X-ray phase-contrast CO(2) angiography for sub-10 μm vessel imaging

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Radiology

Background:

• X-ray in-line phase contrast imaging offers high resolution for small-animal vascular imaging.
• Combining this with carbon dioxide (CO(2)) angiography allows for low radiation dose imaging.

Purpose of the Study:

• To investigate the potential and limitations of X-ray in-line phase contrast imaging with CO(2) angiography.
• To demonstrate visualization of smaller blood vessels than previously reported.

Main Methods:

• Utilized an in-line phase-contrast imaging system with a liquid-metal-jet-anode X-ray source.
• Employed free-space propagation for phase shift to intensity conversion.
• Injected CO(2) gas into the vascular system to replace blood for enhanced contrast.

Main Results:

• Successfully imaged rat-kidney vessels down to 27 μm and mouse-ear vessels down to 8 μm.
• Identified gas penetration and signal-to-noise ratio (dose) as key limitations for observable vessel size.
• Demonstrated that the method requires 1000 times less radiation dose than conventional iodine contrast for sub-50 μm vessels.

Conclusions:

• X-ray in-line phase contrast with CO(2) angiography is a promising technique for high-resolution, low-dose small-animal vascular imaging.
• The achievable resolution is limited by gas penetration and radiation dose.
• This method significantly outperforms conventional contrast agents for visualizing small vasculature.