5 research outputs found
Towards Non-contact 3D Ultrasound for Wrist Imaging
Objective: The objective of this work is an attempt towards non-contact
freehand 3D ultrasound imaging with minimal complexity added to the existing
point of care ultrasound (POCUS) systems. Methods: This study proposes a novel
approach of using a mechanical track for non-contact ultrasound (US) scanning.
The approach thus restricts the probe motion to a linear plane, to simplify the
acquisition and 3D reconstruction process. A pipeline for US 3D volume
reconstruction employing an US research platform and a GPU-based edge device is
developed. Results: The efficacy of the proposed approach is demonstrated
through ex-vivo and in-vivo experiments. Conclusion: The proposed approach with
the adjustable field of view capability, non-contact design, and low cost of
deployment without significantly altering the existing setup would open doors
for up gradation of traditional systems to a wide range of 3D US imaging
applications. Significance: Ultrasound (US) imaging is a popular clinical
imaging modality for the point-of-care bedside imaging, particularly of the
wrist/knee in the pediatric population due to its non-invasive and radiation
free nature. However, the limited views of tissue structures obtained with 2D
US in such scenarios make the diagnosis challenging. To overcome this, 3D US
imaging which uses 2D US images and their orientation/position to reconstruct
3D volumes was developed. The accurate position estimation of the US probe at
low cost has always stood as a challenging task in 3D reconstruction.
Additionally, US imaging involves contact, which causes difficulty to pediatric
subjects while monitoring live fractures or open wounds. Towards overcoming
these challenges, a novel framework is attempted in this work.Comment: 9 Pages, 11 figure
A Simplified 3D Ultrasound Freehand Imaging Framework Using 1D Linear Probe and Low-Cost Mechanical Track
Ultrasound imaging is the most popular medical imaging modality for
point-of-care bedside imaging. However, 2D ultrasound imaging provides only
limited views of the organ of interest, making diagnosis challenging. To
overcome this, 3D ultrasound imaging was developed, which uses 2D ultrasound
images and their orientation/position to reconstruct 3D volumes. The accurate
position estimation of the ultrasound probe at low cost has always stood as a
challenging task in 3D reconstruction. In this study, we propose a novel
approach of using a mechanical track for ultrasound scanning, which restricts
the probe motion to a linear plane, simplifying the acquisition and hence the
reconstruction process. We also present an end-to-end pipeline for 3D
ultrasound volume reconstruction and demonstrate its efficacy with an in-vitro
tube phantom study and an ex-vivo bone experiment. The comparison between a
sensorless freehand and the proposed mechanical track based acquisition is
available online (shorturl.at/jqvX0).Comment: 4 pages, 4 figure
Fast Marching based Tissue Adaptive Delay Estimation for Aberration Corrected Delay and Sum Beamforming in Ultrasound Imaging
Conventional ultrasound (US) imaging employs the delay and sum (DAS) receive
beamforming with dynamic receive focus for image reconstruction due to its
simplicity and robustness. However, the DAS beamforming follows a geometrical
method of delay estimation with a spatially constant speed-of-sound (SoS) of
1540 m/s throughout the medium irrespective of the tissue in-homogeneity. This
approximation leads to errors in delay estimations that accumulate with depth
and degrades the resolution, contrast and overall accuracy of the US image. In
this work, we propose a fast marching based DAS for focused transmissions which
leverages the approximate SoS map to estimate the refraction corrected
propagation delays for each pixel in the medium. The proposed approach is
validated qualitatively and quantitatively for imaging depths of upto ~ 11 cm
through simulations, where fat layer induced aberration is employed to alter
the SoS in the medium. To the best of authors' knowledge, this is the first
work considering the effect of SoS on image quality for deeper imaging.Comment: 5 pages, 4 figure