Feasibility of dual pharmacokinetic modeling using Gd-DTPA/MRI and F-FDG/PET

INTRODUCTION MRI-PET bimodal imaging is already a reality in fundamental and clinical research. Reaching the full potential of such dual imaging approaches for broader clinical acceptance may be through new methodologies that take advantages of one modality to compensate for the limitations of the other. The arterial input function (AIF) is commonly used for several types of MRI and PET pharmacokinetic analyses, but measurement of the AIF remains a challenge for both modalities. The most commonly used MRI contrast agent, GdDTPA, and PET radiotracer, F-FDG, both are subjected to extravasation and excretion, and F-FDG can be further internalized into cells. The aim of our study was to evaluate the correspondence between the AIF derived from MRI and PET, and to determine whether the AIF obtained by one modality can be converted into the AIF for the other modality. Such a conversion would be particularly useful for pharmacokinetic modeling of data acquired with both imaging modalities.