TRANSCRANIAL DOPPLER ULTRASONOGRAPHY OF INTRACRANIAL COLLATERALISATION IN STENOSIS (GREATER-THAN-50-PERCENT) OR OCCLUSION OF THE INTERNAL CAROTID-ARTERY

We prospectively investigated intracranial collateralisation by transcranial Doppler sonography in 58 cases of stenosis (> 50%) or occlusion of the internal carotid artery (ICA). Intracranial collateralisation was observed in severe ICA stenonis (> 90%) and occlusion. The most frequent intracerebral collateral was the contralateral anterior cerebral artery via the anterior communicating artery (90% in cases of ICA-occlusions). A collateral supply via the ophthalmic artery occurred in 53% and/or the vertebrobasilar system in 47% of the patients with ICA occlusion. In patients with TIA or stroke, intracranial collateralisation via the opthalmic artery was observed in 61%, in contrast to 28% of patients without neurological symptoms.