Assessment of Transverse Isotropy in Clinical-Level CT Images of Trabecular Bone Using the Gradient Structure Tensor

David Larsson*, Benoît Luisier, Mariana E. Kersh, Enrico Dall'Ara, Philippe K. Zysset, Marcus G. Pandy, Dieter H. Pahr

*Corresponding author for this work

Research output: Journal article (peer-reviewed)Journal article

29 Citations (Scopus)


The aim of this study was to develop a GST-based methodology for accurately measuring the degree of transverse isotropy in trabecular bone. Using femoral sub-regions scanned in high-resolution peripheral QCT (HR-pQCT) and clinical-level-resolution QCT, trabecular orientation was evaluated using the mean intercept length (MIL) and the gradient structure tensor (GST) on the HR-pQCT and QCT data, respectively. The influence of local degree of transverse isotropy (DTI) and bone mineral density (BMD) was incorporated into the investigation. In addition, a power based model was derived, rendering a 1:1 relationship between GST and MIL eigenvalues. A specific DTI threshold (DTI thres) was found for each investigated size of region of interest (ROI), above which the estimate of major trabecular direction of the GST deviated no more than 30° from the gold standard MIL in 95% of the remaining ROIs (mean error: 16°). An inverse relationship between ROI size and DTI thres was found for discrete ranges of BMD. A novel methodology has been developed, where transversal isotropic measures of trabecular bone can be obtained from clinical QCT images for a given ROI size, DTI thres and power coefficient. Including DTI may improve future clinical QCT finite-element predictions of bone strength and diagnoses of bone disease.

Original languageEnglish
Pages (from-to)950-959
Number of pages10
JournalAnnals of Biomedical Engineering
Issue number5
Publication statusPublished - May 2014
Externally publishedYes


  • Clinical-level quantitative computed tomography
  • Degree of transverse isotropy
  • Fabric tensors
  • Human proximal femur
  • Structural anisotropy

ASJC Scopus subject areas

  • Biomedical Engineering


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