Automatic Dissection Position Selection for Cleavage-Stage Embryo Biopsy.

Embryo biopsies are routinely performed for preimplantation genetic diagnosis (PGD). In order to avoid blastomere membrane rupture and cell lysis, correct selection of a suitable dissection position on the zona pellucida (ZP) is necessary. Although, the technology for automated cell manipulation has advanced greatly over the past decade, fully automated embryo biopsy in PGD has not been realized yet. Automated PGD may ultimately set a new clinical standard that improves the consistency of outcomes, increases cell survival rates, flattens the learning curve of the manual procedure, and reduces the effects of human fatigue. In this paper, we present the first approach to automatically select a suitable ZP dissection position prior to embryo biopsy from a single focused embryo image based on edge detection. The proposed method consists of a technique that estimates the elliptical ZP boundaries and another two techniques that select the suitable position for ZP dissection. These techniques achieved success rates of 96%, 94%, and 94% respectively. In addition, the proposed ZP boundary estimation technique has the potential to perform ZP thickness variation (ZPTV) test and other ZP morphology measurements with further improvement in the future. Our methods provide a starting point for fast position selection prior to automatic embryo biopsy.