Synthetic elevation beamforming and image acquisition capabilities using an 8 /spl times/ 128 1.75D array

Fernandez, A.T.; Gammelmark, Kim; Dahl, Jeremy J.; Keen, C.G.; Gauss, R.C.; Trahey, Gregg E.

doi:10.1109/tuffc.2003.1176524

Cited by 34 publications

(15 citation statements)

References 17 publications

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“…This can be used to sample a large number of elements by using multiplexing as described in [25], which can be used for improving the focusing of the data in. e.g.. the elevation direction.…”

Section: Discussionmentioning

confidence: 99%

Directional synthetic aperture flow imaging

Jensen

Nikolov

2004

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

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Abstract-A method for flow estimation using synthetic aperture imaging and focusing along the flow direction is presented. The method can find the correct velocity magnitude for any flow angle, and full color flow images can be measured using only 32 to 128 pulse emissions. The approach uses spherical wave emissions with a number of defocused elements and a linear frequency-modulated pulse (chirp) to improve the signal-to-noise ratio. The received signals are dynamically focused along the flow direction and these signals are used in a cross-correlation estimator for finding the velocity magnitude. The flow angle is manually determined from the B-mode image. The approach can be used for both tissue and blood velocity determination. The approach was investigated using both simulations and a flow system with a laminar flow. The flow profile was measured with a commercial 7.5 MHz linear array transducer. A plastic tube with an internal diameter of 17 mm was used with an EcoWatt 1 pump generating a laminar, stationary flow. The velocity profile was measured for flow angles of 90 and 60 degrees. The RASMUS research scanner was used for acquiring radio frequency (RF) data from 128 elements of the array, using 8 emissions with 11 elements in each emission. A 20-s chirp was used during emission. The RF data were subsequently beamformed off-line and stationary echo canceling was performed. The 60-degree flow with a peak velocity of 0.15 m/s was determined using 16 groups of 8 emissions, and the relative standard deviation was 0.36% (0.65 mm/s). Using the same setup for purely transverse flow gave a standard deviation of 1.2% (2.1 mm/s). Variation of the different parameters revealed the sensitivity to number of lines, angle deviations, length of correlation interval, and sampling interval. An in vivo image of the carotid artery and jugular vein of a healthy 29-year-old volunteer was acquired. A full color flow image using only 128 emissions could be made with a high-velocity precision.

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Section: Discussionmentioning

confidence: 99%

Directional synthetic aperture flow imaging

Jensen

Nikolov

2004

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

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“…This large number of elements presents considerable technical challenges: fabrication, cross talk, interconnection, signal-to-noise ratio, complexity of electronics, etc. To balance the 3-D imaging need and the system complexity, 1.75-dimensional (1.75-D) arrays have been developed 32,33. These arrays have similar element size in azimuth compared with 2-D arrays, while in elevation the element size is considerably larger, thus limiting beam steering in elevation to a certain degree…”

Section: Introductionmentioning

confidence: 99%

Coregistered three-dimensional ultrasound and photoacoustic imaging system for ovarian tissue characterization

Aguirre¹,

Guo²,

Gamelin³

et al. 2009

J. Biomed. Opt.

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Ovarian cancer has the highest mortality of all gynecologic cancers, with a five-year survival rate of only 30% or less. Current imaging techniques are limited in sensitivity and specificity in detecting early stage ovarian cancer prior to its widespread metastasis. New imaging techniques that can provide functional and molecular contrasts are needed to reduce the high mortality of this disease. One such promising technique is photoacoustic imaging. We develop a 1280-element coregistered 3-D ultrasound and photoacoustic imaging system based on a 1.75-D acoustic array. Volumetric images over a scan range of 80 deg in azimuth and 20 deg in elevation can be achieved in minutes. The system has been used to image normal porcine ovarian tissue. This is an important step toward better understanding of ovarian cancer optical properties obtained with photoacoustic techniques. To the best of our knowledge, such data are not available in the literature. We present characterization measurements of the system and compare coregistered ultrasound and photoacoustic images of ovarian tissue to histological images. The results show excellent coregistration of ultrasound and photoacoustic images. Strong optical absorption from vasculature, especially highly vascularized corpora lutea and low absorption from follicles, is demonstrated.

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“…The multi-lag least-squares cross-correlation algorithm [11], [12], [17] has been used to correct aberrators in the breast and thyroid [13], [18] on 1-D and 1.75-D arrays, and we have previously expanded these results to 2-D matrix arrays [19]. We also wish to capitalize on the parallel-receive processing of our real-time 3-D (RT3D) scanner and implement the temporally-parallel partial-array reference algorithm [20], [21].…”

Section: Introductionmentioning

confidence: 99%

Comparison of 3-D multi-lag cross- correlation and speckle brightness aberration correction algorithms on static and moving targets

Ivancevich

Dahl

Smith

2009

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

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Phase correction has the potential to increase the image quality of 3-D ultrasound, especially transcranial ultrasound. We implemented and compared 2 algorithms for aberration correction, multilag cross-correlation and speckle brightness, using static and moving targets. We corrected three 75-ns rms electronic aberrators with full-width at half-maximum (FWHM) auto-correlation lengths of 1.35, 2.7, and 5.4 mm. Cross-correlation proved the better algorithm at 2.7 and 5.4 mm correlation lengths (P < 0.05). Static cross-correlation performed better than moving-target cross-correlation at the 2.7 mm correlation length (P < 0.05). Finally, we compared the static and moving-target crosscorrelation on a flow phantom with a skull casting aberrator. Using signal from static targets, the correction resulted in an average contrast increase of 22.2%, compared with 13.2% using signal from moving targets. The contrast-to-noise ratio (CNR) increased by 20.5% and 12.8% using static and moving targets, respectively. Doppler signal strength increased by 5.6% and 4.9% for the static and moving-targets methods, respectively.

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Synthetic elevation beamforming and image acquisition capabilities using an 8 /spl times/ 128 1.75D array

Cited by 34 publications

References 17 publications

Directional synthetic aperture flow imaging

Directional synthetic aperture flow imaging

Coregistered three-dimensional ultrasound and photoacoustic imaging system for ovarian tissue characterization

Comparison of 3-D multi-lag cross- correlation and speckle brightness aberration correction algorithms on static and moving targets

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