Purpose-To demonstrate water and fat suppressed proton projection MRI (WASPI) in a clinical scanner to visualize the solid bone matrix in animal and human subjects. Materials and Methods-Pig bone specimens and polymer pellets were used to optimize the WASPI method in terms of soft tissue suppression, image resolution, signal to noise ratio (SNR), and scan time on a 3T MRI scanner. The ankles of healthy 2-3 month old live Yorkshire pigs were scanned with the optimized method. The method was also

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... applied to the wrists of six healthy adult human volunteers to demonstrate the feasibility of the WASPI method in human subjects. A transmit/receive coil built with proton-free materials was utilized to produce a strong B 1 field. A fast transmit/receive switch was developed to reduce the long receiver dead time that would otherwise obscure the signals. Results-Clear 3D WASPI images of pig ankles and human wrists, showing only the solid bone matrix and other tissues with high solid content (e.g., tendons), with a spatial resolution of 1.6 mm in all three dimensions were obtained in as briefly as 18 min. Conclusion-WASPI of the solid matrix of bone in humans and animals in vivo is feasible.