Objective: To identify patients with asymptomatic TSS and normal ICP and describe their characteristics. Background TSS is common among patients with elevated ICP, particularly those with idiopathic intracranial hypertension. Although it is believed that TSS exists in the general population, and is not specific to elevated ICP, the prevalence of TSS among individuals with normal ICP is unclear. Design/Methods: Among 240 adult patients who underwent standardized brain MRI/MRV with contrast at our institution between 09/2009 and 09/2011, 50 had TSS. Medical records were reviewed for symptoms of increased ICP, evidence of papilledema, CSF constituents and opening pressure (OP) and reason for brain imaging. We identified 5/50 (10%) well-documented patients without papilledema and CSF-OP ≤25 cmH 2 O, and 2/50 without measured ICP, but who had no papilledema or other symptoms of increased ICP. Imaging was re-interpreted by a neuroradiologist to assess for signs suggestive of elevated ICP and to characterize the stenoses further. Results: All patients were women (5 African-American, 2 Caucasian, mean age: 41, mean BMI: 37.1). CSF contents were normal but OP were at the upper limit of normal (22, 23, 24, 24, 25cm H 2 O). Indications for MRI/MRV included pituitary abnormality (1), migraine (4), and anomalous-appearing optic nerves (2). All had bilateral TSS. Six had a short TSS and empty sella; one had a long TSS but no empty sella; one had flattening of the globes; two had dilated optic nerve sheaths. None had bony changes. Conclusions: Asymptomatic bilateral TSS does exist in patients with ICP ≤25cmH 2 O, but is likely uncommon. Interestingly, CSF-OP was at the upper limit of normal in our patients, who also had other radiologic signs suggestive (but not specific) of chronically-raised ICP. Findings of bilateral TSS on brain imaging should probably prompt further investigations for raised ICP. Disclosure: Dr. Kelly has nothing to disclose. Dr. Saindane has nothing to disclose. Dr. Bruce has nothing to disclose. Dr. Ridha has nothing to disclose. Dr. Riggeal has nothing to disclose. Dr. Newman has received personal compensation for activities with Biogen Idec. Dr. Biousse has nothing to disclose.