Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI.

Autor: Eckstein K; High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria., Bachrata B; High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria., Hangel G; High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Department of Neurosurgery, Medical University of Vienna, Vienna, Austria., Widhalm G; Department of Neurosurgery, Medical University of Vienna, Vienna, Austria., Enzinger C; Department of Neurology, Medical University of Graz, Graz, Austria., Barth M; School of Information Technology and Electrical Engineering, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, Australia., Trattnig S; High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria., Robinson SD; High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria; Department of Neurology, Medical University of Graz, Graz, Austria; Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia.
Jazyk: angličtina
Zdroj: NeuroImage [Neuroimage] 2021 Aug 15; Vol. 237, pp. 118175. Date of Electronic Publication: 2021 May 15.
DOI: 10.1016/j.neuroimage.2021.118175
Abstrakt: 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.
Competing Interests: Declaration of Competing Interests K.E. and S.R. are authors of a patent on the coil combination method ASPIRE (“Phase offset determination in magnetic resonance imaging”, WO/2018/028855, PCT/EP2017/064131).
(Copyright © 2021. Published by Elsevier Inc.)
Databáze: MEDLINE
Externí odkaz: