Adaptive Filtering and Spectral Analysis of Pulsed Doppler Ultrasound to Aid the Assessment of Cardiovascular Condition

摘要

This paper presents a new approach to filtering wall motion artefact from Doppler ultrasound signals. The technique tracks the wall motion and removes it from the backscattered signal, thus preserving low frequency blood flow information, which would have otherwise been removed had conventional highpass filtering methods been applied. This provides a much-improved representation of the blood flow profile throughout the cardiac cycle. Often when cardiovascular vessels are scanned the Doppler SNR is typically OdB due to the attenuation of tissue, fat and general in-homogenates in the separating medium. The effects of this speckle are much more emphasised after wall motion is removed, as the noise floor is lifted. Hence this paper also examines four adaptive filtering techniques for minimising the effects of this noise in the backscattered Doppler ultrasound signal.