Combining Spectral CT Acquisition Methods for High-Sensitivity Material Decomposition

TL;DR

This paper evaluates combined spectral CT acquisition methods using advanced modeling to improve sensitivity in material decomposition, especially for low contrast agent concentrations, potentially reducing contrast agent dosage.

Contribution

It introduces a comprehensive simulation framework for hybrid spectral CT strategies and demonstrates their improved performance over individual methods in low concentration detection.

Findings

Combined spectral techniques enhance sensitivity and accuracy.

Hybrid approaches outperform single-strategy methods.

Improved low-concentration iodine detection potential.

Abstract

Quantitative estimation of contrast agent concentration is made possible by spectral CT and material decomposition. There are several approaches to modulate the sensitivity of the imaging system to obtain the different spectral channels required for decomposition. Spectral CT technologies that enable this varied sensitivity include source kV-switching, dual-layer detectors, and source-side filtering (e.g., tiled spatial-spectral filters). In this work, we use an advanced physical model to simulate these three spectral CT strategies as well as hybrid acquisitions using all combinations of two or three strategies. We apply model-based material decomposition to a water-iodine phantom with iodine concentrations from 0.1 to 5.0 mg/mL. We present bias-noise plots for the different combinations of spectral techniques and show that combined approaches permit diversity in spectral sensitivity and improve low concentration imaging performance relative to the those strategies applied individually. Better ability to estimate low concentrations of contrast agent has the potential to reduce risks associated with contrast administration (by lowering dosage) or to extend imaging applications into targets with much lower uptake.