Separation of the Intra- and Extracellular Apparent Diffusion Coefficients (ADC) of Water in Rat Skeletal Muscle using Spectroscopic MEMRI
Sotak C, Henninger N, Seland J, Helmer K
Worcester Polytechnic Institute, UMass/Memorial Healthcare
MEMRI was used to separate intracellular (IC) and extracellular (EC) water signals in rat skeletal muscle. Infusion of MnCl2 was through a stairstep schedule using concentrations from 20-70 mM. Diffusion-weighted (DW) inversion-recovery data was fit using a bi-exponential form and the resulting DW compartmental M0 values were then fit for the compartmental ADC values. The separation of water compartment signals was verified using an inverse-Laplace transform method. Results show that the increased relaxivity of Mn2+ over that of GdDTPA2- allows for the separation of the IC and EC signals and the measurement of their ADCs.