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Müller, Max; Egger, Nico; Sommer, Stefan; Wilferth, Tobias; Meixner, Christian; Laun, Frederik Bernd; Mennecke, Angelika; Schmidt, Manuel; Huhn, Konstantin; Rothhammer, Veit; Uder, Michael; Dörfler, Arnd; Nagel, Armin M.

doi:10.1016/j.mri.2021.11.016

Cited by 12 publications

(9 citation statements)

References 78 publications

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“…With the introduction of UTE MRI sequences, which have 100–1000 times shorter echo times than conventional sequences, myelin and its specific changes of demyelination and remyelination can potentially be visualized directly ( Horch et al, 2011 ; Wilhelm et al, 2012 ; Du et al, 2014a ; Boucneau et al, 2018 ; Jang et al, 2021 ; Mueller et al, 2022 ). The 3D IR-UTE Cones sequence allows high-contrast volumetric myelin imaging in MS patients.…”

Section: Discussionmentioning

confidence: 99%

“…With rapidly increasing developments in the field of MRI, it is favorable to establish sequences that allow direct visualization of myelin. As myelin has very short T2* values of less than 1 msec ( Horch et al, 2011 ; Wilhelm et al, 2012 ; Du et al, 2014a ; Boucneau et al, 2018 ; Ma et al, 2020a , b ; Jang et al, 2021 ; Mueller et al, 2022 ), the changes seen on clinical T1- or T2-weighted images are not specific to myelin, as they only depict longer T2 components. With the introduction of ultrashort echo time (UTE) MRI sequences, which have 100–1000 times shorter echo times than conventional sequences, myelin can potentially be visualized directly ( Horch et al, 2011 ; Wilhelm et al, 2012 ; Ma et al, 2020b ).…”

Section: Introductionmentioning

confidence: 99%

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The signal intensity variation of multiple sclerosis (MS) lesions on magnetic resonance imaging (MRI) as a potential biomarker for patients’ disability: A feasibility study

et al. 2023

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IntroductionAlthough many lesion-based MRI biomarkers in multiple sclerosis (MS) patients were investigated, none of the previous studies dealt with the signal intensity variations (SIVs) of MS lesions. In this study, the SIVs of MS lesions on direct myelin imaging and standard clinical sequences as possible MRI biomarkers for disability in MS patients were assessed.MethodsTwenty seven MS patients were included in this prospective study. IR-UTE, FLAIR, and MPRAGE sequences were employed on a 3T scanner. Regions of interest (ROIs) were manually drawn within the MS lesions, and the cerebrospinal fluid (CSF) and signal intensity ratios (SIR) were calculated from the derived values. Variations coefficients were determined from the standard deviations (Coeff 1) and the absolute differences (Coeff 2) of the SIRs. Disability grade was assessed by the expanded disability status scale (EDSS). Cortical/gray matter, subcortical, infratentorial, and spinal lesions were excluded.ResultsThe mean diameter of the lesions was 7.8 ± 1.97 mm, while the mean EDSS score was 4.5 ± 1.73. We found moderate correlations between the EDSS and Coeff 1 and 2 on IR-UTE and MPRAGE images. Accordingly, Pearson’s correlations on IR-UTE were R = 0.51 (p = 0.007) and R = 0.49 (p = 0.01) for Coeff 1 and 2, respectively. For MPRAGE, Pearson’s correlations were R = 0.5 (p = 0.008) and R = 0.48 (p = 0.012) for Coeff 1 and 2, respectively. For FLAIR, only poor correlations could be found.ConclusionThe SIVs of MS lesions on IR-UTE and MPRAGE images, assessed by Coeff 1 and 2, could be used as novel potential MRI biomarkers for patients’ disability.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The signal intensity variation of multiple sclerosis (MS) lesions on magnetic resonance imaging (MRI) as a potential biomarker for patients’ disability: A feasibility study

et al. 2023

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“… 9 Therefore, novel 3D k‐space trajectories with greater curvature per spoke have been proposed for a more efficient sampling strategy, e.g., the spiral‐like extended cones sampling. 9 , 10 Other state‐of‐the‐art 3D UTE techniques include density‐adapted 3D radial UTE, 11 Fermat looped, orthogonally encoded trajectories UTE sequence 12 and a 3D koosh ball trajectory UTE sequence. 13 Rosette k‐space trajectories, which allow a center‐out sampling pattern while providing more samples in the outer k‐space per spoke than radial trajectories, are also potential candidates for 3D UTE MRI.…”

Section: Introductionmentioning

confidence: 99%

Ultra‐short T₂ components imaging of the whole brain using 3D dual‐echo UTE MRI with rosette k‐space pattern

