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Xu R, Bestmann S, Treeby BE, Martin E. Strategies and safety simulations for ultrasonic cervical spinal cord neuromodulation. Phys Med Biol 2024; 69:125011. [PMID: 38788727 DOI: 10.1088/1361-6560/ad506f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/24/2024] [Indexed: 05/26/2024]
Abstract
Objective. Focused ultrasound spinal cord neuromodulation has been demonstrated in small animals. However, most of the tested neuromodulatory exposures are similar in intensity and exposure duration to the reported small animal threshold for possible spinal cord damage. All efforts must be made to minimize the risk and assure the safety of potential human studies, while maximizing potential treatment efficacy. This requires an understanding of ultrasound propagation and heat deposition within the human spine.Approach. Combined acoustic and thermal modelling was used to assess the pressure and heat distributions produced by a 500 kHz source focused to the C5/C6 level via two approaches (a) the posterior acoustic window between vertebral posterior arches, and (b) the lateral intervertebral foramen from which the C6 spinal nerve exits. Pulse trains of fifty 0.1 s pulses (pulse repetition frequency: 0.33 Hz, free-field spatial peak pulse-averaged intensity: 10 W cm-2) were simulated for four subjects and for ±10 mm translational and ±10∘rotational source positioning errors.Main results.Target pressures ranged between 20%-70% of free-field spatial peak pressures with the posterior approach, and 20%-100% with the lateral approach. When the posterior source was optimally positioned, peak spine heating values were below 1 ∘C, but source mispositioning resulted in bone heating up to 4 ∘C. Heating with the lateral approach did not exceed 2 ∘C within the mispositioning range. There were substantial inter-subject differences in target pressures and peak heating values. Target pressure varied three to four-fold between subjects, depending on approach, while peak heating varied approximately two-fold between subjects. This results in a nearly ten-fold range between subjects in the target pressure achieved per degree of maximum heating.Significance. This study highlights the utility of trans-spine ultrasound simulation software and need for precise source-anatomy positioning to assure the subject-specific safety and efficacy of focused ultrasound spinal cord therapies.
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Affiliation(s)
- Rui Xu
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
| | - Sven Bestmann
- Department of Clinical and Movement Neuroscience, University College London, London, United Kingdom
| | - Bradley E Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Eleanor Martin
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
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2
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Bae S, Liu K, Pouliopoulos AN, Ji R, Jiménez-Gambín S, Yousefian O, Kline-Schoder AR, Batts AJ, Tsitsos FN, Kokossis D, Mintz A, Honig LS, Konofagou EE. Transcranial Blood-Brain Barrier Opening in Alzheimer's Disease Patients Using a Portable Focused Ultrasound System with Real-Time 2-D Cavitation Mapping. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2023.12.21.23300222. [PMID: 38196636 PMCID: PMC10775403 DOI: 10.1101/2023.12.21.23300222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Background Focused ultrasound (FUS) in combination with microbubbles has recently shown great promise in facilitating blood-brain barrier (BBB) opening for drug delivery and immunotherapy in Alzheimer's disease (AD). However, it is currently limited to systems integrated within the MRI suites or requiring post-surgical implants, thus restricting its widespread clinical adoption. In this pilot study, we investigate the clinical safety and feasibility of a portable, non-invasive neuronavigation-guided FUS (NgFUS) system with integrated real-time 2-D microbubble cavitation mapping. Methods A phase 1 clinical study with mild to moderate AD patients (N=6) underwent a single session of microbubble-mediated NgFUS to induce transient BBB opening (BBBO). Microbubble activity under FUS was monitored with real-time 2-D cavitation maps and dosing to ensure the efficacy and safety of the NgFUS treatment. Post-operative MRI was used for BBB opening and closure confirmation as well as safety assessment. Changes in AD biomarker levels in both blood serum and extracellular vesicles (EVs) were evaluated, while changes in amyloid-beta (Aβ) load in the brain were assessed through 18F-Florbetapir PET. Results BBBO was achieved in 5 out of 6 subjects with an average volume of 983±626 mm3 following FUS at the right frontal lobe both in white and gray matter regions. The outpatient treatment was completed within 34.8±10.7 min. Cavitation dose significantly correlated with the BBBO volume (R2>0.9, N=4), demonstrating the portable NgFUS system's capability of predicting opening volumes. The cavitation maps co-localized closely with the BBBO location, representing the first report of real-time transcranial 2-D cavitation mapping in the human brain. Larger opening volumes correlated with increased levels of AD biomarkers, including Aβ42 (R2=0.74), Tau (R2=0.95), and P-Tau181 (R2=0.86), assayed in serum-derived EVs sampled 3 days after FUS (N=5). From PET scans, subjects showed a lower Aβ load increase in the treated frontal lobe region compared to the contralateral region. Reduction in asymmetry standardized uptake value ratios (SUVR) correlated with the cavitation dose (R2>0.9, N=3). Clinical changes in the mini-mental state examination over 6 months were within the expected range of cognitive decline with no additional changes observed as a result of FUS. Conclusion We showed the safety and feasibility of this cost-effective and time-efficient portable NgFUS treatment for BBBO in AD patients with the first demonstration of real-time 2-D cavitation mapping. The cavitation dose correlated with BBBO volume, a slowed increase in pathology, and serum detection of AD proteins. Our study highlights the potential for accessible FUS treatment in AD, with or without drug delivery.
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Affiliation(s)
- Sua Bae
- Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA
| | - Keyu Liu
- Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA
| | | | - Robin Ji
- Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA
| | | | - Omid Yousefian
- Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA
| | | | - Alec J. Batts
- Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA
| | - Fotios N. Tsitsos
- Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA
| | - Danae Kokossis
- Department of Radiation Oncology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Akiva Mintz
- Department of Radiology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Lawrence S. Honig
- Department of Neurology and Taub Institute, Columbia University Irving Medical Center 10032, New York, NY, USA
| | - Elisa E. Konofagou
- Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA
- Department of Radiology, Columbia University Irving Medical Center, New York, NY 10032, USA
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Zhao Y, Feng Y, Wu L. Nonlinear effects of dual-frequency focused ultrasound on the on-demand regulation of acoustic droplet vaporization. ULTRASONICS SONOCHEMISTRY 2024; 104:106848. [PMID: 38490060 PMCID: PMC10955418 DOI: 10.1016/j.ultsonch.2024.106848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 03/17/2024]
Abstract
Dual-frequency ultrasound has been widely employed to enhance and regulate acoustic droplet vaporization (ADV) but the role of ultrasonic nonlinear effects on it remains unclear. The main objective of this study is to investigate the influence of nonlinear effects on the control of ADV nucleation under different dual-frequency focused ultrasound conditions. ADV nucleation of PFC nanodroplets activated by nonlinear dual-frequency ultrasound was modeled and parametric studies were conducted to investigate the influence of dual-frequency ultrasound frequency and acoustic power on the degree of nonlinearity (DoN), nucleation rates and dimensions of the nucleation region in a wide parameter range. The results showed that the ultrasonic nonlinearity caused a significant decrease in peak negative pressure due to waveform distortion, which leads to a lower nucleation rate in the nonlinear model compared to that in the linear model. Furthermore, the distributions of nucleation regions were also affected by the interaction between waves of different frequencies and cloud-like spatial distributions were produced, which could be modulated by the dual-frequency ultrasound parameters and have great potentials in the spatial regulation of the ADV and customized treatment protocols in clinical applications. In addition, represented by 1.5 MHz + 3 MHz, such a dual-frequency combination of fundamental and second harmonic could effectively enhance ultrasonic nonlinear effects with relatively lower peak negative pressure and higher DoN. Therefore, nonlinear effect of the dual-frequency ultrasound plays an important role in the ADV regulation, which should be considered in the numerical model and practical applications.
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Affiliation(s)
- Yubo Zhao
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Yi Feng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
| | - Liang Wu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
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Rosnitskiy PB, Khokhlova TD, Schade GR, Sapozhnikov OA, Khokhlova VA. Treatment Planning and Aberration Correction Algorithm for HIFU Ablation of Renal Tumors. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2024; 71:341-353. [PMID: 38231825 PMCID: PMC11003458 DOI: 10.1109/tuffc.2024.3355390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
High-intensity focused ultrasound (HIFU) applications for thermal or mechanical ablation of renal tumors often encounter challenges due to significant beam aberration and refraction caused by oblique beam incidence, inhomogeneous tissue layers, and presence of gas and bones within the beam. These losses can be significantly mitigated through sonication geometry planning, patient positioning, and aberration correction using multielement phased arrays. Here, a sonication planning algorithm is introduced, which uses the simulations to select the optimal transducer position and evaluate the effect of aberrations and acoustic field quality at the target region after aberration correction. Optimization of transducer positioning is implemented using a graphical user interface (GUI) to visualize a segmented 3-D computed tomography (CT)-based acoustic model of the body and to select sonication geometry through a combination of manual and automated approaches. An HIFU array (1.5 MHz, 256 elements) and three renal cell carcinoma (RCC) cases with different tumor locations and patient body habitus were considered. After array positioning, the correction of aberrations was performed using a combination of backpropagation from the focus with an ordinary least squares (OLS) optimization of phases at the array elements. The forward propagation was simulated using a combination of the Rayleigh integral and k-space pseudospectral method (k-Wave toolbox). After correction, simulated HIFU fields showed tight focusing and up to threefold higher maximum pressure within the target region. The addition of OLS optimization to the aberration correction method yielded up to 30% higher maximum pressure compared to the conventional backpropagation and up to 250% higher maximum pressure compared to the ray-tracing method, particularly in strongly distorted cases.
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5
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Liu S, Wang T, Zheng X, Zhu Y, Tian C. On the imaging depth limit of photoacoustic tomography in the visible and first near-infrared windows. OPTICS EXPRESS 2024; 32:5460-5480. [PMID: 38439272 DOI: 10.1364/oe.513538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 01/21/2024] [Indexed: 03/06/2024]
Abstract
It is well known that photoacoustic tomography (PAT) can circumvent the photon scattering problem in optical imaging and achieve high-contrast and high-resolution imaging at centimeter depths. However, after two decades of development, the long-standing question of the imaging depth limit of PAT in biological tissues remains unclear. Here we propose a numerical framework for evaluating the imaging depth limit of PAT in the visible and the first near-infrared windows. The established framework simulates the physical process of PAT and consists of seven modules, including tissue modelling, photon transportation, photon to ultrasound conversion, sound field propagation, signal reception, image reconstruction, and imaging depth evaluation. The framework can simulate the imaging depth limits in general tissues, such as the human breast, the human abdomen-liver tissues, and the rodent whole body and provide accurate evaluation results. The study elucidates the fundamental imaging depth limit of PAT in biological tissues and can provide useful guidance for practical experiments.
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Billot G, Marinus BG, Harri K, Moiny F. Evolution of acoustic nonlinearity in outdoor blast propagation from firearms: On the persistence of nonlinear behavior. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:1021-1035. [PMID: 38341738 DOI: 10.1121/10.0024725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 01/16/2024] [Indexed: 02/13/2024]
Abstract
Acoustic events exceeding a certain threshold of intensity cannot benefit from a linearization of the governing wave equation, posing an additional burden on the numerical modelling. Weak shock theory associates nonlinearity with the generation of high frequency harmonics that compensate for atmospheric attenuation. Overlooking the persistence of this phenomenon at large distances can lead to mispredictions in gun detection procedures, noise abatement protocols, and auditory risk assessment. The state-of-the-art mostly addresses aircraft jet noise, a stationary and largely random type of signal. The extension of such conclusions to muzzle blasts requires caution in considering their peculiar impulsive and broadband nature. A methodology based on the time and frequency analysis of an experimental dataset of eight calibres intends to find quantitative metrics linked to acoustic nonlinearity in outdoor muzzle blast propagation. Propagating three waveforms (SCAR-L 7.62 mm, Browning 9 mm, and Howitzer 105 mm) up to 300 [m] with the in-house numerical solver based on the nonlinear progressive wave equation, demonstrates that the propagation does not downgrade to truly linear.
