Dual-Energy Cone-Beam CT with Three-Material Decomposition for Bone Marrow Edema Imaging

Area of Science:

• Medical Imaging
• Radiology
• Biomedical Engineering

Background:

• Detecting bone marrow edema (BME) using dual-energy Cone-Beam CT (DE-CBCT) is challenging due to spectral mismatches, scatter, and similar material properties of fat and water.
• Accurate BME detection is crucial for diagnosing various bone pathologies and inflammatory conditions.

Purpose of the Study:

• To investigate the feasibility of BME detection using a kV-switching DE-CBCT protocol.
• To develop and validate a comprehensive DE decomposition framework for improved BME imaging.

Main Methods:

• A novel DE decomposition framework was proposed, including projection interpolation, Monte Carlo scatter correction, and a two-stage three-material decomposition (Projection-Domain Decomposition and image-domain base-change).
• Simulations and physical experiments emulated a kV-switching CBCT wrist imaging protocol with specific kV settings and angular shifts.
• Cubic B-spline interpolation was used for resampling projections, and performance was evaluated based on BME detection specificity and fat concentration discrimination.

Main Results:

• The DE decomposition framework demonstrated acceptable BME detection specificity, with minimal erroneous BME volume detected even with scatter magnitude errors.
• Physical experiments successfully discriminated approximately 20% changes in fat concentrations within bone marrow-mimicking solutions.
• Cubic B-spline interpolation proved adequate for aligning spectral projections in the DE-CBCT protocol.

Conclusions:

• The proposed DE decomposition framework is feasible and effective for BME detection using kV-switching DE-CBCT.
• This approach shows promise for enhancing diagnostic capabilities in bone marrow imaging by accurately differentiating BME from normal bone marrow fat.