Fig. 7.

Comparative study of BOLD and TOLD to assess tumor oxygenation. BOLD and TOLD-MRI measures of oxygen gradients overlaid on a high-resolution image of a small Dunning prostate R3327-AT1 tumor in conditions of hyperoxia, 100% O₂ (O₂), return to normal air (Air) and carbogen breathing, 95% O₂ and 5% CO₂ (CB). Changes in signal intensity is represented by %ΔSI. Response maps compare final images versus baseline. Each map shows substantial intratumoral heterogeneity and differences in the heatmap pattern within the same treatment, between BOLD and TOLD