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Affiliation(s)
- Guido Billot
- Department of Mechanical Engineering, Royal Military Academy, Brussels, Belgium
| | - Benoît G Marinus
- Department of Mechanical Engineering, Royal Military Academy, Brussels, Belgium
| | - Kristof Harri
- Department of Mechanical Engineering, Royal Military Academy, Brussels, Belgium
| | - Francis Moiny
- Faculty of Engineering (General Physics Unit), University of Mons, Mons, Belgium
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Singh A, Jiménez-Gambín S, Konofagou EE. An all-ultrasound cranial imaging method to establish the relationship between cranial FUS incidence angle and transcranial attenuation in non-human primates in 3D. Sci Rep 2024; 14:1488. [PMID: 38233480 PMCID: PMC10794232 DOI: 10.1038/s41598-024-51623-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 01/08/2024] [Indexed: 01/19/2024] Open
Abstract
Focused ultrasound (FUS) is a non-invasive and non-ionizing technique which deploys ultrasound waves to induce bio-effects. When paired with acoustically active particles such as microbubbles (MBs), it can open the blood brain barrier (BBB) to facilitate drug delivery otherwise inhibited due to the presence of BBB. One of the parameters that affects the FUS beam propagation is the beam incidence angle on the skull. Prior work by our group has shown that, as incidence angles deviate from 90°, FUS focal pressures attenuate and result in a smaller BBB opening volume. The incidence angles calculated in our prior studies were in 2D and used skull information from CT. The study presented herein develops methods to calculate incidence angle in 3D in non-human primate (NHP) skull fragments using harmonic ultrasound imaging without using ionizing radiation. Our results show that ultrasound harmonic imaging is capable of accurately depicting features such as sutures and eye-sockets of the skull. Furthermore, we were able to reproduce previously reported relationships between the incidence angle and FUS beam attenuation. We also show feasibility of performing ultrasound harmonic imaging in in-vivo non-human primates. The all-ultrasound method presented herein combined with our neuronavigation system stands to increase more widespread adoption of FUS and render it accessible by eliminating the need for CT cranial mapping.
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Affiliation(s)
- Aparna Singh
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | | | - Elisa E Konofagou
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
- Department of Radiology, Columbia University, New York, NY, USA.
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8
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Nagaoka R, Omura M, Hasegawa H. Investigation of a method to estimate the average speed of sound using phase variances of element signals for ultrasound compound imaging. J Med Ultrason (2001) 2024; 51:17-28. [PMID: 37947986 PMCID: PMC10954954 DOI: 10.1007/s10396-023-01378-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 09/06/2023] [Indexed: 11/12/2023]
Abstract
PURPOSE In the receive beamforming of an ultrasonography system, a B-mode image is reconstructed by assuming an average speed of sound (SoS) as a constant value. In our previous studies, we proposed a method for estimating the average SoS based on the coherence factor (CF) and the reciprocal of phase variances of element signals in delay-and-sum (DAS) beamforming. In this paper, we investigate the accuracy of estimation of the average SoS for compound imaging. METHODS For this purpose, two numerical simulations were performed with k-Wave software. Also, the estimation methods based on the CF and the reciprocal were applied to in vivo data from the common carotid artery, and B-mode images were reconstructed using the estimated average SoS. RESULTS In the first numerical simulation using an inhomogeneous phantom, the relationship between the accuracy and the transmission angles for the estimation was investigated, and the root mean squared errors (RMSEs) of estimates obtained based on the CF and the reciprocal of the phase variance were 1.25 ± 0.09, and 0.765 ± 0.17% at the transmission sequence of steering angles of (- 10°, - 5°, 0°, 5°, 10°), respectively. In the second numerical simulation using a cyst phantom, lateral resolutions were improved by reconstructing the image using the estimates obtained using the proposed strategy (reciprocal). By the proposed strategy, improvement of the continuity of the lumen-intima interface in the lateral direction was observed in the in vivo experiment. CONCLUSION Consequently, the results indicated that the proposed strategy was beneficial for estimation of the average SoS and image reconstruction.
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Affiliation(s)
- Ryo Nagaoka
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan.
| | - Masaaki Omura
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
| | - Hideyuki Hasegawa
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
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9
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Yin Y, Yan S, Huang J, Zhang B. Transcranial Ultrasonic Focusing by a Phased Array Based on Micro-CT Images. SENSORS (BASEL, SWITZERLAND) 2023; 23:9702. [PMID: 38139547 PMCID: PMC10747353 DOI: 10.3390/s23249702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 11/30/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023]
Abstract
In this paper, we utilize micro-computed tomography (micro-CT) to obtain micro-CT images with a resolution of 60 μm and establish a micro-CT model based on the k-wave toolbox, which can visualize the microstructures in trabecular bone, including pores and bone layers. The transcranial ultrasound phased array focusing field characteristics in the micro-CT model are investigated. The ultrasonic waves are multiply scattered in skull and time delays calculations from the transducer to the focusing point are difficult. For this reason, we adopt the pulse compression method and the linear frequency modulation Barker code to compute the time delay and implement phased array focusing in the micro-CT model. It is shown by the simulation results that ultrasonic loss is mainly caused by scattering from the microstructures of the trabecular bone. The ratio of main and side lobes of the cross-correlation calculation is improved by 5.53 dB using the pulse compression method. The focusing quality and the calculation accuracy of time delay are improved. Meanwhile, the beamwidth at the focal point and the sound pressure amplitude decrease with the increase in the signal frequency. Focusing at different depths indicates that the beamwidth broadens with the increase in the focusing depth, and beam deflection focusing maintains good consistency in the focusing effect at a distance of 9 mm from the focal point. This indicates that the phased-array method has good focusing results and focus tunability in deep cranial brain. In addition, the sound pressure at the focal point can be increased by 8.2% through amplitude regulation, thereby enhancing focusing efficiency. The preliminary experiment verification is conducted with an ex vivo skull. It is shown by the experimental results that the phased array focusing method using pulse compression to calculate the time delay can significantly improve the sound field focusing effect and is a very effective transcranial ultrasound focusing method.
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Affiliation(s)
- Yuxin Yin
- Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China; (Y.Y.); (S.Y.); (B.Z.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shouguo Yan
- Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China; (Y.Y.); (S.Y.); (B.Z.)
| | - Juan Huang
- Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China; (Y.Y.); (S.Y.); (B.Z.)
| | - Bixing Zhang
- Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China; (Y.Y.); (S.Y.); (B.Z.)
- University of Chinese Academy of Sciences, Beijing 100049, China
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10
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Kakkar M, Patil JM, Trivedi V, Yadav A, Saha RK, Rao S, Vazhayil V, Pandya HJ, Mahadevan A, Shekhar H, Mercado-Shekhar KP. Hermite-scan imaging for differentiating glioblastoma from normal brain: Simulations and ex vivo studies for applications in intra-operative tumor identificationa). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 154:3833-3841. [PMID: 38109407 DOI: 10.1121/10.0023952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 11/28/2023] [Indexed: 12/20/2023]
Abstract
Hermite-scan (H-scan) imaging is a tissue characterization technique based on the analysis of raw ultrasound radio frequency (RF) echoes. It matches the RF echoes to Gaussian-weighted Hermite polynomials of various orders to extract information related to scatterer diameter. It provides a color map of large and small scatterers in the red and blue H-scan image channels, respectively. H-scan has been previously reported for characterizing breast, pancreatic, and thyroid tumors. The present work evaluated H-scan imaging to differentiate glioblastoma tumors from normal brain tissue ex vivo. First, we conducted 2-D numerical simulations using the k-wave toolbox to assess the performance of parameters derived from H-scan images of acoustic scatterers (15-150 μm diameters) and concentrations (0.2%-1% w/v). We found that the parameter intensity-weighted percentage of red (IWPR) was sensitive to changes in scatterer diameters independent of concentration. Next, we assessed the feasibility of using the IWPR parameter for differentiating glioblastoma and normal brain tissues (n = 11 samples per group). The IWPR parameter estimates for normal tissue (44.1% ± 1.4%) were significantly different (p < 0.0001) from those for glioblastoma (36.2% ± 0.65%). These findings advance the development of H-scan imaging for potential use in differentiating glioblastoma tumors from normal brain tissue during resection surgery.
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Affiliation(s)
- Manik Kakkar
- Department of Electrical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Jagruti M Patil
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Vishwas Trivedi
- Department of Electrical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Anushka Yadav
- Department of Electrical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Ratan K Saha
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Prayagraj, Uttar Pradesh 211015, India
| | - Shilpa Rao
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka 560029, India
| | - Vikas Vazhayil
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka 560029, India
| | - Hardik J Pandya
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Anita Mahadevan
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka 560029, India
| | - Himanshu Shekhar
- Department of Electrical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Karla P Mercado-Shekhar
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
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Sallam A, Shahab S. Nonlinear Acoustic Holography With Adaptive Sampling. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2023; 70:1516-1526. [PMID: 37703162 DOI: 10.1109/tuffc.2023.3315011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Accurate and efficient numerical simulation of highly nonlinear ultrasound propagation is essential for a wide range of therapeutic and physical ultrasound applications. However, due to large domain sizes and the generation of higher harmonics, such simulations are computationally challenging, particularly in 3-D problems with shock waves. Current numerical methods are based on computationally inefficient uniform meshes that resolve the highest harmonics across the entire spatial domain. To address this challenge, we present an adaptive numerical algorithm for computationally efficient nonlinear acoustic holography. At each propagation step, the algorithm monitors the harmonic content of the acoustic signal and adjusts its discretization parameters accordingly. This enables efficient local resolution of higher harmonics in areas of high nonlinearity while avoiding unnecessary resolution elsewhere. Furthermore, the algorithm actively adapts to the signal's nonlinearity level, eliminating the need for prior reference simulations or information about the spatial distribution of the harmonic content of the acoustic field. The proposed algorithm incorporates an upsampling process in the frequency domain to accommodate the generation of higher harmonics in forward propagation and a downsampling process when higher harmonics are decimated in backward propagation. The efficiency of the algorithm was evaluated for highly nonlinear 3-D problems, demonstrating a significant reduction in computational cost with a nearly 50-fold speedup over a uniform mesh implementation. Our findings enable a more rapid and efficient approach to modeling nonlinear high-intensity focused ultrasound (HIFU) wave propagation.
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Li F, Villa U, Duric N, Anastasio MA. A Forward Model Incorporating Elevation-Focused Transducer Properties for 3-D Full-Waveform Inversion in Ultrasound Computed Tomography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2023; 70:1339-1354. [PMID: 37682648 PMCID: PMC10775680 DOI: 10.1109/tuffc.2023.3313549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/10/2023]
Abstract
Ultrasound computed tomography (USCT) is an emerging medical imaging modality that holds great promise for improving human health. Full-waveform inversion (FWI)-based image reconstruction methods account for the relevant wave physics to produce high spatial resolution images of the acoustic properties of the breast tissues. A practical USCT design employs a circular ring-array comprised of elevation-focused ultrasonic transducers, and volumetric imaging is achieved by translating the ring-array orthogonally to the imaging plane. In commonly deployed slice-by-slice (SBS) reconstruction approaches, the 3-D volume is reconstructed by stacking together 2-D images reconstructed for each position of the ring-array. A limitation of the SBS reconstruction approach is that it does not account for 3-D wave propagation physics and the focusing properties of the transducers, which can result in significant image artifacts and inaccuracies. To perform 3-D image reconstruction when elevation-focused transducers are employed, a numerical description of the focusing properties of the transducers should be included in the forward model. To address this, a 3-D computational model of an elevation-focused transducer is developed to enable 3-D FWI-based reconstruction methods to be deployed in ring-array-based USCT. The focusing is achieved by applying a spatially varying temporal delay to the ultrasound pulse (emitter mode) and recorded signal (receiver mode). The proposed numerical transducer model is quantitatively validated and employed in computer simulation studies that demonstrate its use in image reconstruction for ring-array USCT.
