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Stability of Radiomic Features across Different Region of Interest Sizes—A CT and MR Phantom Study

We aimed to evaluate radiomic features’ stability across different region of interest (ROI) sizes in CT and MR images. We chose a phantom with a homogenous internal structure so no differences for a feature extracted from ROIs of different sizes would be expected. For this, we scanned a plastic cup...

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Autores principales: Jensen, Laura J., Kim, Damon, Elgeti, Thomas, Steffen, Ingo G., Hamm, Bernd, Nagel, Sebastian N.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8293351/
https://www.ncbi.nlm.nih.gov/pubmed/34201012
http://dx.doi.org/10.3390/tomography7020022
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author Jensen, Laura J.
Kim, Damon
Elgeti, Thomas
Steffen, Ingo G.
Hamm, Bernd
Nagel, Sebastian N.
author_facet Jensen, Laura J.
Kim, Damon
Elgeti, Thomas
Steffen, Ingo G.
Hamm, Bernd
Nagel, Sebastian N.
author_sort Jensen, Laura J.
collection PubMed
description We aimed to evaluate radiomic features’ stability across different region of interest (ROI) sizes in CT and MR images. We chose a phantom with a homogenous internal structure so no differences for a feature extracted from ROIs of different sizes would be expected. For this, we scanned a plastic cup filled with sodium chloride solution ten times in CT and per MR sequence (T1-weighted-gradient-echo and T2-weighted-turbo-inversion-recovery-magnitude). We placed sphere-shaped ROIs of different diameters (4, 8, and 16 mm, and 4, 8, and 16 pixels) into the phantom’s center. Features were extracted using PyRadiomics. We assessed feature stability across ROI sizes with overall concordance correlation coefficients (OCCCs). Differences were tested for significance with the Mann–Whitney U-test. Of 93 features, 87 T1w-derived, 87 TIRM-derived, and 70 CT-derived features were significantly different between ROI sizes. Among MR-derived features, OCCCs showed excellent (>0.90) agreement for mean, median, and root mean squared for ROI sizes between 4 and 16 mm and pixels. We further observed excellent agreement for 10th and 90th percentile in T1w and 10th percentile in T2w TIRM images. There was no excellent agreement among the OCCCs of CT-derived features. In summary, many features indicated significant differences and only few showed excellent agreement across varying ROI sizes, although we examined a homogenous phantom. Since we considered a small phantom in an experimental setting, further studies to investigate this size effect would be necessary for a generalization. Nevertheless, we believe knowledge about this effect is crucial in interpreting radiomics studies, as features that supposedly discriminate disease entities may only indicate a systematic difference in ROI size.
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spelling pubmed-82933512021-07-22 Stability of Radiomic Features across Different Region of Interest Sizes—A CT and MR Phantom Study Jensen, Laura J. Kim, Damon Elgeti, Thomas Steffen, Ingo G. Hamm, Bernd Nagel, Sebastian N. Tomography Article We aimed to evaluate radiomic features’ stability across different region of interest (ROI) sizes in CT and MR images. We chose a phantom with a homogenous internal structure so no differences for a feature extracted from ROIs of different sizes would be expected. For this, we scanned a plastic cup filled with sodium chloride solution ten times in CT and per MR sequence (T1-weighted-gradient-echo and T2-weighted-turbo-inversion-recovery-magnitude). We placed sphere-shaped ROIs of different diameters (4, 8, and 16 mm, and 4, 8, and 16 pixels) into the phantom’s center. Features were extracted using PyRadiomics. We assessed feature stability across ROI sizes with overall concordance correlation coefficients (OCCCs). Differences were tested for significance with the Mann–Whitney U-test. Of 93 features, 87 T1w-derived, 87 TIRM-derived, and 70 CT-derived features were significantly different between ROI sizes. Among MR-derived features, OCCCs showed excellent (>0.90) agreement for mean, median, and root mean squared for ROI sizes between 4 and 16 mm and pixels. We further observed excellent agreement for 10th and 90th percentile in T1w and 10th percentile in T2w TIRM images. There was no excellent agreement among the OCCCs of CT-derived features. In summary, many features indicated significant differences and only few showed excellent agreement across varying ROI sizes, although we examined a homogenous phantom. Since we considered a small phantom in an experimental setting, further studies to investigate this size effect would be necessary for a generalization. Nevertheless, we believe knowledge about this effect is crucial in interpreting radiomics studies, as features that supposedly discriminate disease entities may only indicate a systematic difference in ROI size. MDPI 2021-06-08 /pmc/articles/PMC8293351/ /pubmed/34201012 http://dx.doi.org/10.3390/tomography7020022 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Jensen, Laura J.
Kim, Damon
Elgeti, Thomas
Steffen, Ingo G.
Hamm, Bernd
Nagel, Sebastian N.
Stability of Radiomic Features across Different Region of Interest Sizes—A CT and MR Phantom Study
title Stability of Radiomic Features across Different Region of Interest Sizes—A CT and MR Phantom Study
title_full Stability of Radiomic Features across Different Region of Interest Sizes—A CT and MR Phantom Study
title_fullStr Stability of Radiomic Features across Different Region of Interest Sizes—A CT and MR Phantom Study
title_full_unstemmed Stability of Radiomic Features across Different Region of Interest Sizes—A CT and MR Phantom Study
title_short Stability of Radiomic Features across Different Region of Interest Sizes—A CT and MR Phantom Study
title_sort stability of radiomic features across different region of interest sizes—a ct and mr phantom study
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8293351/
https://www.ncbi.nlm.nih.gov/pubmed/34201012
http://dx.doi.org/10.3390/tomography7020022
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