ABSTRACTThis paper presents a new, three-dimensional (3-D) nuclear magnetic resonance (NMR) imaging technique for spatially mapping proton distributions in green-state ceramic composites. The technique is based on a 3-D back-projection protocol for data acquisition, and a reconstruction technique based on 3-D Radon transform inversion. In principle, the 3-D methodology provides higher spatial resolution of solid materials than is possible with conventional slice-selection protocols. The applicability of 3-D NMR imaging has been demonstrated by mapping the organic additive distribution (2.5 wt.%) in cold-pressed Si34 whisker-reinforced Si34 ceramic composites. Three-dimensional X-ray computed tomography (CT) also has been employed for mapping voids and inclusions within the composite specimen. Combining information from both imaging modalities provides an extremely powerful nondestructive evaluation tool for materials characterization.
True three-dimensional nuclear magnetic resonance neuro-imaging in ischemic stroke: correlation of NMR, X-ray CT and pathology.