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Bae S, Liu K, Pouliopoulos AN, Ji R, Konofagou EE. Real-Time Passive Acoustic Mapping With Enhanced Spatial Resolution in Neuronavigation-Guided Focused Ultrasound for Blood-Brain Barrier Opening. IEEE Trans Biomed Eng 2023; 70:2874-2885. [PMID: 37159313 PMCID: PMC10538424 DOI: 10.1109/tbme.2023.3266952] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
OBJECTIVE Passive acoustic mapping (PAM) provides the spatial information of acoustic energy emitted from microbubbles during focused ultrasound (FUS), which can be used for safety and efficacy monitoring of blood-brain barrier (BBB) opening. In our previous work with a neuronavigation-guided FUS system, only part of the cavitation signal could be monitored in real time due to the computational burden although full-burst analysis is required to detect transient and stochastic cavitation activity. In addition, the spatial resolution of PAM can be limited for a small-aperture receiving array transducer. For full-burst real-time PAM with enhanced resolution, we developed a parallel processing scheme for coherence-factor-based PAM (CF-PAM) and implemented it onto the neuronavigation-guided FUS system using a co-axial phased-array imaging transducer. METHODS Simulation and in-vitro human skull studies were conducted for the performance evaluation of the proposed method in terms of spatial resolution and processing speed. We also carried out real-time cavitation mapping during BBB opening in non-human primates (NHPs). RESULTS CF-PAM with the proposed processing scheme provided better resolution than that of traditional time-exposure-acoustics PAM with a higher processing speed than that of eigenspace-based robust Capon beamformer, which facilitated the full-burst PAM with the integration time of 10 ms at a rate of 2 Hz. In vivo feasibility of PAM with the co-axial imaging transducer was also demonstrated in two NHPs, showing the advantages of using real-time B-mode and full-burst PAM for accurate targeting and safe treatment monitoring. SIGNIFICANCE This full-burst PAM with enhanced resolution will facilitate the clinical translation of online cavitation monitoring for safe and efficient BBB opening.
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14
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Preston C, Alvarez AM, Allard M, Barragan A, Witte RS. Acoustoelectric Time-Reversal for Ultrasound Phase-Aberration Correction. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2023; 70:854-864. [PMID: 37405897 PMCID: PMC10493188 DOI: 10.1109/tuffc.2023.3292595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
Acoustoelectric imaging (AEI) is a technique that combines ultrasound (US) with radio frequency recording to detect and map local current source densities. This study demonstrates a new method called acoustoelectric time reversal (AETR), which uses AEI of a small current source to correct for phase aberrations through a skull or other US-aberrating layers with applications to brain imaging and therapy. Simulations conducted at three different US frequencies (0.5, 1.5, and 2.5 MHz) were performed through media layered with different sound speeds and geometries to induce aberrations of the US beam. Time delays of the acoustoelectric (AE) signal from a monopole within the medium were calculated for each element to enable corrections using AETR. Uncorrected aberrated beam profiles were compared with those after applying AETR corrections, which demonstrated a strong recovery (29%-100%) of lateral resolution and increases in focal pressure up to 283%. To further demonstrate the practical feasibility of AETR, we further conducted bench-top experiments using a 2.5 MHz linear US array to perform AETR through 3-D-printed aberrating objects. These experiments restored lost lateral restoration up to 100% for the different aberrators and increased focal pressure up to 230% after applying AETR corrections. Cumulatively, these results highlight AETR as a powerful tool for correcting focal aberrations in the presence of a local current source with applications to AEI, US imaging, neuromodulation, and therapy.
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15
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Ali R, Brevett T, Zhuang L, Bendjador H, Podkowa AS, Hsieh SS, Simson W, Sanabria SJ, Herickhoff CD, Dahl JJ. Aberration correction in diagnostic ultrasound: A review of the prior field and current directions. Z Med Phys 2023; 33:267-291. [PMID: 36849295 PMCID: PMC10517407 DOI: 10.1016/j.zemedi.2023.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/17/2022] [Accepted: 01/09/2023] [Indexed: 02/27/2023]
Abstract
Medical ultrasound images are reconstructed with simplifying assumptions on wave propagation, with one of the most prominent assumptions being that the imaging medium is composed of a constant sound speed. When the assumption of a constant sound speed are violated, which is true in most in vivoor clinical imaging scenarios, distortion of the transmitted and received ultrasound wavefronts appear and degrade the image quality. This distortion is known as aberration, and the techniques used to correct for the distortion are known as aberration correction techniques. Several models have been proposed to understand and correct for aberration. In this review paper, aberration and aberration correction are explored from the early models and correction techniques, including the near-field phase screen model and its associated correction techniques such as nearest-neighbor cross-correlation, to more recent models and correction techniques that incorporate spatially varying aberration and diffractive effects, such as models and techniques that rely on the estimation of the sound speed distribution in the imaging medium. In addition to historical models, future directions of ultrasound aberration correction are proposed.
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Affiliation(s)
- Rehman Ali
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA
| | - Thurston Brevett
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Louise Zhuang
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Hanna Bendjador
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Anthony S Podkowa
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Scott S Hsieh
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Walter Simson
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Sergio J Sanabria
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA; University of Deusto/ Ikerbasque Basque Foundation for Science, Bilbao, Spain
| | - Carl D Herickhoff
- Department of Biomedical Engineering, University of Memphis, TN, USA
| | - Jeremy J Dahl
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA.
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16
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Zhou C, Xu K, Ta D. Frequency-domain full-waveform inversion-based musculoskeletal ultrasound computed tomography. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 154:279-294. [PMID: 37449785 DOI: 10.1121/10.0020151] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 06/27/2023] [Indexed: 07/18/2023]
Abstract
Recently, full-waveform inversion (FWI) has become a promising tool for ultrasound computed tomography (USCT). However, as a computationally intensive technique, FWI suffers from computational burden, especially in conventional time-domain full-waveform inversion (TDFWI). On the contrary, frequency-domain full-waveform inversion (FDFWI) provides a relatively high computational efficiency as the propagation of discrete frequencies is much cheaper than full time-domain modeling. FDFWI has already been applied in soft tissue imaging, such as breast, but for the musculoskeletal model with high impedance contrast between hard and soft tissues, there is still a lack of an effective source estimation method. In this paper, a water-referenced data calibration method is proposed to address the source estimation challenge in the presence of bones, which achieves consistency between the measured and simulated data before the FDFWI procedure. To avoid the cycle-skipping local minimum effect and facilitate the algorithm convergence, a starting frequency criterion for musculoskeletal FDFWI is further proposed. The feasibility of the proposed method is demonstrated by numerical studies on retrieving the anatomies of the leg models and different musculoskeletal lesions. The study extends the advanced FDFWI method to the musculoskeletal system and provides an alternative solution for musculoskeletal USCT imaging with high computational efficiency.
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Affiliation(s)
- Chenchen Zhou
- Center for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
| | - Kailiang Xu
- Center for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
| | - Dean Ta
- Center for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
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17
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Patchett BD, Anderson BE, Kingsley AD. Numerical modeling of Mach-stem formation in high-amplitude time-reversal focusing. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:2724. [PMID: 37133812 DOI: 10.1121/10.0017974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 04/07/2023] [Indexed: 05/04/2023]
Abstract
In acoustics, time-reversal processing is commonly used to exploit multiple scatterings in reverberant environments to focus sound to a specific location. Recently, the nonlinear characteristics of time-reversal focusing at amplitudes as high as 200 dB have been reported [Patchett and Anderson, J. Acoust. Soc. Am. 151(6), 3603-3614 (2022)]. These studies were experimental in nature and suggested that converging waves nonlinearly interact in the focusing of waves, leading to nonlinear amplification. This study investigates the nonlinear interactions and subsequent characteristics from a model-based approach. Utilizing both finite difference and finite-element models, it is shown that nonlinear interactions between high-amplitude waves lead to free-space Mach-wave coalescence of the converging waves. The number of waves used in both models represents a small piece of the full aperture of converging waves experimentally. Limiting the number of waves limits the number of Mach-stem formations and reduces the nonlinear growth of the focus amplitudes when compared to experiment. However, limiting the number of waves allows the identification of individual Mach waves. Mach wave coalescence leading to Mach-stem formation appears to be the mechanism behind nonlinear amplification of peak focus amplitudes observed in high-amplitude time-reversal focusing.
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Affiliation(s)
- Brian D Patchett
- Acoustics Research Group, Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA
| | - Brian E Anderson
- Acoustics Research Group, Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA
| | - Adam D Kingsley
- Acoustics Research Group, Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA
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18
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Rohlén R, Jiang B, Nyman E, Wester P, Näslund U, Grönlund C. Interframe Echo Intensity Variation of Subregions and Whole Plaque in Two-Dimensional Carotid Ultrasonography: Simulations and In Vivo Observations. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2023; 42:1033-1046. [PMID: 36264181 DOI: 10.1002/jum.16114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/26/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
OBJECTIVES The risk of cardiovascular disease is associated with the echo intensity of carotid plaques in ultrasound images and their cardiac cycle-induced intensity variations. In this study, we aimed to 1) explore the underlying origin of echo intensity variations by using simulations and 2) evaluate the association between the two-dimensional (2D) spatial distribution of these echo intensity variations and plaque vulnerability. METHODS First, we analyzed how out-of-plane motion and compression of simulated scattering spheres of different sizes affect the ultrasound echo intensity. Next, we propose a method to analyze the features of the 2D spatial distribution of interframe plaque echo intensity in carotid ultrasound image sequences and explore their associations with plaque vulnerability in experimental data. RESULTS The simulations showed that the magnitude of echo intensity changes was similar for both the out-of-plane motion and compression, but for scattering objects smaller than 1 mm radius, the out-of-plane motion dominated. In experimental data, maps of the 2D spatial distribution of the echo intensity variations had a low correlation with standard B-mode echo intensity distribution, indicating complementary information on plaque tissue composition. In addition, we found the existence of ∼1 mm diameter subregions with pronounced echo intensity variations associated with plaque vulnerability. CONCLUSIONS The results indicate that out-of-plane motion contributes to intra-plaque regions of high echo intensity variation. The 2D echo intensity variation maps may provide complementary information for assessing plaque composition and vulnerability. Further studies are needed to verify this method's role in identifying vulnerable plaques and predicting cardiovascular disease risk.
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Affiliation(s)
- Robin Rohlén
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Biao Jiang
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Emma Nyman
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Per Wester
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Ulf Näslund
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Christer Grönlund
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
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19
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van Hal VHJ, Muller JW, van Sambeek MRHM, Lopata RGP, Schwab HM. An aberration correction approach for single and dual aperture ultrasound imaging of the abdomen. ULTRASONICS 2023; 131:106936. [PMID: 36774785 DOI: 10.1016/j.ultras.2023.106936] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 06/18/2023]
Abstract
Abdominal ultrasound image quality is hampered by phase aberration, that is mainly caused by the large speed-of-sound (SoS) differences between fat and muscle tissue in the abdominal wall. The mismatch between the assumed and actual SoS distribution introduces general blurring of the ultrasound images, and acoustic refraction can lead to geometric distortion of the imaged features. Large aperture imaging or dual-transducer imaging can improve abdominal imaging at deep locations by providing increased contrast and resolution. However, aberration effects for large aperture imaging can be even more severe, which limits its full potential. In this study, a model-based aberration correction method for arbitrary acquisition schemes is introduced for delay-and-sum (DAS) beamforming and its performance was analyzed for both single- and dual-transducer ultrasound imaging. The method employs aberration corrected wavefront arrival times, using manually assigned local SoS values. Two wavefront models were compared. The first model is based on a straight ray approximation, and the second model on the Eikonal equation, which is solved by a multi-stencils fast marching method. Their accuracy for abdominal imaging was evaluated in acoustic simulations and phantom experiments involving tissue-mimicking and porcine material with large SoS contrast (∼100 m/s). The lateral resolution was improved by up to 90% in simulations and up to 65% in experiments compared to standard DAS, in which the use of Eikonal beamforming generally outperformed straight ray beamforming. Moreover, geometric distortions were mitigated in multi-aperture imaging, leading to a reduction in position error of around 80%. A study on the sensitivity of the aberration correction to shape and SoS of aberrating layers was performed, showing that even with imperfect segmentations or SoS values, aberration correction still outperforms standard DAS.
