Multicontrast Multiphase Intestinal Imaging Using Photon-Counting CT: A Feasibility Study in Rats

Area of Science:

• Medical Imaging
• Radiology
• Biomedical Engineering

Background:

• Photon-counting CT (PCCT) offers improved spectral information compared to conventional CT.
• Material decomposition techniques enable quantitative analysis of different materials in CT images.
• Distinguishing between multiple contrast media (CM) simultaneously is a growing challenge in advanced imaging.

Purpose of the Study:

• To validate a 3-material decomposition algorithm for differentiating iodine-based and tungsten-based CM from water.
• To assess the in vivo performance of the algorithm using a commercial PCCT system.
• To evaluate the generation of quantitative contrast maps, virtual noncontrast (VNC) images, and virtual monoenergetic images (VMI).

Main Methods:

• Six healthy rats were imaged with both iodine-based and tungsten-based CM administered orally and intravenously.
• A 3-material decomposition algorithm was applied to PCCT data acquired at 4 energy thresholds.
• Quantitative contrast maps, VNC maps, and VMI were generated to analyze CM distribution and characteristics.

Main Results:

• Iodine-based CM was exclusively detected in the iodine map, and tungsten-based CM in the tungsten map (P<0.001).
• Virtual noncontrast (VNC) maps showed no enhancement from CM, suggesting potential for omitting pre-contrast scans.
• Virtual monoenergetic images (VMI) demonstrated energy-dependent attenuation profiles, revealing the K-edge of tungsten.

Conclusions:

• PCCT combined with 3-material decomposition effectively delineates two distinct CM and water in vivo.
• The technique accurately reproduced contrast dynamics in major vessels and intestines.
• VNC maps and VMI show promise for enhanced diagnostic capabilities and workflow optimization in CT imaging.