Quantification of bone microarchitecture using photon-counting CT at different radiation doses: A comparison with µCT

Area of Science:

• Medical Imaging
• Bone Biology
• Radiology

Background:

• Accurate assessment of bone fragility relies on trabecular bone microarchitecture measurements.
• Photon-counting detector CT (PCD-CT) offers higher resolution than conventional CT, potentially enabling in-vivo trabecular microarchitecture analysis.

Purpose of the Study:

• To quantify trabecular bone microarchitectural parameters using PCD-CT at varying radiation doses.
• To compare PCD-CT measurements against micro-CT (µCT) as the gold standard.

Main Methods:

• Human bone specimens (radii, tibiae, femoral heads, vertebrae) were scanned ex-vivo using PCD-CT and µCT.
• PCD-CT radiation doses were varied (2.5–120 mGy), and contrast-to-noise ratio and trabecular sharpness were assessed.
• Trabecular bone parameters (bone volume, thickness, number, heterogeneity) were calculated from registered µCT and PCD-CT scans.

Main Results:

• PCD-CT image quality (contrast-to-noise ratio, trabecular sharpness) improved with increasing radiation dose.
• High correlations (R² = 0.55–0.95) were observed between µCT and PCD-CT parameters even at low doses, improving with higher doses (R² = 0.76–0.96 at 20 mGy).

Conclusions:

• PCD-CT is a viable method for quantifying trabecular bone microarchitecture.
• PCD-CT achieves accuracy comparable to µCT.
• Measurements are feasible at clinically relevant radiation doses, supporting its use in assessing bone fragility.