Contrast-enhanced dual-energy subtraction imaging using electronic spectrum-splitting and multi-prism x-ray lenses

TL;DR

This study explores a novel dual-energy subtraction imaging technique using electronic spectrum-splitting and multi-prism x-ray lenses to enhance contrast agent detectability in mammography, aiming to overcome current clinical limitations.

Contribution

The paper introduces a new approach combining electronic spectrum-splitting with multi-prism x-ray lenses to improve dual-energy imaging quality and potential clinical application.

Findings

Electronic spectrum-splitting enhances image quality compared to traditional methods.

Multi-prism x-ray lenses provide tunable spectra with improved signal-to-noise ratio.

Potential for better contrast agent detection in mammography.

Abstract

Dual-energy subtraction imaging (DES) is a method to improve the detectability of contrast agents over a lumpy background. Two images, acquired at x-ray energies above and below an absorption edge of the agent material, are logarithmically subtracted, resulting in suppression of the signal from the tissue background and a relative enhancement of the signal from the agent. Although promising, DES is still not widely used in clinical practice. One reason may be the need for two distinctly separated x-ray spectra that are still close to the absorption edge, realized through dual exposures which may introduce motion unsharpness. In this study, electronic spectrum-splitting with a silicon-strip detector is theoretically and experimentally investigated for a mammography model with iodinated contrast agent. Comparisons are made to absorption imaging and a near-ideal detector using a signal-to-noise ratio that includes both statistical and structural noise. Similar to previous studies, heavy absorption filtration was needed to narrow the spectra at the expense of a large reduction in x-ray flux. Therefore, potential improvements using a chromatic multi-prism x-ray lens (MPL) for filtering were evaluated theoretically. The MPL offers a narrow tunable spectrum, and we show that the image quality can be improved compared to conventional filtering methods.