Brain MRI volumetric changes in the follow-up of patients with anti-NMDAr encephalitis
Introduction
Autoimmune anti NMDAr (N-methyl-D-aspartate receptor) encephalitis is an antibody-mediated disorder characterized by psychiatric symptoms followed by disturbances in the level of consciousness, dysautonomia, hypoventilation and epileptic seizures [1]. The pathophysiology of the disease is directly related to the internalization of the NMDA receptors of the NR1 [2] subtype and the dysfunction of the structures where they are abundant (frontotemporal and insular regions) [3], [4], [5]. The prognosis of the disease is usually good [6], with substantial recovery in the majority of patients - particularly in those who receive early immunotherapy [7]- but with about 20% presenting severe disability [8]. The estimated mortality of the disease is 7% and is related to the severity of the manifestations and associated hospital complications [9].
The objective measurement of changes in brain volume requires a longitudinal study of the patient. Brain volume loss is an unfortunate outcome in several central nervous system conditions [10], [11]. In autoimmune CNS diseases, the evidence shows that loss of brain volume is irreversible [10]. However, some exploratory studies in antiNMDAr encephalitis have demonstrated degrees of reversibility that suggest its association with a better prognosis in patients and could function as a monitoring tool for response to treatment [12].
3D MRI sequences represent a quantitative technique based on tissue segmentation according to the contrast (the difference between signal and noise) of the structures. The utility of quantitative MRI (3D) is that it allows non-invasive identification of cerebral volume loss in different diseases and the objective evaluation of these changes over time [13]. Different automated and validated software allows this analysis, highlighting VolBRAIN. Due to the main objective of documenting whether there are volumetric changes and emphasizing whether these changes correspond to specific brain areas, Volbrain open-access software was used for the segmentation of structures in the two different studies. Volbrain [14], designed by the University of Bordeaux and the University of Valencia has already demonstrated similar and even superior results to other semi-automatic segmentation programs such as Freesurfer or FIRST [15], [16], [17].
The purpose of this study was to determine if there are significant changes in the brain volume of patients with anti-NMDAr encephalitis, between the initial MRI study, obtained during the acute phase of the disease, as compared to a second MRI study, which was obtained during the clinical follow up.
Section snippets
Design
We conducted a longitudinal and observational study. The Institutional Research Committee revised and approved the protocol (Protocol # 86/19). The research project was approved by the Ethics Committee of the National Institute of Neurology of Mexico, and it conforms to the provisions of the Declaration of Helsinki in 1995 (as revised in Edinburgh 2000). All the diagnostic and therapeutic procedures were considered necessary for the clinical assistance of the patients. MRI studies were acquired
General features of the sample
25 patients that met selection criteria were included. As may be seen in Table 1, 11 patients (44%) were female and 14 (56%) were male, with a mean age of 26.64 years (16–55 years, SD 9.69). The mean hospital stay time was 49.38 days (15–200, SD 40,226).
Clinical features
Regarding the initial clinical manifestation, 11 (44%) patients presented an associated prodromal symptom (flu-like syndrome, gastrointestinal symptoms, headache). The initial clinical manifestations were psychiatric/cognitive in 15 (60%) of the
Discussion
The present study represents a descriptive analysis of the volumetric changes of patients with anti-NMDAr encephalitis in the Mexican population. As has been shown in previous studies in Latin American populations, our study included a higher percentage of males as compared to European and North American studies [19]. We provide evidence of global brain volume loss, as well as volume loss in the cerebellum and brainstem. Considering that most patients are young (mean age 26.6, SD 9.6) it is
CRediT authorship contribution statement
Enrique Gomez-Figueroa: Conception, Data collection, Drafting of article. Christian Garcia-Estrada: Drafting the article. Jorge Salado-Burbano: Editing, Drafting of article. Fernando Cortes-Enriquez: Data re analysis, Interpretation. Oscar Marrufo-Melendez: Data collection. Mariana Espinola-Nadurille: Data analysis, Interpretation. Jesus Ramirez-Bermudez: Critical revision of the article. Veronica Rivas-Alonso: Final approval. Teresita Corona: Final approval. Jose Flores-Rivera: Conception,
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2024, Schizophrenia ResearchCitation Excerpt :In contrast to these results, the study by Dean et al. (2020) did not show a difference in total gray matter volume between SSD patients with and without a history of catatonia (Dean et al., 2020). Two of the three studies that examined brain structure in individuals with anti-NMDA receptor encephalitis showed alterations in signal intensity in a minority of individuals (Kerik-Rotenberg et al., 2020; Nguyen Thi Hoang et al., 2017), while a longitudinal study described a significant volume loss in total brain, cerebellar and brain stem volume at two-year follow-up in patients with anti-NMDA receptor encephalitis, which however did not correlate with the presence of severe clinical manifestations such as catatonia or psychosis (Gomez-Figueroa et al., 2021). The results of the sMRI studies are reported in Fig. 2a.
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