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Vascular » Cerebrovascular
Complete left internal carotid artery occlusion
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Author(s) :
S. Manohar, MD, DMRD
Presentation This is a patient who gave a prior clinical history of left carotid endarterectomy. His current complaints involve loss of vision in the left eye.
Caption: Spectral waveform analysis of left ICA origin
Description: No flow is recorded in the left internal carotid artery.
Caption: Spectral waveforms of left CCA and vertebral artery
Description: The left CCA demonstrates an externalized waveform. The vertebral artery waveform is normal.
Caption: Color Doppler image at left carotid bifurcation
Description: An echogenic thrombus is seen occluding the left internal carotid artery. The left common carotid artery appears normal.
Caption: Spectral waveforms of right ECA and vertebral artery
Description: The right external carotid artery and the vertebral artery reveal normal arterial waveforms. [Contrast it with the waveform seen in image 2]
Caption: Spectral waveforms of right common and ICA
Description: Normal arterial waveforms are noted in the right common and internal carotid artery.
Caption: Spectral waveforms of the left MCA and ACA
Description: Both these arteries show flow towards the transducer. This indicates normal flow in the MCA, but indicates reversal of flow in the ACA as the normal ACA flow is away from the probe.
Caption: Spectral waveforms of left MCA and ACA
Description: The left anterior cerebral artery shows reversed flow.
Caption: Waveforms of both ACA from left temporal window
Description: There is increased flow in the right anterior cerebral artery towards the transducer and flow reversal in the left anterior cerebral artery.
Caption: Spectral waveforms of both the MCAs
Description: This is the right and left middle cerebral arteries sampled from the left temporal window. Both show flow in the opposite direction which is normal.
Differential Diagnosis Complete left internal carotid artery occlusion
Final Diagnosis Complete left ICA occlusion with changes in the ipsilateral anterior circulation as described.
Discussion The transcranial Doppler findings in cases of ICA occlusion can help to identify concurrent intracranial occlusions or compensatory changes that occur in the anterior circulation. The spectrum of findings include
- reversed flow in the ipsilateral ACA,
- reduced flow velocity in the ipsilateral MCA  and
- elevated flow velocity in the contralateral ACA [all these findings are noted here].

A few other findings that have been noted in literature include reversed flow in ipsilateral ophthalmic artery and concurrent absent flow in the arteries of the anterior circulation.
Case References 1. Demchuk A., Christou I., Wein T., Felberg R., et al. Specific Transcranial Doppler Flow Findings Related to the Presence and Site of Arterial Occlusion. Stroke. 2000; 31:140.
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