QUANTITATION OF INTRINSIC MAGNETIC SUSCEPTIBILITY-RELATED EFFECTS IN A TISSUE MATRIX - PHANTOM STUDY

A theoretical background and experimental method that allows a separat ion of intrinsic, tissue-matrix-specific magnetic-field inhomogeneity effects from both macroscopic (large compared with voxel dimensions) a nd microscopic (on the order of molecular dimensions) inhomogeneities is proposed, Such separation allows one to take full advantage of thes e tissue-matrix-specific magnetic field inhomogeneity effects to extra ct information about tissue structure, A method to measure the volume fraction occupied by the susceptibility-perturbing component in a tiss ue matrix, the R2' relaxation rate constant, and the susceptibility di fference between the bulk component and the susceptibility-perturbing component in a tissue matrix has been developed and tested on phantoms , This method offers the potential to assess a variety of tissue param eters, including cerebral blood volume, blood volume and blood oxygena tion-level changes in functional MRI, the structure of trabecular bone , and other physiologically important issues.