Basilar Vasospasm Diagnosis

Numerous studies have shown that cerebral vasospasm is one of the leading causes of death and neurological disability after subarachnoid hemorrhage. Most of these studies, however, have focused on anterior circulation vessels. Since the introduction of the transcranial Doppler (TCD), increasing attention has been given to basilar artery (BA) vasospasm, especially in traumatic subarachnoid hemorrhage. As shown for the anterior circulation, however, the significance of elevated flow velocities (FVs) in the posterior vessels may be ambiguous, so vasospasm may not be reliably differentiated from hyperemia. The purpose of the present study was to evaluate the potential additional value of an intracranial/extracranial FV ratio in the posterior circulation to cope with this shortcoming of the TCD in the diagnosis of BA vasospasm.