Multi-dimensional real-time ultrasonic blood flow imaging apparatus and method

Abstract

An ultrasonic diagnostic apparatus and method for real-time multi-dimensional blood flow imaging with enhanced sensitivity to lateral blood flow. The apparatus constitutes an improvement on the ultrasonic diagnostic apparatus of the type wherein an ultrasonic pulse beam is repeatedly transmitted into the subject under examination at a fixed pulse rate and the reflected echoes are picked up, amplified and displayed. The improvement comprises an ultrasonic transducer means comprising a phased array transducer which is electronically and/or mechanically divided into two or more independently controlled sub-apertures and adapted for transmitting ultrasonic pulse beams from one of the two or more sub-apertures and for receiving the reflected echoes with at least two of the two or more sub-apertures. Optionally, the apparatus and method further comprises signal processing means including quadrature detection circuitry comprising sampling means for sampling the echo signals or a downward shifted version of echo signals and Hilbert transform means for filtering the signals so as to obviate the need for mixers, low-pass filters (LPF) and quadrature reference frequencies utilized in conventional ultrasonic blood flow imaging.