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Affiliation(s)
- Vera H J van Hal
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands.
| | - Jan-Willem Muller
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands; Department of Vascular Surgery, Catharina Hospital Eindhoven, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands.
| | - Marc R H M van Sambeek
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands; Department of Vascular Surgery, Catharina Hospital Eindhoven, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands.
| | - Richard G P Lopata
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands.
| | - Hans-Martin Schwab
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands.
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20
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Rajagopal S, Allen T, Berendt M, Lin D, Alam SU, Richardson DJ, Cox BT. The effect of source backing materials and excitation pulse durations on laser-generated ultrasound waveforms. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:2649. [PMID: 37129678 DOI: 10.1121/10.0019306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 04/14/2023] [Indexed: 05/03/2023]
Abstract
In this article, it is shown experimentally that a planar laser-generated ultrasound source with a hard reflective backing will generate higher acoustic pressures than a comparable source with an acoustically matched backing when the stress confinement condition is not met. Furthermore, while the source with an acoustically matched backing will have a broader bandwidth when the laser pulse is short enough to ensure stress confinement, the bandwidths of both source types will converge as the laser pulse duration increases beyond stress confinement. The explanation of the results is supported by numerical simulations.
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Affiliation(s)
- Srinath Rajagopal
- Ultrasound and Underwater Acoustics, National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, United Kingdom
| | - Thomas Allen
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, United Kingdom
| | - Martin Berendt
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Di Lin
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Shaif-Ul Alam
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - David J Richardson
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Ben T Cox
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, United Kingdom
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21
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Wang L, Wang H, Liang L, Li J, Zeng Z, Liu Y. Physics-informed neural networks for transcranial ultrasound wave propagation. ULTRASONICS 2023; 132:107026. [PMID: 37137219 DOI: 10.1016/j.ultras.2023.107026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 04/09/2023] [Accepted: 04/24/2023] [Indexed: 05/05/2023]
Abstract
Transcranial ultrasound imaging has been playing an increasingly important role in the non-invasive treatment of brain disorders. However, the conventional mesh-based numerical wave solvers, which are an integral part of imaging algorithms, suffer from limitations such as high computational cost and discretization error in predicting the wavefield passing through the skull. In this paper, we explore the use of physics-informed neural networks (PINNs) for predicting the transcranial ultrasound wave propagation. The wave equation, two sets of time snapshots data and a boundary condition (BC) are embedded as physical constraints in the loss function during training. The proposed approach has been validated by solving the two-dimensional (2D) acoustic wave equation under three increasingly complex spatially varying velocity models. Our cases demonstrate that due to the meshless nature of PINNs, they can be flexibly applied to different wave equations and types of BCs. By adding physics constraints to the loss function, PINNs can predict wavefields far outside the training data, providing ideas for improving the generalization capability of existing deep learning methods. The proposed approach offers exciting perspectives because of the powerful framework and simple implementation. We conclude with a summary of the strengths, limitations and further research directions of this work.
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Affiliation(s)
- Linfeng Wang
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Hao Wang
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Lin Liang
- Schlumberger-Doll Research, One Hampshire St, Cambridge, MA 02139, USA
| | - Jian Li
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Zhoumo Zeng
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Yang Liu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China.
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22
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Kook G, Jo Y, Oh C, Liang X, Kim J, Lee SM, Kim S, Choi JW, Lee HJ. Multifocal skull-compensated transcranial focused ultrasound system for neuromodulation applications based on acoustic holography. MICROSYSTEMS & NANOENGINEERING 2023; 9:45. [PMID: 37056421 PMCID: PMC10085992 DOI: 10.1038/s41378-023-00513-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/20/2023] [Accepted: 02/14/2023] [Indexed: 06/05/2023]
Abstract
Transcranial focused ultrasound stimulation is a promising therapeutic modality for human brain disorders because of its noninvasiveness, long penetration depth, and versatile spatial control capability through beamforming and beam steering. However, the skull presents a major hurdle for successful applications of ultrasound stimulation. Specifically, skull-induced focal aberration limits the capability for accurate and versatile targeting of brain subregions. In addition, there lacks a fully functional preclinical neuromodulation system suitable to conduct behavioral studies. Here, we report a miniature ultrasound system for neuromodulation applications that is capable of highly accurate multiregion targeting based on acoustic holography. Our work includes the design and implementation of an acoustic lens for targeting brain regions with compensation for skull aberration through time-reversal recording and a phase conjugation mirror. Moreover, we utilize MEMS and 3D-printing technology to implement a 0.75-g lightweight neuromodulation system and present in vivo characterization of the packaged system in freely moving mice. This preclinical system is capable of accurately targeting the desired individual or multitude of brain regions, which will enable versatile and explorative behavior studies using ultrasound neuromodulation to facilitate widespread clinical adoption.
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Affiliation(s)
- Geon Kook
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
| | - Yehhyun Jo
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
| | - Chaerin Oh
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
| | - Xiaojia Liang
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
| | - Jaewon Kim
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
| | - Sang-Mok Lee
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
| | - Subeen Kim
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
| | - Jung-Woo Choi
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
| | - Hyunjoo Jenny Lee
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 South Korea
- KAIST Institute for NanoCentury (KINC), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
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23
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Frizado AP, O'Reilly MA. A numerical investigation of passive acoustic mapping for monitoring bubble-mediated focused ultrasound treatment of the spinal cord. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:2271. [PMID: 37092915 DOI: 10.1121/10.0017836] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/28/2023] [Indexed: 05/03/2023]
Abstract
Focused ultrasound (FUS) combined with intravenous microbubbles (MBs) has been shown to increase drug delivery to the spinal cord in animal models. Eventual clinical translation of such a technique in the sensitive spinal cord requires robust treatment monitoring to ensure efficacy, localization, safety, and provide key intraprocedural feedback. Here, the use of passive acoustic mapping (PAM) of MB emissions with a spine-specific detector array in the context of transvertebral FUS sonications is investigated in silico. Using computed tomography-derived human vertebral geometry, transvertebral detection of MBs is evaluated over varying source locations with and without phase and amplitude corrections (PACs). The impact of prefocal cavitation is studied by simulating concurrent cavitation events in the canal and pre-laminar region. Spatially sensitive application of phase and amplitude is used to balance signal strengths emanating from different axial depths in combination with multiple dynamic ranges to elicit multisource viewing. Collectively, the results of this study encourage the use of PAM in transvertebral FUS applications with PACs to not only localize sources originating in the spinal canal but also multiple sources of innate amplitude mismatches when corrective methods are applied.
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Affiliation(s)
- Andrew Paul Frizado
- Department of Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
| | - Meaghan Anne O'Reilly
- Department of Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
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24
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Szabo TL. Acoustic Radiation Forces at the Crossroads of Ultrasound Exposimetry, HIFU, and Elastography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2023; 70:128-137. [PMID: 36215338 DOI: 10.1109/tuffc.2022.3213021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The applications of the acoustic radiation force (ARF) continue to multiply and extend from elastography into high-intensity focused ultrasound (HIFU), diagnostic imaging, lithotripsy, sonochemistry, levitation, and microsonics yet fundamental principles remain shrouded in mystery. A well-known and popular equation often used for calculating ARF in elastography is in conflict with the equation commonly employed for calculating ARF for determining acoustic power in radiation force balances (RFBs). Controversies have sparked debate for over a century concerning the physical mechanisms underlying ARFs. For over four decades, the science of ultrasound exposimetry has steadily improved and has provided clues in terms of accumulated data about the characteristics of transmitted ultrasound fields. Concurrently, the availability and capability of predicting these fields have improved significantly. The author draws on these sources to re-examine the physical principles behind ARFs. Conflicts are shown to stem from idealized configurations and simplistic assumptions. By more fully accounting for the pulse shape and spectrum, the effect of frequency power law attenuation, diffraction, and nonlinearity, more accurate equations are developed for ARFs for practical applications which are more consistent with exposimetry observations. Simulations compare well to corrected 1.5 MHz RFB data. While some questions await resolution, the approach presented here settles several longstanding conflicts and provides a new broadband framework for future ARF work.
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25
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Hsu KT, Guan S, Chitnis PV. Fast iterative reconstruction for photoacoustic tomography using learned physical model: Theoretical validation. PHOTOACOUSTICS 2023; 29:100452. [PMID: 36700132 PMCID: PMC9867977 DOI: 10.1016/j.pacs.2023.100452] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/21/2022] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
Iterative reconstruction has demonstrated superior performance in medical imaging under compressed, sparse, and limited-view sensing scenarios. However, iterative reconstruction algorithms are slow to converge and rely heavily on hand-crafted parameters to achieve good performance. Many iterations are usually required to reconstruct a high-quality image, which is computationally expensive due to repeated evaluations of the physical model. While learned iterative reconstruction approaches such as model-based learning (MBLr) can reduce the number of iterations through convolutional neural networks, it still requires repeated evaluations of the physical models at each iteration. Therefore, the goal of this study is to develop a Fast Iterative Reconstruction (FIRe) algorithm that incorporates a learned physical model into the learned iterative reconstruction scheme to further reduce the reconstruction time while maintaining robust reconstruction performance. We also propose an efficient training scheme for FIRe, which releases the enormous memory footprint required by learned iterative reconstruction methods through the concept of recursive training. The results of our proposed method demonstrate comparable reconstruction performance to learned iterative reconstruction methods with a 9x reduction in computation time and a 620x reduction in computation time compared to variational reconstruction.
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Chen M, Peng C, Wu H, Huang CC, Kim T, Traylor Z, Muller M, Chhatbar PY, Nam CS, Feng W, Jiang X. Numerical and experimental evaluation of low-intensity transcranial focused ultrasound wave propagation using human skulls for brain neuromodulation. Med Phys 2023; 50:38-49. [PMID: 36342303 PMCID: PMC10099743 DOI: 10.1002/mp.16090] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Low-intensity transcranial focused ultrasound (tFUS) has gained considerable attention as a promising noninvasive neuromodulatory technique for human brains. However, the complex morphology of the skull hinders scholars from precisely predicting the acoustic energy transmitted and the region of the brain impacted during the sonication. This is due to the fact that different ultrasound frequencies and skull morphology variations greatly affect wave propagation through the skull. PURPOSE Although the acoustic properties of human skull have been studied for tFUS applications, such as tumor ablation using a multielement phased array, there is no consensus about how to choose a single-element focused ultrasound (FUS) transducer with a suitable frequency for neuromodulation. There are interests in exploring the magnitude and dimension of tFUS beam through human parietal bone for modulating specific brain lobes. Herein, we aim to investigate the wave propagation of tFUS on human skulls to understand and address the concerns above. METHODS Both experimental measurements and numerical modeling were conducted to investigate the transmission efficiency and beam pattern of tFUS on five human skulls (C3 and C4 regions) using single-element FUS transducers with six different frequencies (150-1500 kHz). The degassed skull was placed in a water tank, and a calibrated hydrophone was utilized to measure acoustic pressure past it. The cranial computed tomography scan data of each skull were obtained to derive a high-resolution acoustic model (grid point spacing: 0.25 mm) in simulations. Meanwhile, we modified the power-law exponent of acoustic attenuation coefficient to validate numerical modeling and enabled it to be served as a prediction tool, based on the experimental measurements. RESULTS The transmission efficiency and -6 dB beamwidth were evaluated and compared for various frequencies. An exponential decrease in transmission efficiency and a logarithmic decrease of -6 dB beamwidth with an increase in ultrasound frequency were observed. It is found that a >750 kHz ultrasound leads to a relatively lower tFUS transmission efficiency (<5%), whereas a <350 kHz ultrasound contributes to a relatively broader beamwidth (>5 mm). Based on these observations, we further analyzed the dependence of tFUS wave propagation on FUS transducer aperture size. CONCLUSIONS We successfully studied tFUS wave propagation through human skulls at different frequencies experimentally and numerically. The findings have important implications to predict tFUS wave propagation for ultrasound neuromodulation in clinical applications, and guide researchers to develop advanced ultrasound transducers as neural interfaces.
