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Xu Z, Khokhlova TD, Cho CS, Khokhlova VA. Histotripsy: A Method for Mechanical Tissue Ablation with Ultrasound. Annu Rev Biomed Eng 2024; 26:141-167. [PMID: 38346277 DOI: 10.1146/annurev-bioeng-073123-022334] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Histotripsy is a relatively new therapeutic ultrasound technology to mechanically liquefy tissue into subcellular debris using high-amplitude focused ultrasound pulses. In contrast to conventional high-intensity focused ultrasound thermal therapy, histotripsy has specific clinical advantages: the capacity for real-time monitoring using ultrasound imaging, diminished heat sink effects resulting in lesions with sharp margins, effective removal of the treated tissue, a tissue-selective feature to preserve crucial structures, and immunostimulation. The technology is being evaluated in small and large animal models for treating cancer, thrombosis, hematomas, abscesses, and biofilms; enhancing tumor-specific immune response; and neurological applications. Histotripsy has been recently approved by the US Food and Drug Administration to treat liver tumors, with clinical trials undertaken for benign prostatic hyperplasia and renal tumors. This review outlines the physical principles of various types of histotripsy; presents major parameters of the technology and corresponding hardware and software, imaging methods, and bioeffects; and discusses the most promising preclinical and clinical applications.
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Affiliation(s)
- Zhen Xu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA;
| | - Tatiana D Khokhlova
- Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
| | - Clifford S Cho
- Department of Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Vera A Khokhlova
- Department of Acoustics, Lomonosov Moscow State University, Moscow, Russia
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2
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Xu P, Wu H, Shen G. Characterization of weakly nonlinear effects in relationship to transducer parameters in focused ultrasound therapy. Med Phys 2024. [PMID: 38935266 DOI: 10.1002/mp.17270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 06/04/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
BACKGROUND Focused ultrasound therapy has been widely used for the treatment of various diseases, employing different types of transducers. The focused ultrasound pressure fields inevitably exhibit nonlinear effects, which can influence the ablation region. However, the nonlinear effects exhibit noticeable variations across different applications. The characterization of the nonlinear pressure fields of ultrasound is important for the effective implementation of focused ultrasound therapy. PURPOSE The traditional angular spectrum method (ASM) was extended to accurately and efficiently simulate the propagation of weakly nonlinear ultrasound in heterogeneous mediums of clinical model. The nonlinear effects were further analyzed in relationship to the transducer parameters that are different in various applications. METHODS The pressure fields were simulated using the extended ASM, incorporating calculations for phase aberration in the frequency domain and magnitude compensation in the spatial domain to account for heterogeneous acoustic impedance mismatch. Validation was performed by comparison to k-Wave simulation results using two simplified clinical models, an abdominal soft tissue and a transcranial skull model. The nonlinear effects were then analyzed in relation to the transducer parameters of f-number and effective source area based on the same acoustic output power. The analysis of nonlinear effects was conducted under both homogeneous medium and the clinical models. RESULTS The simulation results demonstrated a maximum error of 3.93% in the calculated harmonic pressure of the abdominal model, and a maximum error of 4.89% within the transcranial model when comparing the extended ASM simulation results to those obtained from k-Wave simulations. The characterization of the nonlinear effects reveals a strong correlation with the transducer parameters. Specifically, the results indicate that the nonlinear effects intensify with an increase in the effective source area and f-number, under the same acoustic output power of the transducer. However, the clinical model also showed an influence on the nonlinear effects in relation to the f-number. CONCLUSION The extended ASM was demonstrated as an accurate and efficient simulation tool, and the simulation results provide a reference for evaluating the intensity of nonlinear effects in various transducer designs.
