New Aspects of Vasospasm Evaluated in 100 Patients with Aneurysm, Subarachnoid Hemorrhage, and Acute Operation: A Transcranial Doppler Study

Before the development of the transcranial Doppler machine (3), cerebral arterial vasospasm could only be detected by angiography. Using this method, the incidence of vasospasm was primarily detected in large clinical series. Patients underwent repeated angiography only twice or three times when they showed neurological dysfunctions (7, 11, 14) • With the transcranial Doppler machine it is possible to investigate atraumatically the compensatory blood flow velocity increase that is due to arterial vessel lumen narrowing. Thus the individual time course of vasospasm in the different segments of the circle of Willis can be observed (1, 2, 5, 13). The influence of a well or poorly functioning circle of Willis as a result of collateral flow can be measured. Clinical deterioration after subarachnoid hemorrhage (SAH) apart from vasospasm may be caused by intracerebral hemorrhage, edema, infarction, or hydrocephalus. The differential diagnosis of the cause of postoperative delayed neurological deficits can now be carried out using the transcranial Doppler measurements.