Strategies to Obtain Subpitch Precision in Lateral Motion Estimation in Ultrasound Elastography

Selladurai, Sathiyamoorthy; Thittai, Arun K.

doi:10.1109/tuffc.2018.2793195

Cited by 14 publications

(6 citation statements)

References 31 publications

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“…Recently, we demonstrated a method that involved translating the focused US beam of CLA transducer in subpitch range by the following two approaches: (a) ABT (actuator beam translation) uses actuator-assisted beam translation and (b) EBT (electronic beam translation) electronically translates the subaperture by activating an odd and even number of consecutive elements sequentially. [24][25][26] These techniques were shown to provide an opportunity to improve the LDE quality in a relatively inexpensive manner. EBT approach, which requires only reprogramming of the beamforming sequence and no hardware modifications, can provide subaperture translation by only half the element size.…”

Section: Introductionmentioning

confidence: 99%

Actuator-assisted Subpitch Translation-capable Transducer for Elastography: Preliminary Performance Assessment

Selladurai

Thittai

2020

Ultrason Imaging

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In conventional linear array (CLA)–based elastography tissue compression in one direction (e.g., axial) leads to an expansion in all other directions (lateral, elevation). Therefore, the estimation of the lateral displacements and strains may provide additional information on the tissue mechanical properties. However, these are not exploited fully due to the inherent limitation in lateral sampling. Recently, a method named actuator-assisted beam translation (ABT) was demonstrated to address this issue, wherein the focused beam was translated at subpitch locations using an external bench-top setup. However, because such bench-top setup may be impractical for routine clinical use, an ultrasound transducer was customized to have an internal actuator. The performance of the customized transducer was studied through experiments on phantoms for rotation elastography application, which requires precise lateral displacement estimation. Furthermore, the results obtained from ABT was compared against the currently practiced spatial displacement compounding (SDC) method, which is known to yield better quality lateral displacement estimates than conventional approaches. The results show that the ABT method yields a full-width half-maximum (FWHM) value, taken from the lateral profile across a point scatterer, which is 65% and 24% smaller than that obtained using CLA and SDC methods, respectively. Furthermore, the contrast-to-noise ratio (CNR) estimated from rotation elastogram obtained using ABT method is better by 300% and 35% compared with that obtained by using CLA and SDC methods, respectively. Furthermore, the results demonstrate an additional advantage of having larger field of view (FoV) for the ABT method compared with spatial compounding approach.

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Section: Introductionmentioning

confidence: 99%

Actuator-assisted Subpitch Translation-capable Transducer for Elastography: Preliminary Performance Assessment

Selladurai

Thittai

2020

Ultrason Imaging

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“…50 Recently, there have been many methods proposed to obtain better quality lateral displacement estimates in elastography. 18,[51][52][53] We are currently investigating on combining the reference layer methodology and inverse reconstruction approach having access to better quality lateral displacement estimates, and compare it with the simple approach proposed here.…”

Section: Discussionmentioning

confidence: 99%

Toward Quantitative and Operator-independent Quasi-static Ultrasound Elastography: An Ex Vivo Feasibility Study

2020

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It is known that the elasticity of liver reduces progressively in the case of diffuse liver disease. Currently, the diagnosis of diffuse liver disease requires a biopsy, which is an invasive procedure. In this paper, we evaluate and report a noninvasive method that can be used to quantify liver stiffness using quasi-static ultrasound elastography approach. Quasi-static elastography is popular in clinical applications where the qualitative assessment of relative tissue stiffness is enough, whereas its potential is relatively underutilized in liver imaging due to lack of local stiffness contrast in the case of diffuse liver disease. Recently, we demonstrated an approach of using a calibrated reference layer to produce quantitative modulus elastograms of the target tissue in simulations and phantom experiments. In a separate work, we reported the development of a compact handheld device to reduce inter- and intraoperator variability in freehand elastography. In this work, we have integrated the reference layer with a handheld controlled compression device and evaluate it for quantitative liver stiffness imaging application. The performance of this technique was assessed on ex vivo goat liver samples. The Young’s modulus values obtained from indentation measurements of liver samples acted as the ground truth for comparison. The results from this work demonstrate that by combining the handheld device along with reference layer, the estimated Young’s modulus value approaches the ground truth with less error compared with that obtained using freehand compression (8% vs. 15%). The results suggest that the intra- and interoperator reproducibility of the liver elasticity also improved when using the handheld device. Elastography with a handheld compression device and reference layer is a reliable and simple technique to provide a quantitative measure of elasticity.

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“…Another way of improving the RE image quality is by increasing the number of A-lines. In fact, some studies have shown that new A-lines can be incorporated by a sub-pitch translation of the ultrasonic beam or the ultrasound (US) probe itself [12], [13].…”

Section: Introductionmentioning

confidence: 99%

Rotation Elastogram Estimation Using Mechanical Assisted Spatial Compounding: An Experimental Validation Study

Zagaglioni,

Trejo,

Espíndola

et al. 2024

IEEE Access

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In quasi-static ultrasound elastography, breast tumor classification can be performed by using the rotation fill-in signature present in the rotation elastogram. This rotation fill-in signature is a benign tumors marker obtained from lesion rotation as a product of the lateral asymmetric stress field. However, the well-known low lateral resolution limitation of ultrasound imaging devices reduces the image quality of the rotation elastograms. Studies using beam-steering, synthetic transmit aperture (STA), diverging beam with STA, and sub-pitch translation of the ultrasonic beam methods have shown that the rotation elastogram's quality can be significantly improved. In this context, we aim to study the feasibility of improving the rotation elastogram quality by mechanical-assisted spatial compounding of displacement images from different ultrasound probe angles. Recently, through numerical simulations, we have shown the theoretical feasibility of this technique. Here, we present the corresponding experimental validation by using tissue-mimicking gelatin phantoms. Our experimental results show that the contrast-to-noise ratio of the rotation elastogram can be improved by approximately 5 dB by increasing the number of displacement images used in the spatial compounding for small scanning angles of about 1 • . This result confirms the prediction of previous numerical simulations. In addition, we show that the estimation of rotation can be used, in conjunction with the shear strain, to compute a new parameter to quantify the rotation possibility of the inclusion with respect to its shearing nature. In conclusion, our method is technically feasible but requires an exhaustive ultrasound probe position control in synchronism with the ultrasound image acquisition process.INDEX TERMS Quasi-static Ultrasound Elastography, Rotation elastogram, Shear strain elastogram, Spatial compounding.

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Strategies to Obtain Subpitch Precision in Lateral Motion Estimation in Ultrasound Elastography

Cited by 14 publications

References 31 publications

Actuator-assisted Subpitch Translation-capable Transducer for Elastography: Preliminary Performance Assessment

Actuator-assisted Subpitch Translation-capable Transducer for Elastography: Preliminary Performance Assessment

Toward Quantitative and Operator-independent Quasi-static Ultrasound Elastography: An Ex Vivo Feasibility Study

Rotation Elastogram Estimation Using Mechanical Assisted Spatial Compounding: An Experimental Validation Study

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