Imaging diagnosis of carotid-cavernous fistula

Objective: To evaluate the diagnostic value of ultrasound, CT and MRI in carotid-cavernous fistula.

Methods: A retrospective analysis was made of 58 patients with carotid-cavernous fistula who had complete clinical data from 1997-2004. The imaging findings of B-ultrasound, color Doppler ultrasonography, CT and MRI were analyzed and summarized for the diagnosis of carotid-cavernous fistula.

Results: The imaging findings of carotid-cavernous fistula included of dilation of superior ophthalmic vein, enlargement of cavernous sinus, proptosis, and thickness of extraocular muscle. Dilation of superior ophthalmic vein was the specific imaging sign of carotid-cavernous fistula. This was presented in 51 cases by B-ultrasound which showed one tubular no-echo space; presented in 49 patients by color Doppler imaging which showed obvious dilated superior ophthalmic vein with artery blood flow; presented in 58 cases by CT scan which showed fusiform vascular imaging from anterior-inside to posterior-outside; and presented in 58 cases by MRI with the characteristic manifestation: flow void signal of dilated superior ophthalmic vein on T(1)WI and T(2)WI scan, and on the Gd-enhanced MRI. Another specific imaging sign was enlargement of cavernous sinus. This sign was presented in 41 cases by CT with high density imaging and presented in 37 cases by MRI, which showed flow void signal on T(1)WI and T(2)WI scan.

Conclusions: Carotid-cavernous fistula has specific imaging signs which can be found by B-ultrasound, color Doppler ultrasonography, CT and MRI. These imaging signs are important to clinical diagnosis and different diagnosis of carotid-cavernous fistula.