17 figure