Bone metastases do not affect the measurement uncertainties of a global digital volume correlation algorithm

Area of Science:

• Biomechanics
• Medical Imaging
• Orthopedics

Background:

• Digital Volume Correlation (DVC) is a technique used to measure displacements and strains in materials.
• Factors influencing DVC measurement uncertainties include image quality and correlation algorithms.
• The impact of highly heterogeneous trabecular microstructures, common in bone metastases, on DVC precision is not well understood.

Purpose of the Study:

• To investigate whether heterogeneous trabecular microstructures in metastatic vertebrae affect the precision of DVC measurements.
• To assess the relationship between DVC measurement uncertainties and bone microstructural parameters in healthy and metastatic vertebrae.

Main Methods:

• Micro-computed tomography (microCT) scans of 15 metastatic and 9 healthy vertebral bodies under zero-strain conditions.
• Calculation of bone microstructural parameters (Bone Volume Fraction, Structure Thickness, Structure Separation, Structure Number).
• Evaluation of displacements and strains using a global DVC approach (BoneDVC) and analysis of the standard deviation of the error (SDER).

Main Results:

• Metastatic vertebrae exhibited higher variability in SDER compared to healthy vertebrae.
• A weak correlation was observed between SDER and Structure Separation in metastatic vertebrae, indicating minimal impact of microstructure on DVC uncertainty.
• Strain measurement uncertainties were spatially associated with regions of reduced greyscale gradient variation in microCT images.

Conclusions:

• Heterogeneous trabecular microstructures in metastatic vertebrae have a weak influence on BoneDVC measurement uncertainties.
• DVC measurement uncertainties should be assessed for each specific application to interpret results accurately.
• The study highlights the robustness of DVC in analyzing complex bone structures, even in the presence of metastases.