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Affiliation(s)
- Peng Xu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Hao Wu
- Shanghai Shende Green Medical Era Healthcare Technology Co., Ltd, Shanghai, People's Republic of China
| | - Guofeng Shen
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 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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Drainville RA, Chatillon S, Moore D, Snell J, Padilla F, Lafon C. A simulation study on the sensitivity of transcranial ray-tracing ultrasound modeling to skull properties. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 154:1211-1225. [PMID: 37610718 DOI: 10.1121/10.0020761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 08/08/2023] [Indexed: 08/24/2023]
Abstract
In transcranial focused ultrasound therapies, such as treating essential tremor via thermal ablation in the thalamus, acoustic energy is focused through the skull using a phased-array transducer. Ray tracing is a computationally efficient method that can correct skull-induced phase aberrations via per-element phase delay calculations using patient-specific computed tomography (CT) data. However, recent studies show that variations in CT-derived Hounsfield unit may account for only 50% of the speed of sound variability in human skull specimens, potentially limiting clinical transcranial ultrasound applications. Therefore, understanding the sensitivity of treatment planning methods to material parameter variations is essential. The present work uses a ray-tracing simulation model to explore how imprecision in model inputs, arising from clinically significant uncertainties in skull properties or considerations of acoustic phenomena, affects acoustic focusing quality through the skull. We propose and validate new methods to optimize ray-tracing skull simulations for clinical treatment planning, relevant for predicting intracranial target's thermal rise, using experimental data from ex-vivo human skulls.
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Affiliation(s)
| | | | - David Moore
- Focused Ultrasound Foundation, Charlottesville, Virginia 22903, USA
| | - John Snell
- Histosonics, Ann Arbor, Michigan 48103, USA
| | - Frederic Padilla
- Focused Ultrasound Foundation, Charlottesville, Virginia 22903, USA
| | - Cyril Lafon
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, Lyon, France
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5
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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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6
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Williams RP, Simon JC, Khokhlova VA, Sapozhnikov OA, Khokhlova TD. The histotripsy spectrum: differences and similarities in techniques and instrumentation. Int J Hyperthermia 2023; 40:2233720. [PMID: 37460101 PMCID: PMC10479943 DOI: 10.1080/02656736.2023.2233720] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/15/2023] [Accepted: 07/02/2023] [Indexed: 07/20/2023] Open
Abstract
Since its inception about two decades ago, histotripsy - a non-thermal mechanical tissue ablation technique - has evolved into a spectrum of methods, each with distinct potentiating physical mechanisms: intrinsic threshold histotripsy, shock-scattering histotripsy, hybrid histotripsy, and boiling histotripsy. All methods utilize short, high-amplitude pulses of focused ultrasound delivered at a low duty cycle, and all involve excitation of violent bubble activity and acoustic streaming at the focus to fractionate tissue down to the subcellular level. The main differences are in pulse duration, which spans microseconds to milliseconds, and ultrasound waveform shape and corresponding peak acoustic pressures required to achieve the desired type of bubble activity. In addition, most types of histotripsy rely on the presence of high-amplitude shocks that develop in the pressure profile at the focus due to nonlinear propagation effects. Those requirements, in turn, dictate aspects of the instrument design, both in terms of driving electronics, transducer dimensions and intensity limitations at surface, shape (primarily, the F-number) and frequency. The combination of the optimized instrumentation and the bio-effects from bubble activity and streaming on different tissues, lead to target clinical applications for each histotripsy method. Here, the differences and similarities in the physical mechanisms and resulting bioeffects of each method are reviewed and tied to optimal instrumentation and clinical applications.
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Affiliation(s)
- Randall P Williams
- Division of Gastroenterology, Department of Medicine, University of Washington, Seattle, WA, USA
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Julianna C Simon
- Graduate Program in Acoustics, The Pennsylvania State University, University Park, PA, USA
| | - Vera A Khokhlova
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
- Department of Acoustics, Physics Faculty, Moscow State University, Moscow, Russia
| | - Oleg A Sapozhnikov
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
- Department of Acoustics, Physics Faculty, Moscow State University, Moscow, Russia
| | - Tatiana D Khokhlova
- Division of Gastroenterology, Department of Medicine, University of Washington, Seattle, WA, USA
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
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7
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Stocker GE, Lundt JE, Sukovich JR, Miller RM, Duryea AP, Hall TL, Xu Z. A Modular, Kerf-Minimizing Approach for Therapeutic Ultrasound Phased Array Construction. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2766-2775. [PMID: 35617178 PMCID: PMC9594968 DOI: 10.1109/tuffc.2022.3178291] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A novel method for fabricating a modular, kerf-minimizing histotripsy phased array was developed and tested. The method utilizes arbitrarily shaped elements, 3-D printing, water jet cutting, and a thin, 125- [Formula: see text] electrically insulating epoxy coating to maximize aperture utilization while allowing for replacement of individual transducer modules. The method was used to fabricate a 750-kHz truncated circular aperture array (165 mm ×234 mm) transducer with a focal length of 142 mm. The aperture was segmented into 260 arc-shaped modular elements, each approximately 11.5 mm ×11.5 mm, arranged in concentric rings. The resulting aperture utilization was 92%. The full-width-half-maximum (FWHM) focal zone of the array was measured to be 1.6 mm ×1.1 mm ×4.5 mm, and the FWHM electrical steering range was measured to be 38.5 mm ×33 mm 40 mm. The array was estimated to be capable of generating approximately 120-MPa peak negative pressure at the geometric focus. In addition, the array was used to ablate a 5-cm3 volume of tissue with electric focal steering.
