This proposal is to develop new Doppler ultrasound concepts for automatic determination of location of basal arteries of the brain. This technology is needed for quickly and simply obtained diagnosis of pathological blood flow conditions that may indicate acute stroke in progress or the risk for stroke. This technology also presents the potential for dramatically reducing the time necessary to find blood vessels, reducing training time, and opening the door for a much wider group of health professionals to obtain the important information provided with high sensitivity and specificity. The utilization limiting frustrations experienced by current users of transcranial Doppler ultrasound will be eliminated with this technology. This technology will be particularly important in diagnosis and monitoring of the acute stroke patient during the limited time window in which thrombolytic therapy is an option. The work proposed entails: (1) building a novel ultrasound probe and electronics with ability to steer the ultrasound beam, (2) performing high speed signal processing of digitized received echos for determination of spatial location of the associated Doppler shift signals, and (3) steering the ultrasound beam to lock in on this detected blood flow. This plan presents the first step in developing a novel ultrasound probe which will perform unaided location of the basal cerebral arteries.