Axial μCT images are shown for cortical bone specimens from a 48 y.o. male donor (left) and an 82 y.o. male donor (right).

<p>For the 48 and 82 y.o. donors, respectively, avBMD was 1222 and 1135 mg-HA/cm³, and porosity was 4% and 11.3%.</p

Summary of T₂ spectra measured from 40 human cortical bone samples.

<p>All spectra exhibited a short-T₂ component (T₂≈60 µs), derived primarily from collagen protons, an intermediate T₂ components (T₂≈400 µs), derived primarily from collagen-bound water protons, and a broad distribution of long-T₂ components (1 ms2<1 s), derived from a combination of pore water and lipid protons.</p

From each cadaveric bone studied, one strip of cortical bone was extracted, three separate pieces of which were used for NMR, μCT, and mechanical testing.

<p>From each cadaveric bone studied, one strip of cortical bone was extracted, three separate pieces of which were used for NMR, μCT, and mechanical testing.</p

A summary of Pearson's r² for pairwise correlations between imaging measures (¹H NMR and X-ray) and mechanical properties.

<p>All correlations were significant (p<0.05) <i>except</i> those indicated with <b>^*</b>. The imaging measure that was most predictive (highest r²) of each mechanical measure is indicated with boldface type.</p

Correlations of measured peak stress and T₂ spectral component amplitudes (NMR, left) and avBMD measured by μCT (right).

<p>Blue, red, and green data show integrated amplitudes (<i>S_A</i>, <i>S_B</i>, and <i>S_C</i>) of the T₂-discriminated signals from pools A, B, and C, respectively. The black data show the total ¹H NMR signal (<i>S_A</i>+<i>S_B</i>+<i>S_C</i>), and the purple data are derived from μCT-based measures of avBMD. Each of the NMR signals amplitudes shows a significant linear correlation with peak stress and both <i>S_B</i> and <i>S_C</i> correlate more strongly with peak stress than does avBMD. Note that the total ¹H NMR signal does not correlate well with peak stress.</p

A representative stress vs. strain curve for cortical bone is shown (blue) along with graphical depictions of mechanical parameters.

<p>Flexural modulus is the slope of the initial linear mechanical response, yield stress is defined at 0.2% offset from the flexural modulus line, and peak stress is the maximum observed stress. Pre-yield toughness (see text for definition) is proportional to the area under the curve, up to the yield stress.</p

Solid line shows a the T₂ spectrum from a typical bone sample, and the dotted line shows the spectrum that results following the complex average of two signals, with and without an adiabatic full passage magnetization preparation.

<p>The total integrated signal from this long-T₂ suppressed spectrum is 95% from signals with T₂<1 ms, thereby demonstrating in principle a simple and practical method for generating a MRI contrast dominated by <i>S_A</i>+<i>S_B</i>.</p

Rictor CKO Western

Rictor CKO Wester

Western Blots

Western Blot

Cell Counts

Cell Count