Figure 2. Sequential ¹H MR spin echo images (echo time=30 ms) obtained from an apoptotic tumour following injection of the C2-SPIO (superparamagnetic iron oxide) contrast agent. The images were acquired over a period of nearly 2 h. The region of negative contrast, marked by the arrow, was coincident with a region of apoptotic cells observed by histological analysis of a corresponding tumour section obtained post mortem. Figure modified, with permission, from [25].