Quantitative Measurements Versus Receiver Operating Characteristics and Visual Grading Regression in CT Images Reconstructed with Iterative Reconstruction: A Phantom Study

Kristin Jensen; Hilde Kjernlie Andersen; Örjan Smedby; Bjørn Helge Østerås; Anette Aarsnes; Anders Tingberg; Erik Fosse; Anne Catrine Martinsen

doi:10.1016/j.acra.2017.10.020

Quantitative Measurements Versus Receiver Operating Characteristics and Visual Grading Regression in CT Images Reconstructed with Iterative Reconstruction: A Phantom Study

Acad Radiol. 2018 Apr;25(4):509-518. doi: 10.1016/j.acra.2017.10.020. Epub 2017 Nov 29.

Authors

Kristin Jensen¹, Hilde Kjernlie Andersen², Örjan Smedby³, Bjørn Helge Østerås⁴, Anette Aarsnes², Anders Tingberg⁵, Erik Fosse⁶, Anne Catrine Martinsen⁷

Affiliations

¹ Department of Diagnostic Physics, Oslo University Hospital, P.O. Box, 0454 Oslo, Norway; Department of Physics, University of Oslo, P. O. Box 1048 Blindern, N-0316 Oslo, Norway; Department of Life Sciences and Health, Oslo and Akershus University College of Applied Sciences, P.O. Box 4 St. Olavs plass, N-0130 Oslo, Norway. Electronic address: uxjekr@ous-hf.no.
² Department of Diagnostic Physics, Oslo University Hospital, P.O. Box, 0454 Oslo, Norway.
³ KTH Royal Institute of Technology / STH, Huddinge, Sweden.
⁴ Department of Diagnostic Physics, Oslo University Hospital, P.O. Box, 0454 Oslo, Norway; lnstitute of Clinical Medicine, University of Oslo, Oslo, Norway.
⁵ Department of Medical Radiation Physics, Lund University, Skåne University Hospital, Malmö, Sweden.
⁶ The Intervention Centre, Rikshospitalet, Oslo, Norway; lnstitute of Clinical Medicine, University of Oslo, Oslo, Norway.
⁷ Department of Diagnostic Physics, Oslo University Hospital, P.O. Box, 0454 Oslo, Norway; Department of Physics, University of Oslo, P. O. Box 1048 Blindern, N-0316 Oslo, Norway.

PMID: 29198945
DOI: 10.1016/j.acra.2017.10.020

Abstract

Rationale and objectives: This study aimed to evaluate the correlation of quantitative measurements with visual grading regression (VGR) and receiver operating characteristics (ROC) analysis in computed tomography (CT) images reconstructed with iterative reconstruction.

Materials and methods: CT scans on a liver phantom were performed on CT scanners from GE, Philips, and Toshiba at three dose levels. Images were reconstructed with filtered back projection (FBP) and hybrid iterative techniques (ASiR, iDose, and AIDR 3D of different strengths). Images were visually assessed by five readers using a four- and five-grade ordinal scale for liver low contrast lesions and for 10 image quality criteria. The results were analyzed with ROC and VGR. Standard deviation, signal-to-noise ratios, and contrast-to-noise ratios were measured in the images.

Results: All data were compared to FBP. The results of the quantitative measurements were improved for all algorithms. ROC analysis showed improved lesion detection with ASiR and AIDR and decreased lesion detection with iDose. VGR found improved noise properties for all algorithms, increased sharpness with iDose and AIDR, and decreased artifacts from the spine with AIDR, whereas iDose increased the artifacts from the spine. The contrast in the spine decreased with ASiR and iDose.

Conclusions: Improved quantitative measurements in images reconstructed with iterative reconstruction compared to FBP are not equivalent to improved diagnostic image accuracy.

Keywords: CT iterative reconstruction; diagnostic accuracy; quantitative measurements; receiver operating characteristics; visual grading regression.

Publication types

Comparative Study

MeSH terms

Algorithms
Artifacts
Humans
Image Processing, Computer-Assisted / methods*
Liver / diagnostic imaging
Phantoms, Imaging
ROC Curve
Radiation Dosage
Radiographic Image Interpretation, Computer-Assisted*
Signal-To-Noise Ratio
Tomography, X-Ray Computed*