Classification of red blood cell shapes in flow using outlier tolerant machine learning

TL;DR

This paper introduces an outlier tolerant convolutional neural network for automatic classification of red blood cell shapes in flow, enabling objective, reproducible analysis of cell morphology under various conditions.

Contribution

The study presents a novel CNN-based method for outlier tolerant, automated classification of RBC shapes, improving accuracy and objectivity over manual evaluation.

Findings

Identified stable 'slipper' and 'croissant' RBC shapes depending on flow conditions.

Determined the transition point between RBC shape phases.

Generated phase diagrams comparable to manual assessments.

Abstract

The manual evaluation, classification and counting of biological objects demands for an enormous expenditure of time and subjective human input may be a source of error. Investigating the shape of red blood cells (RBCs) in microcapillary Poiseuille flow, we overcome this drawback by introducing a convolutional neural regression network for an automatic, outlier tolerant shape classification. From our experiments we expect two stable geometries: the so-called `slipper' and `croissant' shapes depending on the prevailing flow conditions and the cell-intrinsic parameters. Whereas croissants mostly occur at low shear rates, slippers evolve at higher flow velocities. With our method, we are able to find the transition point between both `phases' of stable shapes which is of high interest to ensuing theoretical studies and numerical simulations. Using statistically based thresholds, from our data, we obtain so-called phase diagrams which are compared to manual evaluations. Prospectively, our concept allows us to perform objective analyses of measurements for a variety of flow conditions and to receive comparable results. Moreover, the proposed procedure enables unbiased studies on the influence of drugs on flow properties of single RBCs and the resulting macroscopic change of the flow behavior of whole blood.