"resistive index is useful to determine the location of the stenotic segment in a blood vessel 6."
"The frequency of the sound waves returned to an ultrasound transducer when interrogating blood flow represents a composite of the heterogenous Doppler shifts yielded by each red blood cell in motion, each of which is in motion at a unique velocity and direction. Spectral Doppler modalities utilise Fourier analysis (fast Fourier transformations) to average the frequencies over a circumscribed time period, usually 5 milliseconds, convert frequencies to velocities using the Doppler equation, and display a "spectrum" of these frequencies as Doppler waveforms (hence the term "spectral") 3."
"Continuous wave Doppler"
"Pulsed wave Doppler"
"Doppler waveforms"
Expected headings
"Continuous wave Doppler"
"Pulsed wave Doppler"
"These velocity-time spectral recordings may be obtained with two conventional modalities, both of which are typically used in conjunction with B-mode ultrasonography; pulsed wave and continuous wave Doppler."