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Affiliation(s)
- Mengyue Chen
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Chang Peng
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA.,School of Biomedical Engineering, ShanghaiTech University, Shanghai, China
| | - Huaiyu Wu
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Chih-Chung Huang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA.,Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Taewon Kim
- Department of Neurology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Zachary Traylor
- Edward P. Fitts Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Marie Muller
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Pratik Y Chhatbar
- Department of Neurology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Chang S Nam
- Edward P. Fitts Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Wuwei Feng
- Department of Neurology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Xiaoning Jiang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA
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Hamilton F, Hoskins P, Corner G, Huang Z. Nonlinear Harmonic Distortion of Complementary Golay Codes. ULTRASONIC IMAGING 2023; 45:22-29. [PMID: 36632798 PMCID: PMC9893299 DOI: 10.1177/01617346221147820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Recent advances in electronics miniaturization have led to the development of low-power, low-cost, point-of-care ultrasound scanners. Low-cost systems employing simple bi-level pulse generation devices need only utilize binary phase modulated coded excitations to significantly improve sensitivity; however the performance of complementary codes in the presence of nonlinear harmonic distortion has not been thoroughly investigated. Through simulation, it was found that nonlinear propagation media with little attenuative properties can significantly deteriorate the Peak Sidelobe Level (PSL) performance of complementary Golay coded pulse compression, resulting in PSL levels of -62 dB using nonlinear acoustics theory contrasted with -198 dB in the linear case. Simulations of 96 complementary pairs revealed that some pairs are more robust to sidelobe degradation from nonlinear harmonic distortion than others, up to a maximum PSL difference of 17 dB between the best and worst performing codes. It is recommended that users consider the effects of nonlinear harmonic distortion when implementing binary phase modulated complementary Golay coded excitations.
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Affiliation(s)
- Fraser Hamilton
- School of Science & Engineering, University of Dundee, Dundee, UK
- IMV Imaging (UK) Ltd., UK
| | - Peter Hoskins
- School of Science & Engineering, University of Dundee, Dundee, UK
| | - George Corner
- School of Science & Engineering, University of Dundee, Dundee, UK
| | - Zhihong Huang
- School of Science & Engineering, University of Dundee, Dundee, UK
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Nagabhushana K, Wang Q, Han A. Pulse-Echo Technique to Compensate for Laminate Membrane Transmission Loss in Phantom-Based Ultrasonic Attenuation Coefficient Measurements. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2023; 42:45-58. [PMID: 35615811 PMCID: PMC9691793 DOI: 10.1002/jum.16005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 03/27/2022] [Accepted: 04/30/2022] [Indexed: 06/15/2023]
Abstract
OBJECTIVES Accurately measuring the attenuation coefficient (AC) of reference phantoms is critical in clinical applications of quantitative ultrasound. Phantom AC measurement requires proper compensation of membrane transmission loss. Conventional methods require separate membrane samples to obtain membrane transmission loss. Unfortunately, separate membrane samples are often unavailable. A pulse-echo approach is proposed herein to compensate for membrane transmission loss without requiring separate membrane samples. METHODS The proposed method consists of the following steps. First, the insertion loss, caused by phantom attenuation and membrane transmission loss, is measured. Second, the membrane reflection coefficient is measured. Third, the unknown acoustic parameters of the membrane and phantom material are estimated by fitting theoretical reflection coefficient to the measured one. Finally, the fitted parameters are used to estimate membrane transmission loss and phantom AC. The proposed method was validated through k-Wave simulations and phantom experiments. Experimental AC measurements were repeated on 5 distinct phantoms by 2 operators to assess the repeatability and reproducibility of the proposed method. Five transducers were used to cover a broad bandwidth (0.7-16 MHz). RESULTS The acquired AC in the simulations had a maximum error of 0.06 dB/cm-MHz for simulated phantom AC values ranging from 0.5 to 1 dB/cm-MHz. The acquired AC in the experiments had a maximum error of 0.045 dB/cm-MHz for phantom AC values ranging from 0.28 to 1.48 dB/cm-MHz. Good repeatability and cross-operator reproducibility were observed with a mean coefficient of variation below 0.054. CONCLUSION The proposed method simplifies phantom AC measurement while providing satisfactory accuracy and precision.
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Affiliation(s)
- Karthik Nagabhushana
- Karthik Nagabhushana and Aiguo Han are with the Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, and National Center for Supercomputing Applications, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Qiuyu Wang
- Qiuyu Wang is with the Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, USA, expecting to receive a B.S. degree in May 2022
| | - Aiguo Han
- Karthik Nagabhushana and Aiguo Han are with the Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, and National Center for Supercomputing Applications, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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29
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Xu R, Treeby BE, Martin E. Experiments and simulations demonstrating the rapid ultrasonic rewarming of frozen tissue cryovials. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:517. [PMID: 36732249 DOI: 10.1121/10.0016886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/02/2023] [Indexed: 06/18/2023]
Abstract
The development of methods to safely rewarm large cryopreserved biological samples remains a barrier to the widespread adoption of cryopreservation. Here, experiments and simulations were performed to demonstrate that ultrasound can increase rewarming rates relative to thermal conduction alone. An ultrasonic rewarming setup based on a custom 444 kHz tubular piezoelectric transducer was designed, characterized, and tested with 2 ml cryovials filled with frozen ground beef. Rewarming rates were characterized in the -20 °C to 5 °C range. Thermal conduction-based rewarming was compared to thermal conduction plus ultrasonic rewarming, demonstrating a tenfold increase in rewarming rate when ultrasound was applied. The maximum recorded rewarming rate with ultrasound was 57° C/min, approximately 2.5 times faster than with thermal conduction alone. Coupled acoustic and thermal simulations were developed and showed good agreement with the heating rates demonstrated experimentally and were also used to demonstrate spatial heating distributions with small (<3° C) temperature differentials throughout the sample when the sample was below 0° C. The experiments and simulations demonstrate the potential for ultrasonic cryovial rewarming with a possible application to large volume rewarming, as faster rewarming rates may improve the viability of cryopreserved tissues and reduce the time needed for cells to regain normal function.
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Affiliation(s)
- Rui Xu
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Bradley E Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Eleanor Martin
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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Samant P, Trevisi LM, Chen Y, Zwart T, Xiang L. 3-D Protoacoustic Imaging Through a Planar Ultrasound Array: A Simulation Workflow. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2023; 7:83-95. [PMID: 37588600 PMCID: PMC10427128 DOI: 10.1109/trpms.2022.3177236] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Bragg peak range uncertainties are a persistent constraint in proton therapy. Pulsed proton beams generate protoacoustic emissions proportional to absorbed proton energy, thereby encoding dosimetry information in a detectable acoustic wave. Here, we seek to derive and model 3D protoacoustic imaging with an ultrasound array and examine the frequency characteristics of protoacoustic emissions. A formalism is presented through which protoacoustic signals can be characterized considering transducer bandwidth as well as pulse duration of the incident beam. We have also collected an experimental proton beam intensity signal from a Mevion S250 clinical machine to analyze our formalism. We also show that proton-acoustic image reconstruction is possible even when the noise amplitude is larger than the signal amplitude on individual transducers. We find that a 4μ s Gaussian proton pulse can generate a signal in the range of MHz as long as the spatial heating function has sufficiently high temperature gradients.
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Affiliation(s)
- Pratik Samant
- Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, 73071, USA and now is with the Department of Oncology, University of Oxford, and Oxford University Hospitals NHS Foundation Trust, Oxford, Oxfordshire, UK
| | - Luis M Trevisi
- Chemical, Biological, & Materials Engineering, University of Oklahoma, Norman, 73071, USA
| | - Yong Chen
- Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Townsend Zwart
- Vice President of Advanced Development at Mevion Medical Systems, Littleton, MA, 01460, USA
| | - Liangzhong Xiang
- Departments of Biomedical Engineering and Radiology, University of California Irvine, Irvine, CA, USA, Department of Radiological Sciences, University of California, Irvine, CA, USA and Beckman Laser Institute & Medical Clinic, University of California, Irvine, Irvine, CA, USA
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31
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Scarpelli A, Stefano M, Cordella F, Zollo L. Evaluation of the effects of focused ultrasound stimulation on the central nervous system through a multiscale simulation approach. Front Bioeng Biotechnol 2022; 10:1034194. [DOI: 10.3389/fbioe.2022.1034194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022] Open
Abstract
The lack of sensory feedback represents one of the main drawbacks of commercial upper limb prosthesis. Transcranial Focused Ultrasound Stimulation (tFUS) seems to be a valid non-invasive technique for restoring sensory feedback allowing to deliver acoustic energy to cortical sensory areas with high spatial resolution and depth penetration. This paper aims at studying in simulation the use of tFUS on cortical sensory areas to evaluate its effects in terms of latency ad firing rate of the cells response, for understanding if these parameters influence the safety and the efficacy of the stimulation. In this paper, in order to study the propagation of the ultrasound wave from the transducer to the cortical cells, a multiscale approach was implemented by building a macroscopic model, which estimates the pressure profile in a simplified 2D human head geometry, and coupling it with the SONIC microscale model, that describes the electrical behaviour of a cortical neuron. The influence of the stimulation parameters and of the skull thickness on the latency and the firing rate are evaluated and the obtained behaviour is linked to the sensory response obtained on human subjects. Results have shown that slight changes in the transducer position should not affect the efficacy of the stimulation; however, high skull thickness leads to lower cells activation. These results will be useful for evaluating safety and effectiveness of tFUS for sensory feedback in closed-loop prosthetic systems.
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Tabak G, Oelze ML, Singer AC. Effects of acoustic nonlinearity on communication performance in soft tissues. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:3583. [PMID: 36586861 PMCID: PMC9759358 DOI: 10.1121/10.0015402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 06/17/2023]
Abstract
Acoustic communication has been gaining traction as an alternative communication method in nontraditional media, such as underwater or through tissue. Acoustic propagation is known to be a nonlinear phenomenon; nonlinear propagation of acoustic waves in soft tissues at biomedical frequencies and intensities has been widely demonstrated. However, the effects of acoustic nonlinearity on communication performance in biological tissues have not yet been examined. In this work, nonlinear propagation of a communication signal in soft tissues is analyzed. The relationship between communication parameters (signal amplitude, bandwidth, and center frequency) and nonlinear distortion of the communication signal propagating in soft tissues with different acoustic properties is investigated. Simulated experiments revealed that, unlike linear channels, bit error rates increase as signal amplitude and bandwidth increase. Linear and decision feedback equalizers fail to address the increased error rates. When tissue properties and transmission parameters can be estimated, receivers based on maximum likelihood sequence estimation approach the performance of an ideal receiver in an ideal additive white Gaussian noise channel.
