Kristin Jensen1, Hilde Kjernlie Andersen2, Örjan Smedby3, Bjørn Helge Østerås4, Anette Aarsnes2, Anders Tingberg5, Erik Fosse6, Anne Catrine Martinsen7. 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.
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.
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.
Authors: Johannes Clemens Godt; Cathrine K Johansen; Anne Catrine T Martinsen; Anselm Schulz; Helga M Brøgger; Kristin Jensen; Arne Stray-Pedersen; Johann Baptist Dormagen Journal: Acta Radiol Open Date: 2021-11-18