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Affiliation(s)
- Greyson E. Stocker
- Department of Biomedical Engineering at the University of Michigan, Ann Arbor, MI 48109
| | | | - Jonathan R. Sukovich
- Department of Biomedical Engineering at the University of Michigan, Ann Arbor, MI 48109
| | | | | | - Timothy L. Hall
- Department of Biomedical Engineering at the University of Michigan, Ann Arbor, MI 48109
| | - Zhen Xu
- Department of Biomedical Engineering at the University of Michigan, Ann Arbor, MI 48109
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8
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Slezak C, Flatscher J, Slezak P. A Comparative Feasibility Study for Transcranial Extracorporeal Shock Wave Therapy. Biomedicines 2022; 10:biomedicines10061457. [PMID: 35740477 PMCID: PMC9219950 DOI: 10.3390/biomedicines10061457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/05/2022] [Accepted: 06/11/2022] [Indexed: 12/03/2022] Open
Abstract
The potential beneficial regenerative and stimulatory extracorporeal shock wave therapy (ESWT) applications to the central nervous system have garnered interest in recent years. Treatment zones for these indications are acoustically shielded by bones, which heavily impact generated sound fields. We present the results of high-resolution tissue-realistic simulations, comparing the viability of different ESWT applicators in their use for transcranial applications. The performances of electrohydraulic, electromagnetic, and piezoelectric transducers for key reflector geometries are compared. Based on density information obtained from CT imaging of the head, we utilized the non-linear wave propagation toolset Matlab k-Wave to obtain spatial therapeutic sound field geometries and waveforms. In order to understand the reliability of results on the appropriate modeling of the skull, three different bone attenuation models were compared. We find that all currently clinically ESWT applicator technologies show significant retention of peak pressures and energies past the bone barrier. Electromagnetic transducers maintain a significantly higher energy flux density compared to other technologies while low focusing strength piezoelectric applicators have the weakest transmissions. Attenuation estimates provide insights into sound field degradation and energy losses, indicating that effective transcranial therapies can readily be attained with current applicators. Furthermore, the presented approach will allow for future targeted in silico development and the design of applicators and therapy plans to ultimately improve therapeutic outcomes.
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Affiliation(s)
- Cyrill Slezak
- Department of Physics, Utah Valley University, Orem, UT 84058, USA;
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, 1200 Vienna, Austria;
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Jonas Flatscher
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, 1200 Vienna, Austria;
| | - Paul Slezak
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, 1200 Vienna, Austria;
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
- Correspondence:
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9
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Transcranial ultrasound stimulation of the human motor cortex. iScience 2021; 24:103429. [PMID: 34901788 PMCID: PMC8637484 DOI: 10.1016/j.isci.2021.103429] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/04/2021] [Accepted: 11/09/2021] [Indexed: 12/22/2022] Open
Abstract
It has been 40 years since the report of long-term synaptic plasticity on the rodent brain. Transcranial ultrasound stimulation (TUS) shows advantages in spatial resolution and penetration depth when compared with electrical or magnetic stimulation. The repetitive TUS (rTUS) can induce cortical excitability alteration on animals, and persistent aftereffects were observed. However, the effects of rTUS on synaptic plasticity in humans remain unelucidated. In the current study, we applied a 15-min rTUS protocol to stimulate left primary motor cortex (l-M1) in 24 male healthy participants. The single-pulsed transcranial magnetic stimulation-evoked motor evoked potential and Stop-signal task was applied to measure the rTUS aftereffects. Here, we report that conditioning the human motor cortex using rTUS may produce long-lasting and statistically significant effects on motor cortex excitability as well as motor behavior, without harmful side effects observed. These findings suggest a considerable potential of rTUS in cortical plasticity modulation and clinical intervention for impulsivity-related disorders.
