<unk>  (ESUS) is a type of ischemic stroke with an unknown origin, defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic<unk> s. As such, it forms a subset of cryptogenic stroke, which is part of the TOAST-classification. The following diagnostic criteria define an ESUS: * Stroke detected by CT or MRI that is not lacunar * No major-risk cardioembolic<unk>  of<unk> m * Absence of extracranial or intracranial atherosclerosis causing 50% luminal stenosis in arteries supplying the area of ischaemia * No other specific cause of stroke identified (e.g., arteritis, dissection, migraine/vasospasm, drug misuse)
Embolic stroke of undetermined source
Lacunar stroke
Posterior circulation infarct
Watershed stroke
Partial anterior circulation infarct
Posterior cerebral artery syndrome
Anterior cerebral artery syndrome
Hemorrhagic infarct