Technical note: Mapping of trabecular bone anisotropy and volume fraction in 3D using μCT images of the human calcaneus

Trabecular bone anisotropy, describing preferential trabecular co-alignment, is a proxy for its long-term loading history. anisotropy varies locally, thus rendering averaged calculations across an entire inutile. Here we present 3D mapping method using vector fields where each reflects the extent of local co-alignment elementary units surface. maps hundreds thousands vectors were visualized by their magnitude and direction. Similarly, volume fraction was mapped as scalar fields. We constructed micro-computed tomography four presumably nonpathologic human calcanei compared signature with pathologically loaded in club foot calcaneonavicular ankylosis. In calcaneus, pattern trajectories (bands) consistently identified dorsal, plantar, Achilles', peroneal bands. Both pathologic specimens deviated from maps. The calcaneus congenitally disused showed very low values, no co-oriented bands, fraction. ankylosed lower than but not to same foot, patchy high directionality bands barely discernable calcaneus. consistent kinetic attributable walking. loss this results absent/vanishing signature. Such adds new dimensions quantitative bioimaging understanding skeletal adaptation.