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Updated: May 16, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Microstructural white matter alterations and cognitive impairment in anti-NMDAR encephalitis: evidence from T1w/T2w
Jinyu Tao1, Shuang Ding2, Yayun Xiang1
1Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Objective:
Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis often causes cognitive impairment, yet conventional MRI lacks sensitivity to detect related microstructural changes. This study aimed to investigate T1-weighted/T2-weighted (T1w/T2w) ratios alterations in normal-appearing white matter (NAWM) and their relationship with cognitive function in patients with anti-NMDAR encephalitis, including a 12-month longitudinal follow-up.
Methods:
Fifty-nine patients with anti-NMDAR encephalitis (31 with mild cognitive impairment (MCI), 28 with no cognitive impairment (NCI)) and 34 healthy controls (HCs) underwent 3.0T whole-brain MRI and comprehensive neuropsychological assessments, including the Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), and domain-specific tests for attention-executive function, memory, and visuospatial reasoning. T1w/T2w ratios were calculated for globel NAWM and multiple major white matter (WM) tracts. Eighteen MCI patients were followed longitudinally for 12 months to evaluate changes in T1w/T2w ratios and cognitive performance over time.
Results:
Compared with NCI patients and HCs, MCI patients exhibited significantly reduced T1w/T2w ratios in global NAWM (P < 0.001) and multiple WM tracts, including the corpus callosum, fornix, left hippocampal cingulum, and right hippocampal cingulum (all P < 0.05). Lower ratios were significantly associated with worse global cognition (r = 0.364, P = 0.023), memory (r = 0.336, P = 0.023), and visuospatial reasoning performance (r = 0.397, P = 0.005). In the 18 MCI patients with 12-month follow-up, increased T1w/T2w ratios in the fornix and hippocampal cingulum (both P = 0.009) were accompanied by significant improvements in visuospatial reasoning and memory functions.
Conclusion:
T1w/T2w ratios derived from routine MRI provide a sensitive, clinically feasible biomarker for detecting NAWM microstructural damage in anti-NMDAR encephalitis. Longitudinal changes in these ratios may parallel cognitive improvement, and these preliminary findings support further investigation of this metric as an imaging biomarker, independent cohorts.
Insights
Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis patients with cognitive impairment show reduced T1w/T2w ratios in white matter. These ratios may serve as imaging biomarkers, potentially improving with cognitive recovery over time.
Area of Science:
- Neuroscience
- Radiology
- Immunology
Background:
- Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis frequently leads to cognitive deficits.
- Conventional MRI often fails to detect subtle microstructural changes in the brain associated with anti-NMDAR encephalitis.
- Investigating imaging markers in normal-appearing white matter (NAWM) is crucial for understanding disease progression and recovery.
Purpose of the Study:
- To explore alterations in T1-weighted/T2-weighted (T1w/T2w) ratios within NAWM in patients with anti-NMDAR encephalitis.
- To assess the relationship between these T1w/T2w ratio changes and cognitive function.
- To conduct a 12-month longitudinal follow-up to observe changes over time.
Main Methods:
- Fifty-nine anti-NMDAR encephalitis patients (31 with mild cognitive impairment (MCI), 28 without cognitive impairment (NCI)) and 34 healthy controls (HCs) underwent 3.0T MRI.
- Comprehensive neuropsychological assessments, including MoCA, MMSE, and domain-specific tests, were performed.
- T1w/T2w ratios were calculated for global NAWM and specific white matter tracts, with longitudinal follow-up for 18 MCI patients.
Main Results:
- MCI patients exhibited significantly lower T1w/T2w ratios in global NAWM and key tracts (corpus callosum, fornix, cingulum) compared to NCI patients and HCs.
- Reduced T1w/T2w ratios correlated with poorer global cognition, memory, and visuospatial reasoning.
- In MCI patients, increased T1w/T2w ratios in the fornix and hippocampal cingulum over 12 months were associated with cognitive improvements.
Conclusions:
- T1w/T2w ratios derived from routine MRI are sensitive biomarkers for detecting NAWM microstructural damage in anti-NMDAR encephalitis.
- Longitudinal changes in T1w/T2w ratios may reflect cognitive recovery.
- These findings support the potential of T1w/T2w ratios as a clinically feasible imaging biomarker for anti-NMDAR encephalitis.
