Abstract #1529

Jensen B, stergaard L, Kiselev V

Concentration of MRI contrast agents (CA) is commonly determined indirectly using their relaxation effect. In quantitative perfusion studies, the change in the relaxation following a bolus passage is converted into concentrations assuming identical relaxivities for tissue and blood. Simulations presented in this study demonstrate that the relaxivity of blood pool CA depends significantly on both the host tissue and the pulse sequence, in agreement with previous experiments. In particular, the relaxation effect of Gd-based CA in brain tissues is several-fold larger than in bulk blood. The results can be applied to quantitation of perfusion, functional MRI and vessel size imaging.