Carotid duplex and transcranial color-coded sonography in evaluation of carotid-cavernous sinus fistulas

We performed carotid duplex and transcranial color-coded sonography in three patients with traumatic and one patient with spontaneous carotid-cavernous fistulas. High flow and low resistance were detected by carotid Doppler imaging in the extracranial internal carotid artery in three cases and in the external carotid artery in one case. The fistula could be demonstrated directly as heterogenous color flashes with turbulent flow by transcranial color-coded sonography through the orbital or temporal window. The transorbital approach showed that the ophthalmic venous flow was normal or to-and-fro bidirectional in patients without proptosis and was retrograde, away from the cavernous sinus with arteriolization in patients with proptosis. Combination of carotid duplex and transcranial color-coded sonography provides a noninvasive method for more accurate hemodynamic study of cerebral circulation and direct imaging of CCF.