Discrimination between leucine-rich glioma-inactivated 1 antibody encephalitis and gamma-aminobutyric acid B receptor antibody encephalitis based on ResNet18

This study aims to discriminate between leucine-rich glioma-inactivated 1(LGI1)antibody encephalitis and gammaaminobutyric acid B(GABAB)receptor antibody encephalitis using a convolutional neural network(CNN)model.A total of 81 patients were recruited for this study.ResNet18,VGG16,and ResNet50 were trained and tested separately using 3828 positron emission tomography image slices that contained the medial temporal lobe(MTL)or basal ganglia(BG).Leave-one-out cross-validation at the patient level was used to evaluate the CNN models.The receiver operating characteristic(ROC)curve and the area under the ROC curve(AUC)were generated to evaluate the CNN models.Based on the prediction results at slice level,a decision strategy was employed to evaluate the CNN models’performance at patient level.The ResNet18 model achieved the best performance at the slice(AUC=0.86,accuracy=80.28%)and patient levels(AUC=0.98,accuracy=96.30%).Specifically,at the slice level,73.28%(1445/1972)of image slices with GABAB receptor antibody encephalitis and 87.72%(1628/1856)of image slices with LGI1 antibody encephalitis were accurately detected.At the patient level,94.12%(16/17)of patients with GABAB receptor antibody encephalitis and 96.88%(62/64)of patients with LGI1 antibody encephalitis were accurately detected.Heatmaps of the image slices extracted using gradient-weighted class activation mapping indicated that the model focused on the MTL and BG for classification.In general,the ResNet18 model is a potential approach for discriminating between LGI1 and GABAB receptor antibody encephalitis.Metabolism in the MTL and BG is important for discriminating between these two encephalitis subtypes.

Leucine-rich glioma-inactivated protein 1 antibody-mediated autoimmune encephalitis in a 4-year-old girl:a case report

Background:Leucine-rich glioma-inactivated protein 1(LGI1)antibody-mediated encephalitis is a rare subtype of autoimmune encephalopathy,which is associated with autoimmunity against the neuronal plasma membrane proteins.The characteristic symptoms of this disease are memory dysfunction,seizures,faciobrachial dystonic seizures,cognitive deficits,neuropsychiatric disturbances,and intractable hyponatremia.The diagnosis of this disease mainly depends on the presence of anti-LGI1 antibody in serum or cerebrospinal fluid of patients.LGI1 antibody encephalitis has been reported mostly in adults,with rare occurrences in children.Case presentation:In this report,we described a 4-year-old girl with typical seizures.Seizure types included focal seizures and generalized tonic-clonic seizures.The electroencephalogram findings showed focal discharges.Brain magnetic resonance imaging(MRI)showed normal.The cerebrospinal fluid(CSF)levels of cells,glucose,and chloride were within the normal range,and the culture did not reveal growth of any pathogen.Test of serum LGI1-Ab was positive,while the tests for autoimmune encephalitis antibody series in CSF were negative.The seizures of the patient were completely controlled after the therapy of immunoglobulin,methylprednisolone and antiepileptic drugs(AEDs),and the mental state almost returned to normal.Conclusion:To our knowledge,the patient described here may be the youngest case of LGI1 antibody encephalitis reported to date.Children with the LGI1 antibody-associated encephalitis may present only with single symptoms such as epileptic seizures and have good response to the therapy of immunoglobulin,methylprednisolone and antiepileptic drugs.Our case report will provide hints for pediatricians in the diagnosis and treatment of LGI1-antibody encephalitis.