Acute cerebral blood flow and its connectivity in patients with anti-LGI1 encephalitis: an arterial spin labeling study

Abstract

Purpose Pseudocontinuous arterial spin labeling (PCASL) is an innovative technique for measuring cerebral blood flow (CBF). The aim of this study was to identify diagnostic CBF connectivity in patients with anti-leucine-rich glioma inactivated 1 autoimmune encephalitis (anti-LGI1 AE) . Methods A total of 46 patients with anti-LGI1 AE including 27 patients with CBF during the acute stage were recruited from May 2017 to Jan 2023. The CBF in 27 patients with anti-LGI1 AE during the acute stage and 65 healthy subjects was analyzed using arterial spin labeling. Regions with CBF alterations were identified and designated as regions of interest (ROIs). Subsequently, the CBF connectivity of the ROIs was also compared between the groups. Result Patients in the acute stage of disease exhibited increased CBF in the bilateral putamen, bilateral amygdala (Amygdala_Bi), bilateral hippocampus (Hippocampus_Bi), bilateral parahippocampus and right insula (Insula_R) (P=0.001, cluster-level familywise error [FWE] corrected). Decreased CBF connectivity was observed between the right hippocampus and the right superior temporal gyrus (STG_R), right rolandic operculum (RO_R), right caudate (Caudate_R), right superior temporal pole (STP_R), right middle cingulate gyrus (MCG_R), and right anterior cingulate gyrus; between the right amygdala and the STG_R, RO_R, STP_R, right putamen, Caudate_R, MCG_R, and right supplementary motor area; and between the Insula_R and the right middle temporal gyrus (MTG_R) and STG_R (P=0.001, cluster-level FWE corrected). Furthermore, the patients also showed decreased CBF connectivity between the right parahippocampus and the STP_R, RO_R, Insula_R, MCG_R and left MTG; between the left hippocampus and the left STG, and left insula; and between the left parahippocampus and the left lingual gyrus, and left precuneus. Increased CBF connectivity was observed between Amygdala_Bi and Hippocampus_Bi (P=0.001, cluster-level FWE corrected). Conclusion The PCASL technique demonstrated high sensitivity in identifying anti-LGI1 AE patients, who in which patients exhibited decreased CBF connectivity originating from subcortical regions with increased CBF.