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Yuldashev PV, Karzova MM, Kreider W, Rosnitskiy PB, Sapozhnikov OA, Khokhlova VA. "HIFU Beam:" A Simulator for Predicting Axially Symmetric Nonlinear Acoustic Fields Generated by Focused Transducers in a Layered Medium. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:2837-2852. [PMID: 33877971 PMCID: PMC8486313 DOI: 10.1109/tuffc.2021.3074611] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
"HIFU beam" is a freely available software tool that comprises a MATLAB toolbox combined with a user-friendly interface and binary executable compiled from FORTRAN source code (HIFU beam. (2021). Available: http://limu.msu.ru/node/3555?language=en). It is designed for simulating high-intensity focused ultrasound (HIFU) fields generated by single-element transducers and annular arrays with propagation in flat-layered media that mimic biological tissues. Numerical models incorporated in the simulator include evolution-type equations, either the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation or one-way Westervelt equation, for radially symmetric ultrasound beams in homogeneous and layered media with thermoviscous or power-law acoustic absorption. The software uses shock-capturing methods that allow for simulating strongly nonlinear acoustic fields with high-amplitude shocks. In this article, a general description of the software is given along with three representative simulation cases of ultrasound transducers and focusing conditions typical for therapeutic applications. The examples illustrate major nonlinear wave effects in HIFU fields including shock formation. Two examples simulate propagation in water, involving a single-element source (1-MHz frequency, 100-mm diameter, 90-mm radius of curvature) and a 16-element annular array (3-MHz frequency, 48-mm diameter, and 35-mm radius of curvature). The third example mimics the scenario of a HIFU treatment in a "water-muscle-kidney" layered medium using a source typical for abdominal HIFU applications (1.2-MHz frequency, 120-mm diameter, and radius of curvature). Linear, quasi-linear, and shock-wave exposure protocols are considered. It is intended that "HIFU beam" can be useful in teaching nonlinear acoustics; designing and characterizing high-power transducers; and developing exposure protocols for a wide range of therapeutic applications such as shock-based HIFU, boiling histotripsy, drug delivery, immunotherapy, and others.
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Wu N, Shen G, Qu X, Wu H, Qiao S, Wang E, Chen Y, Wang H. Design of a Versatile Angle-Rotatable Skull-Shaped Conformal Transcranial Focused Ultrasound Transducer for Noninvasive Brain Therapy. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:116-126. [PMID: 32396086 DOI: 10.1109/tuffc.2020.2993810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Phase-controlled focused ultrasound transducers have opened up a new way to noninvasively treat brain diseases. However, due to the geometry and the heterogeneous medium of the human skull, the currently used hemispherical transducers cannot guarantee that the ultrasound emitted by the transducer penetrates the skull normally; consequently, the impact of the shear wave on the treatment area has to be considered. The usual approach is to turn off elements in the transducer with excessively large incident angles, but this approach reduces the efficiency of the transducer. This article presents the design of a novel transducer that can be rotated according to the different geometric shapes of the skull. The incident angles of the elements in the transducer are modified so that the effect of the shear wave on the treatment area can be ignored and the efficiency of the transducer is improved. The results of computed tomography (CT) model simulation of nine skulls verify the versatility and feasibility of the new transducer. We believe that this kind of rotatable transducer has clinical and engineering significance.
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Qiu W, Bouakaz A, Konofagou EE, Zheng H. Ultrasound for the Brain: A Review of Physical and Engineering Principles, and Clinical Applications. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:6-20. [PMID: 32866096 DOI: 10.1109/tuffc.2020.3019932] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The emergence of new ultrasound technologies has improved our understanding of the brain functions and offered new opportunities for the treatment of brain diseases. Ultrasound has become a valuable tool in preclinical animal and clinical studies as it not only provides information about the structure and function of brain tissues but can also be used as a therapy alternative for brain diseases. High-resolution cerebral flow images with high sensitivity can be acquired using novel functional ultrasound and super-resolution ultrasound imaging techniques. The noninvasive treatment of essential tremors has been clinically approved and it has been demonstrated that the ultrasound technology can revolutionize the currently existing treatment methods. Microbubble-mediated ultrasound can remotely open the blood-brain barrier enabling targeted drug delivery in the brain. More recently, ultrasound neuromodulation received a great amount of attention due to its noninvasive and deep penetration features and potential therapeutic benefits. This review provides a thorough introduction to the current state-of-the-art research on brain ultrasound and also introduces basic knowledge of brain ultrasound including the acoustic properties of the brain/skull and engineering techniques for ultrasound. Ultrasound is expected to play an increasingly important role in the diagnosis and therapy of brain diseases.
