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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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Lee K, Park TY, Lee W, Kim H. A review of functional neuromodulation in humans using low-intensity transcranial focused ultrasound. Biomed Eng Lett 2024; 14:407-438. [PMID: 38645585 PMCID: PMC11026350 DOI: 10.1007/s13534-024-00369-0] [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: 12/31/2023] [Revised: 02/17/2024] [Accepted: 02/23/2024] [Indexed: 04/23/2024] Open
Abstract
Transcranial ultrasonic neuromodulation is a rapidly burgeoning field where low-intensity transcranial focused ultrasound (tFUS), with exquisite spatial resolution and deep tissue penetration, is used to non-invasively activate or suppress neural activity in specific brain regions. Over the past decade, there has been a rapid increase of tFUS neuromodulation studies in healthy humans and subjects with central nervous system (CNS) disease conditions, including a recent surge of clinical investigations in patients. This narrative review summarized the findings of human neuromodulation studies using either tFUS or unfocused transcranial ultrasound (TUS) reported from 2013 to 2023. The studies were categorized into two separate sections: healthy human research and clinical studies. A total of 42 healthy human investigations were reviewed as grouped by targeted brain regions, including various cortical, subcortical, and deep brain areas including the thalamus. For clinical research, a total of 22 articles were reviewed for each studied CNS disease condition, including chronic pain, disorder of consciousness, Alzheimer's disease, Parkinson's disease, depression, schizophrenia, anxiety disorders, substance use disorder, drug-resistant epilepsy, and stroke. Detailed information on subjects/cohorts, target brain regions, sonication parameters, outcome readouts, and stimulatory efficacies were tabulated for each study. In later sections, considerations for planning tFUS neuromodulation in humans were also concisely discussed. With an excellent safety profile to date, the rapid growth of human tFUS research underscores the increasing interest and recognition of its significant potential in the field of non-invasive brain stimulation (NIBS), offering theranostic potential for neurological and psychiatric disease conditions and neuroscientific tools for functional brain mapping.
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Affiliation(s)
- Kyuheon Lee
- Bionics Research Center, Biomedical Research Division, Korea Institute of Science and Technology, 5 Hwarangro 14-gil, Seongbuk-gu, Seoul, 02792 South Korea
- Department of Brain and Cognitive Engineering, Korea University, Seoul, South Korea
| | - Tae Young Park
- Bionics Research Center, Biomedical Research Division, Korea Institute of Science and Technology, 5 Hwarangro 14-gil, Seongbuk-gu, Seoul, 02792 South Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, South Korea
| | - Wonhye Lee
- Bionics Research Center, Biomedical Research Division, Korea Institute of Science and Technology, 5 Hwarangro 14-gil, Seongbuk-gu, Seoul, 02792 South Korea
- Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA USA
| | - Hyungmin Kim
- Bionics Research Center, Biomedical Research Division, Korea Institute of Science and Technology, 5 Hwarangro 14-gil, Seongbuk-gu, Seoul, 02792 South Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, South Korea
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Seo H, Han M, Choi JR, Kim S, Park J, Lee EH. Numerical Investigation of Layered Homogeneous Skull Model for Simulations of Transcranial Focused Ultrasound. Neuromodulation 2024:S1094-7159(24)00072-2. [PMID: 38691075 DOI: 10.1016/j.neurom.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/24/2024] [Accepted: 04/02/2024] [Indexed: 05/03/2024]
Abstract
BACKGROUND AND OBJECTIVES The influence of the intracranial pressure field must be discussed with the development of a single-element transducer for low-intensity transcranial focused ultrasound because the skull plays a significant role in blocking and dispersing ultrasound wave propagation. Ultrasound propagation is mainly affected by the structure and acoustic properties of the skull; thus, we aimed to investigate the impact of simplifying the acoustic properties of the skull on the simulation of the transcranial pressure field to present guidance for efficient skull modeling in full-wave simulations. MATERIALS AND METHODS We constructed a three-dimensional computational model for ultrasound transmission with the same structure but varying acoustic properties of the skull. The structural information and heterogeneous acoustic properties of the skull were acquired from computed tomography images, and we segmented the skull into three layers (3 L), including spongy and compact bones. We then assigned homogeneous acoustic properties to a single layer (1 L) or 3 L of the skull. In addition, we investigated the