  In this work we consider the image reconstruction problem of sparsely sampled
dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). DCE-MRI is a
technique for acquiring a series of MR images before, during and after
intravenous contrast agent administration, and it is used to study
microvascular structure and perfusion. To overcome the ill-posedness of the
related spatio-temporal inverse problem, we use regularization. In
regularization one of the main problems is how to determine the regularization
parameter which controls the balance between data fitting term and
regularization term. Most methods for selecting this parameter require the
computation of a large number of estimates even in stationary problems. In
dynamic imaging, the parameter selection is even more time consuming since
separate regularization parameters are needed for the spatial and temporal
regularization functionals. In this work, we study the possibility of using the
S-curve with DCE-MR data. We select the spatial regularization parameter using
the S-curve, leaving the temporal regularization parameter as the only free
parameter in the reconstruction problem. In this work, the temporal
regularization parameter is selected manually by computing reconstructions with
several values of the temporal regularization parameter.
