Serial Cerebral Blood Flow Changes in AMPAR Encephalitis Presenting with Left Hemiplegia and Nonfluent Aphasia

A 69-year-old man initially developed cognitive impairment followed by nonfluent aphasia and left hemiparesis five months later. Initial N-isopropyl-p-[¹²³I] iodoamphetamine (¹²³I-IMP) single-photon emission computed tomography (SPECT) revealed increased regional cerebral blood flow (rCBF) in a broad area of the right cerebral cortex, including the central sulcus, as well as in the left frontal lobe. Follow-up SPECT demonstrated a decreased rCBF in the right hemisphere. The patient was diagnosed with anti-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) encephalitis. In this case, disease progression was monitored using ¹²³I-IMP SPECT, suggesting that rCBF alterations in AMPAR encephalitis may provide insight into the underlying pathophysiology.