[Pulsed transcranial Doppler examination in the acute phase of stroke]

Transcranial pulsed Doppler sonography with or without imagery is used in the acute phase of ischemic stroke in order to define stroke mechanism and intracranial hemodynamic consequences.

This non-invasive low-cost investigation can be undertaken rapidly, within 10 minutes if guided by focal symptomatology. It detects middle cerebral artery stenosis in >or=50 p. cent of cases with a sensitivity between 75 and 90 p. cent, comparatively with conventional angiography, and middle cerebral artery occlusion with 90 p. cent sensitivity. When a temporal acoustic window is lacking, intravenous injection of a contrast agent allows good visualization of the intracranial vessels and the circle of Willis, in two-third of cases. Moreover, transcranial Doppler data have good prognostic value and facilitate analysis of recanalization after thrombolytic therapy.

Beside its diagnostic and prognostic interest, transcranial Doppler sonography using a 2 MHz frequency appears to have therapeutic impact by favoring the thrombolysis process. Future developments may include early and prolonged insonation of patients suffering from stroke.