A comparative study of trabecular bone micro-structural measurements using different CT modalities

Abstract

Osteoporosis, characterized by reduced bone mineral density and micro-architectural degeneration, significantly enhances fracture-risk. There are several viable methods for trabecular bone micro-imaging, which widely vary in terms of technology, reconstruction principle, spatial resolution, and acquisition time. We have performed an excised cadaveric bone specimen study to evaluate different CT-imaging modalities for trabecular bone microstructural analysis. Excised cadaveric bone specimens from the distal radius were scanned using micro-CT and four in vivo CT imaging modalities: HR-pQCT, dental CBCT, wholebody MDCT, and extremity CBCT. A new algorithm was developed to optimize soft thresholding parameters for individual in vivo CT modalities for computing quantitative bone volume fraction maps. Finally, agreement of trabecular bone micro-structural measures, derived from different in vivo CT imaging, with reference measures from micro-CT imaging was examined. Observed values of most trabecular measures, including trabecular bone volume, network area, transverse and plate-rod micro-structure, thickness, and spacing, for in vivo CT modalities were higher than their micro-CT-based reference values. In general, HR-pQCT-based trabecular bone measures were closer to their reference values as compared to other in vivo CT modalities. Despite large differences in observed values of measures among modalities, high linear correlation (r Î [0.94 0.99]) was found between micro-CT and in vivo CT-derived measures of trabecular bone volume, transverse and plate micro-structural volume, and network area. All HR-pQCT-derived trabecular measures, except the erosion index, showed high correlation (r Î [0.91 0.99]). The plate-width measure showed a higher correlation (r Î [0.72 0.91]) among in vivo and micro-CT modalities than its counterpart binary plate-rod characterization-based measure erosion index (r Î [0.65 0.81]). Although a strong correlation was observed between micro-structural measures from in vivo and micro-CT imaging, large shifts in their values for in vivo modalities warrant proper scanner calibration prior to adopting in multi-site and longitudinal studies.

Finite element analysis of trabecular bone microstructure using CT imaging and continuum mechanical modeling

“…Large deviation in CT‐derived modulus values as compared to micro‐CT or mechanical test‐derived results was observed, which suggests that CT‐derived modulus values may not be used as actual modulus measures. Also, our observations on CT‐based computation of Tb microstructural modulus are consistent with our findings related to CT‐ and micro‐CT‐derived values of Tb microstructural metrics and those reported in literature 20,46,47 . Finally, it may be clarified that, since the r values (∈ [0.87 0.90]) are high, it is always possible to use the corresponding regression equation to estimate the reference modulus values from CT‐based FEA‐derived values.…”

“…Also, our observations on CT-based computation of Tb microstructural modulus are consistent with our findings related to CT-and micro-CT-derived values of Tb microstructural metrics and those reported in literature. 20,46,47 Finally, it may be clarified that, since the r values (∈ [0.87 0.90]) are high, it is always possible to use the corresponding regression equation to estimate the reference modulus values from CT-based FEA-derived values.…”

Generation of Vertebra Micro-CT-like Image from MDCT: A Deep-Learning-Based Image Enhancement Approach

“…However, the correlation between Tb.Th and Tb.Sp in the results of Issever et al [ 5 ] was considerably weaker and rare (R 2 = 0.19–0.26), which is consistent with our MDCT image results. Guha [ 6 ] and Chen [ 7 ] explored the correlation between trabecular bone structural measurements of MDCT and the corresponding micro-CT images using in vitro tibial and distal radius specimens. Although the anatomical positions of the study specimens were different, the correlation coefficients of Tb.Th and Tb.Sp was also relatively moderate (R < 0.80, Pearson).…”

“…Clinical multidetector computed tomography (MDCT) is widely used in the imaging diagnosis of spinal diseases, but it does not allow for accurate measurements of bone microstructure to be determined. Previously published in vitro studies have investigated the feasibility of using MDCT to measure bone structure, with some parameters exhibiting only a moderate correlation with that of micro-CT [ 5 , 6 , 7 ]. The trabecular bone thickness (Tb.Th) is approximately 100 microns, which is far less than the maximum resolution of MDCT images of approximately 200–500 microns [ 8 ].…”

Predicting the trabecular bone apparent stiffness tensor with spherical convolutional neural networks

“…Notice that we use local maps of Tb.Th and Tb.Sp instead of the customary use of the mean in the analysis of bone specimens, e.g., Guha et al (2020) ; Steiner et al (2020) . The thickness and spacing maps used in the experiments were computed with BoneJ ( Doube et al, 2010 ).…”