1
|
Chesney KM, Keating GF, Patel N, Kilburn L, Fonseca A, Wu CC, Nazarian J, Packer RJ, Donoho DA, Oluigbo C, Myseros JS, Keating RF, Syed HR. The role of focused ultrasound for pediatric brain tumors: current insights and future implications on treatment strategies. Childs Nerv Syst 2024; 40:2333-2344. [PMID: 38702518 DOI: 10.1007/s00381-024-06413-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 04/14/2024] [Indexed: 05/06/2024]
Abstract
INTRODUCTION Focused ultrasound (FUS) is an innovative and emerging technology for the treatment of adult and pediatric brain tumors and illustrates the intersection of various specialized fields, including neurosurgery, neuro-oncology, radiation oncology, and biomedical engineering. OBJECTIVE The authors provide a comprehensive overview of the application and implications of FUS in treating pediatric brain tumors, with a special focus on pediatric low-grade gliomas (pLGGs) and the evolving landscape of this technology and its clinical utility. METHODS The fundamental principles of FUS include its ability to induce thermal ablation or enhance drug delivery through transient blood-brain barrier (BBB) disruption, emphasizing the adaptability of high-intensity focused ultrasound (HIFU) and low-intensity focused ultrasound (LIFU) applications. RESULTS Several ongoing clinical trials explore the potential of FUS in offering alternative therapeutic strategies for pathologies where conventional treatments fall short, specifically centrally-located benign CNS tumors and diffuse intrinsic pontine glioma (DIPG). A case illustration involving the use of HIFU for pilocytic astrocytoma is presented. CONCLUSION Discussions regarding future applications of FUS for the treatment of gliomas include improved drug delivery, immunomodulation, radiosensitization, and other technological advancements.
Collapse
Affiliation(s)
- Kelsi M Chesney
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
- Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, DC, USA
| | - Gregory F Keating
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
- Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, DC, USA
| | - Nirali Patel
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
- Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, DC, USA
| | - Lindsay Kilburn
- Brain Tumor Institute, Children's National Hospital, Washington, DC, USA
| | - Adriana Fonseca
- Brain Tumor Institute, Children's National Hospital, Washington, DC, USA
| | - Cheng-Chia Wu
- Department of Radiation Oncology, Columbia University Irving Medical Center, New York, NY, USA
| | - Javad Nazarian
- Brain Tumor Institute, Children's National Hospital, Washington, DC, USA
| | - Roger J Packer
- Brain Tumor Institute, Children's National Hospital, Washington, DC, USA
| | - Daniel A Donoho
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
- Department of Neurosurgery, George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Chima Oluigbo
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
- Department of Neurosurgery, George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - John S Myseros
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
- Department of Neurosurgery, George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Robert F Keating
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
- Department of Neurosurgery, George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Hasan R Syed
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA.
- Department of Neurosurgery, George Washington University School of Medicine & Health Sciences, Washington, DC, USA.
| |
Collapse
|
2
|
Tian Z, Olmstead M, Jing Y, Han A. Transcranial Phase Correction Using Pulse-Echo Ultrasound and Deep Learning: A 2-D Numerical Study. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2024; 71:117-126. [PMID: 38060357 PMCID: PMC10858766 DOI: 10.1109/tuffc.2023.3340597] [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: 01/10/2024]
Abstract
Phase aberration caused by human skulls severely degrades the quality of transcranial ultrasound images, posing a major challenge in the practical application of transcranial ultrasound techniques in adults. Aberration can be corrected if the skull profile (i.e., thickness distribution) and speed of sound (SOS) are known. However, accurately estimating the skull profile and SOS using ultrasound with a physics-based approach is challenging due to the complexity of the interaction between ultrasound and the skull. A deep learning approach is proposed herein to estimate the skull profile and SOS using ultrasound radiofrequency (RF) signals backscattered from the skull. A numerical study was performed to test the approach's feasibility. Realistic numerical skull models were constructed from computed tomography (CT) scans of five ex vivo human skulls in this numerical study. Acoustic simulations were performed on 3595 skull segments to generate array-based ultrasound backscattered signals. A deep learning model was developed and trained to estimate skull thickness and SOS from RF channel data. The trained model was shown to be highly accurate. The mean absolute error (MAE) was 0.15 mm (2% error) for thickness estimation and 13 m/s (0.5% error) for SOS estimation. The Pearson correlation coefficient between the estimated and ground-truth values was 0.99 for thickness and 0.95 for SOS. Aberration correction performed using deep-learning-estimated skull thickness and SOS values yielded significantly improved beam focusing (e.g., narrower beams) and transcranial imaging quality (e.g., improved spatial resolution and reduced artifacts) compared with no aberration correction. The results demonstrate the feasibility of the proposed approach for transcranial phase aberration correction.
