A Digital Method for the Detection of Blood Flow Direction in Ultrasonic Doppler Systems

Abstract

DOPPLER ULTRASOUND SYSTEMS ARE WIDELY USED TO STUDY BLOOD FLOW AND DIAGNOSIS OF VASCULAR DISEASES. AN IMPORTANT CHARACTERISTIC OF THESE SYSTEMS IS THE ABILITY TO DETECT THE DIRECTION OF THE BLOOD FLOW. MOST DOPPLER ULTRASOUND SYSTEMS APPLY A QUADRATURE DEMODULATION TECHNIQUE ON THE ULTRASONIC TRANSDUCER OUTPUT SIGNAL. THEREFORE ADDITIONAL TREATMENT IS NECESSARY TO SEPARATE FORWARD AND REVERSE FLOW SIGNALS. THIS WORK PRESENTS A DIGITAL METHOD TO CONVERT SIGNALS IN QUADRATURE INTO DIRECTIONAL SIGNALS USING A FAST FOURIER TRANSFORM(FFT) APPROACH. VALIDATION OF THE METHODHASBEENACHIEVEDUSINGSIMULATEDDOPPLERULTRASOUNDSIGNALS.