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NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging

BACKGROUND: In integrated PET/MR hybrid imaging the evaluation of PET performance characteristics according to the NEMA standard NU 2–2007 is challenging because of incomplete MR-based attenuation correction (AC) for phantom imaging. In this study, a strategy for CT-based AC of the NEMA image qualit...

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Autores principales: Ziegler, Susanne, Jakoby, Bjoern W., Braun, Harald, Paulus, Daniel H., Quick, Harald H.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer International Publishing 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4542864/
https://www.ncbi.nlm.nih.gov/pubmed/26501819
http://dx.doi.org/10.1186/s40658-015-0122-3
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author Ziegler, Susanne
Jakoby, Bjoern W.
Braun, Harald
Paulus, Daniel H.
Quick, Harald H.
author_facet Ziegler, Susanne
Jakoby, Bjoern W.
Braun, Harald
Paulus, Daniel H.
Quick, Harald H.
author_sort Ziegler, Susanne
collection PubMed
description BACKGROUND: In integrated PET/MR hybrid imaging the evaluation of PET performance characteristics according to the NEMA standard NU 2–2007 is challenging because of incomplete MR-based attenuation correction (AC) for phantom imaging. In this study, a strategy for CT-based AC of the NEMA image quality (IQ) phantom is assessed. The method is systematically evaluated in NEMA IQ phantom measurements on an integrated PET/MR system. METHODS: NEMA IQ measurements were performed on the integrated 3.0 Tesla PET/MR hybrid system (Biograph mMR, Siemens Healthcare). AC of the NEMA IQ phantom was realized by an MR-based and by a CT-based method. The suggested CT-based AC uses a template μ-map of the NEMA IQ phantom and a phantom holder for exact repositioning of the phantom on the systems patient table. The PET image quality parameters contrast recovery, background variability, and signal-to-noise ratio (SNR) were determined and compared for both phantom AC methods. Reconstruction parameters of an iterative 3D OP-OSEM reconstruction were optimized for highest lesion SNR in NEMA IQ phantom imaging. RESULTS: Using a CT-based NEMA IQ phantom μ-map on the PET/MR system is straightforward and allowed performing accurate NEMA IQ measurements on the hybrid system. MR-based AC was determined to be insufficient for PET quantification in the tested NEMA IQ phantom because only photon attenuation caused by the MR-visible phantom filling but not the phantom housing is considered. Using the suggested CT-based AC, the highest SNR in this phantom experiment for small lesions (<= 13 mm) was obtained with 3 iterations, 21 subsets and 4 mm Gaussian filtering. CONCLUSION: This study suggests CT-based AC for the NEMA IQ phantom when performing PET NEMA IQ measurements on an integrated PET/MR hybrid system. The superiority of CT-based AC for this phantom is demonstrated by comparison to measurements using MR-based AC. Furthermore, optimized PET image reconstruction parameters are provided for the highest lesion SNR in NEMA IQ phantom measurements.
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spelling pubmed-45428642015-08-25 NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging Ziegler, Susanne Jakoby, Bjoern W. Braun, Harald Paulus, Daniel H. Quick, Harald H. EJNMMI Phys Original Research BACKGROUND: In integrated PET/MR hybrid imaging the evaluation of PET performance characteristics according to the NEMA standard NU 2–2007 is challenging because of incomplete MR-based attenuation correction (AC) for phantom imaging. In this study, a strategy for CT-based AC of the NEMA image quality (IQ) phantom is assessed. The method is systematically evaluated in NEMA IQ phantom measurements on an integrated PET/MR system. METHODS: NEMA IQ measurements were performed on the integrated 3.0 Tesla PET/MR hybrid system (Biograph mMR, Siemens Healthcare). AC of the NEMA IQ phantom was realized by an MR-based and by a CT-based method. The suggested CT-based AC uses a template μ-map of the NEMA IQ phantom and a phantom holder for exact repositioning of the phantom on the systems patient table. The PET image quality parameters contrast recovery, background variability, and signal-to-noise ratio (SNR) were determined and compared for both phantom AC methods. Reconstruction parameters of an iterative 3D OP-OSEM reconstruction were optimized for highest lesion SNR in NEMA IQ phantom imaging. RESULTS: Using a CT-based NEMA IQ phantom μ-map on the PET/MR system is straightforward and allowed performing accurate NEMA IQ measurements on the hybrid system. MR-based AC was determined to be insufficient for PET quantification in the tested NEMA IQ phantom because only photon attenuation caused by the MR-visible phantom filling but not the phantom housing is considered. Using the suggested CT-based AC, the highest SNR in this phantom experiment for small lesions (<= 13 mm) was obtained with 3 iterations, 21 subsets and 4 mm Gaussian filtering. CONCLUSION: This study suggests CT-based AC for the NEMA IQ phantom when performing PET NEMA IQ measurements on an integrated PET/MR hybrid system. The superiority of CT-based AC for this phantom is demonstrated by comparison to measurements using MR-based AC. Furthermore, optimized PET image reconstruction parameters are provided for the highest lesion SNR in NEMA IQ phantom measurements. Springer International Publishing 2015-08-20 /pmc/articles/PMC4542864/ /pubmed/26501819 http://dx.doi.org/10.1186/s40658-015-0122-3 Text en © Ziegler et al. 2015 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Original Research
Ziegler, Susanne
Jakoby, Bjoern W.
Braun, Harald
Paulus, Daniel H.
Quick, Harald H.
NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging
title NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging
title_full NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging
title_fullStr NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging
title_full_unstemmed NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging
title_short NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging
title_sort nema image quality phantom measurements and attenuation correction in integrated pet/mr hybrid imaging
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4542864/
https://www.ncbi.nlm.nih.gov/pubmed/26501819
http://dx.doi.org/10.1186/s40658-015-0122-3
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