influence of different types of transducers and different ultrasound frequencies (1.1 MHz, 0.5 MHz, and 0.25 MHz) on the intracranial pressure field to provide a comparison of the heterogenous and homogeneous models. RESULTS We indicated the importance of numerical simulations in estimating the intracranial pressure field of the skull owing to beam distortions. When we simplified the skull model, both the 1 L and 3 L models showed contours of the acoustic focus comparable to those of the heterogeneous model. When we evaluated the peak pressure and volume of the acoustic focus, the 1 L model produced a better estimation of peak pressure with a difference <10%, and the 3 L model is suitable to obtain smaller errors in the volume of the acoustic focus. CONCLUSIONS In conclusion, we examined the possibility of simplification of skull models using 1 L and 3 L homogeneous properties in the numerical simulation for focused ultrasound. The results show that the layered homogeneous model can provide characteristics comparable to those of the acoustic focus in heterogeneous models.
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Affiliation(s)
- Hyeon Seo
- Department of AI Convergence Engineering, Gyeongsang National University, Jinju, Republic of Korea; Department of Computer Science, Gyeongsang National University, Jinju, Republic of Korea
| | - Mun Han
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu, Korea
| | - Jong-Ryul Choi
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu, Korea
| | - Seungmin Kim
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu, Korea
| | - Juyoung Park
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu, Korea; Department of High-Tech Medical Device, College of Future Industry, Gachon University, Seongnam, Korea
| | - Eun-Hee Lee
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu, Korea.
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Sherman J, Bortz E, Antonio ES, Tseng HA, Raiff L, Han X. Ultrasound pulse repetition frequency preferentially activates different neuron populations independent of cell type. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.25.586645. [PMID: 38585918 PMCID: PMC10996595 DOI: 10.1101/2024.03.25.586645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Transcranial ultrasound activates mechanosensitive cellular signaling and modulates neural dynamics. Given that intrinsic neuronal activity is limited to a couple hundred hertz and often exhibits frequency preference, we examined whether pulsing ultrasound at physiologic pulse repetition frequencies (PRFs) could selectively influence neuronal activity in the mammalian brain. We performed calcium imaging of individual motor cortex neurons, while delivering 0.35 MHz ultrasound at PRFs of 10, 40, and 140 Hz in awake mice. We found that most neurons were preferentially activated by only one of the three PRFs, highlighting unique cellular effects of physiologic PRFs. Further, ultrasound evoked responses were similar between excitatory neurons and parvalbumin positive interneurons regardless of PRFs, indicating that individual cell sensitivity dominates ultrasound-evoked effects, consistent with the heterogeneous mechanosensitive channel expression we found across single neurons in mice and humans. These results highlight the feasibility of tuning ultrasound neuromodulation effects through varying PRFs.
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Riis T, Feldman D, Losser A, Mickey B, Kubanek J. Device for Multifocal Delivery of Ultrasound Into Deep Brain Regions in Humans. IEEE Trans Biomed Eng 2024; 71:660-668. [PMID: 37695955 PMCID: PMC10803076 DOI: 10.1109/tbme.2023.3313987] [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] [Indexed: 09/13/2023]
Abstract
Low-intensity focused ultrasound provides the means to noninvasively stimulate or release drugs in specified deep brain targets. However, successful clinical translations require hardware that maximizes acoustic transmission through the skull, enables flexible electronic steering, and provides accurate and reproducible targeting while minimizing the use of MRI. We have developed a device that addresses these practical requirements. The device delivers ultrasound through the temporal and parietal skull windows, which minimize the attenuation and distortions of the ultrasound by the skull. The device consists of 252 independently controlled elements, which provides the ability to modulate multiple deep brain targets at a high spatiotemporal resolution, without the need to move the device or the subject. And finally, the device uses a mechanical registration method that enables accurate deep brain targeting both inside and outside of the MRI. Using this method, a single MRI scan is necessary for accurate targeting; repeated subsequent treatments can be performed reproducibly in an MRI-free manner. We validated these functions by transiently modulating specific deep brain regions in two patients with treatment-resistant depression.
