Susac Syndrome: MRI Findings Predict Vision and Hearing Loss in Largest Cohort Study
Two new studies from the largest single-center cohort of Susac syndrome patients reveal that small-vessel infarcts on MRI predict vision loss from retinal artery occlusions, and the complete disease triad may affect up to 70% of patients. The findings were presented at the International Stroke Conference 2026.
Cerebrovascular small-vessel infarcts on brain MRI are associated with vision loss due to branch retinal artery occlusions in Susac syndrome, a rare autoimmune vasculitis, according to two studies presented at the International Stroke Conference 2026. The research, based on the largest single-center cohort of Susac syndrome patients to date, also found that the complete triad of encephalopathy, vision loss and hearing loss may be present in up to 70% of patients, far higher than previous estimates.
Susac syndrome involves the central nervous system, retina and cochlea, causing symptoms such as visual field defects, sensorineural hearing loss, headache, confusion and memory impairment. The hallmark MRI features include corpus callosum lesions resembling snowballs, but the new studies show that cerebrovascular involvement extends beyond these classic lesions.
Among 70 patients in the cohort, three-quarters were female with a median age of 34 years. The most common initial symptom was vision loss, occurring in 89.6% of patients, followed by hearing loss (82.9%), cognitive impairment (76.8%) and confusion (69.1%). Brain MRI data available for 57 patients revealed corpus callosum lesions in 84%, while cerebellar involvement was seen in 47.4%, brainstem in 24.6% and middle cerebellar peduncle in 15.8%. Deep gray matter lesions were present in 35.1% and leptomeningeal enhancement in 19.3%. Notably, over half (52.6%) showed small-vessel infarcts, with the vast majority (96.7%) being deep subcortical.
Non-central nervous system manifestations included branch retinal artery occlusions (BRAOs) in 75.9% of patients, bilateral in 59.1%. A significant association was found between cerebrovascular small-vessel infarcts and new BRAOs, regardless of acuity or depth. Ophthalmologic evaluations showed vascular leakage in 62.3% and retinal atrophy in 41.2%, while audiography detected sensorineural hearing loss in 71.4%.
The high prevalence of the complete triad—contrasting with the 40% rate previously reported in the literature—suggests that a thorough diagnostic workup may reveal evidence of all three organ systems being affected. Half the cohort had tiny infarcts linked to BRAO, which can lead to blindness and may influence treatment decisions.
A second study compared brain MRI features of 63 Susac patients with 33 patients who had primary angiitis of the central nervous system (PACNS), a similar small-vessel vasculitis confined to the CNS. Accurately differentiating the two conditions is critical because management differs. The researchers aimed to identify distinguishing imaging markers, reviewing scans for corpus callosum involvement and white matter patterns.