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Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications

BACKGROUND: Attenuation correction is one of the most crucial correction factors for accurate PET data quantitation in hybrid PET/MR scanners, and computing accurate attenuation coefficient maps from MR brain acquisitions is challenging. Here, we develop a method for accurate bone and air segmentati...

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Autores principales: Baran, Jakub, Chen, Zhaolin, Sforazzini, Francesco, Ferris, Nicholas, Jamadar, Sharna, Schmitt, Ben, Faul, David, Shah, Nadim Jon, Cholewa, Marian, Egan, Gary F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220492/
https://www.ncbi.nlm.nih.gov/pubmed/30400875
http://dx.doi.org/10.1186/s12880-018-0283-3
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author Baran, Jakub
Chen, Zhaolin
Sforazzini, Francesco
Ferris, Nicholas
Jamadar, Sharna
Schmitt, Ben
Faul, David
Shah, Nadim Jon
Cholewa, Marian
Egan, Gary F.
author_facet Baran, Jakub
Chen, Zhaolin
Sforazzini, Francesco
Ferris, Nicholas
Jamadar, Sharna
Schmitt, Ben
Faul, David
Shah, Nadim Jon
Cholewa, Marian
Egan, Gary F.
author_sort Baran, Jakub
collection PubMed
description BACKGROUND: Attenuation correction is one of the most crucial correction factors for accurate PET data quantitation in hybrid PET/MR scanners, and computing accurate attenuation coefficient maps from MR brain acquisitions is challenging. Here, we develop a method for accurate bone and air segmentation using MR ultrashort echo time (UTE) images. METHODS: MR UTE images from simultaneous MR and PET imaging of five healthy volunteers was used to generate a whole head, bone and air template image for inclusion into an improved MR derived attenuation correction map, and applied to PET image data for quantitative analysis. Bone, air and soft tissue were segmented based on Gaussian Mixture Models with probabilistic tissue maps as a priori information. We present results for two approaches for bone attenuation coefficient assignments: one using a constant attenuation correction value; and another using an estimated continuous attenuation value based on a calibration fit. Quantitative comparisons were performed to evaluate the accuracy of the reconstructed PET images, with respect to a reference image reconstructed with manually segmented attenuation maps. RESULTS: The DICE coefficient analysis for the air and bone regions in the images demonstrated improvements compared to the UTE approach, and other state-of-the-art techniques. The most accurate whole brain and regional brain analyses were obtained using constant bone attenuation coefficient values. CONCLUSIONS: A novel attenuation correction method for PET data reconstruction is proposed. Analyses show improvements in the quantitative accuracy of the reconstructed PET images compared to other state-of-the-art AC methods for simultaneous PET/MR scanners. Further evaluation is needed with radiopharmaceuticals other than FDG, and in larger cohorts of participants.
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spelling pubmed-62204922018-11-15 Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications Baran, Jakub Chen, Zhaolin Sforazzini, Francesco Ferris, Nicholas Jamadar, Sharna Schmitt, Ben Faul, David Shah, Nadim Jon Cholewa, Marian Egan, Gary F. BMC Med Imaging Research Article BACKGROUND: Attenuation correction is one of the most crucial correction factors for accurate PET data quantitation in hybrid PET/MR scanners, and computing accurate attenuation coefficient maps from MR brain acquisitions is challenging. Here, we develop a method for accurate bone and air segmentation using MR ultrashort echo time (UTE) images. METHODS: MR UTE images from simultaneous MR and PET imaging of five healthy volunteers was used to generate a whole head, bone and air template image for inclusion into an improved MR derived attenuation correction map, and applied to PET image data for quantitative analysis. Bone, air and soft tissue were segmented based on Gaussian Mixture Models with probabilistic tissue maps as a priori information. We present results for two approaches for bone attenuation coefficient assignments: one using a constant attenuation correction value; and another using an estimated continuous attenuation value based on a calibration fit. Quantitative comparisons were performed to evaluate the accuracy of the reconstructed PET images, with respect to a reference image reconstructed with manually segmented attenuation maps. RESULTS: The DICE coefficient analysis for the air and bone regions in the images demonstrated improvements compared to the UTE approach, and other state-of-the-art techniques. The most accurate whole brain and regional brain analyses were obtained using constant bone attenuation coefficient values. CONCLUSIONS: A novel attenuation correction method for PET data reconstruction is proposed. Analyses show improvements in the quantitative accuracy of the reconstructed PET images compared to other state-of-the-art AC methods for simultaneous PET/MR scanners. Further evaluation is needed with radiopharmaceuticals other than FDG, and in larger cohorts of participants. BioMed Central 2018-11-06 /pmc/articles/PMC6220492/ /pubmed/30400875 http://dx.doi.org/10.1186/s12880-018-0283-3 Text en © The Author(s). 2018 Open AccessThis 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. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Baran, Jakub
Chen, Zhaolin
Sforazzini, Francesco
Ferris, Nicholas
Jamadar, Sharna
Schmitt, Ben
Faul, David
Shah, Nadim Jon
Cholewa, Marian
Egan, Gary F.
Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications
title Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications
title_full Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications
title_fullStr Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications
title_full_unstemmed Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications
title_short Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications
title_sort accurate hybrid template–based and mr-based attenuation correction using ute images for simultaneous pet/mr brain imaging applications
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220492/
https://www.ncbi.nlm.nih.gov/pubmed/30400875
http://dx.doi.org/10.1186/s12880-018-0283-3
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