[The Doppler test: its practical importance in the study of lesions of the supra-aortic trunks].

Ultrasonography by the Doppler effect is of indisputable use in the investigation of lesions of the supra-aortic trunks leading to the brain. It allows a direct study of the extracranial carotidian and vertebral axes, and gives an idea of the intracerebral circulation. It detects the main lesions affecting them, provided that such lesions have hemodynamic repercussions. The Doppler does not replace arteriography, but is a complementary exam making it possible to decide on or to dismiss the need for it. Its harmlessness and simplicity make it a standard exam in cerebral vascular pathology.