HR-pQCT

XamFlow is used to analyze High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT) images from SCANCO XtremeCT I and II devices. The main parameters are the volumetric bone mineral density (vBMD) and bone microarchitecture parameters at distal radius and tibia. The SCANCO IPL software can be integrated to ensure comparability and continuitity with standard parameters.

Analysis Steps and Methods

Calibration

  • The ISQ images are calibrated using hydroxyapatite phantoms. This metadata is used to ensure accurate reporting of bone mineral densities in mg HA/cm³ units.

Filtering

  • Standard Gaussian filtering

  • Laplace-Hamming filtering

  • NLM denoising with fast GPU acceleration

  • Larger-than-memory datasets support

Segmentation

  • Separate the cortical compartment from the trabecular compartment and surrounding soft tissue.

  • Classical or ML-based automatic methods

  • Interactive UI

  • Combined semi-automated approaches support manual corrections (only) when needed.

  • Flexible workflows allow defining new comparments e.g. by distance to bone surface or angle (quadrant).

../_images/bone_hrpqct_workflow.png

Quantify Bone Density

  • Quantify the Volumetric Bone Mineral Density (vBMD) and Content (vBMC) by compartment.

  • Tt.vBMD (Total vBMD): Density of the entire bone cross-section.

  • Tb.vBMD (Trabecular vBMD): Density of the cancellous (spongy) bone.

  • Ct.vBMD (Cortical vBMD): Density of the dense outer shell.

Characterize Microstructure

  • Measure key geometric and structural characteristics of the trabecular network and cortical shell.

  • Trabecular Microarchitecture Parameters characterize the internal spongy bone structure.

  • Ct.Th (Cortical Thickness)

  • BV/TV (Bone Volume/Total Volume)

  • Tb.N (Trabecular Number)

  • Tb.Th (Trabecular Thickness)

  • Tb.Sp (Trabecular Separation)

  • SMI (Structure Model Index)

  • Conn.D (Connectivity Density)

  • For more see Bone Morphometry

Longitudinal Analysis

  • Registration between scans at different timepoints.

  • Quantify dynamic parameters of formed, resorbed and quiescent bone.

Individual Trabecular Segmentation (ITS)

  • Differentiate and quantify the rod-like vs. plate-like nature of trabecular bone.

  • Local SMI: volumetric quantification of plates, rods, and junctions in trabecular bone.

../_images/localsmi.png

Micro-Finite Element Analysis (μFEA) & Biomechanical Modeling

  • Model Generation: The high-resolution HR-pQCT images (voxels) can be converted directly into a finite element model using hexahedral elements.

  • Loading Simulation: The model is subjected to simulated mechanical loads (e.g., axial compression or bending) to estimate the mechanical properties of the bone.

  • See Finite Elements Analysis for the external solvers that can be integrated.

Advanced Studies

  • Manage metadata: Control group and disease samples, covariates,

  • Characterize bone quality and assess fracture risk in the context of bone diseases like osteoporosis.

  • Assess localized damage: Quantify and characterize bone loss and erosions in inflammatory diseases like Rheumatoid Arthritis.

  • Quantification of vessel calcification