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13
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Peek AT, Hunter C, Kreider W, Khokhlova TD, Rosnitskiy PB, Yuldashev PV, Sapozhnikov OA, Khokhlova VA. Bilayer aberration-inducing gel phantom for high intensity focused ultrasound applications. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 148:3569. [PMID: 33379925 PMCID: PMC8097711 DOI: 10.1121/10.0002877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/04/2020] [Accepted: 11/15/2020] [Indexed: 05/19/2023]
Abstract
Aberrations induced by soft tissue inhomogeneities often complicate high-intensity focused ultrasound (HIFU) therapies. In this work, a bilayer phantom made from polyvinyl alcohol hydrogel and ballistic gel was built to mimic alternating layers of water-based and lipid tissues characteristic of an abdominal body wall and to reproducibly distort HIFU fields. The density, sound speed, and attenuation coefficient of each material were measured using a homogeneous gel layer. A surface with random topographical features was designed as an interface between gel layers using a 2D Fourier spectrum approach and replicating different spatial scales of tissue inhomogeneities. Distortion of the field of a 256-element 1.5 MHz HIFU array by the phantom was characterized through hydrophone measurements for linear and nonlinear beam focusing and compared to the corresponding distortion induced by an ex vivo porcine body wall of the same thickness. Both spatial shift and widening of the focal lobe were observed, as well as dramatic reduction in focal pressures caused by aberrations. The results suggest that the phantom produced levels of aberration that are similar to a real body wall and can serve as a research tool for studying HIFU effects as well as for developing algorithms for aberration correction.
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Affiliation(s)
- Alex T Peek
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105, USA
| | - Christopher Hunter
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105, USA
| | - Wayne Kreider
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105, USA
| | - Tatiana D Khokhlova
- Division of Gastroenterology, Department of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, Washington 98195, USA
| | - Pavel B Rosnitskiy
- Department of Acoustics, Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Petr V Yuldashev
- Department of Acoustics, Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Oleg A Sapozhnikov
- Department of Acoustics, Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Vera A Khokhlova
- Department of Acoustics, Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991, Russia
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Fomenko A, Chen KHS, Nankoo JF, Saravanamuttu J, Wang Y, El-Baba M, Xia X, Seerala SS, Hynynen K, Lozano AM, Chen R. Systematic examination of low-intensity ultrasound parameters on human motor cortex excitability and behavior. eLife 2020; 9:e54497. [PMID: 33236981 PMCID: PMC7728443 DOI: 10.7554/elife.54497] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 11/24/2020] [Indexed: 12/23/2022] Open
Abstract
Low-intensity transcranial ultrasound (TUS) can non-invasively modulate human neural activity. We investigated how different fundamental sonication parameters influence the effects of TUS on the motor cortex (M1) of 16 healthy subjects by probing cortico-cortical excitability and behavior. A low-intensity 500 kHz TUS transducer was coupled to a transcranial magnetic stimulation (TMS) coil. TMS was delivered 10 ms before the end of TUS to the left M1 hotspot of the first dorsal interosseous muscle. Varying acoustic parameters (pulse repetition frequency, duty cycle, and sonication duration) on motor-evoked potential amplitude were examined. Paired-pulse measures of cortical inhibition and facilitation, and performance on a visuomotor task was also assessed. TUS safely suppressed TMS-elicited motor cortical activity, with longer sonication durations and shorter duty cycles when delivered in a blocked paradigm. TUS increased GABAA-mediated short-interval intracortical inhibition and decreased reaction time on visuomotor task but not when controlled with TUS at near-somatosensory threshold intensity.
