  Purpose: The purpose of our study was to use Dual-TR STE-MR protocol as a
clinical tool for cortical bone free water quantification at 1.5T and validate
it by comparing the obtained results (MR-derived results) with dehydration
results. Methods: Human studies were compliant with HIPPA and were approved by
the institutional review board. Short Echo Time (STE) MR imaging with different
Repetition Times (TRs) was used for quantification of cortical bone free water
T1 (T1free) and concentration (\r{ho}free). The proposed strategy was compared
with the dehydration technique in seven bovine cortical bone samples. The
agreement between the two methods was quantified by using Bland and Altman
analysis. Then we applied the technique on a cross-sectional population of
thirty healthy volunteers (18F/12M) and examined the association of the
biomarkers with age. Results: The mean values of \r{ho}free for bovine cortical
bone specimens were quantified as 4.37% and 5.34% by using STE-MR and
dehydration techniques, respectively. The Bland and Altman analysis showed good
agreement between the two methods along with the suggestion of 0.99% bias
between them. Strong correlations were also reported between \r{ho}free (r2 =
0.62) and T1free and age (r2 = 0.8). The reproducibility of the method,
evaluated in eight subjects, yielded an intra-class correlation of 0.95.
Conclusion: STE-MR imaging with dual-TR strategy is a clinical solution for
quantifying cortical bone \r{ho}free and T1free.