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Koga T, Kida H, Yamasaki Y, Feril LB, Endo H, Itaka K, Abe H, Tachibana K. Intracranial Gene Delivery Mediated by Albumin-Based Nanobubbles and Low-Frequency Ultrasound. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:285. [PMID: 38334557 PMCID: PMC10856598 DOI: 10.3390/nano14030285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/27/2024] [Accepted: 01/28/2024] [Indexed: 02/10/2024]
Abstract
Research in the field of high-intensity focused ultrasound (HIFU) for intracranial gene therapy has greatly progressed over the years. However, limitations of conventional HIFU still remain. That is, genes are required to cross the blood-brain barrier (BBB) in order to reach the neurological disordered lesion. In this study, we introduce a novel direct intracranial gene delivery method, bypassing the BBB using human serum albumin-based nanobubbles (NBs) injected through a less invasive intrathecal route via lumbar puncture, followed by intracranial irradiation with low-frequency ultrasound (LoFreqUS). Focusing on both plasmid DNA (pDNA) and messenger RNA (mRNA), our approach utilizes LoFreqUS for deeper tissue acoustic penetration and enhancing gene transfer efficiency. This drug delivery method could be dubbed as the "Spinal Back-Door Approach", an alternative to the "front door" BBB opening method. Experiments showed that NBs effectively responded to LoFreqUS, significantly improving gene transfer in vitro using U-87 MG cell lines. In vivo experiments in mice demonstrated significantly increased gene expression with pDNA; however, we were unable to obtain conclusive results using mRNA. This novel technique, combining albumin-based NBs and LoFreqUS offers a promising, efficient, targeted, and non-invasive solution for central nervous system gene therapy, potentially transforming the treatment landscape for neurological disorders.
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Affiliation(s)
- Takayuki Koga
- Department of Neurosurgery, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan; (T.K.); (H.A.)
- Department of Anatomy, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan; (H.K.); (Y.Y.); (L.B.F.J.); (H.E.)
| | - Hiroshi Kida
- Department of Anatomy, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan; (H.K.); (Y.Y.); (L.B.F.J.); (H.E.)
| | - Yutaro Yamasaki
- Department of Anatomy, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan; (H.K.); (Y.Y.); (L.B.F.J.); (H.E.)
| | - Loreto B. Feril
- Department of Anatomy, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan; (H.K.); (Y.Y.); (L.B.F.J.); (H.E.)
| | - Hitomi Endo
- Department of Anatomy, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan; (H.K.); (Y.Y.); (L.B.F.J.); (H.E.)
| | - Keiji Itaka
- Department of Biofunction Research, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Tokyo 101-0062, Japan;
| | - Hiroshi Abe
- Department of Neurosurgery, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan; (T.K.); (H.A.)
| | - Katsuro Tachibana
- Department of Anatomy, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan; (H.K.); (Y.Y.); (L.B.F.J.); (H.E.)
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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.
