EM-Assisted Quantization of Absolute Cleavage Timing and Symmetry for Blastomere

This study addresses the issue of blastomere cleavage timing, which is traditionally deemed the most important indicator in embryo quality assessment. We propose a novel quantization method for analyzing Time-lapse Incubator (TLI) images of embryos. This method incorporates five image classifiers, an instance segmentor, and the Expectation-Maximization (EM) algorithm to provide a cost-effective and reliable tool and to offer interpretable data for further research in the reproductive medicine field. The method is characterized in that the EM algorithm is employed to enhance the performance of classifiers and segmentor in fitting different patient data sources. The method enables (1) to identify the absolute cleavage timing of blastomere, i.e., tPNa, tPNf, t2, t3, t4, t8, t6, t7, and t8, (2) tracking the cleavage process of blastomere to highlight the irregular cleavage (IRC) patterns, (3) to quantitatively assess the symmetry degree of blastomere. Our method reduces the average time difference between Ground Truth and CTP to just 2.9 hours, a significant improvement over the 6.13 hours reported by Vitrolife™. Moreover, our method identifies up to eight cleavage time points, surpassing the six cleavage time points provided by Vitrolife™.