Dose-efficient assessment of trabecular microstructure using ultra-high-resolution photon-counting CT

Area of Science:

• Medical Imaging
• Radiology
• Biomedical Engineering

Background:

• Conventional energy-integrating (EI) detectors in computed tomography (CT) have limitations in spatial resolution and detective efficiency.
• Photon-counting (PC) detectors offer potential improvements for clinical CT imaging.
• Quantifying trabecular bone microstructure is crucial for diagnosing bone diseases and requires high-resolution imaging.

Purpose of the Study:

• To investigate if photon-counting CT (PCCT) can reduce radiation dose while maintaining accuracy in quantifying trabecular bone microstructure.
• To compare the imaging performance of PCCT with conventional EI CT for bone analysis.
• To assess the impact of PCCT on bone mineral density (BMD) and trabecular separation (Tb.Sp) measurements.

Main Methods:

• Human vertebral bodies were scanned using an experimental dual-source CT with both EI and PC detectors.
• Acquisitions included dose-matched (UHRdm) and noise-matched (UHRnm) PCCT protocols, alongside conventional EI CT.
• Measurements of BMD and Tb.Sp were compared against a gold-standard peripheral CT device, analyzing image noise, relative error, and reproducibility.

Main Results:

• PCCT demonstrated significantly lower image noise compared to EI CT at similar dose levels.
• Noise-matched PCCT (UHRnm) achieved comparable diagnostic performance for BMD and Tb.Sp with a 56% dose reduction.
• PCCT exhibited superior short-term reproducibility for Tb.Sp measurements compared to EI CT.

Conclusions:

• Ultra-high resolution PCCT (UHR-PCCT) provides lower image noise and enhanced reproducibility for bone microstructure assessment.
• PCCT enables significant radiation dose reduction (up to 56%) without compromising the accuracy of BMD and Tb.Sp measurements.
• PCCT represents a promising advancement for quantitative CT-based bone analysis, potentially improving patient safety and diagnostic capabilities.