Test-retest reproducibility of in vivo magnetization transfer ratio and saturation index in mice at 9.4 Tesla

Background: Magnetization transfer saturation (MTsat) imaging was developed to reduce T1 dependence and improve specificity to myelin compared to the widely used MT ratio (MTR), while maintaining a feasible scan time. Knowledge of MTsat reproducibility is necessary to apply MTsat in preclinical neuroimaging. Purpose: To assess the test-retest reproducibility of MTR and MTsat in the mouse brain at 9.4 T and calculate sample sizes required to detect various effect sizes. Study Type: Prospective. Animal Model: C57Bl/6 Mouse Model (6 females and 6 males, aged 12 to 14 weeks). Field Strength/Sequence: Magnetization Transfer Imaging at 9.4 T. Assessment: All mice were scanned at two timepoints (5 days apart). MTR and MTsat maps were analyzed using mean region of interest (ROI), and whole brain voxel-wise analysis. Statistical Tests: Bland Altman plots assessed biases between test and retest measurements. Test retest reproducibility was evaluated via between and within-subject coefficients of variation (CV). Sample sizes required were calculated (at a 95 % significance level and power of 80 %), given various minimum detectable effect sizes, using both between and within-subject approaches. Results: Bland Altman plots showed negligible biases between test and retest sessions. ROI based and voxel-wise CVs revealed high reproducibility for both MTR (ROI: CVs < 8 %) and MTsat (ROI: CVs < 10 %). With a sample size of 6, changes on the order of 15% can be detected in MTR and MTsat, both between and within subjects, while smaller changes (6 to 8 %) require sample sizes of 10 to 15 for MTR, and 15 to 20 for MTsat. Data Conclusion: MTsat exhibits comparable reproducibility to MTR, while providing sensitivity to myelin with less T1 dependence than MTR. Our findings suggest both MTR and MTsat can detect moderate changes, common in pathologies, with feasible preclinical sample sizes. Keywords: magnetization transfer ratio, magnetization transfer saturation, reproducibility, preclinical rodent imaging

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Surface-in pathology in multiple sclerosis: a new view on pathogenesis?

Brain ◽

10.1093/brain/awab025 ◽

2021 ◽

Author(s):

Matteo Pardini ◽

J William L Brown ◽

Roberta Magliozzi ◽

Richard Reynolds ◽

Declan T Chard

Keyword(s):

Multiple Sclerosis ◽

White Matter ◽

Grey Matter ◽

Magnetization Transfer ◽

Neuronal Loss ◽

Magnetization Transfer Ratio ◽

Supporting Evidence ◽

Transfer Ratio ◽

Meningeal Inflammation

Abstract While multiple sclerosis can affect any part of the CNS, it does not do so evenly. In white matter it has long been recognized that lesions tend to occur around the ventricles, and grey matter lesions mainly accrue in the outermost (subpial) cortex. In cortical grey matter, neuronal loss is greater in the outermost layers. This cortical gradient has been replicated in vivo with magnetization transfer ratio and similar gradients in grey and white matter magnetization transfer ratio are seen around the ventricles, with the most severe abnormalities abutting the ventricular surface. The cause of these gradients remains uncertain, though soluble factors released from meningeal inflammation into the CSF has the most supporting evidence. In this Update, we review this ‘surface-in’ spatial distribution of multiple sclerosis abnormalities and consider the implications for understanding pathogenic mechanisms and treatments designed to slow or stop them.

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A fast B1-mapping method for the correction and normalization of magnetization transfer ratio maps at 3 T

NeuroImage ◽

10.1016/j.neuroimage.2009.11.054 ◽

2010 ◽

Vol 49 (4) ◽

pp. 3015-3026 ◽

Cited By ~ 52

Author(s):

Steffen Volz ◽

Ulrike Nöth ◽

Anna Rotarska-Jagiela ◽

Ralf Deichmann

Keyword(s):

Magnetization Transfer ◽

Mapping Method ◽

Magnetization Transfer Ratio ◽

Transfer Ratio ◽

B1 Mapping

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Cervical cord magnetization transfer ratio and clinical changes over 18 months in patients with relapsing-remitting multiple sclerosis: a preliminary study

Multiple Sclerosis Journal ◽

10.1177/1352458506070714 ◽

2006 ◽

Vol 12 (5) ◽

pp. 662-665 ◽

Cited By ~ 18

Author(s):

A Charil ◽

D Caputo ◽

R Cavarretta ◽

M P Sormani ◽

P Ferrante ◽

...

