Owen Carl Richardson1, Steven F. Tanner1,
1Division of Medical Physics, University of Leeds, Leeds, West Yorkshire, United Kingdom; 2AstraZeneca, Alderley Park, Cheshire, United Kingdom
The contrast agent gadofosveset (Ablavar) displays altered relaxivity and kinetic behaviour on binding with albumin. This study investigates gadofosveset relaxivity variance with field strength, and binding site influence on model fitting. Free and observed relaxivities were calculated from measured T1 relaxation times for in vitro gadofosveset solutions with/without albumin at four field strengths and concentrations 10mM. Bound relaxivity was calculated using a model fit for 1-3 binding sites at low and high concentrations. Single binding underestimates high-concentration relaxivity at low fields. Bound and free gadofosveset relaxivities converge at high fields, although the kinetics characteristics remain a differentiating feature.