Figure 7. Significant changes in blood oxygenation level dependent (BOLD) signal intensity following antivascular targeting treatment. Axial BOLD spoiled gradient echo MR images (TR=100 ms, TE=60 ms, flip angle=40°) through the mid-pelvis shows a large, left inferior hypogastric lymph node (arrow) in a patient with malignant peritoneal carcinoma. Images were obtained twice before (–5 days and –1 day) and 4 h and 24 h after the first administration of a vascular targeting agent (Combretastatin-A4-phosphate, 52 mg m^–2). Darkening within the centre of the lesion at 4 h with treatment is consistent with the presence of reduced blood flow and an increase in the amount of deoxyhaemoglobin. This BOLD effect reverses by 24 h. Corresponding signal intensity time curves are shown which show marked but reversible alteration in contrast agent kinetics.