Keyword(s):

Multiple Sclerosis ◽

Relapse Rate ◽

Magnetization Transfer ◽

Small Sample ◽

Cervical Cord ◽

Magnetization Transfer Ratio ◽

Short Term ◽

Disease Evolution ◽

Transfer Ratio ◽

Relapsing Remitting

Background Magnetization transfer ratio (MTR) permits the quantitative estimation of cervical cord tissue damage in patients with multiple sclerosis (MS). Objective To determine whether a single time-point MTR scan of the cervical cord is associated with short-term disease evolution in patients with relapsing-remitting (RR) MS. Methods Using a 1.5-T magnetic resonance imaging (MRI) system with a tailored cervical cord phased array coil, fast short-tau inversion recovery (fast-STIR) and MTR scans were obtained from 14 untreated patients with RRMS at baseline. Cervical cord MTR histograms were derived. Over the 18- month follow-up period, relapse rate was measured and disability assessed by the Expanded Disability Status Scale (EDSS) score. Results Average cervical cord MTR was correlated with relapse rate ( r= -0.56, P = 0.037). A moderate correlation ( r values ranging from -0.33 to -0.36) between baseline cervical cord MTR metrics and EDSS changes over 18 months was also noted, albeit statistical significance was not reached ( P = 0.26 and 0.21, respectively) perhaps because of the relatively small sample size. Conclusions This study suggests that a ‘snapshot’ MT MRI assessment of the cervical cord may detect cervical cord tissue changes associated with short-term disease evolution in RRMS.

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Measurement of magnetization transfer ratio (MTR) from cervical spinal cord: Multicenter reproducibility and variability

Journal of Magnetic Resonance Imaging ◽

10.1002/jmri.26537 ◽

2018 ◽

Vol 49 (6) ◽

pp. 1777-1785 ◽

Cited By ~ 1

Author(s):

Benoit Combès ◽

Laureline Monteau ◽

Elise Bannier ◽

Virginie Callot ◽

Pierre Labauge ◽

...

Keyword(s):

Spinal Cord ◽

Cervical Spinal Cord ◽

Magnetization Transfer ◽

Magnetization Transfer Ratio ◽

Transfer Ratio

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Magnetization Transfer Ratio in Peripheral Nerve Tissue

Investigative Radiology ◽

10.1097/rli.0000000000000455 ◽

2018 ◽

Vol 53 (7) ◽

pp. 397-402 ◽

Cited By ~ 10

Author(s):

Jennifer Kollmer ◽

Thorsten Kästel ◽

Johann M.E. Jende ◽

Martin Bendszus ◽

Sabine Heiland

Keyword(s):

Peripheral Nerve ◽

Magnetization Transfer ◽

Nerve Tissue ◽

Magnetization Transfer Ratio ◽

Transfer Ratio

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Multiparametric MRI detects longitudinal evolution of folic acid-induced nephropathy in mice

AJP Renal Physiology ◽

10.1152/ajprenal.00128.2018 ◽

2018 ◽

Vol 315 (5) ◽

pp. F1252-F1260 ◽

Cited By ~ 5

Author(s):

Kai Jiang ◽

Tristan A. Ponzo ◽

Hui Tang ◽

Prasanna K. Mishra ◽

Slobodan I. Macura ◽

...

Keyword(s):

Folic Acid ◽

Interstitial Fibrosis ◽

Magnetization Transfer ◽

Kidney Injury ◽

Multiparametric Mri ◽

Magnetization Transfer Ratio ◽

Kidney Volume ◽

Kidney Size ◽

Functional Changes

The rodent model of folic acid (FA)-induced acute kidney injury (AKI) provides a useful model for studying human AKI, but little is known about longitudinal changes in renal hemodynamics and evolution of renal fibrosis in vivo. In this work, we aimed to longitudinally assess renal structural and functional changes using multiparametric magnetic resonance imaging (MRI). Ten adult mice were injected with FA, after which a multiparametric MRI was used to measure kidney volume, hypoxia index R2*, magnetization transfer ratio (MTR), perfusion, T1, and glomerular filtration rate (GFR) at 2 wk posttreatment. Then five mice were euthanized for histology, and the other five underwent MRI again at 4 wk, followed by histology. Control mice ( n = 5) were injected with vehicle and studied with MRI at 2 wk. Trichrome and hematoxylin-eosin staining were performed to assess FA-induced tissue injuries. Whereas kidney size and oxygenation showed progressive deterioration, a transient impairment in renal perfusion and normalized GFR slightly improved by 4 wk. Kidney fluid content, as reflected by T1, was prominent at 2 wk and tended to regress at 4 wk, consistent with observed tubular dilation. Trichrome staining revealed patchy necrosis and mild interstitial fibrosis at 2 wk, which exacerbated at 4 wk. MTR detected increased fibrosis at 4 wk. In conclusion, multiparametric MRI captured the longitudinal progression in kidney damage evolving within the first month after treatment with folic acid and may provide a useful tool for assessment of therapeutic strategies.

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