Neuroimaging Findings in CHANTER Syndrome: A Case Series

Recently, a distinct clinicoradiologic entity involving cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) on MR imaging was identified. Patients present in an unresponsive state following exposure to drugs of abuse. Very little information exists regarding this entity, particularly in the radiology literature. We identify and describe 3 patients at our institution with similar clinical and radiographic findings. Multifocal restricted diffusion in the brain is typically associated with poor outcomes. By contrast, CHANTER involves intraventricular obstructive hydrocephalus that, when treated, can lead to substantial recovery. This novel syndrome should be on the differential in patients who present in an unresponsive state after recent opioid use in the context of the above imaging findings. Additional diagnoses on the differential can include ischemic stroke, hypoxic-ischemic encephalopathy, "chasing the dragon," leukoencephalopathy, opioid-associated amnestic syndrome, and pediatric opioid-use-associated neurotoxicity with cerebellar edema.