PURPOSE: To describe the CT findings of distensible orbital venous anomalies. METHODS: We reviewed the records of 17 consecutive patients who met the imaging criteria for orbital venous anomalies. We analyzed the clinical data and the CT scans qualitatively and quantitatively. RESULTS: Distensible venous anomalies usually occupied both intraconal and extraconal spaces of the orbit (65%). The contour of the mass was ovoid or fusiform in 3 of the orbits (18%) and tubular or lobular in 14 orbits (82%). The optic nerve was encased by the mass in 8 orbits. Changes in the adjacent bone were detected in 9 orbits. The average volume of the venous anomalies was 1.1 mL in the axial scan and 5.7 mL in the coronal scan. The patients who showed clinically evident exophthalmos on the Valsalva maneuver had larger volumes than those who did not. CONCLUSIONS: The orbital structures adjacent to the distensible orbital venous anomalies were vulnerable to intermittent compression. CT scans, including both postcontrast axial and coronal images, were useful in demonstrating the presence of distensible venous anomalies, even in cases with no apparent exophthalmos on the Valsalva maneuver.
PURPOSE: To describe the CT findings of distensible orbital venous anomalies. METHODS: We reviewed the records of 17 consecutive patients who met the imaging criteria for orbital venous anomalies. We analyzed the clinical data and the CT scans qualitatively and quantitatively. RESULTS: Distensible venous anomalies usually occupied both intraconal and extraconal spaces of the orbit (65%). The contour of the mass was ovoid or fusiform in 3 of the orbits (18%) and tubular or lobular in 14 orbits (82%). The optic nerve was encased by the mass in 8 orbits. Changes in the adjacent bone were detected in 9 orbits. The average volume of the venous anomalies was 1.1 mL in the axial scan and 5.7 mL in the coronal scan. The patients who showed clinically evident exophthalmos on the Valsalva maneuver had larger volumes than those who did not. CONCLUSIONS: The orbital structures adjacent to the distensible orbital venous anomalies were vulnerable to intermittent compression. CT scans, including both postcontrast axial and coronal images, were useful in demonstrating the presence of distensible venous anomalies, even in cases with no apparent exophthalmos on the Valsalva maneuver.