Using Microbubble as Contrast Agent for High-Energy X-Ray In-line Phase Contrast Imaging: Demonstration and...

Area of Science:

• Medical Imaging
• Radiography
• Biomedical Engineering

Background:

• Conventional radiography has limitations in imaging microstructures.
• Phase contrast imaging offers potential for enhanced imaging quality.
• Microbubbles are being explored as contrast agents in medical imaging.

Purpose of the Study:

• To investigate the effectiveness of microbubbles in improving imaging quality using high-energy in-line phase contrast radiography.
• To compare the performance of in-line phase contrast imaging with conventional contact-mode radiography using microbubble suspensions.
• To evaluate the impact of microbubble concentration on image quality metrics.

Main Methods:

• A custom phantom simulating blood vessels with microbubble suspensions was used.
• In-line phase contrast imaging and conventional contact-mode radiography were compared under identical radiation doses.
• Contrast-to-noise ratio (CNR) was measured at varying microbubble concentrations.
• Phase-attenuation duality phase retrieval was applied to enhance phase contrast images.

Main Results:

• Microbubble suspensions improved CNR compared to water-only images, showing a monotonic increase with concentration.
• High-energy in-line phase contrast yielded lower CNR than conventional methods at high microbubble concentrations.
• At low microbubble concentrations, in-line phase contrast showed comparable or superior CNR to conventional methods.
• Phase-attenuation duality phase retrieval improved image quality, especially in low-concentration areas.

Conclusions:

• Microbubble performance as x-ray contrast agents is influenced by system efficiency and shell material properties.
• Phase-attenuation duality phase retrieval is a promising technique for preserving image quality with low microbubble concentrations.
• Selecting microbubble contrast agents should consider shell attenuation and electron density differences for optimal phase contrast imaging.