Funktionelle transkranielle Dopplersonographie

Functional transcranial Doppler sonography (fTCD) examines cerebral hemodynamics at rest and during diverse activation manoeuvres. In the fTCD during visual activation the posterior cerebral artery (PCA) is insonated. Further fTCD methods for the evaluation of the posterior circulation are the simultaneous insonation of the middle cerebral artery (MCA) and the PCA or direct insonation of the basilar artery (BA) during vestibular stimulation using caloric irrigation. The fTCD during tilt-table-test with head-up tilt is meanwhile a very established method for autonomic testing. The fTCD during head-down tilt is still experimental for testing cerebrovascular autoregulation in healthy volunteers. The autoregulative stimulus is the rapid cephal blood influx which probably activates the myogenic mechanism of cerebrovascular autoregulation. The fTCD during ergometry examines cerebrovascular changes during physical stress. The cerebrovascular changes reflect the complex coactivation of diverse autoregulative mechanisms (neurogenic, metabolic, myogenic). In patients with defined cerebrovascular disturbances (chronic tension type headache, migraine) abnormal findings were detected. FTCD is a new method which enables noninvasive and with exact time correlation changes analysis of cerebrovascular hemodynamics during diverse activation procedures. Clinical applications can be seen in patients with cerebrovascular or autonomic diseases and in testing of cerebrovascular autoregulation following pharmacological treatment (e.g. antihypertensive drugs).