Shen

Özen

Sunjar

et al. 2022

Magnetic Resonance in Med

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Purpose This study aimed to develop a new 3D dual‐echo rosette k‐space trajectory, specifically designed for UTE MRI applications. The imaging of the ultra‐short transverse relaxation time (uT2) of brain was acquired to test the performance of the proposed UTE sequence. Theory and Methods The rosette trajectory was developed based on rotations of a “petal‐like” pattern in the kx–ky plane, with oscillated extensions in the kz‐direction for 3D coverage. Five healthy volunteers underwent 10 dual‐echo 3D rosette UTE scans with various TEs. Dual‐exponential complex model fitting was performed on the magnitude data to separate uT2 signals, with the output of uT2 fraction, uT2 value, and long‐T2 value. Results The 3D rosette dual‐echo UTE sequence showed better performance than a 3D radial UTE acquisition. More significant signal intensity decay in white matter than gray matter was observed along with the TEs. The white matter regions had higher uT2 fraction values than gray matter (10.9% ± 1.9% vs. 5.7% ± 2.4%). The uT2 value was approximately 0.10 ms in white matter . Conclusion The higher uT2 fraction value in white matter compared to gray matter demonstrated the ability of the proposed sequence to capture rapidly decaying signals.

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“…Both the ultrashort echo time (UTE) (31) and the zero echo time (ZTE) (32) sequence designs offer more adequate time efficiency than SPI. UTE has been used in several myelin bilayer imaging studies (33)(34)(35)(36)(37)(38)(39)(40)(41), but, because the imaging gradient (whose amplitude determines the spatial encoding speed) is not ramped up until after tissue excitation, UTE is primarily sensitive to signals with T 2 's in the hundreds of microseconds range (15), whereas the vast majority of myelin bilayer signals exhibit T 2 's in the tens of microseconds range (16). As such, UTE images are considered to include only small contributions from the myelin bilayer.…”

Section: Discussionmentioning

confidence: 99%

Quantitative magnetic resonance mapping of the myelin bilayer reflects pathology in multiple sclerosis brain tissue

Baadsvik,

Weiger,

Froidevaux

et al. 2023

Sci. Adv.

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Multiple sclerosis (MS) is a neuroinflammatory disease characterized by loss of myelin (demyelination) and, to a certain extent, subsequent myelin repair (remyelination). To better understand the pathomechanisms underlying de- and remyelination and to monitor the efficacy of treatments aimed at regenerating myelin, techniques offering noninvasive visualizations of myelin are warranted. Magnetic resonance (MR) imaging has long been at the forefront of efforts to visualize myelin, but it has only recently become feasible to access the rapidly decaying resonance signals stemming from the myelin lipid-protein bilayer itself. Here, we show that direct MR mapping of the bilayer yields highly specific myelin maps in brain tissue from patients with MS. Furthermore, examination of the bilayer signal behavior is found to reveal pathological alterations in normal-appearing white and gray matter. These results indicate promise for in vivo implementations of the myelin bilayer mapping technique, with prospective applications in basic research, diagnostics, disease monitoring, and drug development.

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Direct imaging of white matter ultrashort T2∗ components at 7 Tesla

Cited by 12 publications

References 78 publications

The signal intensity variation of multiple sclerosis (MS) lesions on magnetic resonance imaging (MRI) as a potential biomarker for patients’ disability: A feasibility study

The signal intensity variation of multiple sclerosis (MS) lesions on magnetic resonance imaging (MRI) as a potential biomarker for patients’ disability: A feasibility study

Ultra‐short T₂ components imaging of the whole brain using 3D dual‐echo UTE MRI with rosette k‐space pattern

Quantitative magnetic resonance mapping of the myelin bilayer reflects pathology in multiple sclerosis brain tissue

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Direct imaging of white matter ultrashort T2∗ components at 7 Tesla

Cited by 12 publications

References 78 publications

The signal intensity variation of multiple sclerosis (MS) lesions on magnetic resonance imaging (MRI) as a potential biomarker for patients’ disability: A feasibility study

The signal intensity variation of multiple sclerosis (MS) lesions on magnetic resonance imaging (MRI) as a potential biomarker for patients’ disability: A feasibility study

Ultra‐short T2 components imaging of the whole brain using 3D dual‐echo UTE MRI with rosette k‐space pattern

Quantitative magnetic resonance mapping of the myelin bilayer reflects pathology in multiple sclerosis brain tissue

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Ultra‐short T₂ components imaging of the whole brain using 3D dual‐echo UTE MRI with rosette k‐space pattern