Cancellation of Doppler intrinsic spectral broadening using ultrafast Doppler imaging

Osmanski, Bruno-Félix; Bercoff, Jérémy; Montaldo, Gabriel; Loupas, T.; Fink, Mathias; Tanter, Mickaël

doi:10.1109/tuffc.2014.3049

Cited by 11 publications

(7 citation statements)

References 34 publications

(27 reference statements)

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“…To avoid the theoretical approximation done to calculate the pre factor of the TVCF of the noise 14 , we can directly retrieve the TVCF of the noise from the data. We compute the TVCF for every location in the image, as most of spatial pixels signals correspond to noise, the median of all TVCF will give the value of the TVCF of the noise.…”

Section: Methodsmentioning

confidence: 99%

Discriminative imaging of maternal and fetal blood flow within the placenta using ultrafast ultrasound

Osmanski

Lecarpentier

Montaldo

et al. 2015

Sci Rep

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Being able to map accurately placental blood flow in clinics could have major implications in the diagnosis and follow-up of pregnancy complications such as intrauterine growth restriction (IUGR). Moreover, the impact of such an imaging modality for a better diagnosis of placental dysfunction would require to solve the unsolved problem of discriminating the strongly intricated maternal and fetal vascular networks. However, no current imaging modality allows both to achieve sufficient sensitivity and selectivity to tell these entangled flows apart. Although ultrasound imaging would be the clinical modality of choice for such a problem, conventional Doppler echography both lacks of sensibility to detect and map the placenta microvascularization and a concept to discriminate both entangled flows. In this work, we propose to use an ultrafast Doppler imaging approach both to map with an enhanced sensitivity the small vessels of the placenta (~100 μm) and to assess the variation of the Doppler frequency simultaneously in all pixels of the image within a cardiac cycle. This approach is evaluated in vivo in the placenta of pregnant rabbits: By studying the local flow pulsatility pixel per pixel, it becomes possible to separate maternal and fetal blood in 2D from their pulsatile behavior. Significance Statement: The in vivo ability to image and discriminate maternal and fetal blood flow within the placenta is an unsolved problem which could improve the diagnosis of pregnancy complications such as intrauterine growth restriction or preeclampsia. To date, no imaging modality has both sufficient sensitivity and selectivity to discriminate these intimately entangled flows. We demonstrate that Ultrafast Doppler ultrasound method with a frame rate 100x faster than conventional imaging solves this issue. It permits the mapping of small vessels of the placenta (~100 μm) in 2D with an enhanced sensitivity. By assessing pixel-per-pixel pulsatility within single cardiac cycles, it achieves maternal and fetal blood flow discrimination.

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Section: Methodsmentioning

confidence: 99%

Discriminative imaging of maternal and fetal blood flow within the placenta using ultrafast ultrasound

Osmanski

Lecarpentier

Montaldo

et al. 2015

Sci Rep

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“…The phenomenon is called intrinsic spectral broadening and it occurs more or less in all the transducers, causing values overestimation. [17][18][19] Including flow data in ml/s could have resulted in an easier description. Nevertheless, flow measurement assessed by absolute values in ml/s leads to the potential systemic bias associated with the same intrinsic spectral broadening effect.…”

Section: Discussionmentioning

confidence: 99%

Altered velocity gradient in lower limb chronic venous disease

et al. 2018

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Background In physiology, velocity of the deep venous compartment is higher than the one in the saphenous compartment which is higher than the one in the tributaries. Considering that velocity variation is associated with changes in the pressure gradient, aim of the present study is to assess changes in venous kinetics in case of superficial chronic venous disease, so to provide further clues in venous drainage direction determination. Methods Venous ultrasound scanning was performed on 40 lower limbs of 28 chronic venous disease patients (C2-6Ep,As,Pr). Velocities were measured in three different venous segments: great saphenous vein at 2 cm above the origin of the incompetent tributary (Group-A). great saphenous vein at 2 cm below the origin of tributary (Group-B). tributary at 2 cm from its origin from the great saphenous vein (Group-C.) Results Diastolic time average velocity was higher in group-C (-21.3 ± 8.5 cm/s) than in group-A (-15.7 ± 5.2 cm/s; p = .0001) and group-B (-11.1 ± 2.9 cm/s; p = .0001), thus indicating an inversion of the physiological velocity gradient in chronic venous disease patients. Discussion Chronic venous disease presents a subverted velocity gradient. These data introduce objective hemodynamics data, paving the way for further investigation in venous drainage direction determination.

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“…If combined with an anti-aliasing algorithm, other least squares vector Doppler implementations such as that described by Yiu et al [34] could be used. If mean velocity estimates can be shown to be as reliable as maximum velocity estimates, it would be possible to use another velocity distribution estimator aimed at reducing spectral broadening [35], based on calculating histograms of mean velocities within a region of interest. Finally, using a single transmit angle instead of two allows use of the maximum PRF at the cost of reduced lateral resolution and a higher beam-to-flow angle when generating velocity spectra.…”

Section: Discussionmentioning

confidence: 99%

Combined 2-D Vector Velocity Imaging and Tracking Doppler for Improved Vascular Blood Velocity Quantification

Avdal

Løvstakken

Torp

et al. 2017

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

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Measurement of the maximum blood flow velocity is the primary means for determining the degree of carotid stenosis using ultrasound. The current standard for estimating the maximum velocity is pulsed-wave Doppler with manual angle correction, which is prone to error and interobserver variability. In addition, spectral broadening in the velocity spectra leads to overestimation of maximal velocities. In this paper, we propose to combine two velocity estimation methods to reduce the bias and variability in maximum velocity measurements. First, the direction of the blood flow is estimated using an aliasing-resistant least squares vector Doppler technique. Then, tracking Doppler is performed on the same data, using the direction of the vector Doppler estimate as the tracking direction. Simulations show that the method can estimate a maximum velocity of 2 m/s with accuracy 5% for beam-to-flow angles between 20° and 75°, and that the primary source of error is inaccuracy in the flow direction estimate from vector Doppler. Simulations of complex flow in a carotid bifurcation demonstrated that the combined technique provided spectral velocity profiles corresponding well with the true maximum velocity trace, and that the bias originating from the directional estimate was within 5% for all spatial points. A healthy volunteer and a volunteer with carotid artery stenosis were imaged, showing in vivo feasibility of the method, for high velocities and with beam-to-flow angles varying throughout the cardiac cycle.

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Cancellation of Doppler intrinsic spectral broadening using ultrafast Doppler imaging

Cited by 11 publications

References 34 publications

Discriminative imaging of maternal and fetal blood flow within the placenta using ultrafast ultrasound

Discriminative imaging of maternal and fetal blood flow within the placenta using ultrafast ultrasound

Altered velocity gradient in lower limb chronic venous disease

Combined 2-D Vector Velocity Imaging and Tracking Doppler for Improved Vascular Blood Velocity Quantification

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