Feasibility of multi-contrast imaging on dual-source photon counting detector (PCD) CT: An initial phantom study

Area of Science:

• Medical Imaging Physics
• Radiological Technology
• Photon-Counting Detector CT

Background:

• Photon-counting-detector CT (PCD-CT) enables simultaneous imaging of multiple contrast agents like iodine (I), gadolinium (Gd), and bismuth (Bi).
• Technical limitations of PCDs (e.g., charge sharing, K-edge escape, pulse pile-up) can degrade spectral separation and multi-contrast imaging performance.

Purpose of the Study:

• To evaluate the performance of a dual-source (DS) PCD-CT system.
• To compare DS-PCD-CT against a single-source (SS) PCD-CT system for separating simultaneously imaged I, Gd, and Bi contrast agents.

Main Methods:

• Phantom experiments utilized research-grade PCD-CT systems (single-source and dual-source emulation).
• Simultaneous multi-contrast imaging of I, Gd, and Bi was performed using specific tube potentials and energy thresholds.
• Material decomposition techniques were applied to generate material-specific images, followed by root-mean-square error (RMSE) and noise power spectra (NPS) analysis.

Main Results:

• DS-PCD-CT demonstrated reduced noise levels in I, Gd, and Bi specific images compared to SS-PCD-CT.
• RMSE for material concentration quantification was significantly lower with DS-PCD-CT across both head and body phantoms.
• Noise texture analysis indicated similar noise characteristics between the two systems.

Conclusions:

• DS-PCD-CT is feasible for simultaneous imaging and accurate quantification of I, Gd, and Bi.
• DS-PCD-CT outperforms SS-PCD-CT in reducing quantification errors for multi-contrast imaging, particularly when cross-scattering is absent.