Abstract #1880

Tunable Manganese Porphyrin as Gd-Free T1 Contrast Agents for Broad Applications

Hai-Ling Margaret Cheng¹,², Weiran Cheng³,⁴, Inga E. Haedicke³,⁴, Joris Tchouala Nofiele¹,², Xiao-an Zhang³,⁴

¹Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; ²The Hospital for Sick Children, Toronto, Ontario, Canada; ³Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada; ⁴Chemistry, University of Toronto, Toronto, Ontario, Canada

Gadolinium-based contrast agents are less efficient at high fields and are potentially toxic. Recently, the Zhang group developed a new class of T1 contrast agents based on the manganese porphyrin (MnP) structure with improved efficacy and safety. This study investigates MRI properties of two specific versions: a small polar MnP and a larger dimer. In-vitro measurements at 3 Tesla demonstrate high T1 relaxivities and a relatively weak T2 effect. Signal enhancement in rats is significantly greater compared to Gd-DTPA, and biodistribution is specific to each MnP. Potential applications are broad and include cardiac, liver, angiography, and perfusion and permeability imaging.