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Tarvainen T, Cox B. Quantitative photoacoustic tomography: modeling and inverse problems. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:S11509. [PMID: 38125717 PMCID: PMC10731766 DOI: 10.1117/1.jbo.29.s1.s11509] [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] [Received: 09/20/2023] [Revised: 11/19/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
Significance Quantitative photoacoustic tomography (QPAT) exploits the photoacoustic effect with the aim of estimating images of clinically relevant quantities related to the tissue's optical absorption. The technique has two aspects: an acoustic part, where the initial acoustic pressure distribution is estimated from measured photoacoustic time-series, and an optical part, where the distributions of the optical parameters are estimated from the initial pressure. Aim Our study is focused on the optical part. In particular, computational modeling of light propagation (forward problem) and numerical solution methodologies of the image reconstruction (inverse problem) are discussed. Approach The commonly used mathematical models of how light and sound propagate in biological tissue are reviewed. A short overview of how the acoustic inverse problem is usually treated is given. The optical inverse problem and methods for its solution are reviewed. In addition, some limitations of real-life measurements and their effect on the inverse problems are discussed. Results An overview of QPAT with a focus on the optical part was given. Computational modeling and inverse problems of QPAT were addressed, and some key challenges were discussed. Furthermore, the developments for tackling these problems were reviewed. Although modeling of light transport is well-understood and there is a well-developed framework of inverse mathematics for approaching the inverse problem of QPAT, there are still challenges in taking these methodologies to practice. Conclusions Modeling and inverse problems of QPAT together were discussed. The scope was limited to the optical part, and the acoustic aspects were discussed only to the extent that they relate to the optical aspect.
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Affiliation(s)
- Tanja Tarvainen
- University of Eastern Finland, Department of Technical Physics, Kuopio, Finland
| | - Ben Cox
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
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Cornelssen C, Finlinson E, Rolston JD, Wilcox KS. Ultrasonic therapies for seizures and drug-resistant epilepsy. Front Neurol 2023; 14:1301956. [PMID: 38162441 PMCID: PMC10756913 DOI: 10.3389/fneur.2023.1301956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/09/2023] [Indexed: 01/03/2024] Open
Abstract
Ultrasonic therapy is an increasingly promising approach for the treatment of seizures and drug-resistant epilepsy (DRE). Therapeutic focused ultrasound (FUS) uses thermal or nonthermal energy to either ablate neural tissue or modulate neural activity through high- or low-intensity FUS (HIFU, LIFU), respectively. Both HIFU and LIFU approaches have been investigated for reducing seizure activity in DRE, and additional FUS applications include disrupting the blood-brain barrier in the presence of microbubbles for targeted-drug delivery to the seizure foci. Here, we review the preclinical and clinical studies that have used FUS to treat seizures. Additionally, we review effective FUS parameters and consider limitations and future directions of FUS with respect to the treatment of DRE. While detailed studies to optimize FUS applications are ongoing, FUS has established itself as a potential noninvasive alternative for the treatment of DRE and other neurological disorders.
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Affiliation(s)
- Carena Cornelssen
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Eli Finlinson
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - John D. Rolston
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Department of Neurosurgery, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, United States
| | - Karen S. Wilcox
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, United States
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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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11
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Xu P, Wu N, Shen G. A rapid element pressure field simulation method for transcranial phase correction in focused ultrasound therapy. Phys Med Biol 2023; 68:235015. [PMID: 37934058 DOI: 10.1088/1361-6560/ad0a59] [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: 08/03/2023] [Accepted: 11/07/2023] [Indexed: 11/08/2023]
Abstract
Transcranial focused ultrasound ablation has emerged as a promising technique for treating neurological disorders. The clinical system exclusively employed the ray tracing method to compute phase aberrations induced by the human skull, taking into account computational time constraints. However, this method compromises slightly on accuracy compared to simulation-based methods. This study evaluates a fast simulation method that simulates the time-harmonic pressure field within the region of interest for effective phase correction. Experimental validation was carried out using a 512-element, 670 kHz hemispherical transducer for fourex vivoskulls. The ray tracing method achieved a restoration ratio of 64.81% ± 4.33% of acoustic intensity normalized to hydrophone measurements. In comparison, the rapid simulation method demonstrated improved results with a restoration ratio of 73.10% ± 7.46%, albeit slightly lower than the full-wave simulation which achieved a restoration ratio of 75.87% ± 5.40%. The rapid simulation methods exhibited computational times that were less than five minutes for parallel computation with 8 threads. The incident angle was calculated, and a maximum difference of 6.8 degrees was found when the fixed position of the skull was changed. Meanwhile, the restoration ratio of acoustic intensity was validated to be above 70% for different target positions away from the geometrical focus of the transducer. The favorable balance between time consumption and correction accuracy makes this method valuable for clinical treatment applications.
