Specific Transcranial Doppler Flow Findings Related to the Presence and Site of Arterial Occlusion

Abstract

Background and Purpose —Transcranial Doppler (TCD) can localize arterial occlusion in stroke patients. Our aim was to evaluate the frequency of specific TCD flow findings with different sites of arterial occlusion. Methods —Using a standard insonation protocol, we prospectively evaluated the frequency of specific TCD findings in patients with or without proximal extracranial or intracranial occlusion determined by digital subtraction or MR angiography. Results —Of 190 consecutive patients studied, angiography showed occlusion in 48 patients. With proximal internal carotid artery (ICA) occlusion, TCD showed abnormal middle cerebral artery (MCA) waveforms (AMCAW) in 66.7%, reversed ophthalmic artery (OA) in 70.6%, anterior cross-filling via anterior communicating artery (ACoA) in 78.6%, posterior communicating artery (PCoA) in 71.4%, and contralateral compensatory velocity increase (CVI) in 84.6% of patients. With distal ICA occlusion, TCD showed AMCAW in 88.9%, OA in 16.7%, ACoA in 50%, PCoA in 60%, and CVI in 88.9% of patients. With MCA occlusion, TCD showed AMCAW in 100%, OA in 23.5%, ACoA in 31.3%, PCoA in 23.1%, and CVI in 62.5%. With no anterior circulation occlusion at angiography, TCD showed these parameters in 1.8% to 17.9%, χ 2 P ≤0.003. Parameters localizing anterior circulation occlusion were stenotic terminal ICA velocities 46% versus 10% in patent vessels; flow diversion to perforators 73% versus 1.8%; OA 70.6% versus 5.6%; ACoA 78.6% versus 8.2%; PCoA 71.4% versus 8.5%, all at P <0.05. In patients with basilar artery (BA) occlusion, ABAW were found in 80% versus 3% (patent BA); flow diversion to anterior vessels in 60% versus 5.7%; BA flow reversal in 20% versus 0%; and PCoA in 100% versus 13.7%, all at P <0.001. No individual parameters differentiated BA from the terminal vertebral occlusion. Conclusions —Specific TCD findings are common with major arterial occlusion and can be used to broaden diagnostic batteries and improve the predictive value of noninvasive screening in stroke patients. TCD findings useful to localize anterior circulation occlusion include collaterals, abnormal waveforms or velocities, and flow diversion to perforators.