A method for constructing a personalized contrast medium protocol at contrast enhanced, Coronary CT Angiography (CCTA) is presented. A one compartment pharmacokinetic model is parameterized and identified with a minimal data set from a test-bolus injection. A direct-search optimization is performed to construct a protocol that achieves target enhancement in the cardiac structures. Clinical results demonstrating the method's ability to achieve prospectively chosen image enhancement levels while reducing contrast medium dose are presented.