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Abstract #3222

Contrast Agent Diffusion in DGEMRIC: Exploring Donnan Equlibrium In Vitro & In Vivo

Eveliina Lammentausta1,2, Eliot H. Frank3, Zana Hawezi2, Alan J. Grodzinsky3, Leif E. Dahlberg2

1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2Joint & Soft Tissue Unit, Department of Clinical Sciences, Lund University, Malm, Sweden; 3MIT, Cambridge, MA, United States

Human femoral head cartilage was used to measure T1 relaxation time at constant intervals after exposure to Gd-DTPA2- until ten hours and to determine the depth-wise diffusion characteristics and fixed charge density in cartilage assuming Donnan equilibrium. This information was applied into a dynamic in vivo dGEMRIC data to estimate the evolution of Gd concentration of synovial fluid until two hours after intravenous injection of Gd-DTPA2-. The results suggest that Gd concentration is never in true equilibrium within the cartilage in vivo. To improve in vivo dGEMRIC, careful analysis by time and depth should be considered.