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 mum) 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, 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 x 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 mus, and the mean T, 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. (C) 2004 Wiley-Liss, Inc.