Cortical atrophy in early-stage patients with anti-NMDA receptor encephalitis: a machine-learning MRI study with

Sisi Shen1, Ran Wei2, Yu Gao2

  • 1Department of Neurology, West China Hospital of Sichuan University, 37 GuoXue Alley, Chengdu 610041, China.

Insights

Machine learning models applied to brain MRI radiomics can identify anti-N-methyl-D-aspartate-receptor encephalitis (NMDARE) in patients with normal imaging. This approach reveals cortical atrophy and aids in diagnosing NMDARE, even when MRI is initially negative.

Area of Science:

  • Neuroimaging
  • Artificial Intelligence in Medicine
  • Neurology

Background:

  • Conventional brain MRI for anti-N-methyl-D-aspartate-receptor encephalitis (NMDARE) lacks specificity, posing diagnostic challenges, particularly in MRI-negative cases.
  • Identifying reliable imaging biomarkers is crucial for early and accurate diagnosis of NMDARE, especially when standard MRI findings are absent.

Purpose of the Study:

  • To develop and validate machine learning models using radiomics features from brain MRI to differentiate NMDARE patients from healthy controls (HC) and viral encephalitis (VE) cases.
  • To characterize structural alterations in MRI-negative NMDARE patients and assess the diagnostic potential of radiomics-based models.

Main Methods:

  • Support vector machine (SVM) models were trained and validated using radiomics features extracted from brain MRI scans of NMDARE patients, HCs, and VE patients.
  • The study included 109 NMDARE, 108 HC, and 84 VE cases for training, and 29 NMDARE, 28 HC, and 26 VE cases for validation.
  • Eighty radiomics features were identified that distinguished NMDARE from HCs, and the NMDARE versus VE model was also evaluated.

Main Results:

  • The NMDARE versus HC model achieved a high diagnostic performance with an area under the receiver operating characteristic curve (AUC) of 0.963 in the validation set.
  • NMDARE patients exhibited significantly reduced cortical thickness, area, and volume, along with increased mean curvature compared to HCs, predominantly in the frontal and temporal lobes.
  • The NMDARE versus VE model demonstrated diagnostic utility with an AUC of 0.879 in the validation set.

Conclusions:

  • Radiomics analysis of brain MRI can detect subtle structural changes, such as widespread cortical atrophy, in acute NMDARE patients, even with initially normal MRI.
  • Machine learning models utilizing radiomics features show significant potential to improve the diagnostic accuracy for MRI-negative NMDARE, aiding differential diagnosis from other encephalitides.

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