Brain magnetic resonance imaging predictors in anti‐N‐methyl‐D‐aspartate receptor encephalitis

OBJECTIVE: Brain magnetic resonance imaging (MRI) findings in anti‐N‐methyl‐D‐aspartate receptor (NMDAR) encephalitis are nonspecific and rarely have obvious associations with clinical characteristics and outcomes. This study aimed to comprehensively describe the MRI features of patients with NMDAR encephalitis, examine their associations with clinical characteristics, and evaluate their predictive power for disease recurrence and prognosis. METHODS: We retrospectively extracted the clinical data and brain MRI findings of 144 patients with NMDAR encephalitis. Patients underwent a 2‐year follow‐up to assess disease outcomes. We evaluated the associations of brain MRI findings at the onset with clinical characteristics, recurrence, and prognosis. RESULTS: Initial MRI showed typical abnormalities in 65 patients (45.1%); of these, 34 (29.3%) developed recurrence and 10 (9.4%) had poor prognosis (mRS ≥3). Binary logistic regression analyses revealed that insula abnormalities were associated with acute seizure (odds ratio [OR] = 3.048, 95% confidence interval [CI]: 1.026–9.060) and white matter lesions were associated with cognitive impairment (OR = 2.730, 95% CI: 1.096–6.799). Risk factors for a poor 2‐year prognosis included a higher number of brain MRI abnormalities (OR = 1.573, 95% CI: 1.129–2.192) and intensive care unit (ICU) admissions (OR = 15.312, 95% CI: 1.684–139.198). The risk factors for 2‐year recurrence included abnormalities of the thalamus (HR = 3.780, 95% CI: 1.642–8.699). INTERPRETATIONS: Brain MRI features of patients with NMDAR encephalitis were associated with clinical manifestations, prognosis, and recurrence. Higher numbers of MRI abnormalities and ICU admissions were predictive of poor prognosis. Abnormalities of the thalamus constituted a recurrence‐related risk factor.