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Affiliation(s)
- Peng Xu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Nan 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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Kirchner T, Villringer C, Laufer J. Evaluation of ultrasound sensors for transcranial photoacoustic sensing and imaging. PHOTOACOUSTICS 2023; 33:100556. [PMID: 38021292 PMCID: PMC10658602 DOI: 10.1016/j.pacs.2023.100556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/11/2023] [Accepted: 09/11/2023] [Indexed: 12/01/2023]
Abstract
Photoacoustic imaging through skull bone causes strong attenuation and distortion of the acoustic wavefront, which diminishes image contrast and resolution. As a result, transcranial photoacoustic measurements in humans have been challenging to demonstrate. In this study, we investigated the acoustic transmission through the human skull to design an ultrasound sensor suitable for transcranial PA imaging and sensing. We measured the frequency dependent losses of human cranial bones ex vivo, compared the performance of a range of piezoelectric and optical ultrasound sensors, and imaged skull phantoms using a PA tomograph based on a planar Fabry-Perot sensor. All transcranial photoacoustic measurements show the typical effects of frequency and thickness dependent attenuation and aberration associated with acoustic propagation through bone. The performance of plano-concave optical resonator ultrasound sensors was found to be highly suitable for transcranial photoacoustic measurements.
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Affiliation(s)
- Thomas Kirchner
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle (Saale), Germany
| | - Claus Villringer
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle (Saale), Germany
- Technische Hochschule Wildau, Hochschulring 1, 15745 Wildau, Germany
| | - Jan Laufer
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle (Saale), Germany
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Mondou P, Mériaux S, Nageotte F, Vappou J, Novell A, Larrat B. State of the art on microbubble cavitation monitoring and feedback control for blood-brain-barrier opening using focused ultrasound. Phys Med Biol 2023; 68:18TR03. [PMID: 37369229 DOI: 10.1088/1361-6560/ace23e] [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: 01/05/2023] [Accepted: 06/27/2023] [Indexed: 06/29/2023]
Abstract
Focused ultrasound (FUS) is a non-invasive and highly promising method for targeted and reversible blood-brain barrier permeabilization. Numerous preclinical studies aim to optimize the localized delivery of drugs using this method in rodents and non-human primates. Several clinical trials have been initiated to treat various brain diseases in humans using simultaneous BBB permeabilization and drug injection. This review presents the state of the art ofin vitroandin vivocavitation control algorithms for BBB permeabilization using microbubbles (MB) and FUS. Firstly, we describe the different cavitation states, their physical significance in terms of MB behavior and their translation into the spectral composition of the backscattered signal. Next, we report the different indexes calculated and used during the ultrasonic monitoring of cavitation. Finally, the differentin vitroandin vivocavitation control strategies described in the literature are presented and compared.
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Affiliation(s)
- Paul Mondou
- Université de Strasbourg, CNRS, ICube, UMR7357, Strasbourg, France
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, 91191, Gif-sur-Yvette, France
| | - Sébastien Mériaux
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, 91191, Gif-sur-Yvette, France
| | - Florent Nageotte
- Université de Strasbourg, CNRS, ICube, UMR7357, Strasbourg, France
| | - Jonathan Vappou
- Université de Strasbourg, CNRS, ICube, UMR7357, Strasbourg, France
| | - Anthony Novell
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, 91191, Gif-sur-Yvette, France
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, SHFJ, 91401 , Orsay, France
| | - Benoit Larrat
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, 91191, Gif-sur-Yvette, France
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14
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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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15
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Hughes A, Khan DS, Alkins R. Current and Emerging Systems for Focused Ultrasound-Mediated Blood-Brain Barrier Opening. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:1479-1490. [PMID: 37100672 DOI: 10.1016/j.ultrasmedbio.2023.02.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/09/2023] [Accepted: 02/23/2023] [Indexed: 05/17/2023]
Abstract
With an ever-growing list of neurological applications of focused ultrasound (FUS), there has been a consequent increase in the variety of systems for delivering ultrasound energy to the brain. Specifically, recent successful pilot clinical trials of blood-brain barrier (BBB) opening with FUS have generated substantial interest in the future applications of this relatively novel therapy, with divergent, purpose-built technologies emerging. With many of these technologies at various stages of pre-clinical and clinical investigation, this article seeks to provide an overview and analysis of the numerous medical devices in active use and under development for FUS-mediated BBB opening.
