Overcoming the Nyquist limit in blood flow velocity estimation

Gudmundson, Erik; Jakobsson, Andreas; Gran, Fredrik

doi:10.1109/ultsym.2012.0404

Cited by 2 publications

(1 citation statement)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The proposed algorithm is an extension of the recent BIAA algorithm [16][17][18] to the TO case. As shown in [16], the BIAA algorithm allows for reliable high-resolution estimates of the axial velocity, and also allows for the use of irregularly sampling schemes, thereby enabling flexibility in the interleaved transmissions used to form the velocity estimation and the B-mode images necessary for navigation inside the vessel; the latter transmissions are currently interleaved between the transmissions used for velocity estimation, thereby halving the effective dynamic span of the velocity estimate (see also [19]). The algorithm presented here, termed the TO-BIAA, shares this benefit, as well as allows for a computationally efficient implementation reminiscent to the one presented in [17].…”

Section: Introductionmentioning

confidence: 99%

Data adaptive estimation of transversal blood flow velocities

Pirnia

Jakobsson

Gudmundson

et al. 2014

2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

View full text Add to dashboard Cite

The examination of blood flow inside the body may yield important information about vascular anomalies, such as possible indications of, for example, stenosis. Current medical ultrasound systems suffer from only allowing for measuring the blood flow velocity along the direction of irradiation, posing natural difficulties due to the complex behaviour of blood flow, and due to the natural orientation of most blood vessels. Recently, a transversal modulation scheme was introduced to induce also an oscillation along the transversal direction, thereby allowing for the measurement of also the transversal blood flow. In this paper, we propose a novel data-adaptive blood flow estimator exploiting this modulation scheme. Using realistic Field II simulations, the proposed estimator is shown to achieve a notable performance improvement as compared to current state-of-the-art techniques.

show abstract

Section: Introductionmentioning

confidence: 99%

Data adaptive estimation of transversal blood flow velocities

Pirnia

Jakobsson

Gudmundson

et al. 2014

2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

View full text Add to dashboard Cite

show abstract

Effects of reverberations and clutter filtering in pulsed Doppler using sparse sequences

Avdal

Løvstakken

Torp

2015

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

Duplex ultrasound is a modality in which an ultrasound system is used for simultaneous acquisition of both B-mode images and velocity (Doppler) data. Conventional duplex sequences interleave packets of B-mode and Doppler transmissions, producing undesirable gaps during B-mode interruptions. In recent years, several techniques have been proposed for avoiding such gaps by using sparse sequences, in which velocity spectra are generated from nonuniformly sampled Doppler data containing frequent B-mode interruptions. In this work, two negative effects are discussed that may influence velocity estimation when using nonuniformly sampled sequences. First, it is shown that long reverberation times lead to discontinuities in the signal from stationary clutter after each B-mode interruption. Second, using frequency analysis, it is shown that clutter filtering of nonuniformly sampled data may introduce artifacts in the velocity spectrum, and also lead to significant bias in mean velocity estimates. Methods are presented for quantification of these effects, and utilized to analyze three types of sparse duplex sequences for blood velocity estimation. In particular, it is argued that the use of such sequences in cardiac applications is not recommended because of long reverberation time. Additionally, it is found that the use of regression filters to filter nonuniformly sampled data may produce significant artifacts in pulsed wave Doppler spectra, but is less significant for color Doppler imaging applications. In vitro and in vivo examples are included showing the presence and magnitude of these problems in clinically relevant applications.

show abstract

Overcoming the Nyquist limit in blood flow velocity estimation

Cited by 2 publications

References 11 publications

Data adaptive estimation of transversal blood flow velocities

Data adaptive estimation of transversal blood flow velocities

Effects of reverberations and clutter filtering in pulsed Doppler using sparse sequences

Contact Info

Product

Resources

About