Design and construction of a low-frequency ultrasound acquisition device for 2-D brain imaging using full-waveform inversion
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The main techniques used to image the brain and obtain structural data are magnetic resonance imaging and X-ray computed tomography. These techniques produce images with high spatial resolution, but with the disadvantage of requiring very large equipment with special installation needs. In addition, X-ray tomography uses ionizing radiation, which limits their use. Ultrasound imaging is a safe technology that is delivered using compact and mobile devices. However, conventional ultrasound reconstruction techniques have failed to obtain images of the brain because of, fundamentally, the presence of the skull and the distortion that it produces on ultrasound. Recent studies have indicated that full-waveform inversion, a computational technique originally from Earth science, has the potential to generate accurate 3-D images of the brain. This technology can overcome the limitations of conventional ultrasound imaging, but a prototype for transcranial applications does not yet exist. Here, we investigate different designs of an annular array of ultrasound transducers to optimize the number of elements and rotations needed to conduct transcranial imaging with full-waveform inversion. This device uses small-diameter, low-frequency transducers that readily propagate ultrasound through the skull with good signal-to-noise ratios. It also incorporates the use of rotations to produce a high-density coverage of the target and acquire redundant traces that are beneficial for full-waveform inversion. We have built a ring of 40 transducers to illustrate that this design is capable of reconstructing images of the brain, retrieving its anatomy and acoustic properties with millimeter resolution. Laboratory results reveal the ability of this device to successfully image a 2.5-D brain- and skull-mimicking phantom using full-waveform inversion. To our knowledge, this is the first prototype ever used for transcranial-like imaging. The importance of these findings and their implications for the design of a 3-D reconstruction system with possible clinical applications are discussed.
Date Issued
2022-10-01
Date Acceptance
2022-05-17
Citation
Ultrasound in Medicine and Biology, 2022, 48 (10), pp.1995-2008
ISSN
0301-5629
Publisher
Elsevier
Start Page
1995
End Page
2008
Journal / Book Title
Ultrasound in Medicine and Biology
Volume
48
Issue
10
Copyright Statement
© 2022 The Author(s). Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine & Biology. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/35902276
PII: S0301-5629(22)00410-0
Subjects
Acoustics
ATTENUATION
Brain imaging
Full-waveform inversion
HEAD
Life Sciences & Biomedicine
Low frequency
Multi-element array
PROPAGATION
Radiology, Nuclear Medicine & Medical Imaging
SCATTERING
Science & Technology
SOUND
SPEED
Technology
TOMOGRAPHY
TRANSCRANIAL FOCUSED ULTRASOUND
Transcranial ultrasound
Transducer design
Ultrasound tomography
Publication Status
Published
Coverage Spatial
England
Date Publish Online
2022-07-25