  Purpose: We present a new morphometric measure of trabecular bone
microarchitecture, called mean node strength (NdStr), which is part of a newly
developed approach called long range node-strut analysis. Our general aim is to
describe and quantify the apparent "latticelike" microarchitecture of the
trabecular bone network.
  Methods: Similar in some ways to the topological node-strut analysis
introduced by Garrahan et al. [J. Microsc. 142, 341-349 (1986)], our method is
distinguished by an emphasis on long-range trabecular connectivity. Thus, while
the topological classification of a pixel (after skeletonization) as a node,
strut, or terminus, can be determined from the 3x3 neighborhood of that pixel,
our method, which does not involve skeletonization, takes into account a much
larger neighborhood. In addition, rather than giving a discrete classification
of each pixel as a node, strut, or terminus, our method produces a continuous
variable, node strength. The node strength is averaged over a region of
interest to produce the mean node strength of the region.
  Results: We have applied our long range node-strut analysis to a set of 26
high-resolution ... The Nd/Tm ratios were computed using traditional
histomorphometry performed on bone biopsies obtained at the same location as
the pQCT scans.
  Conclusions: The newly introduced morphometric measure allows a quantitative
assessment of the long-range connectivity of trabecular bone. One advantage of
this method is that it is based on pQCT images that can be obtained
noninvasively from patients, i.e., without having to obtain a bone biopsy from
the patient.

Medical Physics;Data Analysis, Statistics and Probability;Tissues and Organs