Microspheres in MRI scanning. Artwork of spherical microcapsules (one at lower left) with pH-sensitive components that have been developed for use in MRI (magnetic resonance imaging) scanning. This research, reported in the journal Nature, aided the monitoring of cell survival and functionality after in vivo transplantation as part of cell therapy. This scanning technique allowed accurate study of in vivo cell death and cell viability patterns. A vein (blue) and artery (red) are at top.