KINETICS OF MRI CONTRAST AGENTS WITH A SIZE RANGING BETWEEN GD-DTPA AND ALBUMIN-GD-DTPA - USE OF CASCADE-GD-DTPA-24 POLYMER

A unified kinetic theory describing the dynamic properties of magnetic resonance imaging (MRI) contrast agents with a size ranging between t hat of Gd-DTPA and albumin-(Gd-DTPA)(30) was developed and tested in d isease models of cancer and myocardial reperfusion injury. Specificall y, a two-compartment kinetic model was solved analytically, and a rang e of special cases of the model was studied. MRI was performed with st rongly T-1-weighted sequences before and dynamically after administrat ion of albumin-(Gd-DTPA)(30) a prototype macromolecular contrast mediu m (MMCM) designed for blood-pool enhancement; a new MMCM: Gd-DTPA-casc ade polymer (Schering AC, Berlin, Germany, MW < 30 kDa); or Gd-DTPA, r epresenting small paramagnetic extracellular agents. The greatest dyna mic range of contrast-agent sensitivity to disease was found for album in-(Gd-DTPA)(30).