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Affiliation(s)
- Alec Hughes
- School of Medicine, Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Dure S Khan
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada
| | - Ryan Alkins
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada; Division of Neurosurgery, Department of Surgery, Kingston Health Sciences Centre, Queen's University, Kingston, ON, Canada.
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16
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Zhang F, Zhang J, Shen Y, Gao Z, Yang C, Liang M, Gao F, Liu L, Zhao H, Gao F. Photoacoustic digital brain and deep-learning-assisted image reconstruction. PHOTOACOUSTICS 2023; 31:100517. [PMID: 37292518 PMCID: PMC10244697 DOI: 10.1016/j.pacs.2023.100517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/10/2023]
Abstract
Photoacoustic tomography (PAT) is a newly developed medical imaging modality, which combines the advantages of pure optical imaging and ultrasound imaging, owning both high optical contrast and deep penetration depth. Very recently, PAT is studied in human brain imaging. Nevertheless, while ultrasound waves are passing through the human skull tissues, the strong acoustic attenuation and aberration will happen, which causes photoacoustic signals' distortion. In this work, we use 180 T1 weighted magnetic resonance imaging (MRI) human brain volumes along with the corresponding magnetic resonance angiography (MRA) brain volumes, and segment them to generate the 2D human brain numerical phantoms for PAT. The numerical phantoms contain six kinds of tissues, which are scalp, skull, white matter, gray matter, blood vessel and cerebrospinal fluid. For every numerical phantom, Monte-Carlo based optical simulation is deployed to obtain the photoacoustic initial pressure based on optical properties of human brain. Then, two different k-wave models are used for the skull-involved acoustic simulation, which are fluid media model and viscoelastic media model. The former one only considers longitudinal wave propagation, and the latter model takes shear wave into consideration. Then, the PA sinograms with skull-induced aberration is taken as the input of U-net, and the skull-stripped ones are regarded as the supervision of U-net to train the network. Experimental result shows that the skull's acoustic aberration can be effectively alleviated after U-net correction, achieving conspicuous improvement in quality of PAT human brain images reconstructed from the corrected PA signals, which can clearly show the cerebral artery distribution inside the human skull.
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Affiliation(s)
- Fan Zhang
- Hybrid Imaging System Laboratory, School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jiadong Zhang
- Hybrid Imaging System Laboratory, School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yuting Shen
- Hybrid Imaging System Laboratory, School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zijian Gao
- Hybrid Imaging System Laboratory, School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Changchun Yang
- Hybrid Imaging System Laboratory, School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Mingtao Liang
- Hybrid Imaging System Laboratory, School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Feng Gao
- Hybrid Imaging System Laboratory, School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Li Liu
- Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Hulin Zhao
- Department of Neural Surgery, Chinese PLA General Hospital, Beijing, China
| | - Fei Gao
- Hybrid Imaging System Laboratory, School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Shanghai Engineering Research Center of Intelligent Vision and Imaging, Shanghai 201210, China
- Shanghai Clinical Research and Trial Center, Shanghai 201210, China
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17
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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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18
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Blackmore DG, Razansky D, Götz J. Ultrasound as a versatile tool for short- and long-term improvement and monitoring of brain function. Neuron 2023; 111:1174-1190. [PMID: 36917978 DOI: 10.1016/j.neuron.2023.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/19/2023] [Accepted: 02/13/2023] [Indexed: 03/15/2023]
Abstract
Treating the brain with focused ultrasound (FUS) at low intensities elicits diverse responses in neurons, astroglia, and the extracellular matrix. In combination with intravenously injected microbubbles, FUS also opens the blood-brain barrier (BBB) and facilitates focal drug delivery. However, an incompletely understood cellular specificity and a wide parameter space currently limit the optimal application of FUS in preclinical and human studies. In this perspective, we discuss how different FUS modalities can be utilized to achieve short- and long-term improvements, thereby potentially treating brain disorders. We review the ongoing efforts to determine which parameters induce neuronal inhibition versus activation and how mechanoreceptors and signaling cascades are activated to induce long-term changes, including memory improvements. We suggest that optimal FUS treatments may require different FUS modalities and devices, depending on the targeted brain area or local pathology, and will be greatly enhanced by new techniques for monitoring FUS efficacy.
