Evaluation of the Sensitivity of Inhomogeneous Magnetization Transfer (ihMT) MRI for Multiple Sclerosis

Obberghen, Elise Van; Mchinda, Samira; Troter, Arnaud Le; Prevost, Valentin H.; Viout, Patrick; Guye, Maxime; Varma, Gopal; Alsop, David C.; Ranjeva, Jean Philippe; Pelletier, Jean; Girard, Olivier; Duhamel, Guillaume

doi:10.3174/ajnr.a5563

Cited by 51 publications

(75 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Magnetization transfer ratio correlated with cognitive disability in SPMS patients’ NAGM ( r = 0.46, p < 0.0001) and NAWM ( r = 0.33, p < 0.0001) but not with EDSS . Inhomogeneous magnetization transfer ratio in white matter structures correlated with physical disability . Lastly, the T 1 /T 2 ‐weighted ratio has recently been applied clinically to found differences in the cortex and in the white matter of MS patients compared to controls, but its specificity to myelin, primarily in white matter, has been questioned .…”

Section: Discussionmentioning

confidence: 99%

Validation of Rapid Magnetic Resonance Myelin Imaging in Multiple Sclerosis

Ouellette

Mangeat

Polyak

et al. 2020

Annals of Neurology

View full text Add to dashboard Cite

Objective Magnetic resonance imaging (MRI) is essential for multiple sclerosis diagnostics but is conventionally not specific to demyelination. Myelin imaging is often hampered by long scanning times, complex postprocessing, or lack of clinical approval. This study aimed to assess the specificity, robustness, and clinical value of Rapid Estimation of Myelin for Diagnostic Imaging, a new myelin imaging technique based on time‐efficient simultaneous T1/T2 relaxometry and proton density mapping in multiple sclerosis. Methods Rapid myelin imaging was applied using 3T MRI ex vivo in 3 multiple sclerosis brain samples and in vivo in a prospective cohort of 71 multiple sclerosis patients and 21 age/sex‐matched healthy controls, with scan–rescan repeatability in a subcohort. Disability in patients was assessed by the Expanded Disability Status Scale and the Symbol Digit Modalities Test at baseline and 2‐year follow‐up. Results Rapid myelin imaging correlated with myelin‐related stains (proteolipid protein immunostaining and Luxol fast blue) and demonstrated good precision. Multiple sclerosis patients had, relative to controls, lower normalized whole‐brain and normal‐appearing white matter myelin fractions, which correlated with baseline cognitive and physical disability. Longitudinally, these myelin fractions correlated with follow‐up physical disability, even with correction for baseline disability. Interpretation Rapid Estimation of Myelin for Diagnostic Imaging provides robust myelin quantification that detects diffuse demyelination in normal‐appearing tissue in multiple sclerosis, which is associated with both cognitive and clinical disability. Because the technique is fast, with automatic postprocessing and US Food and Drug Administration/CE clinical approval, it can be a clinically feasible biomarker that may be suitable to monitor myelin dynamics and evaluate treatments aiming at remyelination. ANN NEUROL 2020;87:710–724

show abstract

Section: Discussionmentioning

confidence: 99%

Validation of Rapid Magnetic Resonance Myelin Imaging in Multiple Sclerosis

Ouellette

Mangeat

Polyak

et al. 2020

Annals of Neurology

View full text Add to dashboard Cite

show abstract

“…Further studies comparing SyMRI MVF and myelin water imaging in patients with MS should be conducted to analyze the association between these metrics. Second, we chose to investigate MTsat, which is thought to be an improvement over MTR, but some new magnetization transfer techniques, for example, inhomogeneous magnetization transfer, have been developed that may increase the sensitivity and specificity for myelin [56]. Third, even though we slightly undersegmented plaques to mitigate possible misregistration and the partial volume effect, the acquired images were gapped at 1 mm and there may have been inevitable partial volume effects that have contributed to bias in the results.…”

