Arterial input function: Relevance of eleven analytical models in DCE-MRI studies

The assessment of the micro circulatory parameters in tissues by dynamic contrast enhanced MRI (DCE- MRI) requires the knowledge of the arterial input function (AIF). In several situations the estimation of the true AIF can be improved by a mathematical modeling. However, the mathematical modeling can introduce wrong a priori and generate artifacts. It is then necessary to verify its coherence. Several models are proposed in the literature to fit the AIF. In this study, several models were tested. The test consisted in the assessment of the ability of the models to describe a large range of experimental AIF, extracted of a DCE-MRI multicentric study. Simple models, such as exponential or gamma variate functions were not able to correctly describe all the measured AIF. Conversely, the AIF data were correctly described by multi-phase models and especially by an original function based on a "mutli-exponential gamma" function.