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Park TY, Koh H, Lee W, Park SH, Chang WS, Kim H. Real-Time Acoustic Simulation Framework for tFUS: A Feasibility Study Using Navigation System. Neuroimage 2023; 282:120411. [PMID: 37844771 DOI: 10.1016/j.neuroimage.2023.120411] [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: 06/04/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 10/18/2023] Open
Abstract
Transcranial focused ultrasound (tFUS), in which acoustic energy is focused on a small region in the brain through the skull, is a non-invasive therapeutic method with high spatial resolution and depth penetration. Image-guided navigation has been widely utilized to visualize the location of acoustic focus in the cranial cavity. However, this system is often inaccurate because of the significant aberrations caused by the skull. Therefore, acoustic simulations using a numerical solver have been widely adopted to compensate for this inaccuracy. Although the simulation can predict the intracranial acoustic pressure field, real-time application during tFUS treatment is almost impossible due to the high computational cost. In this study, we propose a neural network-based real-time acoustic simulation framework and test its feasibility by implementing a simulation-guided navigation (SGN) system. Real-time acoustic simulation is performed using a 3D conditional generative adversarial network (3D-cGAN) model featuring residual blocks and multiple loss functions. This network was trained by the conventional numerical acoustic simulation program (i.e., k-Wave). The SGN system is then implemented by integrating real-time acoustic simulation with a conventional image-guided navigation system. The proposed system can provide simulation results with a frame rate of 5 Hz (i.e., about 0.2 s), including all processing times. In numerical validation (3D-cGAN vs. k-Wave), the average peak intracranial pressure error was 6.8 ± 5.5%, and the average acoustic focus position error was 5.3 ± 7.7 mm. In experimental validation using a skull phantom (3D-cGAN vs. actual measurement), the average peak intracranial pressure error was 4.5%, and the average acoustic focus position error was 6.6 mm. These results demonstrate that the SGN system can predict the intracranial acoustic field according to transducer placement in real-time.
Collapse
Affiliation(s)
- Tae Young Park
- Bionics Research Center, Biomedical Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
| | - Heekyung Koh
- Bionics Research Center, Biomedical Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Wonhye Lee
- Bionics Research Center, Biomedical Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - So Hee Park
- Department of Neurosurgery, Yeungnam University Medical Center, Daegu 42415, Republic of Korea
| | - Won Seok Chang
- Department of Neurosurgery, Brain Research Institute, Yonsei University College of Medicine, Seoul 04527, Republic of Korea
| | - Hyungmin Kim
- Bionics Research Center, Biomedical Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea.
