Susac's syndrome - the crucial role of imaging tests for proper diagnosis.

Susac's syndrome (SS) is a rare, autoimmune-mediated endoteliopathy characterized by a clinical triad of encephalopathy, branch retinal artery occlusion, and sensorineural hearing loss. SS is also characterized by a neuroimaging triad consisting of white matter lesions, grey matter lesions, and leptomeningeal enhancement on magnetic resonance imaging (MRI). Considering the rarity of SS, as well as certain similarity to other, more frequent neurological diseases, such as multiple sclerosis (MS), this syndrome is sometimes incorrectly diagnosed and treated. The aim of the study is to present the current state of knowledge on SS, with particular consideration for the differential diagnostics between SS and MS, using the latest available imaging techniques, such as brain MRI, optical coherence tomography (OCT), OCT angiography (OCTA) and fluorescein angiography (FA). The major electronic databases (PubMed, Google Scholar) were searched manually in order to identify the relevant studies published on SS. Distinguishing SS from MS is a diagnostic challenge. In the majority of cases, patients with SS do not present the complete clinical or neuroimaging triad, and a delay in making the correct diagnosis exposes the patient to the occurrence of complications, resulting from the development of the underlying disease, or/and the application of improper treatment. In the case of SS the results of brain MRI and FA are essential for making the correct diagnosis as they may reveal pathognomonic changes. Imaging examinations, such as brain MRI, FA, and OCT complement each other, due to which the diagnosis of SS may be simpler, irrespective of the stage of the disease.