Tract-specific quantitative MRI better correlates with disability than conventional MRI in multiple sclerosis

Area of Science:

• Neuroimaging
• Biomarker Discovery
• Multiple Sclerosis Research

Background:

• Conventional MRI measures like lesion volume and cerebral volume fraction (CVF) are standard in multiple sclerosis (MS) assessment.
• The utility of advanced MRI techniques, such as diffusion tensor imaging (DTI) and magnetization transfer ratio (MTR), as biomarkers for MS-related disability remains under investigation.
• Comparing DTI and MTR with conventional MRI is crucial for identifying more sensitive markers of disease progression and disability.

Purpose of the Study:

• To evaluate whether diffusion tensor imaging (DTI) and magnetization transfer ratio (MTR) are more effective biomarkers of disability in multiple sclerosis (MS) than conventional MRI measures.
• To assess the correlation of DTI and MTR values with measures of brain atrophy and lesion volume.
• To compare the predictive power of DTI and MTR with conventional MRI indices for disability outcomes.

Main Methods:

• MRI scans were acquired from 117 participants with MS and 26 healthy volunteers.
• Mean values for DTI indices and MTR were calculated for the supratentorial brain and three specific white matter tracts.
• Nested model regression analysis was used to compare the correlations of DTI, MTR, lesion volume, and cerebral volume fraction (CVF) with clinical disability measures.

Main Results:

• DTI and MTR values showed equivalent correlations with lesion volume and cerebral volume fraction (CVF).
• Thalamic volumes correlated with DTI indices in the optic radiations and corpus callosum.
• DTI indices in the optic radiations demonstrated stronger correlations with the Expanded Disability Status Scale and low-contrast visual acuity compared to CVF and lesion volume.

Conclusions:

• Abnormalities in DTI and MTR are equally associated with brain atrophy and inflammatory lesion burden in MS, indicating they reflect diverse aspects of MS pathology.
• Specific DTI and MTR indices show a stronger association with patient disability than conventional MRI measures.
• These findings support the potential use of DTI and MTR as targeted, system-specific clinical trial outcome measures in MS research.