3D Radial Multi Gradient Echo Dynamic MRI for Characterization of Microvasculature in Tumor Models Subjected to Respiratory Motion

Julien Vautier^1,2, Melanie Heilmann³, Christine Walczak^1,2, Jol Mispelter^1,2, Andreas Volk^1,2

Preclinical dynamic MRI to characterize microvasculature in tumor models is typically performed with gradient- or spin-echo sequences and Cartesian k-space sampling which is not optimal for tumors subjected to respiratory motion. Radial k-space sampling, rather insensitive to motion, should be more appropriate. In this study, we have developed and validated a 3D radial multi gradient echo sequence. It allows for simultaneous measurement of T₁ and T₂* upon contrast agent administration at 1min30 time resolution. A first in vivo study comparing 3D K^trans maps for two contrast agents of different molecular weights was performed on motion animated subcutaneous tumors in mice.