Active inflammation increases the heterogeneity of MRI texture in mice with relapsing experimental allergic
Yunyan Zhang1, Jennifer Wells2, Richard Buist3
1Department of Radiology, University of Calgary, 2500 University Drive Calgary, Alberta, Canada T2N 1N4; Department of Clinical Neurosciences, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4; Hotchkiss Brain Institute, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4.
Abstract:
Inflammation modulates tissue damage in relapsing-remitting multiple sclerosis (MS) both acutely and chronically, but its severity is difficult to evaluate with conventional MRI analysis. In mice with experimental allergic encephalomyelitis (EAE, a model of MS), we administered ultra small particles of iron oxide to track macrophage-mediated inflammation during the onset (relapse) and recovery (remission) of disease activity using high field MRI. We performed MRI texture analysis, a sensitive measure of tissue regularity, and T2 assessment both in EAE lesions and the control tissue, and measured spinal cord volume. We found that inflammation was 3 times more remarkable at onset than at recovery of EAE in histology yet demyelination appeared similar across animals and disease course. In MRI, lesion texture was more heterogeneous; T2 was lower; and spinal cord volume was greater in EAE than in controls, but only MRI texture was worse at relapse than at remission of EAE. Moreover, MRI texture correlated with spinal cord volume and tended to correlate with the extent of disability in EAE. While subject to further confirmation, our findings may suggest the sensitivity of MRI texture analysis for accessing inflammation.
Insights
MRI texture analysis shows promise for evaluating inflammation in multiple sclerosis (MS) models. This technique detected inflammation differences between relapse and remission stages, unlike conventional MRI methods.
Area of Science:
- Neuroscience
- Radiology
- Immunology
Background:
- Inflammation significantly impacts tissue damage in multiple sclerosis (MS), affecting both acute and chronic phases.
- Conventional MRI analysis faces challenges in accurately quantifying the severity of MS-related inflammation.
- Experimental allergic encephalomyelitis (EAE) in mice serves as a valuable model for studying MS pathology.
Purpose of the Study:
- To investigate the utility of MRI texture analysis in assessing macrophage-mediated inflammation during different disease stages in an EAE mouse model.
- To compare the sensitivity of MRI texture analysis with conventional MRI metrics and histology for inflammation evaluation.
- To explore the correlation between MRI-derived parameters and disease severity in EAE.
Main Methods:
- Administration of ultra-small iron oxide particles to track inflammation in EAE mice using high-field MRI.
- Application of MRI texture analysis and T2 assessment on EAE lesions and control tissues.
- Measurement of spinal cord volume and correlation with MRI findings and clinical disability.
Main Results:
- Histology revealed significantly higher inflammation at EAE onset compared to recovery, though demyelination appeared similar.
- MRI demonstrated more heterogeneous lesion texture, lower T2 values, and increased spinal cord volume in EAE compared to controls.
- Only MRI texture analysis showed significant differences between EAE relapse and remission stages.
- MRI texture analysis correlated with spinal cord volume and showed a trend towards correlating with EAE disability.
Conclusions:
- MRI texture analysis demonstrates potential as a sensitive tool for quantifying inflammation in MS models.
- This technique may offer advantages over conventional MRI methods for assessing inflammatory activity during different disease phases.
- Further validation is warranted to confirm the clinical applicability of MRI texture analysis in multiple sclerosis.
