Gadocoletic acid (also Gadoletic acid trisodium salt, or B22956/1) is a magnetic resonance contrast agent. Based on results from animal imaging experiments and pharmacokinetic data it was suggested that gadocoletic acid trisodium salt has strong potential for clinical use in Magnetic Resonance Coronary Angiography and Myocardial Perfusion Imaging. The small molecules of gadocoletic acid are bound after injection to large human serum albumin molecules in coronary vessels with the result of high vessel/muscle contrast. The ability of B229563− (anion) to bind to more than one site on the albumin molecule allows a positive correlation between dose and blood relaxation rate enhancement at doses higher than 0.05 mmol/kg, the dose that produces roughly a total plasma concentration equimolar to the albumin concentration at equilibrium distribution. Gadocoletic acid is thought to be highly efficacious in inversion recovery-prepared 3D gradient-recalled echo, navigator echo-gated coronary angiography in humans already at doses below 0.1 mmol/kg.