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Affiliation(s)
- Gizem Tabak
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Michael L Oelze
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Andrew C Singer
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
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Miscouridou M, Pineda-Pardo JA, Stagg CJ, Treeby BE, Stanziola A. Classical and Learned MR to Pseudo-CT Mappings for Accurate Transcranial Ultrasound Simulation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2896-2905. [PMID: 35984788 DOI: 10.1109/tuffc.2022.3198522] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Model-based treatment planning for transcranial ultrasound therapy typically involves mapping the acoustic properties of the skull from an X-ray computed tomography (CT) image of the head. Here, three methods for generating pseudo-CT (pCT) images from magnetic resonance (MR) images were compared as an alternative to CT. A convolutional neural network (U-Net) was trained on paired MR-CT images to generate pCT T images from either T1-weighted or zero-echo time (ZTE) MR images (denoted tCT and zCT, respectively). A direct mapping from ZTE to pCT was also implemented (denoted cCT). When comparing the pCT and ground-truth CT images for the test set, the mean absolute error was 133, 83, and 145 Hounsfield units (HU) across the whole head, and 398, 222, and 336 HU within the skull for the tCT, zCT, and cCT images, respectively. Ultrasound simulations were also performed using the generated pCT images and compared to simulations based on CT. An annular array transducer was used targeting the visual or motor cortex. The mean differences in the simulated focal pressure, focal position, and focal volume were 9.9%, 1.5 mm, and 15.1% for simulations based on the tCT images; 5.7%, 0.6 mm, and 5.7% for the zCT; and 6.7%, 0.9 mm, and 12.1% for the cCT. The improved results for images mapped from ZTE highlight the advantage of using imaging sequences, which improves the contrast of the skull bone. Overall, these results demonstrate that acoustic simulations based on MR images can give comparable accuracy to those based on CT.
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Solgi R, Ghadiri H. Effects of Beamforming Techniques on Quality of Ultrasound Computed Tomography Images. J Biomed Phys Eng 2022; 12:349-358. [PMID: 36059289 PMCID: PMC9395622 DOI: 10.31661/jbpe.v0i0.2107-1367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 10/20/2021] [Indexed: 06/15/2023]
Abstract
BACKGROUND In body tissues, tumors generally have different speeds of sound (SOS) than normal tissues. In this respect, ultrasound computed tomography (UCT) can generate a cross-sectional SOS map as an innovative ultrasound imaging method. This technique can produce images with a resolution of millimeters and a high signal-to-noise ratio. OBJECTIVE This study aimed to improve UCT image quality without increasing breast cancer screening and diagnosis time. MATERIAL AND METHODS In this analytical study, a ring-shaped UCT breast imaging system was simulated using the K-wave toolbox of MATLAB. The system has a 20 cm diameter and 256 ultrasonic piezoelectrics placed in the ring's circumference. Different beamforming techniques imaged two designed phantoms (i.e., resolution and contrast), and the resolution and contrast to noise ratio (CNR) were calculated. RESULTS The results of resolution phantom imaging without any beamforming showed that only bars with the value of 0.125 and 0.167 lp/mm were distinguishable, and the 0.1 bars were not recognizable in the imaging. In addition, increasing the number of transmitters led to no noticeable change in resolution for 0.125 and 0.167 lp/mm bars. In all beamforming techniques for imaging the contrast phantom, the CNR parameter up to an object with a diameter of 8 mm increases with increasing diameter without any change. CONCLUSION The beamforming technique using three simultaneous transmitters improved the resolution by about 1 mm compared to the normal strategy. In addition to high-contrast images, beamforming with 9 simultaneous transmitters led to a preferable technique.
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Affiliation(s)
- Razieh Solgi
- MSc, Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
- MSc, Preclinical Lab, Core Facility, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Ghadiri
- PhD, Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
- PhD, Advanced Medical Technologies and Equipment Institute, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
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Aubry JF, Bates O, Boehm C, Butts Pauly K, Christensen D, Cueto C, Gélat P, Guasch L, Jaros J, Jing Y, Jones R, Li N, Marty P, Montanaro H, Neufeld E, Pichardo S, Pinton G, Pulkkinen A, Stanziola A, Thielscher A, Treeby B, van 't Wout E. Benchmark problems for transcranial ultrasound simulation: Intercomparison of compressional wave models. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:1003. [PMID: 36050189 DOI: 10.5281/zenodo.6020543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Computational models of acoustic wave propagation are frequently used in transcranial ultrasound therapy, for example, to calculate the intracranial pressure field or to calculate phase delays to correct for skull distortions. To allow intercomparison between the different modeling tools and techniques used by the community, an international working group was convened to formulate a set of numerical benchmarks. Here, these benchmarks are presented, along with intercomparison results. Nine different benchmarks of increasing geometric complexity are defined. These include a single-layer planar bone immersed in water, a multi-layer bone, and a whole skull. Two transducer configurations are considered (a focused bowl and a plane piston operating at 500 kHz), giving a total of 18 permutations of the benchmarks. Eleven different modeling tools are used to compute the benchmark results. The models span a wide range of numerical techniques, including the finite-difference time-domain method, angular spectrum method, pseudospectral method, boundary-element method, and spectral-element method. Good agreement is found between the models, particularly for the position, size, and magnitude of the acoustic focus within the skull. When comparing results for each model with every other model in a cross-comparison, the median values for each benchmark for the difference in focal pressure and position are less than 10% and 1 mm, respectively. The benchmark definitions, model results, and intercomparison codes are freely available to facilitate further comparisons.
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Affiliation(s)
- Jean-Francois Aubry
- Physics for Medicine Paris, National Institute of Health and Medical Research (INSERM) U1273, ESPCI Paris, Paris Sciences and Lettres University, French National Centre for Scientific Research (CNRS) UMR 8063, Paris, France
| | - Oscar Bates
- Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Christian Boehm
- Institute of Geophysics, Swiss Federal Institute of Technology (ETH) Zürich, Sonneggstrasse 5, 8092 Zürich, Switzerland
| | - Kim Butts Pauly
- Department of Radiology, Stanford University, Stanford, California 94305, USA
| | - Douglas Christensen
- Department of Biomedical Engineering and Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, USA
| | - Carlos Cueto
- Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Pierre Gélat
- Department of Surgical Biotechnology, Division of Surgery and Interventional Science, University College London, London NW3 2PF, United Kingdom
| | - Lluis Guasch
- Earth Science and Engineering Department, Imperial College London, London, United Kingdom
| | - Jiri Jaros
- Centre of Excellence IT4Innovations, Faculty of Information Technology, Brno University of Technology, Bozetechova 2, Brno 612 00, Czech Republic
| | - Yun Jing
- Graduate Program in Acoustics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Rebecca Jones
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA and North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Ningrui Li
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Patrick Marty
- Institute of Geophysics, Swiss Federal Institute of Technology (ETH) Zürich, Sonneggstrasse 5, 8092 Zürich, Switzerland
| | - Hazael Montanaro
- Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland
| | - Esra Neufeld
- Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland
| | - Samuel Pichardo
- Radiology and Clinical Neurosciences Departments, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Gianmarco Pinton
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA and North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Aki Pulkkinen
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
| | - Antonio Stanziola
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | | | - Bradley Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Elwin van 't Wout
- Institute for Mathematical and Computational Engineering, School of Engineering and Faculty of Mathematics, Pontificia Universidad Católica de Chile, Santiago, Chile
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36
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Aubry JF, Bates O, Boehm C, Butts Pauly K, Christensen D, Cueto C, Gélat P, Guasch L, Jaros J, Jing Y, Jones R, Li N, Marty P, Montanaro H, Neufeld E, Pichardo S, Pinton G, Pulkkinen A, Stanziola A, Thielscher A, Treeby B, van 't Wout E. Benchmark problems for transcranial ultrasound simulation: Intercomparison of compressional wave models. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:1003. [PMID: 36050189 PMCID: PMC9553291 DOI: 10.1121/10.0013426] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Computational models of acoustic wave propagation are frequently used in transcranial ultrasound therapy, for example, to calculate the intracranial pressure field or to calculate phase delays to correct for skull distortions. To allow intercomparison between the different modeling tools and techniques used by the community, an international working group was convened to formulate a set of numerical benchmarks. Here, these benchmarks are presented, along with intercomparison results. Nine different benchmarks of increasing geometric complexity are defined. These include a single-layer planar bone immersed in water, a multi-layer bone, and a whole skull. Two transducer configurations are considered (a focused bowl and a plane piston operating at 500 kHz), giving a total of 18 permutations of the benchmarks. Eleven different modeling tools are used to compute the benchmark results. The models span a wide range of numerical techniques, including the finite-difference time-domain method, angular spectrum method, pseudospectral method, boundary-element method, and spectral-element method. Good agreement is found between the models, particularly for the position, size, and magnitude of the acoustic focus within the skull. When comparing results for each model with every other model in a cross-comparison, the median values for each benchmark for the difference in focal pressure and position are less than 10% and 1 mm, respectively. The benchmark definitions, model results, and intercomparison codes are freely available to facilitate further comparisons.
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Affiliation(s)
- Jean-Francois Aubry
- Physics for Medicine Paris, National Institute of Health and Medical Research (INSERM) U1273, ESPCI Paris, Paris Sciences and Lettres University, French National Centre for Scientific Research (CNRS) UMR 8063, Paris, France
| | - Oscar Bates
- Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Christian Boehm
- Institute of Geophysics, Swiss Federal Institute of Technology (ETH) Zürich, Sonneggstrasse 5, 8092 Zürich, Switzerland
| | - Kim Butts Pauly
- Department of Radiology, Stanford University, Stanford, California 94305, USA
| | - Douglas Christensen
- Department of Biomedical Engineering and Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, USA
| | - Carlos Cueto
- Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Pierre Gélat
- Department of Surgical Biotechnology, Division of Surgery and Interventional Science, University College London, London NW3 2PF, United Kingdom
| | - Lluis Guasch
- Earth Science and Engineering Department, Imperial College London, London, United Kingdom
| | - Jiri Jaros
- Centre of Excellence IT4Innovations, Faculty of Information Technology, Brno University of Technology, Bozetechova 2, Brno 612 00, Czech Republic
| | - Yun Jing
- Graduate Program in Acoustics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Rebecca Jones
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA and North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Ningrui Li
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Patrick Marty
- Institute of Geophysics, Swiss Federal Institute of Technology (ETH) Zürich, Sonneggstrasse 5, 8092 Zürich, Switzerland
| | - Hazael Montanaro
- Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland
| | - Esra Neufeld
- Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland
| | - Samuel Pichardo
- Radiology and Clinical Neurosciences Departments, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Gianmarco Pinton
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA and North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Aki Pulkkinen
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
| | - Antonio Stanziola
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | | | - Bradley Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Elwin van 't Wout
- Institute for Mathematical and Computational Engineering, School of Engineering and Faculty of Mathematics, Pontificia Universidad Católica de Chile, Santiago, Chile
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Yeats E, Gupta D, Xu Z, Hall TL. Effects of phase aberration on transabdominal focusing for a large aperture, low f-number histotripsy transducer. Phys Med Biol 2022; 67:10.1088/1361-6560/ac7d90. [PMID: 35772383 PMCID: PMC9396534 DOI: 10.1088/1361-6560/ac7d90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 06/30/2022] [Indexed: 11/12/2022]
Abstract
Objective. Soft tissue phase aberration may be particularly severe for histotripsy due to large aperture and lowf-number transducer geometries. This study investigated how phase aberration from human abdominal tissue affects focusing of a large, strongly curved histotripsy transducer.Approach.A computational model (k-Wave) was experimentally validated withex vivoporcine abdominal tissue and used to simulate focusing a histotripsy transducer (radius: 14.2 cm,f-number: 0.62, central frequencyfc: 750 kHz) through the human abdomen. Abdominal computed tomography images from 10 human subjects were segmented to create three-dimensional acoustic property maps. Simulations were performed focusing at 3 target locations in the liver of each subject with ideal phase correction, without phase correction, and after separately matching the sound speed of water and fat to non-fat soft tissue.Main results.Experimental validation in porcine abdominal tissue showed that simulated and measured arrival time differences agreed well (average error, ∼0.10 acoustic cycles atfc). In simulations with human tissue, aberration created arrival time differences of 0.65μs (∼0.5 cycles) at the target and shifted the focus from the target by 6.8 mm (6.4 mm pre-focally along depth direction), on average. Ideal phase correction increased maximum pressure amplitude by 95%, on average. Matching the sound speed of water and fat to non-fat soft tissue decreased the average pre-focal shift by 3.6 and 0.5 mm and increased pressure amplitude by 2% and 69%, respectively.Significance.Soft tissue phase aberration of large aperture, lowf-number histotripsy transducers is substantial despite low therapeutic frequencies. Phase correction could potentially recover substantial pressure amplitude for transabdominal histotripsy. Additionally, different heterogeneity sources distinctly affect focusing quality. The water path strongly affects the focal shift, while irregular tissue boundaries (e.g. fat) dominate pressure loss.
