First-pass imaging of the isolated, perfused rat heart. ( a ) 12 of the 128 images acquired prior to, during and after bolus Gd infusion from control and ex vivo occluded perfused hearts: ( b ) Images showing effect of different Gd bolus volumes; ( c ) Signal intensity/time curves from inferior (inf), lateral (lat) and anterior (ant) regions of a heart in which the coronary artery was occluded on the rig. Arrow indicates time of bolus infusion: ( d ) Graph of rates of change in signal intensity in different regions of control (n = 12) and ex vivo occluded (n = 8) hearts. Positive values calculated from contrast influx, negative values calculated from contrast efflux. *p < 0.05 compared with lateral remote tissue.