TY - JOUR
T1 - A Vector Flow Imaging Method for Portable Ultrasound Using Synthetic Aperture Sequential Beamforming
AU - Di Ianni, Tommaso
AU - Villagomez Hoyos, Carlos Armando
AU - Ewertsen, Caroline
AU - Kjeldsen, Thomas Kim
AU - Mosegaard, Jesper
AU - Nielsen, Michael Bachmann
AU - Jensen, Jorgen Arendt
PY - 2017/11/1
Y1 - 2017/11/1
N2 - This paper presents a vector flow imaging method for the integration of quantitative blood flow imaging in portable ultrasound systems. The method combines directional transverse oscillation (TO) and synthetic aperture sequential beamforming to yield continuous velocity estimation in the whole imaging region. Six focused emissions are used to create a high-resolution image (HRI), and a dual-stage beamforming approach is used to lower the data throughput between the probe and the processing unit. The transmit/receive focal points are laterally separated to obtain a TO in the HRI that allows for the velocity estimation along the lateral and axial directions using a phase-shift estimator. The performance of the method was investigated with constant flow measurements in a flow rig system using the SARUS scanner and a 4.1-MHz linear array. A sequence was designed with interleaved B-mode and flow emissions to obtain continuous data acquisition. A parametric study was carried out to evaluate the effect of critical parameters. The vessel was placed at depths from 20 to 40 mm, with beam-to-flow angles of 65 degrees, 75 degrees, and 90 degrees. For the lateral velocities at 20 mm, a bias between -5% and -6.2% was obtained, and the standard deviation (SD) was between 6% and 9.6%. The axial bias was lower than 1% with an SD around 2%. The mean estimated angles were 66.70 degrees +/- 2.86 degrees, 72.65 degrees +/- 2.48 degrees, and 89.13 degrees +/- 0.79 degrees for the three cases. A proof-of-concept demonstration of the real-time processing and wireless transmission was tested in a commercial tablet obtaining a frame rate of 27 frames/s and a data rate of 14 MB/s. An in vivo measurement of a common carotid artery of a healthy volunteer was finally performed to show the potential of the method in a realistic setting. The relative SD averaged over a cardiac cycle was 4.33%.
AB - This paper presents a vector flow imaging method for the integration of quantitative blood flow imaging in portable ultrasound systems. The method combines directional transverse oscillation (TO) and synthetic aperture sequential beamforming to yield continuous velocity estimation in the whole imaging region. Six focused emissions are used to create a high-resolution image (HRI), and a dual-stage beamforming approach is used to lower the data throughput between the probe and the processing unit. The transmit/receive focal points are laterally separated to obtain a TO in the HRI that allows for the velocity estimation along the lateral and axial directions using a phase-shift estimator. The performance of the method was investigated with constant flow measurements in a flow rig system using the SARUS scanner and a 4.1-MHz linear array. A sequence was designed with interleaved B-mode and flow emissions to obtain continuous data acquisition. A parametric study was carried out to evaluate the effect of critical parameters. The vessel was placed at depths from 20 to 40 mm, with beam-to-flow angles of 65 degrees, 75 degrees, and 90 degrees. For the lateral velocities at 20 mm, a bias between -5% and -6.2% was obtained, and the standard deviation (SD) was between 6% and 9.6%. The axial bias was lower than 1% with an SD around 2%. The mean estimated angles were 66.70 degrees +/- 2.86 degrees, 72.65 degrees +/- 2.48 degrees, and 89.13 degrees +/- 0.79 degrees for the three cases. A proof-of-concept demonstration of the real-time processing and wireless transmission was tested in a commercial tablet obtaining a frame rate of 27 frames/s and a data rate of 14 MB/s. An in vivo measurement of a common carotid artery of a healthy volunteer was finally performed to show the potential of the method in a realistic setting. The relative SD averaged over a cardiac cycle was 4.33%.
KW - Portable ultrasound
KW - synthetic aperture (SA)
KW - transverse oscillation (TO)
KW - vector flow imaging (VFI)
KW - SYSTEM
KW - TRANSVERSE OSCILLATION
KW - VELOCIMETRY
KW - AUTOCORRELATION
KW - VELOCITY ESTIMATION
KW - BLOOD-FLOW
KW - DOPPLER
UR - http://www.scopus.com/inward/record.url?scp=85028510265&partnerID=8YFLogxK
U2 - 10.1109/TUFFC.2017.2742599
DO - 10.1109/TUFFC.2017.2742599
M3 - Journal article
C2 - 28841555
AN - SCOPUS:85028510265
SN - 0885-3010
VL - 64
SP - 1655
EP - 1665
JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
IS - 11
M1 - 8013832
ER -