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Affiliation(s)
- Ellen Yeats
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, United States of America
| | - Dinank Gupta
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, United States of America
| | - Zhen Xu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, United States of America
| | - Timothy L Hall
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, United States of America
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Fang X, Zhou R, Gan H, Ding M, Yuchi M. Time-of-flight completion in ultrasound computed tomography based on the singular value threshold algorithm. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:10160-10175. [PMID: 36031989 DOI: 10.3934/mbe.2022476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ultrasound computed tomography (USCT) has been developed for breast tumor screening. The sound-speed modal of USCT can provide quantitative sound-speed values to help tumor diagnosis. Time-of-flight (TOF) is the critical input in sound-speed reconstruction. However, we found that the missing data problem in the detected TOF causes artifacts on the reconstructed sound-speed images, which may affect the tumor identification. In this study, to address the missing TOF data problem, we first adopted the singular value threshold (SVT) algorithm to complete the TOF matrix. The threshold value in SVT is difficult to determine, so we proposed a selection strategy, that is, to enumerate the threshold values as the multiples of the maximum singular value of the incomplete matrix and then evaluate the image quality to select the proper threshold value. In the numerical breast phantom experiment, the artifacts are eliminated, and the accuracy is higher than the accuracy of the compared methods. In the in vivo experiment, we reconstructed the sound-speed image of the breast of a volunteer with invasive breast cancer, and the SVT algorithm improved the image sharpness. The completion of DTOF based on SVT gives better accuracy than the compared methods, but too large a threshold value decreases the accuracy. In the future, the selection method of the threshold value needs further research, and more USCT cases should be included in the experiments.
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Affiliation(s)
- Xiaoyue Fang
- School of Computer Science, Hubei University of Technology, No. 28, Nanli Road, Hongshan District, Wuhan, China
| | - Ran Zhou
- School of Computer Science, Hubei University of Technology, No. 28, Nanli Road, Hongshan District, Wuhan, China
| | - Haitao Gan
- School of Computer Science, Hubei University of Technology, No. 28, Nanli Road, Hongshan District, Wuhan, China
| | - Mingyue Ding
- School of Life Science and Technology, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Hongshan District, Wuhan, China
- Wuhan Wesee Medical Imaging Co. LTD, East Lake High-tech Creation Zone, Wutong Lake District, Ezhou, China
| | - Ming Yuchi
- School of Life Science and Technology, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Hongshan District, Wuhan, China
- Wuhan Wesee Medical Imaging Co. LTD, East Lake High-tech Creation Zone, Wutong Lake District, Ezhou, China
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Scarpelli A, Stefano M, Cordella F, Zollo L. Multiscale approach for tFUS neurocomputational modelling. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:4712-4715. [PMID: 36086564 DOI: 10.1109/embc48229.2022.9871341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Among the non-invasive methods employed for brain stimulation, trans cranial Focused Ultrasound Stimulation (tFUS) is the technique with the best penetration into the tissues and spatial resolution. The development of computational models of US propagation in brain tissue can be useful for estimating the behaviour of neural cells subjected to mechanical stimulus due to US. This paper aims at studying the neural cell response of a cortical Regular Spiking point neuron model, for different values of stimulus Duty Cycle (DC). The main goal is to use a multiscale approach to couple the results obtained from a macroscale simulation on wave propagation in tissue, with neuron model described by Hodgkin-Huxley equations to study latency and firing rate of the RS model. The obtained results showed that latency and firing rate have slight variations along the propagation direction of the US beam, in the focal region under the skull model, for different stimulus DC.
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Cao E, Greillier P, Loyet R, Chavrier F, Robert J, Bessière F, Dillenseger JL, Lafon C. Development of a Numerical Model of High-Intensity Focused Ultrasound Treatment in Mobile and Elastic Organs: Application to a Beating Heart. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:1215-1228. [PMID: 35430101 DOI: 10.1016/j.ultrasmedbio.2022.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
High-intensity focused ultrasound (HIFU) is a promising method used to treat cardiac arrhythmias, as it can induce lesions at a distance throughout myocardium thickness. Numerical modeling is commonly used for ultrasound probe development and optimization of HIFU treatment strategies. This study was aimed at describing a numerical method to simulate HIFU thermal ablation in elastic and mobile heart models. The ultrasound pressure field is computed on a 3-D orthonormal grid using the Rayleigh integral method, and the attenuation is calculated step by step between cells. The temperature distribution is obtained by resolution of the bioheat transfer equation on a 3-D non-orthogonally structured curvilinear grid using the finite-volume method. The simulation method is applied on two regions of the heart (atrioventricular node and ventricular apex) to compare the thermal effects of HIFU ablation depending on deformation, motion type and amplitude. The atrioventricular node requires longer sonication than the ventricular apex to reach the same lesion volume. Motion considerably influences treatment duration, lesion shape and distribution in cardiac HIFU treatment. These results emphasize the importance of considering local motion and deformation in numerical studies to define efficient and accurate treatment strategies.
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Affiliation(s)
- Elodie Cao
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, LYON, France..
| | - Paul Greillier
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, LYON, France
| | - Raphaël Loyet
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, LYON, France
| | - Françoise Chavrier
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, LYON, France
| | - Jade Robert
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, LYON, France
| | - Francis Bessière
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, LYON, France.; Hospices Civils de Lyon, Hôpital Cardiovasculaire Louis Pradel, Lyon, France
| | | | - Cyril Lafon
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, LYON, France
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41
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Cigier A, Varray F, Garcia D. SIMUS: An open-source simulator for medical ultrasound imaging. Part II: Comparison with four simulators. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 220:106774. [PMID: 35398580 DOI: 10.1016/j.cmpb.2022.106774] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE Computational ultrasound imaging has become a well-established methodology in the ultrasound community. In the accompanying paper (part I), we described a new ultrasound simulator (SIMUS) for MATLAB, which belongs to the Matlab UltraSound Toolbox (MUST). SIMUS can generate pressure fields and radiofrequency RF signals for simulations in medical ultrasound imaging. It works in a harmonic domain and uses far-field and paraxial linear equations. METHODS In this article (part II), we illustrate how SIMUS compares with other ultrasound simulators (Field II, k-Wave, FOCUS, and Verasonics) for a homogeneous medium. We designed different transmit sequences (focused, planar, and diverging wavefronts) and calculated the corresponding 2-D and 3-D (with elevation focusing) RMS pressure fields. RESULTS SIMUS produced pressure fields similar to those of Field II, FOCUS, and k-Wave. The acoustic fields provided by the Verasonics simulator were significantly different from those of SIMUS and k-Wave, although the overall appearance remained consistent. CONCLUSION Our simulations tend to demonstrate that SIMUS is reliable and can be used for realistic medical ultrasound simulations.
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Affiliation(s)
- Amanda Cigier
- CREATIS: Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé, Lyon, France
| | - François Varray
- CREATIS: Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé, Lyon, France.
| | - Damien Garcia
- CREATIS: Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé, Lyon, France.
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42
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Coila A, Oelze ML. Ultrasonic backscatter coefficient estimation in nonlinear regime using an in situ calibration target. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:4196. [PMID: 35778186 PMCID: PMC9239729 DOI: 10.1121/10.0011743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/29/2022] [Accepted: 06/01/2022] [Indexed: 06/03/2023]
Abstract
Tissue characterization based on the backscatter coefficient (BSC) can be degraded by acoustic nonlinearity. Often, this degradation is due to the method used for obtaining a reference spectrum, i.e., using a planar reference in water compared to a reference phantom approach resulted in more degradation. We hypothesize that an in situ calibration approach can improve BSC estimates in the nonlinear regime compared to using the reference phantom approach. The in situ calibration target provides a reference within the medium being interrogated and, therefore, nonlinear effects would already be contained in the in situ reference signal. Simulations and experiments in phantoms and in vivo were performed. A 2 mm diameter titanium bead was embedded in the interrogated media. An L9-4/38 probe (BK Ultrasound, Peabody, MA) and an analysis bandwidth from 4.5 to 7.4 MHz were used in experiments. Radiofrequency data from the sample, bead, and reference phantoms were acquired at a quasi-linear baseline power level and at further increments of output power. Better agreement between the BSC obtained at low power compared to high power was observed for the in situ calibration compared to the reference phantom approach.
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Affiliation(s)
- Andres Coila
- Beckman Institute for Advanced Science and Technology, Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Michael L Oelze
- Beckman Institute for Advanced Science and Technology, Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
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43
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Phipps MA, Jonathan S, Yang PF, Chen LM, Grissom W, Caskey CF. A reduced aperture allows for transcranial focus localization at lower pressure. JASA EXPRESS LETTERS 2022; 2:062001. [PMID: 35782333 PMCID: PMC9245740 DOI: 10.1121/10.0011695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Localizing the focus during transcranial focused ultrasound procedures is important to ensure accurate targeting of specific brain regions and interpretation of results. Magnetic resonance acoustic radiation force imaging uses the displacement induced by the ultrasound focus in the brain to localize the beam, but the high pressure required to displace brain tissue may cause damage or confounds during subsequent neuromodulatory experiments. Here, reduced apertures were applied to a phased array transducer to generate comparable displacement to the full aperture but with 20% lower free field pressure.
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Affiliation(s)
- M Anthony Phipps
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Sumeeth Jonathan
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, USA , , , , ,
| | - Pai-Feng Yang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Li Min Chen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - William Grissom
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, USA , , , , ,
| | - Charles F Caskey
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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Gubbi MR, Gonzalez EA, Bell MAL. Theoretical Framework to Predict Generalized Contrast-to-Noise Ratios of Photoacoustic Images With Applications to Computer Vision. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2098-2114. [PMID: 35446763 DOI: 10.1109/tuffc.2022.3169082] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The successful integration of computer vision, robotic actuation, and photoacoustic imaging to find and follow targets of interest during surgical and interventional procedures requires accurate photoacoustic target detectability. This detectability has traditionally been assessed with image quality metrics, such as contrast, contrast-to-noise ratio, and signal-to-noise ratio (SNR). However, predicting target tracking performance expectations when using these traditional metrics is difficult due to unbounded values and sensitivity to image manipulation techniques like thresholding. The generalized contrast-to-noise ratio (gCNR) is a recently introduced alternative target detectability metric, with previous work dedicated to empirical demonstrations of applicability to photoacoustic images. In this article, we present theoretical approaches to model and predict the gCNR of photoacoustic images with an associated theoretical framework to analyze relationships between imaging system parameters and computer vision task performance. Our theoretical gCNR predictions are validated with histogram-based gCNR measurements from simulated, experimental phantom, ex vivo, and in vivo datasets. The mean absolute errors between predicted and measured gCNR values ranged from 3.2 ×10-3 to 2.3 ×10-2 for each dataset, with channel SNRs ranging -40 to 40 dB and laser energies ranging 0.07 [Formula: see text] to 68 mJ. Relationships among gCNR, laser energy, target and background image parameters, target segmentation, and threshold levels were also investigated. Results provide a promising foundation to enable predictions of photoacoustic gCNR and visual servoing segmentation accuracy. The efficiency of precursory surgical and interventional tasks (e.g., energy selection for photoacoustic-guided surgeries) may also be improved with the proposed framework.
