Possibilities and results of the preoperative and postoperative application of transcranial doppler sonography

The non-invasive, repeatable method of measuring blood flow velocities in the arterial circle of Willis by transcranial Doppler sonography is a method for assessing the hemodynamics of neurovascular diseases. For aneurysm surgery it provides information on the severity and extent of the vasospasms, as well as on the possible effect of therapy. The flow velocity, which is the hemodynamic measuring parameter, is used to judge whether the cerebral circulation is raised (arteriovenous angioma), lowered, or unchanged (hemodynamic effective stenoses, cerebral circulatory cessation). Knowledge of the intracranial hemodynamics is a prerequisite for the accurate interpretation of the Doppler findings