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Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI
PURPOSE: Susceptibility Weighted Imaging (SWI) has become established in the clinical investigation of stroke, microbleeds, tumor vascularization, calcification and iron deposition, but suffers from a number of shortcomings and artefacts. The goal of this study was to reduce the sensitivity of SWI t...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7612087/ https://www.ncbi.nlm.nih.gov/pubmed/34000407 http://dx.doi.org/10.1016/j.neuroimage.2021.118175 |
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author | Eckstein, Korbinian Bachrata, Beata Hangel, Gilbert Widhalm, Georg Enzinger, Christian Barth, Markus Trattnig, Siegfried Robinson, Simon Daniel |
author_facet | Eckstein, Korbinian Bachrata, Beata Hangel, Gilbert Widhalm, Georg Enzinger, Christian Barth, Markus Trattnig, Siegfried Robinson, Simon Daniel |
author_sort | Eckstein, Korbinian |
collection | PubMed |
description | PURPOSE: Susceptibility Weighted Imaging (SWI) has become established in the clinical investigation of stroke, microbleeds, tumor vascularization, calcification and iron deposition, but suffers from a number of shortcomings and artefacts. The goal of this study was to reduce the sensitivity of SWI to strong B(1) and B(0) inhomogeneities at ultra-high field to generate homogeneous images with increased contrast and free of common artefacts. All steps in SWI processing have been addressed −coil combination, phase unwrapping, image combination over echoes, phase filtering and homogeneity correction −and applied to an efficient bipolar multi-echo acquisition to substantially improve the quality of SWI. PRINCIPAL RESULTS: Our findings regarding the optimal individual processing steps lead us to propose a Contrast-weighted, Laplace-unwrapped, bipolar multi-Echo, ASPIRE-combined, homogeneous, improved Resolution SWI, or CLEAR-SWI. CLEAR-SWI was compared to two other multi-echo SWI methods and standard, single-echo SWI with the same acquisition time at 7 T in 10 healthy volunteers and with single-echo SWI in 13 patients with brain tumors. CLEAR-SWI had improved contrast-to-noise and homogeneity, reduced signal dropout and was not compromised by the artefacts which affected standard SWI in 10 out of 13 cases close to tumors (as assessed by expert raters), as well as generating T2* maps and phase images which can be used for Quantitative Susceptibility Mapping. In a comparison with other multi-echo SWI methods, CLEAR-SWI had the fewest artefacts, highest SNR and generally higher contrast-to-noise. MAJOR CONCLUSIONS: CLEAR-SWI eliminates the artefacts common in standard, single-echo SWI, reduces signal dropouts and improves image homogeneity and contrast-to-noise. Applied clinically, in a study of brain tumor patients, CLEAR-SWI was free of the artefacts which affected standard, single-echo SWI. |
format | Online Article Text |
id | pubmed-7612087 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
record_format | MEDLINE/PubMed |
spelling | pubmed-76120872021-12-10 Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI Eckstein, Korbinian Bachrata, Beata Hangel, Gilbert Widhalm, Georg Enzinger, Christian Barth, Markus Trattnig, Siegfried Robinson, Simon Daniel Neuroimage Article PURPOSE: Susceptibility Weighted Imaging (SWI) has become established in the clinical investigation of stroke, microbleeds, tumor vascularization, calcification and iron deposition, but suffers from a number of shortcomings and artefacts. The goal of this study was to reduce the sensitivity of SWI to strong B(1) and B(0) inhomogeneities at ultra-high field to generate homogeneous images with increased contrast and free of common artefacts. All steps in SWI processing have been addressed −coil combination, phase unwrapping, image combination over echoes, phase filtering and homogeneity correction −and applied to an efficient bipolar multi-echo acquisition to substantially improve the quality of SWI. PRINCIPAL RESULTS: Our findings regarding the optimal individual processing steps lead us to propose a Contrast-weighted, Laplace-unwrapped, bipolar multi-Echo, ASPIRE-combined, homogeneous, improved Resolution SWI, or CLEAR-SWI. CLEAR-SWI was compared to two other multi-echo SWI methods and standard, single-echo SWI with the same acquisition time at 7 T in 10 healthy volunteers and with single-echo SWI in 13 patients with brain tumors. CLEAR-SWI had improved contrast-to-noise and homogeneity, reduced signal dropout and was not compromised by the artefacts which affected standard SWI in 10 out of 13 cases close to tumors (as assessed by expert raters), as well as generating T2* maps and phase images which can be used for Quantitative Susceptibility Mapping. In a comparison with other multi-echo SWI methods, CLEAR-SWI had the fewest artefacts, highest SNR and generally higher contrast-to-noise. MAJOR CONCLUSIONS: CLEAR-SWI eliminates the artefacts common in standard, single-echo SWI, reduces signal dropouts and improves image homogeneity and contrast-to-noise. Applied clinically, in a study of brain tumor patients, CLEAR-SWI was free of the artefacts which affected standard, single-echo SWI. 2021-08-15 2021-05-15 /pmc/articles/PMC7612087/ /pubmed/34000407 http://dx.doi.org/10.1016/j.neuroimage.2021.118175 Text en https://creativecommons.org/licenses/by/4.0/This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/) |
spellingShingle | Article Eckstein, Korbinian Bachrata, Beata Hangel, Gilbert Widhalm, Georg Enzinger, Christian Barth, Markus Trattnig, Siegfried Robinson, Simon Daniel Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI |
title | Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI |
title_full | Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI |
title_fullStr | Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI |
title_full_unstemmed | Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI |
title_short | Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI |
title_sort | improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: clear-swi |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7612087/ https://www.ncbi.nlm.nih.gov/pubmed/34000407 http://dx.doi.org/10.1016/j.neuroimage.2021.118175 |
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