Year: 2025
Type: article
Abstract: BACKGROUND/OBJECTIVES: This study evaluates photon-counting CT (PCCT) for the imaging of mouse femurs and investigates how APOE genotype, sex, and humanized nitric oxide synthase (HN) expression influence bone morphology during aging. METHODS: A custom-built micro-CT system with a photon-counting detector (PCD) was used to acquire dual-energy scans of mouse femur samples. PCCT projections were corrected for tile gain differences, iteratively reconstructed with 20 µm isotropic resolution, and decomposed into calcium and water maps. PCD spatial resolution was benchmarked against an energy-integrating detector (EID) using line profiles through trabecular bone. The contrast-to-noise ratio quantified the effects of iterative reconstruction and material decomposition. Femur features such as mean cortical thickness, mean trabecular spacing (TbSp_mean), and trabecular bone volume fraction (BV/TV) were extracted from calcium maps using BoneJ. The statistical analysis used 57 aged mice representing the APOE22, APOE33, and APOE44 genotypes, including 27 expressing HN. We used generalized linear models (GLMs) to evaluate the main interaction effects of age, sex, genotype, and HN status on femur features and Mann-Whitney U tests for stratified analyses. RESULTS: PCCT outperformed EID-CT in spatial resolution and enabled the effective separation of calcium and water. Female HN mice exhibited reduced BV/TV compared to both male HN and female non-HN mice. While genotype effects were modest, a genotype-by-sex stratified analysis found significant effects of HN status in female APOE22 and APOE44 mice only. Linear regression showed that age significantly decreased cortical thickness and increased TbSp_mean in male mice only. CONCLUSIONS: These results demonstrate PCCT's utility for femur analysis and reveal strong effects of sex/HN interaction on trabecular bone health in mice.
Source: Tomography
Institutions: Duke University, Duke Medical Center
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
Awards: G1597981744, G1695814554, Sex and APOE genotype interact to alter immune regulated metabolism in AD, Brain networks in mouse models of aging, Development of a New Generation Micro-CT imaging for Functional and Molecular Imaging of Cancer, G9000124253, Cardiac photon counting CT and its application in studying interactions between Alzheimer's and heart disease, Development of a Virtual Preclinical CT Platform for Advanced Imaging and Theranostics in Head and Neck Cancer Research, Detecting Growth of Intracranial Aneurysms Using Non-Invasive Photon Counting CT in a Murine Model.
OpenAlex ID: W4416167147