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Affiliation(s)
- Daniel G Blackmore
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Daniel Razansky
- Institute for Biomedical Engineering, Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, 8057 Zurich, Switzerland; Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, 8093 Zurich, Switzerland
| | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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19
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Jing B, Strassle Rojas S, Lindsey BD. Effect of skull porosity on ultrasound transmission and wave mode conversion at large incidence angles. Med Phys 2023; 50:3092-3102. [PMID: 36810723 DOI: 10.1002/mp.16318] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/19/2023] [Accepted: 02/06/2023] [Indexed: 02/24/2023] Open
Abstract
BACKGROUND Transcranial ultrasound imaging and therapy depend on the efficient transmission of acoustic energy through the skull. Multiple previous studies have concluded that a large incidence angle should be avoided during transcranial-focused ultrasound therapy to ensure transmission through the skull. Alternatively, some other studies have shown that longitudinal-to-shear wave mode conversion might improve transmission through the skull when the incidence angle is increased above the critical angle (i.e., 25° to 30°). PURPOSE The effect of skull porosity on the transmission of ultrasound through the skull at varying incidence angles was investigated for the first time to elucidate why transmission through the skull at large angles of incidence is decreased in some cases but improved in other cases. METHODS Transcranial ultrasound transmission at varying incidence angles (0°-50°) was investigated in phantoms and ex vivo skull samples with varying bone porosity (0% to 28.54% ± 3.36%) using both numerical and experimental methods. First, the elastic acoustic wave transmission through the skull was simulated using micro-computed tomography data of ex vivo skull samples. The trans-skull pressure was compared between skull segments having three levels of porosity, that is, low porosity (2.65% ± 0.03%), medium porosity (13.41% ± 0.12%), and high porosity (26.9%). Next, transmission through two 3D-printed resin skull phantoms (compact vs. porous phantoms) was experimentally measured to test the effect of porous microstructure alone on ultrasound transmission through flat plates. Finally, the effect of skull porosity on ultrasound transmission was investigated experimentally by comparing transmission through two ex vivo human skull segments having similar thicknesses but different porosities (13.78% ± 2.05% vs. 28.54% ± 3.36%). RESULTS Numerical simulations indicated that an increase in transmission pressure occurs at large incidence angles for skull segments having low porosities but not for those with high porosity. In experimental studies, a similar phenomenon was observed. Specifically, for the low porosity skull sample (13.78% ± 2.05%), the normalized pressure was 0.25 when the incidence angle increased to 35°. However, for the high porosity sample (28.54% ± 3.36%), the pressure was no more than 0.1 at large incidence angles. CONCLUSIONS These results indicate that the skull porosity has an evident effect on the transmission of ultrasound at large incidence angles. The wave mode conversion at large, oblique incidence angles could enhance the transmission of ultrasound through parts of the skull having lower porosity in the trabecular layer. However, for transcranial ultrasound therapy in the presence of highly porous trabecular bone, transmission at a normal incidence angle is preferable relative to oblique incidence angles due to the higher transmission efficiency.
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Affiliation(s)
- Bowen Jing
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | - Stephan Strassle Rojas
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Brooks D Lindsey
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA.,School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
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20
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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.
