Artificial Intelligence in Digital Holographic Imaging

15Automated Analysis of Red Blood Cell Storage Lesions

15.1 Introduction

RBCs serve many purposes in the human body. One of the most important RBC functions is to transfer oxygen and carbon dioxide between the lungs and the rest of the body's tissues. Importantly, the shape of an RBC should be optimized for maximal deformation, a maximum surface at a given volume, rapid changes, and cell survival during repeated passages through narrow channels. Surface area is one of the most important properties of RBCs because the exchange of oxygen and carbon dioxide takes place at the cell surface. A larger surface area allows for greater oxygen and carbon dioxide exchange in the lungs and other bodily tissues. These conditions are satisfied by a biconcave disk shape, which is the medical norm for RBCs. The biconcave shape of RBCs has a flexible membrane with a high surface‐area‐to‐volume ratio that facilitates extensive, reversible elastic deformation of the RBC as it repeatedly passes through narrow capillaries. The biconcave shape is thought to be the result of minimizing the free energy of membranes under area and volume constraints because there are no complicated inner structures in RBC. However, during the storage period, RBCs undergo metabolic, biochemical, biomechanical, and molecular changes, which are referred to as storage lesions [1]. Furthermore, many adverse effects related to RBC storage are reported in critically ill patients when the RBC storage period exceeds four weeks ...