Table 1.

Diagnostic criteria of Susac syndrome as proposed by EuSaC in 2016.

	i. Symptoms and clinical findings	ii. Imaging or examination
1. Brain involvement	New cognitive impairment and/or behavioral changes and/or new focal neurological symptoms and/or new headache	Typical findings in cranial MRI–hyperintense, multifocal, round small lesions, at least one of them in the corpus callosum (“snowball”) in T2W (or FLAIR) sequences.
(at least one symptom and one MRI finding required)
2. Retinal involvement	Not required	BRAOs or AWH in fluorescein angiography or characteristic signs of retinal branch ischemia in fundoscopy or SD-OCT
(only ophthalmological finding required)
3. Vestibulocochlear involvement	New tinnitus and/or hearing loss and/or peripheral vertigo	Hearing loss supported by an audiogram; vestibular vertigo supported by specific diagnostics
(clinical finding supported by corresponding examination required in case of hearing loss and vertigo)

Definite diagnosis: all three criteria met. Probable diagnosis: two out of three criteria met. Possible diagnosis: only one criterion met. AWH, Arterial wall hyperfluorescence; BRAOs, Branch retinal artery occlusions; FLAIR, Fluid-attenuated inversion recovery; T2W, T2-weighted; and SD-OCT, Spectral domain optical coherence tomography.