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The normal appearing grey matter in primary progressive multiple sclerosis: a magnetisation transfer imaging study
J Dehmeshki1, D T Chard, S M Leary
1Medicsight plc, 46 Berkley Square, London W1J 5AT, UK.
Journal of Neurology
|January 16, 2003
Summary
Primary progressive multiple sclerosis (PPMS) patients show reduced magnetization transfer ratio (MTR) in normal appearing grey matter (NAGM). NAGM MTR significantly correlates with disability, suggesting grey matter abnormalities in PPMS.
Area of Science:
- Neuroimaging
- Neurology
- Radiology
Background:
- Primary progressive multiple sclerosis (PPMS) accounts for 10-15% of MS cases, characterized by slow disability progression without relapses.
- The underlying mechanisms of disability progression in PPMS remain poorly understood.
- Magnetization transfer ratio (MTR) imaging is utilized to investigate tissue integrity in normal appearing white matter (NAWM) and normal appearing grey matter (NAGM).
Purpose of the Study:
- To investigate MTR measures in NAWM and NAGM in patients with PPMS.
- To explore the relationship between MTR measures in different brain tissues and clinical disability in PPMS.
- To identify potential imaging biomarkers for disability progression in PPMS.
Main Methods:
- Thirty patients with PPMS and 30 age-matched controls underwent MTR imaging.
- Brain segmentation into NAWM and NAGM was performed using SPM99, with lesions segmented via a semi-automated local thresholding technique.
- Six MTR parameters were measured from normalized histograms, alongside mean lesion MTR and T2 lesion volume. Disability was assessed using the Kurtzke Expanded Disability Status Scale (EDSS).
Main Results:
- PPMS patients showed significantly reduced mean MTR in both NAWM (p=0.001) and NAGM (p=0.004) compared to controls.
- EDSS scores significantly correlated with mean NAGM MTR (r=-0.41, p=0.02), 25th percentile of NAGM MTR (r=-0.37, p=0.05), and T2 lesion volume (r=0.39, p=0.04).
- Multiple regression analysis confirmed that the association between EDSS and mean NAGM MTR remained significant, even when controlling for other MR parameters.
Conclusions:
- Significant abnormalities are present in the normal appearing grey matter (NAGM) of patients with PPMS.
- Grey matter integrity, as measured by MTR, is associated with disability levels in PPMS.
- Further research into the pathological basis and functional significance of grey matter abnormalities in PPMS is warranted.