The aim of this study is to clarify whether it is possible to diagnose occlusion of the internal carotid artery (ICA) by observing the existence of anterograde diastolic flow at the cervical ICA by duplex carotid Sonography (DCS) . 77 patients (cardioembolic brain infarction, 12 cases ; atherothrombotic brain infarction, 22 cases ; lacunar brain infarction, 12 cases ; other brain infarction or miscellaneous brain infarction, 9 cases ; TIA, 8 cases ; other disease, 14 cases) who had undergone both cerebral angiography and DCS were included. For all cases we established whether or not anterograde diastolic flow at the cervical ICA could be detected by DCS, and these findings were compared with those of cerebral angiography. All the 8 cases without anterograde diastolic flow in the internal carotid artery were diagnosed by cerebral angiography as having occluded internal carotid artery. Sixty - eight of the 69 patients with anterograde diastolic flow were diagnosed as having patent internal carotid artery. We conclude that diagnosis of internal carotid artery occlusion can be made by observing the presence of anterograde diastolic flow at the cervical ICA by DCS.
