Reproducibility of inhomogeneous magnetization transfer (ihMT): A test-retest, multi-site study

Zhang, Lei; Chen, Tao; Tian, Hongzhe; Xue, Hongqiang; Ren, Huipeng; Li, Li; Fan, Qing Ming; Wen, Baohong; Ren, Zhuanqin

doi:10.1016/j.mri.2018.11.010

Cited by 18 publications

(35 citation statements)

References 28 publications

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“…The ICC scores of inverse ihMTR were slightly superior to ihMTR. Our ICC values are lower than a repeatability study of a steady-state Cartesian ihMT study 51 . However, the values are not directly comparable as that study used a 2.4×2.4×3.2 mm voxel size compared to our 1.5 mm isotropic voxel size, with a similar overall scan time.…”

Section: Discussioncontrasting

confidence: 72%

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Silent myelin-weighted magnetic resonance imaging

et al. 2020

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Background: Inhomogeneous Magnetization Transfer (ihMT) is an emerging, uniquely myelin-specific magnetic resonance imaging (MRI) contrast. Current ihMT acquisitions utilise fast Gradient Echo sequences which are among the most acoustically noisy MRI sequences, reducing patient comfort during acquisition. We sought to address this by modifying a near silent MRI sequence to include ihMT contrast. Methods: A Magnetization Transfer preparation module was incorporated into a radial Zero Echo-Time sequence. Repeatability of the ihMT ratio and inverse ihMT ratio were assessed in a cohort of healthy subjects. We also investigated how head orientation affects ihMT across subjects, as a previous study in a single subject suggests this as a potential confound. Results: We demonstrated that ihMT ratios comparable to existing, acoustically loud, implementations could be obtained with the silent sequence. We observed a small but significant effect of head orientation on inverse ihMTR. Conclusions: Silent ihMT imaging is a comparable alternative to conventional, noisy, alternatives. For all future ihMT studies we recommend careful positioning of the subject within the scanner.

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Section: Discussioncontrasting

confidence: 72%

“…To minimise the number of resampling operations all transforms between the MNI space and the MT-weighted native space were concatenated before application. Ten bilateral white matter tract ROIs were selected 51 .…”

Section: Methodsmentioning

confidence: 99%

Silent myelin-weighted magnetic resonance imaging

et al. 2020

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“…The definition for the steady-state used here, that is, one off-resonance MT RF pulse between successive acquisition modules and a recovery period (if present) less than the time between adjacent MT pulses, also holds for other instances of simultaneous dual-offset RF irradiation. 5,7,17 The ihMT acquisitions proposed by Mchinda et al within a steady-state sequence do not fit this definition, because they make use of multiple, closely spaced (< 1 ms) MT pulses of alternating frequency for the dual-frequency experiments. Although the sequence proposed by Malik et al constitutes a true steadystate with one readout per TR, 17 that implementation is relatively SAR-intensive, while not making use of the increased ihMT signal available through a low duty-cycle implementation.…”

Section: Discussionmentioning

confidence: 99%

“…sequence comparable (albeit with more readouts) to previous steady-state ihMT implementations, 5,7 as well as a recent one that makes use of multiband pulses to achieve simultaneous RF irradiation, on-resonance and off-resonance. 17 This was in contrast to the prepared, ihMTRAGE sequence in which multiple MT pulses were used within the preparation module before acquisition.…”

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confidence: 99%

Three‐dimensional inhomogeneous magnetization transfer with rapid gradient‐echo (3D ihMTRAGE) imaging

Varma

Munsch

Burns³

et al. 2020

Magnetic Resonance in Med

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Purpose To demonstrate the feasibility of integrating the magnetization transfer (MT) preparations required for inhomogeneous MT (ihMT) within an MPRAGE‐style acquisition. Such a sequence allows for reduced power deposition and easy inclusion of other modules. Methods An ihMT MPRAGE–style sequence (ihMTRAGE) was initially simulated to investigate acquisition of the 3D ihMT data sequentially, or in an interleaved manner. The ihMTRAGE sequence was implemented on a 3T clinical scanner to acquire ihMT data from the brain and spine. Results Both simulations and in vivo data provided an ihMT signal that was significantly greater using a sequential ihMTRAGE acquisition, compared with an interleaved implementation. Comparison with a steady‐state ihMT acquisition (defined as having one MT RF pulse between successive acquisition modules) demonstrated how ihMTRAGE allows for a reduction in average power deposition, or greater ihMT signal at equal average power deposition. Inclusion of a prospective motion‐correction module did not significantly affect the ihMT signal obtained from regions of interest in the brain. The ihMTRAGE acquisition allowed combination with a spatial saturation module to reduce phase wrap artifacts in a cervical spinal cord acquisition. Conclusions Use of preparations necessary for ihMT experiments within an MPRAGE‐style sequence provides a useful alternative for acquiring 3D ihMT data. Compared with our steady‐state implementation, ihMTRAGE provided reduced power deposition, while allowing use of the maximum intensity from off‐resonance RF pulses. The 3D ihMTRAGE acquisition allowed combination of other modules with the preparation necessary for ihMT experiments, specifically motion compensation and spatial saturation modules.

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“…Recent developments in quantitative MT (qMT) methods attempt to reduce these confounding influences by providing more tissue-specific indices. 52 Another promising technique is inhomogeneous magnetization transfer (ihMT) 53 which appears to be specific to CNS lipids, which enrich myelin. Myelin water imaging (MWI) is another MRI technique designed to detect myelin alterations.…”

Section: Advances In Understanding Disease Mechanismsmentioning

confidence: 99%

Advances in brain imaging in multiple sclerosis

Cortese

Collorone

Ciccarelli

et al. 2019

Ther Adv Neurol Disord

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Brain imaging is increasingly used to support clinicians in diagnosing multiple sclerosis (MS) and monitoring its progression. However, the role of magnetic resonance imaging (MRI) in MS goes far beyond its clinical application. Indeed, advanced imaging techniques have helped to detect different components of MS pathogenesis in vivo, which is now considered a heterogeneous process characterized by widespread damage of the central nervous system, rather than multifocal demyelination of white matter. Recently, MRI biomarkers more sensitive to disease activity than clinical disability outcome measures, have been used to monitor response to anti-inflammatory agents in patients with relapsing–remitting MS. Similarly, MRI markers of neurodegeneration exhibit the potential as primary and secondary outcomes in clinical trials for progressive phenotypes. This review will summarize recent advances in brain neuroimaging in MS from the research setting to clinical applications.

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Reproducibility of inhomogeneous magnetization transfer (ihMT): A test-retest, multi-site study

Cited by 18 publications

References 28 publications

Silent myelin-weighted magnetic resonance imaging

Silent myelin-weighted magnetic resonance imaging

Three‐dimensional inhomogeneous magnetization transfer with rapid gradient‐echo (3D ihMTRAGE) imaging

Advances in brain imaging in multiple sclerosis

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