Time-scale detection of microemboli in flowing blood with Doppler ultrasound.
BS Krongold, AM Sayeed, MA Moehring, JA Ritcey, MP Spencer, DL Jones
IEEE Trans Biomed Eng | Published : 1999
Small formed elements and gas bubbles in flowing blood, called microemboli, can be detected using Doppler ultrasound. In this application, a pulsed constant-frequency ultrasound signal insonates a volume of blood in the middle cerebral artery, and microemboli moving through its sample volume produce a Doppler-shifted transient reflection. Current detection methods include searching for these transients in a short-time Fourier transform (STFT) of the reflected signal. However, since the embolus transit time through the Doppler sample volume is inversely proportional to the embolus velocity (Doppler-shift frequency), a matched-filter detector should in principle use a wavelet transform, rather..View full abstract