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Updated: Jan 2, 2026
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Longitudinal evaluation of demyelinated lesions in a multiple sclerosis model using ultrashort echo time
Caroline Guglielmetti1, Tanguy Boucneau2, Peng Cao2
1Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; Bio-Imaging Laboratory, Department of Biomedical Sciences, University of Antwerp, 2000, Antwerp, Belgium.
Abstract:
Alterations in myelin integrity are involved in many neurological disorders and demyelinating diseases, such as multiple sclerosis (MS). Although magnetic resonance imaging (MRI) is the gold standard method to diagnose and monitor MS patients, clinically available MRI protocols show limited specificity for myelin detection, notably in cerebral grey matter areas. Ultrashort echo time (UTE) MRI has shown great promise for direct imaging of lipids and myelin sheaths, and thus holds potential to improve lesion detection. In this study, we used a sequence combining magnetization transfer (MT) with UTE ("UTE-MT", TE = 76 μs) and with short TE ("STE-MT", TE = 3000 μs) to evaluate spatial and temporal changes in brain myelin content in the cuprizone mouse model for MS on a clinical 7 T scanner. During demyelination, UTE-MT ratio (UTE-MTR) and STE-MT ratio (STE-MTR) values were significantly decreased in most white matter and grey matter regions. However, only UTE-MTR detected cortical changes. After remyelination in subcortical and cortical areas, UTE-MTR values remained lower than baseline values, indicating that UTE-MT, but not STE-MT, imaging detected long-lasting changes following a demyelinating event. Next, we evaluated the potential correlations between imaging values and underlying histopathological markers. The strongest correlation was observed between UTE-MTR and percent coverage of myelin basic protein (MBP) immunostaining (r2 = 0.71). A significant, although lower, correlation was observed between STE-MTR and MBP (r2 = 0.48), and no correlation was found between UTE-MTR or STE-MTR and gliosis immunostaining. Interestingly, correlations varied across brain substructures. Altogether, our results demonstrate that UTE-MTR values significantly correlate with myelin content as measured by histopathology, not only in white matter, but also in subcortical and cortical grey matter regions in the cuprizone mouse model for MS. Readily implemented on a clinical 7 T system, this approach thus holds great potential for detecting demyelinating/remyelinating events in both white and grey matter areas in humans. When applied to patients with neurological disorders, including MS patient populations, UTE-MT methods may improve the non-invasive longitudinal monitoring of brain lesions, not only during disease progression but also in response to next generation remyelinating therapies.
Insights
Ultrashort echo time magnetization transfer (UTE-MT) MRI effectively detects myelin changes in grey and white matter, correlating with histopathology. This advanced MRI technique shows promise for monitoring neurological disorders like multiple sclerosis (MS).
Area of Science:
- Neuroimaging
- Demyelinating Diseases
- Magnetic Resonance Imaging (MRI)
Background:
- Myelin integrity alterations are central to neurological disorders, including multiple sclerosis (MS).
- Current MRI protocols lack specificity for myelin detection, especially in cerebral grey matter.
- Ultrashort echo time (UTE) MRI offers potential for direct myelin imaging and improved lesion detection.
Purpose of the Study:
- To evaluate spatial and temporal changes in brain myelin content using UTE-MT and STE-MT sequences.
- To assess the correlation between UTE-MT/STE-MT imaging values and histopathological myelin markers.
- To determine the potential of UTE-MT for detecting demyelination and remyelination in grey and white matter.
Main Methods:
- Utilized a combined magnetization transfer (MT) with UTE (UTE-MT) and short TE (STE-MT) sequence on a 7T clinical scanner.
- Applied the method to the cuprizone mouse model, a standard model for MS-induced demyelination.
- Correlated imaging metrics (UTE-MTR, STE-MTR) with myelin basic protein (MBP) and gliosis immunostaining.
Main Results:
- Both UTE-MT ratio (UTE-MTR) and STE-MT ratio (STE-MTR) decreased during demyelination, with UTE-MTR detecting cortical changes.
- UTE-MTR revealed persistent myelin deficits post-remyelination, unlike STE-MTR, indicating long-lasting changes.
- UTE-MTR showed a strong correlation (r²=0.71) with MBP immunostaining, confirming its sensitivity to myelin content in grey and white matter.
Conclusions:
- UTE-MT imaging accurately reflects myelin content in both white and grey matter, outperforming STE-MT in detecting lasting demyelination.
- This readily implementable 7T MRI technique holds significant potential for diagnosing and monitoring MS and other neurological disorders.
- UTE-MT offers improved non-invasive longitudinal monitoring of brain lesions and response to therapies in patient populations.
