Nuclear magnetic resonance method and apparatus for bone analysis and imaging

Abstract

A method for analyzing a bone is disclosed. The method includes measuring nuclear magnetic resonance signals corresponding to an amount of hydrogen nuclei from within a selected portion of the bone. The signals measured includes components corresponding to bound water in the bone. Specific bone tissue volume is determined from an amplitude of the components corresponding to the bound water. In one example, the relaxation times are transverse relaxation times determined from CPMG spin echo amplitudes. In one example, the amplitudes are measured using truncated CPMG sequences having waiting time less than the recovery time of slower relaxing components of the bone being analyzed. In one embodiment, the collagen content of the bone is determined by determining a fluid volume from steady state free precession amplitude of the selected portion. The fluid volume and a bone mineral volume determined from the bound water signal are then subtracted from the total volume of the selected portion to determine the collagen volume. A method for magnetic resonance imaging of a bone is also disclosed, including inducing nuclear magnetic resonance within a selected discrete volume of the bone, determining an amplitude of components in detected NMR signals bound water and repeating bound water amplitude measurements at other selected discrete volumes within the bone to develop an image of the bone.