Quantitative magnetic resonance method and apparatus for bone analysis

Abstract

A method for analyzing a bone is disclosed, including measuring a nuclear magnetic resonance signal corresponding to an amount of hydrogen within a known volume of the bone. The volume is large enough that so the signal corresponds to bulk properties within the volume. A bone matrix volume is determined from the signal. In one embodiment, the signal is a steady state free precession amplitude. The selected known volume in one example is selected by a sensitive point technique which includes imparting a substantially homogeneous static magnetic field to the bone and superimposing thereon mutually orthogonal oscillating gradient magnetic fields. In another example, the signal amplitude can be used to directly calculate bone mineral density of the bone. An apparatus according to one example of the invention includes a receptacle adapted to receive the foot and to substantially immobilize the foot, a magnet for inducing a static magnetic field within the calcaneus bone, a radio frequency pulse generator and an antenna coupled thereto positioned to induce a radio frequency magnetic field in the calcaneus bone to excite nuclear magnetic resonance therein, a receiver and an antenna coupled thereto to detect nuclear magnetic resonance signals originating in the calcaneus bone, means for localizing generation and detection of the nuclear magnetic resonance signals from within a selected known volume within the calcaneus bone, and means for calculating a property of specific bone tissue within the calcaneus bone from the nuclear magnetic resonance measurements.

Dependencies are inferred from the claim text.