Modelling of contrast enhancement for cardiac multi-detector row CT

Cardiac computed tomography (CT) requires intravascular injection of iodinated contrast agent to visualize the cardiac chambers, large vessels, and coronary arteries. Currently, the standard injection protocol used clinically is uniphasic (fixed volume of contrast agent injected at a single flow rate). This results in non-uniform enhancement of the blood pool in some patients. The purpose of this work was to develop an algorithm for determining patient-specific contrast injection protocols necessary to consistently achieve optimal uniform enhancement in the left heart on multi-detector row CT (MDCT) images. A model was developed using the patient-function approach: the injection administered to the patient was the input and the corresponding enhancement observed in the region-of-interest was the output of the system. These input and output functions were related via the transfer-function which was computed in the Fourier domain. The model was first validated clinically using standard uniphasic contrast injection protocols. Then, the model was implemented to determine the patient-specific injection protocol necessary to achieve the desired enhancement in the left heart. The resulting enhancement in the diagnostic images was in agreement with the desired enhancement. The results indicate that it is possible to determine a patient-specific injection protocol in order to achieve uniform enhancement in MDCT images of the left heart.