Human imaging of phosphorus in cortical and trabecular bone in vivo

Phosphorus was imaged in vivo in human cortical and trabecular bone and the T 1 and T   2 *were measured. An ultrashort TE (UTE) pulse sequence (TE = 70 μm) was used with half pulse excitation and radial mapping of k ‐space from the center out. T   2 *was measured using multiple echo times and T 1 was measured both by saturation recovery and by a method using different RF pulse amplitudes. Seven normal subjects (32–85 years) were examined. Phosphorus was imaged, with a true in‐plane resolution of 2.9 × 2.9 mm and a signal‐to‐noise ratio (SNR) of 19:1, in both cortical and trabecular bone. The mean T   2 *value was 207 ± 12 μs, and the mean T 1 value was 8.6 ± 3.0 sec. Images and measurements were obtained in realistic times on a clinical MR system. This may provide a new approach to characterizing disease of bone. Magn Reson Med 51:888–892, 2004. © 2004 Wiley‐Liss, Inc.