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Mean diffusivity and fractional anisotropy histograms of patients with multiple sclerosis
M Cercignani1, M Inglese, E Pagani
1Neuroimaging Research Unit, Department of Neuroscience, Scientific Institute Ospedale San Raffaele and University Milan, Via Olgettina, 60, 20132 Milan, Italy.
Background And Purpose:
Compared with conventional T2-weighted MR imaging, diffusion tensor MR imaging provides quantitative indices with increased specificity to the most destructive aspects of multiple sclerosis. In this study, we obtained brain mean diffusivity (_D) and fractional anisotropy histograms of patients with multiple sclerosis to compare them with those of healthy volunteers and to investigate the correlation between diffusion tensor MR imaging histogram-derived measures and the level of disability and quantities derived from conventional MR imaging.
Methods:
Dual-echo and diffusion tensor MR images were obtained from 78 patients with relapsing-remitting, secondary progressive, or primary progressive multiple sclerosis and from 20 healthy control volunteers. After obtaining mean diffusivity (_D) and fractional anisotropy images and image coregistration, _D and fractional anisotropy histograms were created. From each histogram, the following measures were derived: the average _D and fractional anisotropy, the histogram peak heights, and the histogram peak locations.
Results:
All the _D and fractional anisotropy histogram-derived measures were different between patients and controls at a significance level of P <.001. No differences were found in any of the considered quantities among the three multiple sclerosis phenotypes. In patients with relapsing-remitting multiple sclerosis, disability was correlated with histogram average_D (r = 0.4, P =.01) and peak height (r = -0.4, P =.01). In patients with secondary progressive multiple sclerosis, disability was correlated with fractional anisotropy histogram peak position (r = -0.6, P =.01). Significant correlations were also found between T2 lesion load and various diffusion tensor MR quantities.
Conclusion:
This study shows that brain _D and fractional anisotropy histograms are different for patients with multiple sclerosis compared with control volunteers. This study also shows that quantities derived from diffusion tensor MR imaging are correlated with disability in patients with relapsing-remitting multiple sclerosis and secondary progressive multiple sclerosis, suggesting that they might serve as additional measures of outcome when monitoring multiple sclerosis evolution in these patients.
Insights
Diffusion tensor MR imaging reveals distinct brain diffusion and anisotropy histograms in multiple sclerosis patients compared to controls. These quantitative MRI measures correlate with disability, aiding in monitoring disease progression.
Area of Science:
- Neuroimaging
- Quantitative MRI
- Multiple Sclerosis Research
Background:
- Multiple sclerosis (MS) involves destructive neurological changes.
- Conventional MRI has limitations in quantifying MS pathology.
- Diffusion tensor MR imaging (DTMRI) offers quantitative insights into tissue microstructure.
Purpose of the Study:
- To compare brain mean diffusivity (D) and fractional anisotropy (FA) histograms between MS patients and healthy controls.
- To investigate correlations between DTMRI histogram measures and disability levels in MS.
- To explore relationships between DTMRI metrics and conventional MRI findings.
Main Methods:
- DTMRI and conventional MR images acquired from 78 MS patients and 20 controls.
- Generation of D and FA histograms from coregistered DTMRI data.
- Derivation of histogram measures including average D, FA, peak heights, and peak locations.
Main Results:
- Significant differences in D and FA histogram measures between MS patients and controls (P <.001).
- No significant differences in histogram measures across different MS phenotypes.
- Disability correlated with D and FA histogram parameters in relapsing-remitting and secondary progressive MS.
- Correlations observed between T2 lesion load and DTMRI-derived quantities.
Conclusions:
- Brain D and FA histograms effectively differentiate MS patients from healthy individuals.
- DTMRI-derived histogram measures show potential as biomarkers for disability in MS.
- These quantitative DTMRI metrics may enhance monitoring of MS evolution and patient outcomes.