Fig. 4

Relationship between peak arterial phase tissue enhancement (peak ΔHU) and organ perfusion (mL/s/mL) in a parenchymatous organ with a t_max of approximately 35 s for different peak feeding vessel enhancements and α parameters. To estimate peak arterial phase tissue enhancement, we assumed that contrast medium, injected in a peripheral vein or in a central venous catheter, is diluted by the right and left heart into the whole cardiac output before entering arterial circulation. Assuming a negligible total volume change due to contrast agent injection, if we inject 1.25 mL/kg of a iodinated contrast agent with a 350 mgI/mL concentration at 3.2 mL/s flow rate in a 80 kg man with an average cardiac output of 5000 mL/min (approximately 83 mL/s) and we acquire a CT scan at 120 kVp (with a constant of 26.18 for ΔHU calculation), peak ΔHU will then be \(\frac{3.2\times 350\times 26.18}{83}=350\;\mathrm{HU}\)