Assessment and characterization of BBB permeability parameters in autoimmune encephalitis based on 99mTc-DTPA SPECT/CT

The study focuses on understanding the disruption of the blood-brain barrier (BBB) in autoimmune encephalitis (AIE) using 99mTc-DTPA Single-photon emission computed tomography/computed tomography (SPECT/CT) and the associations between BBB permeability and clinical parameters. Forty-five AIE patients and 24 healthy controls (HCs) were studied. All underwent 99mTc-DTPA SPECT/CT for BBB imaging. Statistical methods (Mann-Whitney U, t-tests, Chi-square, Fisher’s exact test) were used to compare quantitative and categorical variables. Correlations were analyzed using Pearson or Spearman correlation analysis. Abnormal BBB permeability was assessed with Statistical Parametric Mapping (SPM). Multiple correspondence analysis (MCA) and hierarchical clustering were used to identify AIE subgroups. AIE patients had higher Bave (average relative counts values of the entire brain region) and Bmax (maximum relative counts values of the entire brain region) than HCs (p = 0.000; p = 0.001, respectively). Bave and Bmax correlated with modified Rankin Scale (mRS) scores in AIE patients (r = 0.83, p < 0.001; r = 0.54, p < 0.001). Patients in cluster 1 had a high frequency of movement disorder than those in cluster 2 (p = 0.004), whereas patients in cluster 2 had a higher frequency of psychosis than those in cluster 1 (p < 0.001). The median values of both Bave and Bmax after treatment in the poor prognosis group were higher than those in the good prognosis group (p = 0.0007; p = 0.0333). BBB permeability, measured by 99mTc-DTPA SPECT/CT, was elevated in AIE patients and correlated with disease severity and prognosis.