Energy Spectrum Extraction and Optimal Imaging via Dual-Energy Material Decomposition

TL;DR

This study introduces a dual-energy material decomposition method to extract energy spectra and enhance soft-tissue contrast in CT imaging, resulting in improved image quality and contrast-to-noise ratio compared to standard techniques.

Contribution

The paper presents a novel spectrum extraction and reweighting approach that significantly improves contrast resolution in CT scans using dual-energy data.

Findings

Extracted energy spectrum closely matches PCD spectrum with low RMSE and energy difference.

Enhanced contrast-to-noise ratio (CNRD) for iodine solutions compared to standard detectors.

Reconstructed images show superior soft-tissue contrast with the proposed method.

Abstract

Inferior soft-tissue contrast resolution is a major limitation of current CT scanners. The aim of the study is to improve the contrast resolution of CT scanners using dual-energy acquisition. Based on dual-energy material decomposition, the proposed method starts with extracting the outgoing energy spectrum by polychromatic forward projecting the material-selective images. The extracted spectrum is then reweighted to boost the soft-tissue contrast. A simulated water cylinder phantom with inserts that contain a series of six solutions of varying iodine concentration (range, 0-20 mg/mL) is used to evaluate the proposed method. Results show the root mean square error (RMSE) and mean energy difference between the extracted energy spectrum and the spectrum acquired using an energy-resolved photon counting detector(PCD), are 0.044 and 0.01 keV, respectively. Compared to the method using the standard energy-integrating detectors, dose normalized contrast-to-noise ratio (CNRD) for the proposed method are improved from 1 to 2.15 and from 1 to 1.88 for the 8 mg/mL and 16 mg/mL iodine concentration inserts, respectively. The results show CT image reconstructed using the proposed method is superior to the image reconstructed using the standard method that using an energy-integrating detector.