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Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Peak width of skeletonized mean diffusivity (PSMD) and cognitive functions in relapsing-remitting multiple sclerosis
C Vinciguerra1, A Giorgio1, J Zhang1
1Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.
Abstract:
Peak width of skeletonized mean diffusivity (PSMD) is a new MRI marker, which has shown clinical relevance in some neurological conditions and, in preliminary data, in multiple sclerosis (MS). We aimed here to investigate, in a group of relapsing-remitting MS (RRMS) patients, the relationship between PSMD and cognitive performances, in comparison with other MRI measures. RRMS patients (n = 60) and normal controls (n = 15) underwent a 3 T MRI examination. MRI-based white matter (WM) lesion volume, microstructural integrity (assessed with Tract-Based Spatial Statistics of diffusion tensor imaging [DTI] images) and brain volumes (i.e., total brain, grey matter [GM] and WM) were computed. In addition, PSMD was calculated through "skeletonization" of WM tracts and diffusion histograms. Cognition was evaluated with Rao's Brief Repeatable Battery (BRB), which incorporated tests of verbal and visual memory, attention, concentration, information processing speed and verbal fluency. PSMD closely correlated with symbol digit modalities test (SDMT) (r = -0.70, p < 0.001) and, to a lesser extent, with verbal and visual memory tests. Multiple regression analysis showed that PSMD explained SDMT variance (R2 = 0.54, p < 0.001) more than other MRI measures. Results point out the relevance of microstructural damage, as assessed by PSMD, as a reliable marker of cognition in MS, especially in explaining dysfunction in information processing speed.
Insights
Peak width of skeletonized mean diffusivity (PSMD) is a novel MRI marker that accurately reflects cognitive function in relapsing-remitting multiple sclerosis (RRMS). PSMD is a superior predictor of information processing speed deficits compared to other MRI metrics.
Area of Science:
- Neuroimaging
- Neurology
- Cognitive Science
Background:
- Multiple Sclerosis (MS) is a demyelinating disease affecting the central nervous system.
- Cognitive impairment is a significant issue in MS patients, impacting quality of life.
- Existing MRI markers have limitations in fully capturing the extent of neurological damage and its cognitive correlates.
Purpose of the Study:
- To investigate the relationship between Peak Width of Skeletonized Mean Diffusivity (PSMD), a novel MRI marker, and cognitive performance in relapsing-remitting MS (RRMS) patients.
- To compare the efficacy of PSMD against other established MRI measures in explaining cognitive deficits.
- To assess the utility of PSMD as a reliable biomarker for cognitive dysfunction in MS.
Main Methods:
- Sixty RRMS patients and fifteen healthy controls underwent 3T MRI scans.
- MRI analysis included white matter (WM) lesion volume, diffusion tensor imaging (DTI) for microstructural integrity using Tract-Based Spatial Statistics, and brain volume measurements.
- PSMD was calculated via skeletonization of WM tracts and diffusion histograms. Cognitive function was assessed using Rao's Brief Repeatable Battery (BRB).
Main Results:
- PSMD showed a strong negative correlation with the Symbol Digit Modalities Test (SDMT) (r = -0.70, p < 0.001) and moderate correlations with verbal and visual memory tests.
- Multiple regression analysis revealed that PSMD significantly explained variance in SDMT performance (R² = 0.54, p < 0.001), outperforming other MRI measures.
- The findings highlight PSMD's sensitivity to microstructural damage impacting cognitive functions, particularly information processing speed.
Conclusions:
- PSMD is a relevant and sensitive MRI marker for assessing microstructural damage in MS.
- PSMD demonstrates significant clinical relevance by reliably reflecting cognitive impairments, especially in information processing speed, in RRMS patients.
- This study supports PSMD as a valuable tool for monitoring disease progression and cognitive status in MS.
