Journal article
Transverse Spectral Velocity Estimation
A transverse oscillation (TO)-based method for calculating the velocity spectrum for fully transverse flow is described. Current methods yield the mean velocity at one position, whereas the new method reveals the transverse velocity spectrum as a function of time at one spatial location. A convex array probe is used along with two different estimators based on the correlation of the received signal.
They can estimate the velocity spectrum as a function of time as for ordinary spectrograms, but they also work at a beam-to-flow angle of 90°. The approach is validated using simulations of pulsatile flow using the Womersly–Evans flow model. The relative bias of the mean estimated frequency is 13.6% and the mean relative standard deviation is 14.3% at 90°, where a traditional estimator yields zero velocity.
Measurements have been conducted with an experimental scanner and a convex array transducer. A pump generated artificial femoral and carotid artery flow in the phantom. The estimated spectra degrade when the angle is different from 90°, but are usable down to 60° to 70°. Below this angle the traditional spectrum is best and should be used.
The conventional approach can automatically be corrected for angles from 0° to 70° to give fully quantitative velocity spectra without operator intervention.
Language: | English |
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Publisher: | IEEE |
Year: | 2014 |
Pages: | 1815-1823 |
ISSN: | 15258955 and 08853010 |
Types: | Journal article |
DOI: | 10.1109/TUFFC.2014.006488 |
ORCIDs: | Jensen, Jørgen Arendt |
Arrays Estimation Frequency measurement Oscillators Transducers Ultrasonic imaging Ultrasonic variables measurement Womersly-Evans flow model beam-to-flow angle biological fluid dynamics blood vessels carotid artery flow convex array probe convex array transducer estimators flow simulation fully transverse flow mean estimated frequency mean velocity phantom phantoms pulsatile flow pulsatile flow simulations pump generated artificial femoral flow received signal correlation relative bias spatial location spectrograms transverse oscillation-based method transverse spectral velocity estimation