[Extra-intracranial arterial bypasses. Evaluation of their permeability by use of the Doppler effect].

40 temporo-sylvian anastomoses were controlled using Doppler ultrasonic examination. The results are compared to post-operative arteriograms. The Doppler examination has proved to be highly accurate when compared to contrast arteriography in the survey of extra-intracranial anastomosis. This non invasive procedure can easily be repeated. However the size of the revascularized area cannot be estimated. The simultaneous isotopic studies of regional cerebral blood flow could provide a means of quantifying the results of the anastomoses.