Cerebral Vascular accidents remain one of major causes of die and handicap the most frequently met in occidental countries. These ones are often associated to emboli transit, foreign bodies to blood normal composition, in cerebral circulation. Emboli number, nature are also directly related to a pathological degree. It seems obvious that a good emboli detection needs rejection of artifacts, which are undesirable events. The aim of this work is to proceed different artifact Doppler signals and to introduce a priori and a posteriori parameters which are able to characterize them at best. We discuss about their reliability for artifact rejection.