. Author manuscript; available in PMC: 2008 Mar 1.

Published in final edited form as: Bone. 2006 Dec 15;40(3):767–774. doi: 10.1016/j.bone.2006.10.025

Table 2.

Equations used to calculate QCT-based “mechanics of solids” (MOS) measures of vertebral strength.

Measure	Method of Calculation
(EA)_tBMD	E_tBMD A_minwhere E_tBMD = −34.7 + 3.23(tBMD)
(EA)_iBMD	E_iBMD A_minwhere E_iBMD = −34.7 + 3.23(iBMD)
(EA)_min	min[(EA)_l]where ${(E A)}_{l} = Σ_{k = 1}^{n} E_{k} A_{k} and E_{k} = - 34.7 + 32.3 {(BMD)}_{k}$

E = Young’s modulus, modulus-density relationship from Kopperdahl et al. [25]

A_min = Minimum transverse plane cross-sectional area

E_k, A_k = Young’s modulus and cross-sectional area, respectively, associated with a given pixel, k

l = axial slice number