Section: Discussionmentioning

confidence: 99%

Myelin Measurement Using Quantitative Magnetic Resonance Imaging: A Correlation Study Comparing Various Imaging Techniques in Patients with Multiple Sclerosis

Saccenti

Hagiwara

Andica

et al. 2020

Cells

View full text Add to dashboard Cite

Evaluation of myelin by magnetic resonance imaging (MRI) is a difficult challenge, but holds promise in demyelinating diseases, such as multiple sclerosis (MS). Although multiple techniques have been developed, no gold standard has been established. This study aims to evaluate the correlation between synthetic MRI myelin volume fraction (SyMRIMVF) and myelin fraction estimated by other techniques, i.e., magnetization transfer saturation (MTsat), T1-weighted images divided by T2-weighted images (T1w/T2w), and radial diffusivity (RD) in patients with MS. We also compared the sensitivities of these techniques for detecting MS-related myelin damage. SyMRIMVF, MTsat, T1w/T2w, and RD were averaged on plaque, periplaque white matter, and normal-appearing white matter (NAWM). Pairwise correlation was calculated using Spearman’s correlation analysis. For all segmented regions, strong correlations were found between SyMRIMVF and T1w/T2w (Rho = 0.89), MTsat (Rho = 0.82), or RD (Rho = −0.75). For each technique, the average estimated myelin differed significantly among regions, but the percentage change of NAWM from both periplaque white matter and plaque were highest in SyMRIMVF. SyMRIMVF might be suitable for myelin evaluation in MS patients, with relevant results as compared to other well-studied techniques. Moreover, it presented better sensitivity for the detection of the difference between plaque or periplaque white matter and NAWM.

show abstract

“…The dependence of apparent T 1D on power has been demonstrated in this work, and yielded important knowledge on how the ihMT signal is generated and filtered, all consistent with the dipolar order theory. Currently, clinical investigations of ihMT are typically performed at either 1.5T or 3T [40], which can deliver B 1RM S around 4µT and 2µT , respectively. Whereas the RF power may reach higher levels during the saturation periods [27,28], one has to keep these orders of magnitude in mind when interpreting in vivo ihMT data and associate them with putative T 1D values.…”

Section: In Vivo Multiple Tmentioning

confidence: 99%

MRI assessment of multiple dipolar relaxation time (T1D) components in biological tissues interpreted with a generalized inhomogeneous magnetization transfer (ihMT) model

Carvalho

Hertanu

Grélard

et al. 2020

Journal of Magnetic Resonance

Self Cite

View full text Add to dashboard Cite

T 1D , the relaxation time of dipolar order, is sensitive to slow motional processes. Thus T 1D is a probe for membrane dynamics and organization that could be used to characterize myelin, the lipid-rich membrane of axonal fibers. A mono-component T 1D model associated with a modified ihMT sequence was previously proposed for in vivo evaluation of T 1D with MRI. However, experiments have suggested that myelinated tissues exhibit multiple T 1D components probably due to a heterogeneous molecular mobility. A bi-component T 1D model is proposed and implemented. ihMT images of ex-vivo, fixed rat spinal cord were acquired with multiple frequency alternation rate. Fits to data yielded two T 1D s of about 500 µs and 10 ms. The proposed model seems to further explore the complexity of myelin organization compared to the previously reported mono-component T 1D model.

show abstract

Evaluation of the Sensitivity of Inhomogeneous Magnetization Transfer (ihMT) MRI for Multiple Sclerosis

Cited by 51 publications

References 27 publications

Validation of Rapid Magnetic Resonance Myelin Imaging in Multiple Sclerosis

Validation of Rapid Magnetic Resonance Myelin Imaging in Multiple Sclerosis

Myelin Measurement Using Quantitative Magnetic Resonance Imaging: A Correlation Study Comparing Various Imaging Techniques in Patients with Multiple Sclerosis

MRI assessment of multiple dipolar relaxation time (T1D) components in biological tissues interpreted with a generalized inhomogeneous magnetization transfer (ihMT) model

Contact Info

Product

Resources

About