Transition Metal Cluster and Polygadolinium Compounds as a New Paradigm For High Attenuation and/or Relaxivity in Contrast Media Design: Crashing The Molecular r1 = 100 Barrier

Louis Messerle, PhD,*1,2 Donald Nolting, BS1, Lizann Bolinger, PhD3, Alan H. Stolpen, MD/PhD2, Brian F. Mullan, MD,2 Dale Swenson, PhD,1 and Mark Madsen, PhD2 1Department of Chemistry, The University of Iowa, Iowa City IA 52242, 2Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, 3National Research Council Canada, Institute for Biodiagnostics, Winnipeg, MB, R3B 1Y6