An ultrasonic Doppler blood flow sensing apparatus comprises a probe for sending an ultrasonic wave into a living body and receiving echoes, an ultrasonic diagnosing device for processing the echoes received to provide a tomogram signal, an ultrasonic Doppler blood flow meter for processing the echoes...http://www.google.es/patents/US4501279?utm_source=gb-gplus-sharePatente US4501279 - Ultrasonic blood flow sensing apparatus