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Heimbuch IS, Fan TK, Wu AD, Faas GC, Charles AC, Iacoboni M. Ultrasound stimulation of the motor cortex during tonic muscle contraction. PLoS One 2022; 17:e0267268. [PMID: 35442956 PMCID: PMC9020726 DOI: 10.1371/journal.pone.0267268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 04/05/2022] [Indexed: 11/18/2022] Open
Abstract
Transcranial ultrasound stimulation (tUS) shows potential as a noninvasive brain stimulation (NIBS) technique, offering increased spatial precision compared to other NIBS techniques. However, its reported effects on primary motor cortex (M1) are limited. We aimed to better understand tUS effects in human M1 by performing tUS of the hand area of M1 (M1hand) during tonic muscle contraction of the index finger. Stimulation during muscle contraction was chosen because of the transcranial magnetic stimulation-induced phenomenon known as cortical silent period (cSP), in which transcranial magnetic stimulation (TMS) of M1hand involuntarily suppresses voluntary motor activity. Since cSP is widely considered an inhibitory phenomenon, it presents an ideal parallel for tUS, which has often been proposed to preferentially influence inhibitory interneurons. Recording electromyography (EMG) of the first dorsal interosseous (FDI) muscle, we investigated effects on muscle activity both during and after tUS. We found no change in FDI EMG activity concurrent with tUS stimulation. Using single-pulse TMS, we found no difference in M1 excitability before versus after sparsely repetitive tUS exposure. Using acoustic simulations in models made from structural MRI of the participants that matched the experimental setups, we estimated in-brain pressures and generated an estimate of cumulative tUS exposure experienced by M1hand for each subject. We were unable to find any correlation between cumulative M1hand exposure and M1 excitability change. We also present data that suggest a TMS-induced MEP always preceded a near-threshold cSP.
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Affiliation(s)
- Ian S. Heimbuch
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
- Ahmanson-Lovelace Brain Mapping Center, University of California, Los Angeles, Los Angeles, California, United States of America
- * E-mail:
| | - Tiffany K. Fan
- David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Allan D. Wu
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Evanston, Illinois, United States of America
| | - Guido C. Faas
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Andrew C. Charles
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Marco Iacoboni
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
- Ahmanson-Lovelace Brain Mapping Center, University of California, Los Angeles, Los Angeles, California, United States of America
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Gröhl J, Dreher KK, Schellenberg M, Rix T, Holzwarth N, Vieten P, Ayala L, Bohndiek SE, Seitel A, Maier-Hein L. SIMPA: an open-source toolkit for simulation and image processing for photonics and acoustics. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210395SSR. [PMID: 35380031 PMCID: PMC8978263 DOI: 10.1117/1.jbo.27.8.083010] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/28/2022] [Indexed: 05/09/2023]
Abstract
SIGNIFICANCE Optical and acoustic imaging techniques enable noninvasive visualisation of structural and functional properties of tissue. The quantification of measurements, however, remains challenging due to the inverse problems that must be solved. Emerging data-driven approaches are promising, but they rely heavily on the presence of high-quality simulations across a range of wavelengths due to the lack of ground truth knowledge of tissue acoustical and optical properties in realistic settings. AIM To facilitate this process, we present the open-source simulation and image processing for photonics and acoustics (SIMPA) Python toolkit. SIMPA is being developed according to modern software design standards. APPROACH SIMPA enables the use of computational forward models, data processing algorithms, and digital device twins to simulate realistic images within a single pipeline. SIMPA's module implementations can be seamlessly exchanged as SIMPA abstracts from the concrete implementation of each forward model and builds the simulation pipeline in a modular fashion. Furthermore, SIMPA provides comprehensive libraries of biological structures, such as vessels, as well as optical and acoustic properties and other functionalities for the generation of realistic tissue models. RESULTS To showcase the capabilities of SIMPA, we show examples in the context of photoacoustic imaging: the diversity of creatable tissue models, the customisability of a simulation pipeline, and the degree of realism of the simulations. CONCLUSIONS SIMPA is an open-source toolkit that can be used to simulate optical and acoustic imaging modalities. The code is available at: https://github.com/IMSY-DKFZ/simpa, and all of the examples and experiments in this paper can be reproduced using the code available at: https://github.com/IMSY-DKFZ/simpa_paper_experiments.
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Affiliation(s)
- Janek Gröhl
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
| | - Kris K. Dreher
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
- Heidelberg University, Faculty of Physics and Astronomy, Heidelberg, Germany
| | - Melanie Schellenberg
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
- Heidelberg University, Faculty of Mathematics and Computer Science, Heidelberg, Germany
- HIDSS4Health - Helmholtz Information and Data Science School for Health, Heidelberg, Germany
| | - Tom Rix
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
- Heidelberg University, Faculty of Mathematics and Computer Science, Heidelberg, Germany
| | - Niklas Holzwarth
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
| | - Patricia Vieten
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
- Heidelberg University, Faculty of Physics and Astronomy, Heidelberg, Germany
| | - Leonardo Ayala
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
- Heidelberg University, Medical Faculty, Heidelberg, Germany
| | - Sarah E. Bohndiek
- University of Cambridge, Cancer Research UK Cambridge Institute, Robinson Way, Cambridge, United Kingdom
- University of Cambridge, Department of Physics, Cambridge, United Kingdom
| | - Alexander Seitel
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
| | - Lena Maier-Hein
- German Cancer Research Center (DKFZ), Division of Intelligent Medical Systems, Heidelberg, Germany
- Heidelberg University, Faculty of Mathematics and Computer Science, Heidelberg, Germany
- Heidelberg University, Medical Faculty, Heidelberg, Germany
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Prasad S, Almekkawy M. DeepUCT: Complex cascaded deep learning network for improved ultrasound tomography. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac5296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 02/07/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Ultrasound computed tomography is an inexpensive and radiation-free medical imaging technique used to quantify the tissue acoustic properties for advanced clinical diagnosis. Image reconstruction in ultrasound tomography is often modeled as an optimization scheme solved by iterative methods like full-waveform inversion. These iterative methods are computationally expensive, while the optimization problem is ill-posed and nonlinear. To address this problem, we propose to use deep learning to overcome the computational burden and ill-posedness, and achieve near real-time image reconstruction in ultrasound tomography. We aim to directly learn the mapping from the recorded time-series sensor data to a spatial image of acoustical properties. To accomplish this, we develop a deep learning model using two cascaded convolutional neural networks with an encoder–decoder architecture. We achieve a good representation by first extracting the intermediate mapping-knowledge and later utilizing this knowledge to reconstruct the image. This approach is evaluated on synthetic phantoms where simulated ultrasound data are acquired from a ring of transducers surrounding the region of interest. The measurement data is acquired by forward modeling the wave equation using the k-wave toolbox. Our simulation results demonstrate that our proposed deep-learning method is robust to noise and significantly outperforms the state-of-the-art traditional iterative method both quantitatively and qualitatively. Furthermore, our model takes substantially less computational time than the conventional full-wave inversion method.
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Di Sciacca G, Maffeis G, Farina A, Dalla Mora A, Pifferi A, Taroni P, Arridge S. Evaluation of a pipeline for simulation, reconstruction, and classification in ultrasound-aided diffuse optical tomography of breast tumors. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210385GRR. [PMID: 35332743 PMCID: PMC8943242 DOI: 10.1117/1.jbo.27.3.036003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/28/2022] [Indexed: 06/01/2023]
Abstract
SIGNIFICANCE Diffuse optical tomography is an ill-posed problem. Combination with ultrasound can improve the results of diffuse optical tomography applied to the diagnosis of breast cancer and allow for classification of lesions. AIM To provide a simulation pipeline for the assessment of reconstruction and classification methods for diffuse optical tomography with concurrent ultrasound information. APPROACH A set of breast digital phantoms with benign and malignant lesions was simulated building on the software VICTRE. Acoustic and optical properties were assigned to the phantoms for the generation of B-mode images and optical data. A reconstruction algorithm based on a two-region nonlinear fitting and incorporating the ultrasound information was tested. Machine learning classification methods were applied to the reconstructed values to discriminate lesions into benign and malignant after reconstruction. RESULTS The approach allowed us to generate realistic US and optical data and to test a two-region reconstruction method for a large number of realistic simulations. When information is extracted from ultrasound images, at least 75% of lesions are correctly classified. With ideal two-region separation, the accuracy is higher than 80%. CONCLUSIONS A pipeline for the generation of realistic ultrasound and diffuse optics data was implemented. Machine learning methods applied to a optical reconstruction with a nonlinear optical model and morphological information permit to discriminate malignant lesions from benign ones.
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Affiliation(s)
- Giuseppe Di Sciacca
- University College London, Department of Computer Science, London, United Kingdom
- Politecnico di Milano, Dipartimento di Fisica, Milano, Italy
| | - Giulia Maffeis
- Politecnico di Milano, Dipartimento di Fisica, Milano, Italy
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milano, Italy
| | | | - Antonio Pifferi
- Politecnico di Milano, Dipartimento di Fisica, Milano, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milano, Italy
| | - Paola Taroni
- Politecnico di Milano, Dipartimento di Fisica, Milano, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milano, Italy
| | - Simon Arridge
- University College London, Department of Computer Science, London, United Kingdom
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Darmani G, Bergmann T, Butts Pauly K, Caskey C, de Lecea L, Fomenko A, Fouragnan E, Legon W, Murphy K, Nandi T, Phipps M, Pinton G, Ramezanpour H, Sallet J, Yaakub S, Yoo S, Chen R. Non-invasive transcranial ultrasound stimulation for neuromodulation. Clin Neurophysiol 2022; 135:51-73. [DOI: 10.1016/j.clinph.2021.12.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 12/13/2022]
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Fincke J, Zhang X, Shin B, Ely G, Anthony BW. Quantitative Sound Speed Imaging of Cortical Bone and Soft Tissue: Results From Observational Data Sets. IEEE TRANSACTIONS ON MEDICAL IMAGING 2022; 41:502-514. [PMID: 34570702 DOI: 10.1109/tmi.2021.3115790] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This work presents the first quantitative ultrasonic sound speed images of ex vivo limb cross-sections containing both soft tissue and bone using Full Waveform Inversion (FWI) with level set (LS) and travel time regularization. The estimated bulk sound speed of bone and soft tissue are within 10% and 1%, respectively, of ground truth estimates. The sound speed imagery shows muscle, connective tissue and bone features. Typically, ultrasound tomography (UST) using FWI is applied to imaging breast tissue properties (e.g. sound speed and density) that correlate with cancer. With further development, UST systems have the potential to deliver volumetric operator independent tissue property images of limbs with non-ionizing and portable hardware platforms. This work addresses the algorithmic challenges of imaging the sound speed of bone and soft tissue by combining FWI with LS regularization and travel time methods to recover soft tissue and bone sound speed with improved accuracy and reduced soft tissue artifacts when compared to conventional FWI. The value of leveraging LS and travel time methods is realized by evidence of improved bone geometry estimates as well as promising convergence properties and reduced risk of final model errors due to un-modeled shear wave propagation. Ex vivo bulk measurements of sound speed and MRI cross-sections validates the final inversion results.
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