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Affiliation(s)
- Anton Fomenko
- Krembil Research Institute, University Health NetworkTorontoCanada
| | - Kai-Hsiang Stanley Chen
- Krembil Research Institute, University Health NetworkTorontoCanada
- Department of Neurology, National Taiwan University Hospital Hsin-Chu BranchHsin-ChuTaiwan
| | | | | | - Yanqiu Wang
- Krembil Research Institute, University Health NetworkTorontoCanada
| | - Mazen El-Baba
- Krembil Research Institute, University Health NetworkTorontoCanada
| | - Xue Xia
- Division of Neurology, Department of Medicine, University of TorontoTorontoCanada
| | | | | | - Andres M Lozano
- Krembil Research Institute, University Health NetworkTorontoCanada
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of TorontoTorontoCanada
| | - Robert Chen
- Krembil Research Institute, University Health NetworkTorontoCanada
- Division of Neurology, Department of Medicine, University of TorontoTorontoCanada
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15
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Treeby BE, Wise ES, Kuklis F, Jaros J, Cox BT. Nonlinear ultrasound simulation in an axisymmetric coordinate system using a k-space pseudospectral method. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 148:2288. [PMID: 33138501 DOI: 10.1121/10.0002177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A full-wave model for nonlinear ultrasound propagation through a heterogeneous and absorbing medium in an axisymmetric coordinate system is developed. The model equations are solved using a nonstandard or k-space pseudospectral time domain method. Spatial gradients in the axial direction are calculated using the Fourier collocation spectral method, and spatial gradients in the radial direction are calculated using discrete trigonometric transforms. Time integration is performed using a k-space corrected finite difference scheme. This scheme is exact for plane waves propagating linearly in the axial direction in a homogeneous and lossless medium and significantly reduces numerical dispersion in the more general case. The implementation of the model is described, and performance benchmarks are given for a range of grid sizes. The model is validated by comparison with several analytical solutions. This includes one-dimensional absorption and nonlinearity, the pressure field generated by plane-piston and bowl transducers, and the scattering of a plane wave by a sphere. The general utility of the model is then demonstrated by simulating nonlinear transcranial ultrasound using a simplified head model.
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Affiliation(s)
- Bradley E Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Elliott S Wise
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Filip Kuklis
- Centre of Excellence IT4Innovations, Faculty of Information Technology, Brno University of Technology, Božetěchova 2, Brno, 612 00, Czech Republic
| | - Jiri Jaros
- Centre of Excellence IT4Innovations, Faculty of Information Technology, Brno University of Technology, Božetěchova 2, Brno, 612 00, Czech Republic
| | - B T Cox
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
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16
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Brinker ST, Preiswerk F, White PJ, Mariano TY, McDannold NJ, Bubrick EJ. Focused Ultrasound Platform for Investigating Therapeutic Neuromodulation Across the Human Hippocampus. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:1270-1274. [PMID: 32088061 PMCID: PMC7239323 DOI: 10.1016/j.ultrasmedbio.2020.01.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/03/2020] [Accepted: 01/13/2020] [Indexed: 05/25/2023]
Abstract
Pulsed low-intensity focused ultrasound (PLIFUS) has shown promise in inducing neuromodulation in several animal and human studies. Therefore, it is of clinical interest to develop experimental platforms to test repetitive PLIFUS as a therapeutic modality in humans with neurologic disorders. In the study described here, our aim was to develop a laboratory-built experimental device platform intended to deliver repetitive PLIFUS across the hippocampus in seizure onset zones of patients with drug-resistant temporal lobe epilepsy. The system uses neuronavigation targeting over multiple therapeutic sessions. PLIFUS (548 kHz) was emitted across multiple hippocampal targets in a human subject with temporal lobe epilepsy using a mechanically steered piezoelectric transducer. Stimulation was delivered up to 2.25 W/cm2 spatial peak temporal average intensity (free-field equivalent), with 36%-50% duty cycle, 500-ms sonications and 7-s inter-stimulation intervals lasting 140 s per target and repeated for multiple sessions. A first-in-human PLIFUS course of treatment was successfully delivered using the device platform with no adverse events.
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Affiliation(s)
- Spencer T Brinker
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Frank Preiswerk
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Phillip J White
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Department of Physics, Simmons College, Boston, Massachusetts, USA
| | - Timothy Y Mariano
- Center for Neurorestoration and Neurotechnology, Providence Veterans Affairs Medical Center, Providence, Rhode Island, USA; Butler Hospital, Providence, Rhode Island, USA; Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Nathan J McDannold
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
| | - Ellen J Bubrick
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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