DSA imaging to test the effects of phenylephrine on a rat’s cardiopulmonary system. The two columns in (a) show selected DSA images corresponding to pre-drug phase and a corresponding series 2 minutes after drug infusion. Three ROIs were selected in the aorta, left pulmonary artery, and left ventricle. The changes over time in mean attenuation values for these ROIs are shown for pre-drug (b) and post-drug (c) illustrating that drug-induced vasoconstriction delayed the flow of blood from right ventricle to aortic outflow in addition to distention of pulmonary arteries and left ventricle. We have fitted gamma variate curves to the measurement points in (b) and (c).