Table 1.

The characteristics of morphometric variables investigated in the present study and calculated by CTAn. software (according to the manual Bruker MicroCT Morphometric parameters measured by CT-analyzer software 1.15.4.0 by Bruker microCT).

Abbreviation	Variable	Description	Standard Unit
BV/TV	Bone volume fraction	Relative volume of calcified tissue in the selected volume of interest (VOI).	%
BS/TV	Bone surface density	The ratio of surface area to total volume measured in 3D, within the VOI.	mm−1
BS/BV	Bone surface / volume ratio	Surface to volume ratio of calcified tissue or “specific surface” is useful for characterising the complexity and thickness of structures.	mm−1
Tb.Th	Trabecular thickness	Mean thickness of trabeculae, assessed using direct 3D methods.	mm
Tb.Sp	Trabecular separation	Trabecular separation is essentially the thickness of the spaces as defined by binarisation within the VOI.	mm
Tb.Pf	Trabecular bone pattern factor	This is an index of connectivity of trabecular bone; it calculates an index of relative convexity or concavity of the total bone surface, on the principle that concavity indicates connectivity (and the presence of “nodes”), and convexity indicates isolated disconnected structures (struts).	1/mm
Po(tot)	Total porosity	Total porosity is the volume of all open plus closed pores as a percent of the total VOI volume.	%
Po(op)	Open porosity	Percent open porosity is the volume of open pores as a percent of the total VOI volume.	%
Conn.	Connectivity	One useful and fast algorithm for calculating the Euler connectivity in 3D is the “Conneulor”. It measures what might be called “redundant connectivity”, the degree to which parts of the object are multiply connected. It is a measure of how many connections in a structure can be severed before the structure falls into two separate pieces.	none