Mapping Water Exchange in Rat Tumour Xenografts: Using Multiple Flip Angles During Late-Uptake Stages Contrast Agent Injection

Colleen Bailey¹, ², Firas Moosvi¹, ², Greg J. Stanisz¹, ²

Intra-to-extracellular water exchange has been shown to increase during apoptotic cell death In Vitro. To map exchange in vivo, four flip angles were used during the late near-constant stages of uptake following three separate injections of Gd-DTPA-BMA in rat tumour xenografts. High extracellular water fraction corresponded to low cellularity on H&E. Regions of low water exchange were negative on TUNEL staining, while regions of high water exchange were positive, indicating apoptosis. High water exchange was observed even in cases where cells had not cleared and water fraction did not yet show a change.