Segmentation of nuclei and cells using membrane related protein markers

Segmenting individual cell nuclei from microscope images normally involves volume labelling of the nuclei with a DNA stain. However, this method often fails when the nuclei are tightly clustered in the tissue, because there i s little evidence from the images on where the borders of the nuclei are. I n this paper we present a method which solves this limitation and furthermo re enables segmentation of whole cells. Instead of using volume stains, we used stains that specifically label the surface of nuclei or cells: lamins for the nuclear envelope and alpha-6 or beta-1 integrins for the cellular s urface. The segmentation is performed by identifying unique seeds for each nucleus/cell and expanding the boundaries of the seeds until they reach the limits of the nucleus/cell, as delimited by the lamin or integrin staining , using gradient-curvature flow techniques. We tested the algorithm using c omputer-generated objects to evaluate its robustness against noise and appl ied it to cells in culture and to tissue specimens. In all the cases that w e present the algorithm gave accurate results.