Connecting the dots: Linking superior ophthalmic vein and internal jugular vein diameter to carotid cavernous fistula type and location

Background: The specific objectives of this study are to identify the carotid cavernous fistula (CCF) type based on computerized tomography angiography (CTA) results, determine the cut-off diameter of the superior ophthalmic vein (SOV) and internal jugular vein (IJV) in CCF patients, and to evaluate the correlation between diameters of the right and left SOV and IJV with CCF type and location. Methods: A retrospective analysis of data from 35 CCF patients at our institution was conducted between January 2016 and October 2022. The analysis separated the vascular diameters of the right and left SOV and IJV, which were compared to 35 non-CCF patients. The non-CCF group consisted of individuals who underwent CTA for conditions unrelated to vascular abnormalities. Results: In 35 CCF patients, the dilatation of the left SOV was significantly correlated with direct CCF type with a cutoff of >0.5 cm and significantly associated with indirect CCF type with a cutoff of <0.5 cm (P = 0.017), while the right SOV was not significantly correlated (P = 0.187). There was no significant correlation between the right and left IJV with CCF type or location (right IJV, P = 0.996 and left IJV, P = 0.558). However, the analysis indicated that IJV size differences between CCF and non-CCF patients were significant. Conclusion: Dilation of the left SOV correlates with both direct and indirect CCF types, while the right SOV and IJV (both sides) do not show a significant correlation with CCF type or location. This suggests that left SOV dilation may serve as an early indicator of CCF type, particularly in cases involving the left side.