A new pulsed wave Doppler ultrasound system to measure blood velocities beyond the Nyquist limit

Author

Nitzpon, H.J. ; Rajaonah, J.C. ; Burckhardt, C.B. ; Dousse, B. ; Meister, J-J.

Author_Institution

Kontron Instrum., Basel, Switzerland

Volume

42

Issue

2

fYear

1995

fDate

3/1/1995 12:00:00 AM

Firstpage

265

Lastpage

279

Abstract

Conventional pulsed wave (PW) Doppler ultrasound systems measure blood velocities unambiguously as long as the velocities are less than the Nyquist velocity. Here, a new PW Doppler ultrasound system is described, which can measure velocities up to 4.5 times higher than the Nyquist velocity. The new PW system presented here utilizes two ultrasound carrier frequencies, such that an appropriate processing of the Doppler frequencies results in an extended mean-velocity range. With this extended mean-velocity information, the complex Doppler signal is interpolated to reconstruct aliased Doppler spectra. The interpolation algorithm has been tested by computer simulations demonstrating the capabilities and limits. The integration into a commercial Doppler scanner allowed the evaluation of the new PW system in real time. In vitro and in vivo tests demonstrate the effective reconstruction of highly aliased Doppler spectra.<>

Keywords

Doppler measurement; biomedical equipment; biomedical measurement; biomedical ultrasonics; haemodynamics; ultrasonic velocity measurement; Nyquist limit; Nyquist velocity; aliased Doppler spectra reconstruction; blood velocities measurement; commercial Doppler scanner; complex Doppler signal; computer simulations; extended mean-velocity range; highly aliased Doppler spectra; in vitro tests; in vivo tests; medical instrumentation; pulsed wave Doppler ultrasound system; ultrasound carrier frequencies; Blood; Computer simulation; Frequency; Interpolation; Pulse measurements; Real time systems; Testing; Ultrasonic imaging; Ultrasonic variables measurement; Velocity measurement;

fLanguage

English

Journal_Title

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Publisher

ieee

ISSN

0885-3010

Type

jour

DOI

10.1109/58.365240

Filename

365240