Angiographic and Doppler diagnosis of cerebral artery vasospasm following subarachnoid haemorrhage.

Angiographic middle and anterior cerebral artery diameter and transcranial ultrasound flow velocity measurements were performed within 24 h of each other in 102 patients with recent aneurysmal subarachnoid haemorrhage. There was a significant inverse correlation between middle cerebral artery diameter and flow velocity (r = -0.54, p < 0.001). No such correlation was seen for anterior cerebral arteries (r = -0.25). The ratio of middle cerebral artery to extracranial internal carotid artery velocities, which is an index of vasospasm, did not show improved correlation with arteriographic diameters, compared with uncorrected middle cerebral artery readings. Middle and anterior cerebral artery velocities and diameters both began to show significant changes indicative of vasospasm from day 4-5 onwards, suggesting that an increase in Doppler velocity is a good indicator of middle cerebral artery diameter, as shown by angiography. These studies indicate that transcranial Doppler is a useful non-invasive monitor for the development of delayed vasospasm following subarachnoid haemorrhage.