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Diffusion tensor imaging in early relapsing-remitting multiple sclerosis
C M Griffin1, D T Chard, O Ciccarelli
1NMR Research Unit, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, UK.
Abstract:
Diffusion tensor magnetic resonance imaging (DTI) indices are abnormal in patients with established multiple sclerosis (MS). The objective of this study was to examine the diffusion characteristics of MS lesions, normal appearing white matter (NAWM) and normal appearing grey matter (NAGM) in MS patients with early relapsing-remitting disease. A further objective was to investigate the relationship between three DTI parameters (fractional anisotropy (FA), mean diffusivity (MD) and volume ratio (VR)) and clinical outcome measures (Kurtzke expanded disability status scale (EDSS) and MS Functional Composite Measure) in early disease. DTI was performed in 28 patients and 27 controls. Analysis was carried out using a region of interest (ROI) approach. ROIs were placed in 12 NAWM and nine NAGM regions. Significant differences were found in FA, MD and VR between lesions and NAWM (P< 0.001 for all three DTI parameters). No significant differences were found between patients and controls when examining NAWM or NAGM, although there was a trend for abnormal NAWM FA and VR in some regions. No correlation was found between DTI parameters in lesions, NAWM or NAGM and the clinical outcome measures. The lack of significant DTI abnormality in the NAWM and NAGM may reflect a lack of pathological change or a limited sensitivity of DTI using ROI methodology. Previous studies have shown abnormalities in TI relaxation time, magnetisation transfer ratio (MTR) and N-Acetyl aspartate (NM) in this cohort of patients, and as such, DTI using a region of interest (ROI) approach may not be as sensitive as other MR techniques in detecting subtle changes in normal appearing brain
Insights
Diffusion tensor imaging (DTI) showed significant differences in multiple sclerosis (MS) lesions compared to normal-appearing white matter. However, early MS patients did not exhibit significant DTI abnormalities in normal-appearing white or grey matter, nor did DTI correlate with clinical outcomes.
Area of Science:
- Neuroimaging
- Radiology
- Neurology
Background:
- Diffusion tensor imaging (DTI) indices are known to be abnormal in established multiple sclerosis (MS).
- Early relapsing-remitting MS may present subtle changes not yet detectable by standard DTI.
- Understanding diffusion characteristics in early MS is crucial for monitoring disease progression.
Purpose of the Study:
- To examine DTI characteristics in MS lesions, normal-appearing white matter (NAWM), and normal-appearing grey matter (NAGM) in early relapsing-remitting MS.
- To investigate the relationship between DTI parameters (FA, MD, VR) and clinical outcomes (EDSS, MSFC) in early MS.
- To assess the sensitivity of DTI with a region of interest (ROI) approach in early MS.
Main Methods:
- Diffusion tensor imaging (DTI) was performed on 28 early relapsing-remitting MS patients and 27 healthy controls.
- Region of interest (ROI) analysis was applied to 12 NAWM and 9 NAGM regions.
- Key DTI parameters analyzed included fractional anisotropy (FA), mean diffusivity (MD), and volume ratio (VR).
Main Results:
- Significant differences in FA, MD, and VR were found between MS lesions and NAWM (P<0.001).
- No significant DTI differences were observed between MS patients and controls in NAWM or NAGM, despite a trend for abnormal FA and VR in some NAWM regions.
- No correlation was found between DTI parameters (lesions, NAWM, NAGM) and clinical outcome measures (EDSS, MSFC).
Conclusions:
- DTI with ROI methodology may lack sensitivity to detect subtle pathological changes in NAWM and NAGM in early MS.
- Other MRI techniques like MTR or N-Acetyl aspartate may be more sensitive for detecting early microstructural changes in normal-appearing brain tissue.
- Further research with advanced DTI techniques or complementary MRI methods is warranted for early MS assessment.