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Figure 5a. (a) Graph depicts exponential curves for three injection profiles for a 120-second injection with an initial injection rate of 2 mL/sec and decay coefficients of 0.01 (dotted line), 0.02 (solid line), and 0.03 (dashed line). Slower exponential decay results in a higher total amount of contrast medium injected (larger area under the curve) and a higher final injection rate. (b) Graph depicts aortic time-enhancement curves that were simulated with the mathematic model (with porcine physiologic parameters) by solving Equations (A1)-(A5) with input exponential injections. Uniform, plateau aortic enhancement was observed with an exponential decay coefficient of 0.02. With decay coefficients of 0.01 or 0.03, contrast enhancement either steadily increased above the plateau or decreased after a peak below the plateau, respectively.