| |
Collapse
|
5
|
Hosseini S, Puonti O, Treeby B, Hanson LG, Thielscher A. A head template for computational dose modelling for transcranial focused ultrasound stimulation. Neuroimage 2023; 277:120227. [PMID: 37321357 DOI: 10.1016/j.neuroimage.2023.120227] [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: 03/07/2023] [Revised: 06/04/2023] [Accepted: 06/12/2023] [Indexed: 06/17/2023] Open
Abstract
Transcranial focused Ultrasound Stimulation (TUS) at low intensities is emerging as a novel non-invasive brain stimulation method with higher spatial resolution than established transcranial stimulation methods and the ability to selectively stimulate also deep brain areas. Accurate control of the focus position and strength of the TUS acoustic waves is important to enable a beneficial use of the high spatial resolution and to ensure safety. As the human skull causes strong attenuation and distortion of the waves, simulations of the transmitted waves are needed to accurately determine the TUS dose distribution inside the cranial cavity. The simulations require information of the skull morphology and its acoustic properties. Ideally, they are informed by computed tomography (CT) images of the individual head. However, suited individual imaging data is often not readily available. For this reason, we here introduce and validate a head template that can be used to estimate the average effects of the skull on the TUS acoustic wave in the population. The template was created from CT images of the heads of 29 individuals of different ages (between 20-50 years), gender and ethnicity using an iterative non-linear co-registration procedure. For validation, we compared acoustic and thermal simulations based on the template to the average of the simulation results of all 29 individual datasets. Acoustic simulations were performed for a model of a focused transducer driven at 500 kHz, placed at 24 standardized positions by means of the EEG 10-10 system. Additional simulations at 250 kHz and 750 kHz at 16 of the positions were used for further confirmation. The amount of ultrasound-induced heating at 500 kHz was estimated for the same 16 transducer positions. Our results show that the template represents the median of the acoustic pressure and temperature maps from the individuals reasonably well in most cases. This underpins the usefulness of the template for the planning and optimization of TUS interventions in studies of healthy young adults. Our results further indicate that the amount of variability between the individual simulation results depends on the position. Specifically, the simulated ultrasound-induced heating inside the skull exhibited strong interindividual variability for three posterior positions close to the midline, caused by a high variability of the local skull shape and composition. This should be taken into account when interpreting simulation results based on the template.
Collapse
Affiliation(s)
- Seyedsina Hosseini
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Denmark
| | - Oula Puonti
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Denmark
| | - Bradley Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, GowerStreet, London, WC1E 6BT, United Kingdom
| | - Lars G Hanson
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Denmark
| | - Axel Thielscher
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Denmark.
| |
Collapse
|
6
|
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.
Collapse
|
7
|
Mazzotti M, Kohtanen E, Erturk A, Ruzzene M. Optimizing transcranial ultrasound delivery at large incident angles by leveraging cranial leaky guided wave dispersion. ULTRASONICS 2023; 128:106882. [PMID: 36402116 DOI: 10.1016/j.ultras.2022.106882] [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: 05/05/2022] [Revised: 09/08/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
We investigate the role of leaky guided waves in transcranial ultrasound transmission in temporal and parietal bones at large incidence angles. Our numerical and experimental results show that the dispersion characteristics of the fundamental leaky guided wave mode with longitudinal polarization can be leveraged to estimate the critical angle above which efficient shear mode conversion takes place, and below which major transmission drops can be expected. Simulations that employ a numerical propagator matrix and a Semi-Analytical approach establish the transcranial dispersion characteristics and transmission coefficients at different incident angles. Experimental transmission tests conducted at 500 kHz and radiation tests performed in the 200-800 kHz range confirm the numerical findings in terms of transmitted peak pressure and frequency-radiation angle spectra, based on which the connection between critical angles, dispersion and transmission is demonstrated. Our results support the identification of transcranial ultrasound strategies that leverage shear mode conversion, which is less sensitive to phase aberrations compared to normal incidence ultrasound. These findings can also enable higher transmission rates in cranial bones with low porosity by leveraging dispersion information extracted through signal processing, without requiring measurement of geometric and mechanical properties of the cranial bone.
Collapse
Affiliation(s)
- Matteo Mazzotti
- P.M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, USA.
| | - Eetu Kohtanen
- G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, USA
| | - Alper Erturk
- G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, USA
| | - Massimo Ruzzene
- P.M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, USA
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Hu Z, Yang Y, Xu L, Hao Y, Chen H. Binary acoustic metasurfaces for dynamic focusing of transcranial ultrasound. Front Neurosci 2022; 16:984953. [PMID: 36117633 PMCID: PMC9475195 DOI: 10.3389/fnins.2022.984953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 08/11/2022] [Indexed: 11/30/2022] Open
Abstract
Transcranial focused ultrasound (tFUS) is a promising technique for non-invasive and spatially targeted neuromodulation and treatment of brain diseases. Acoustic lenses were designed to correct the skull-induced beam aberration, but these designs could only generate static focused ultrasound beams inside the brain. Here, we designed and 3D printed binary acoustic metasurfaces (BAMs) for skull aberration correction and dynamic ultrasound beam focusing. BAMs were designed by binarizing the phase distribution at the surface of the metasurfaces. The phase distribution was calculated based on time reversal to correct the skull-induced phase aberration. The binarization enabled the ultrasound beam to be dynamically steered along wave propagation direction by adjusting the operation frequency of the incident ultrasound wave. The designed BAMs were manufactured by 3D printing with two coding bits, a polylactic acid unit for bit “1” and a water unit for bit “0.” BAMs for single- and multi-point focusing through the human skull were designed, 3D printed, and validated numerically and experimentally. The proposed BAMs with subwavelength scale in thickness are simple to design, easy to fabric, and capable of correcting skull aberration and achieving dynamic beam steering.
