MR Relaxation in Multiple Sclerosis

MacKay, Alexander L.; Vavasour, Irene M.; Rauscher, Alexander; Kolind, Shannon; Mädler, Burkhard; Moore, George R.; Traboulsee, Anthony; Li, D.K.B.; Laule, Cornelia

doi:10.1016/j.nic.2008.09.007

Cited by 86 publications

(82 citation statements)

References 196 publications

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“…Our observations are in overall agreement with sensitivity of MT ratio and R1 to pathologic changes in normal-appearing brain tissues found in earlier studies (1,28,35), and relatively weak (if significant) correlations with disability (36-38) and limited distinctions between patients and controls (38,39). Notably, correlations between these variables and MPF show different patterns within specific brain tissues.…”

Section: Discussionsupporting

confidence: 92%

Fast Whole-Brain Three-dimensional Macromolecular Proton Fraction Mapping in Multiple Sclerosis

Yarnykh¹,

Bowen²,

Samsonov³

et al. 2015

Radiology

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).q RSNA, 2014 Purpose:To evaluate the clinical utility of fast whole-brain macromolecular proton fraction (MPF) mapping in multiple sclerosis (MS) and compare MPF with established quantitative magnetic resonance (MR) imaging measures of tissue damage including magnetization transfer (MT) ratio and relaxation rate (R1). Materials and Methods:In this institutional review board-approved and HIPAAcompliant study, 14 healthy control participants, 18 relapsing-remitting MS (RRMS) patients, and 12 secondary progressive MS (SPMS) patients provided written informed consent and underwent 3-T MR imaging. Threedimensional MPF maps were reconstructed from MTweighted images and R1 maps by the single-point method.Mean MPF, R1, and MT ratio in normal-appearing white matter (WM), gray matter (GM), and lesions were compared between subject groups by using analysis of variance. Results:RRMS patients had lower WM and GM MPF than controls, with percentage decreases of 6.5% (P , .005) and 5.4% (P , .05). MPF in SPMS was reduced relative to RRMS in WM, GM, and lesions by 6.4% (P , .005), 13.4% (P , .005), and 11.7% (P , .05), respectively. EDSS and MSFC demonstrated strongest correlations with MPF in GM (r = 20.74 and 0.81; P , .001) followed by WM (r = 20.57 and 0.72; P , .01) and lesions (r = 20.42 and 0.50; P , .05). R1 and MT ratio in all tissues were significantly less correlated with clinical scores than GM MPF (P , .05). Conclusion:MPF mapping enables quantitative assessment of demyelination in normal-appearing brain tissues and shows primary clinical relevance of GM damage in MS. MPF outperforms MT ratio and R1 in detection of MS-related tissue changes.q RSNA, 2014

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Section: Discussionsupporting

confidence: 92%

Fast Whole-Brain Three-dimensional Macromolecular Proton Fraction Mapping in Multiple Sclerosis

Yarnykh¹,

Bowen²,

Samsonov³

et al. 2015

Radiology

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“…MCR is a well established technique that has been used to investigate myelin content changes in demyelinating disorders such as MS (MacKay et al, 2009). Studies have shown strong correlation between derived MWF and histological estimates of myelin content (Webb et al, 2003;Stanisz et al, 2004, Laule et al, 2006, with insensitivity to inflammation and edema (Gareau et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

Mapping Infant Brain Myelination with Magnetic Resonance Imaging

Deoni¹,

Mercure²,

Blasi³

et al. 2011

J. Neurosci.

437

351

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Myelination, the elaboration of myelin surrounding neuronal axons, is essential for normal brain function. The development of the myelin sheath enables rapid synchronized communication across the neural systems responsible for higher order cognitive functioning. Despite this critical role, quantitative visualization of myelination in vivo is not possible with current neuroimaging techniques including diffusion tensor and structural magnetic resonance imaging (MRI). Although these techniques offer insight into structural maturation, they reflect several different facets of development, e.g., changes in axonal size, density, coherence, and membrane structure; lipid, protein, and macromolecule content; and water compartmentalization. Consequently, observed signal changes are ambiguous, hindering meaningful inferences between imaging findings and metrics of learning, behavior or cognition. Here we present the first quantitative study of myelination in healthy human infants, from 3 to 11 months of age. Using a new myelin-specific MRI technique, we report a spatiotemporal pattern beginning in the cerebellum, pons, and internal capsule; proceeding caudocranially from the splenium of the corpus callosum and optic radiations (at 3-4 months); to the occipital and parietal lobes (at 4 -6 months); and then to the genu of the corpus callosum and frontal and temporal lobes (at 6 -8 months). Our results also offer preliminary evidence of hemispheric myelination rate differences. This work represents a significant step forward in our ability to appreciate the fundamental process of myelination, and provides the first ever in vivo visualization of myelin maturation in healthy human infancy.

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“…In MS, T1 has been shown to be increased in different pathologic processes, most prominently axonal damage but also edema, demyelination, and gliosis. 4,[11][12][13][14][15][16] MTR mapping produces voxelwise maps of the relative amount of signal-intensity decrease that results from adding a magnetization-preparation prepulse to a pulse sequence. The MTR is a semiquantitative measure that is ultimately determined by more fundamental parameters such as the fraction of bound pool protons, the magnetization exchange rate between bound and free protons, and the relaxation rates.…”

Section: Quantitative Mr Imaging Techniquesmentioning

confidence: 99%