title: Assessment of Spectral Doppler for an Array-Based Preclinical Ultrasound Scanner Using a Rotating Phantom.
abstract: Velocity measurement errors were investigated for an array-based preclinical ultrasound scanner (Vevo 2100, FUJIFILM VisualSonics, Toronto, ON, Canada). Using a small-size rotating phantom made from a tissue-mimicking material, errors in pulse-wave Doppler maximum velocity measurements were observed. The extent of these errors was dependent on the Doppler angle, gate length, gate depth, gate horizontal placement and phantom velocity. Errors were observed to be up to 172% at high beam-target angles. It was found that small gate lengths resulted in larger velocity errors than large gate lengths, a phenomenon that has not previously been reported (e.g., for a beam-target angle of 0°, the error was 27.8% with a 0.2-mm gate length and 5.4% with a 0.98-mm gate length). The error in the velocity measurement with sample volume depth changed depending on the operating frequency of the probe. Some edge effects were observed in the horizontal placement of the sample volume, indicating a change in the array aperture size. The error in the velocity measurements increased with increased phantom velocity, from 22% at 2.4 cm/s to 30% at 26.6 cm/s. To minimise the impact of these errors, an angle-dependent correction factor was derived based on a simple ray model of geometric spectral broadening. Use of this angle-dependent correction factor reduces the maximum velocity measurement errors to <25% in all instances, significantly improving the current estimation of maximum velocity from pulse-wave Doppler ultrasound.
authors.affiliation: Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom. Electronic address: da.kenwright@gmail.com.
authors.forename: David A
authors.initials: DA
authors.lastname: Kenwright
authors.affiliation: Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: Anderson
authors.affiliation: Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Carmel M
authors.initials: CM
authors.lastname: Moran
authors.affiliation: Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Hoskins
mesh_terms: D000818:Animals; D001158:Arteries / Q000000981:diagnostic imaging* / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000295:instrumentation; D019047:Phantoms, Imaging / Q000662:veterinary*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler / Q000295:instrumentation* / Q000662:veterinary*
keywords: Blood velocity; Doppler phantom; Doppler ultrasound; High-frequency ultrasound; Preclinical ultrasound