Collapse
Affiliation(s)
- Zhongtao Hu
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, United States
| | - Yaoheng Yang
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, United States
| | - Lu Xu
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, United States
| | - Yao Hao
- Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO, United States
| | - Hong Chen
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, United States
- Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO, United States
- *Correspondence: Hong Chen,
| |
Collapse
|
10
|
Li L, Zhang X, Zhou J, Zhang L, Xue J, Tao W. Non-Invasive Thermal Therapy for Tissue Engineering and Regenerative Medicine. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107705. [PMID: 35475541 DOI: 10.1002/smll.202107705] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/11/2022] [Indexed: 06/14/2023]
Abstract
Owing to the development of nanotechnology and noninvasive treatment, thermal therapy in combination with external stimuli has been applied for tissue engineering and regenerative medicine (TERM), which has attracted more and more attention in recent years. In this review, the recent progress of applying a variety of non-invasive thermal therapeutic modalities for TERM, including photothermal therapy, magnetic thermotherapy, and ultrasound thermotherapy, as well as other thermal therapeutics are discussed. The parameters and conditions that need to be considered and regulated to realize a well-controlled thermal therapy for tissue regeneration are also discussed. Afterwards, the current concerns and challenges of putting thermal therapy into clinical applications are pointed out. At last, perspectives are provided for the future development directions, aiming to providing opportunities and a novel pathway for TERM.
Collapse
Affiliation(s)
- Longfei Li
- Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Xiaodi Zhang
- Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, United States
| | - Jun Zhou
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, United States
| | - Liqun Zhang
- Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Jiajia Xue
- Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Wei Tao
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, United States
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Xu R, O'Reilly MA. Establishing density-dependent longitudinal sound speed in the vertebral lamina. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:1516. [PMID: 35364923 DOI: 10.1121/10.0009316] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
Focused ultrasound treatments of the spinal cord may be facilitated using a phased array transducer and beamforming to correct spine-induced focal aberrations. Simulations can non-invasively calculate aberration corrections using x-ray computed tomography (CT) data that are correlated to density (ρ) and longitudinal sound speed (cL). We aimed to optimize vertebral lamina-specific cL(ρ) functions at a physiological temperature (37 °C) to maximize time domain simulation accuracy. Odd-numbered ex vivo human thoracic vertebrae were imaged with a clinical CT-scanner (0.511 × 0.511 × 0.5 mm), then sonicated with a transducer (514 kHz) focused on the canal via the vertebral lamina. Vertebra-induced signal time shifts were extracted from pressure waveforms recorded within the canals. Measurements were repeated 5× per vertebra, with 2.5 mm vertical vertebra shifts between measurements. Linear functions relating cL with CT-derived density were optimized. The optimized function was cL(ρ)=0.35(ρ-ρw)+ cL,w m/s, where w denotes water, giving the tested laminae a mean bulk density of 1600 ± 30 kg/m3 and a mean bulk cL of 1670 ± 60 m/s. The optimized lamina cL(ρ) function was accurate to λ/16 when implemented in a multi-layered ray acoustics model. This modelling accuracy will improve trans-spine ultrasound beamforming.
Collapse
Affiliation(s)
- Rui Xu
- Department of Medical Biophysics, University of Toronto, 101 College Street, Suite 15-701, Toronto, Ontario, M5G 1L7, Canada
| | - Meaghan A O'Reilly
- Physical Sciences Platform, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
| |
Collapse
|