Image quality with iterative reconstruction techniques in CT of the lungs-A phantom study

Hilde Kjernlie Andersen; David Völgyes; Anne Catrine Trægde Martinsen

doi:10.1016/j.ejro.2018.02.002

Image quality with iterative reconstruction techniques in CT of the lungs-A phantom study

Eur J Radiol Open. 2018 Mar 8:5:35-40. doi: 10.1016/j.ejro.2018.02.002. eCollection 2018.

Authors

Hilde Kjernlie Andersen¹, David Völgyes², Anne Catrine Trægde Martinsen^{1

3}

Affiliations

¹ Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.
² Faculty of Computer Science and Media Technology, Norwegian University of Science and Technology (NTNU), Gjøvik, Norway.
³ The Department of Physics, University in Oslo, Oslo, Norway.

Abstract

Background: Iterative reconstruction techniques for reducing radiation dose and improving image quality in CT have proved to work differently for different patient sizes, dose levels, and anatomical areas.

Purpose: This study aims to compare image quality in CT of the lungs between four high-end CT scanners using the recommended reconstruction techniques at different dose levels and patient sizes.

Material and methods: A lung phantom and an image quality phantom were scanned with four high-end scanners at fixed dose levels. Images were reconstructed with and without iterative reconstruction. Contrast-to-noise ratio, modulation transfer function, and peak frequency of the noise power spectrum were measured.

Results: IMR1 Sharp+ and VEO improved contrast-to-noise ratio to a larger extent than the other iterative techniques, while maintaining spatial resolution. IMR1 Sharp+ also maintained noise texture.

Conclusions: IMR1 Sharp+ was the only reconstruction technique in this study which increased CNR to a large extent, while maintaining all other image quality parameters measured in this study.

Keywords: CNR, contrast-to-noise ratio; CT; CT, computed tomography; FBP, filtered back-projection; Iterative reconstruction; Lung; MTF, modulation transfer function; NPS, noise power spectrum; Physics.