Concepts and Tradeoffs in Velocity Estimation With Plane-Wave Contrast-Enhanced Doppler.
IEEE Trans Ultrason Ferroelectr Freq Control
; 63(11): 1890-1905, 2016 11.
Article
in En
| MEDLINE
| ID: mdl-27824566
ABSTRACT
While long Doppler ensembles are, in principle, beneficial for velocity estimates, short acoustic pulses must be used in microbubble contrast-enhanced (CE) Doppler to mitigate microbubble destruction. This introduces inherent tradeoffs in velocity estimates with autocorrelators, which are studied here. A model of the autocorrelation function adapted to the microbubble Doppler signal accounting for transit time, the echo frequency uncertainty, and contrast-agent destruction is derived and validated in vitro. It is further demonstrated that a local measurement of the center frequency of the microbubble echo is essential in order to avoid significant bias in velocity estimates arising from the linear and nonlinear frequency-dependent scattering of microbubbles and compensate for the inherent speckle nature of the received echo frequency. For these reasons, broadband Doppler estimators (2-D autocorrelator and Radon projection) are better suited than simpler narrow-band estimators (1-D autocorrelator and 1-D Fourier transform) for CE flow assessment. A case study of perfusion in a VX-2 carcinoma using CE plane-wave Doppler is also shown. We demonstrate that even when considering all uncertainties associated with microbubble-related decorrelation (destruction, pulse bandwidth, transit time, and flow gradient) and the need for real-time imaging, a coefficient of variation of 4% on the axial velocity is achievable with plane-wave imaging.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Signal Processing, Computer-Assisted
/
Ultrasonography, Doppler
/
Microbubbles
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
IEEE Trans Ultrason Ferroelectr Freq Control
Journal subject:
MEDICINA NUCLEAR
Year:
2016
Type:
Article