BV/TV

% of total volume of ROI

Tb.Th

Direct 3-D measurement of average trabecular thickness within the selected
volumetric region of interest, TV

Tb.N

Direct 3-D measurement of average trabecular number per unit length within the selected volumetric region of interest, TV

Tb.Sp.

Direct 3-D measurement of average surface-to-surface trabecular separation
within the selected volumetric region of interest, TV

Conn. D

volumetric number of bifurctions per cubic mm

SMI

Descriptor of relatively more rodlike (higher number) vs plate-like (lower number). Toward 0 = more plate-like structure; Toward 3 = more rod-like structure. Mathematical formulation describing the structural model that the trabeculae resemble. The number will be below 0 for very dense non-trabecular structures, and above 3 for very sparse trabecular structure.

Tissue D.

mg of hydroxyapatite per cubic cm of mineralized bone matrix

App D.

BS/TV

Normalized bone surface area normalized to selected volumetric region of interest, TV. 1/mm = mm2/mm3

TV

Total Volume selected for analysis. Selected within endosteal border to
exclude all cortex.

BV

Trabecular bone volume, obtained by image segmentation (exclusion of background soft tissue, marrow, etc. using a Gaussian threshold filter).

DA

Ratio of the maximum to minimum directional orientation of trabeculae. If trabecular orientation, number, thickness, etc. are identical in orthogonal directions (i.e., isotropic), then this DA = 1. Mathematically, ratio of eigenvalues.