Carotid cavernous sinus fistulas without superior ophthalmic vein enlargement

Purpose: Diagnosis of carotid cavernous fistula (CCF) relies on clinical findings, such as proptosis, chemosis, and pulsatile tinnitus, plus imaging features including enlargement of the superior ophthalmic vein (SOV). This study reviewed patients with CCF, with a focus on those who were clinically symptomatic but had a normal-appearing SOV on routine scans. Methods: Retrospective review was conducted on the clinical records of patients with CCF seen by ophthalmology or interventional neuroradiology, with attention to clinical and imaging features, angiography findings, management, and outcomes. Results: Forty patients presented with CCF. History of head trauma was present in 13 (average age 43.8 years; all direct or complex), while the remainder occurred spontaneously (average 66 years; 85% indirect). The most common presenting ophthalmologic signs or symptoms were proptosis (65%), binocular diplopia (60%), redness (57.5%), and chemosis (47.5%). After diagnosis, 36 underwent endovascular treatment, with successful occlusion achieved in 90% of cases for whom follow-up data was available (n = 21). Notably, 3 patients with CCF did not have SOV enlargement on any imaging modality including catheter angiography. Conclusions: In this series of patients with clinical signs of CCF, there was no radiologic evidence of enlarged SOV in 26% of patients on noninvasive imaging and in 8% on catheter angiography. To avoid inappropriate interventions or delays in diagnosis and care, it is important to recognize that CCF can exist without SOV enlargement. Patients with clinical features suspicious for CCF should undergo catheter angiography if treatment is being considered. Endovascular treatment can produce clinical improvement or resolution.