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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
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21
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Angla C, Larrat B, Gennisson JL, Chatillon S. Transcranial ultrasound simulations: A review. Med Phys 2023; 50:1051-1072. [PMID: 36047387 DOI: 10.1002/mp.15955] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/06/2022] Open
Abstract
Transcranial ultrasound is more and more used for therapy and imaging of the brain. However, the skull is a highly attenuating and aberrating medium, with different structures and acoustic properties among samples and even within a sample. Thus, case-specific simulations are needed to perform transcranial focused ultrasound interventions safely. In this article, we provide a review of the different methods used to model the skull and to simulate ultrasound propagation through it.
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Affiliation(s)
| | - Benoit Larrat
- Université Paris Saclay, CNRS, CEA, DRF/JOLIOT/NEUROSPIN/BAOBAB, Gif-sur-Yvette, France
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22
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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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23
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Attali D, Tiennot T, Schafer M, Fouragnan E, Sallet J, Caskey CF, Chen R, Darmani G, Bubrick EJ, Butler C, Stagg CJ, Klein-Flügge M, Verhagen L, Yoo SS, Pauly KB, Aubry JF. Three-layer model with absorption for conservative estimation of the maximum acoustic transmission coefficient through the human skull for transcranial ultrasound stimulation. Brain Stimul 2023; 16:48-55. [PMID: 36549480 DOI: 10.1016/j.brs.2022.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/05/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Transcranial ultrasound stimulation (TUS) has been shown to be a safe and effective technique for non-invasive superficial and deep brain stimulation. Safe and efficient translation to humans requires estimating the acoustic attenuation of the human skull. Nevertheless, there are no international guidelines for estimating the impact of the skull bone. A tissue independent, arbitrary derating was developed by the U.S. Food and Drug Administration to take into account tissue absorption (0.3 dB/cm-MHz) for diagnostic ultrasound. However, for the case of transcranial ultrasound imaging, the FDA model does not take into account the insertion loss induced by the skull bone, nor the absorption by brain tissue. Therefore, the estimated absorption is overly conservative which could potentially limit TUS applications if the same guidelines were to be adopted. Here we propose a three-layer model including bone absorption to calculate the maximum pressure transmission through the human skull for frequencies ranging between 100 kHz and 1.5 MHz. The calculated pressure transmission decreases with the frequency and the thickness of the bone, with peaks for each thickness corresponding to a multiple of half the wavelength. The 95th percentile maximum transmission was calculated over the accessible surface of 20 human skulls for 12 typical diameters of the ultrasound beam on the skull surface, and varies between 40% and 78%. To facilitate the safe adjustment of the acoustic pressure for short ultrasound pulses, such as transcranial imaging or transcranial ultrasound stimulation, a table summarizes the maximum pressure transmission for each ultrasound beam diameter and each frequency.
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Affiliation(s)
- David Attali
- Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS UMR8063, PSL University, Paris, France; Pôle Paris 16 (Secteurs 17-18) et Pôle Neuro Sainte-Anne, Centre Hospitalier Sainte-Anne, GHU Paris Psychiatrie & Neurosciences, Université Paris Cité, Paris, France
| | - Thomas Tiennot
- Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS UMR8063, PSL University, Paris, France
| | - Mark Schafer
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Elsa Fouragnan
- Brain Research Imaging Center and School of Psychology, University of Plymouth, Plymouth, UK; School of Psychology, Portland Square, Plymouth PL4 8AA, UK
| | - Jérôme Sallet
- Univ Lyon, Université Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Charles F Caskey
- Vanderbilt University Institute of Imaging Sciences, VU Medical Center, Nashville, TN, United States
| | - Robert Chen
- Division of Neurology, Department of Medicine, University of Toronto, Canada; Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Ghazaleh Darmani
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Ellen J Bubrick
- Brigham and Women's Hospital, Harvard Medical School, Department of Neurology, 75 Francis St., Boston, MA, USA
| | - Christopher Butler
- Department of Brain Sciences, Imperial College London, 9th Floor, Sir Michael Uren Hub, 86 Wood Lane, London, W12 0BZ, UK
| | - Charlotte J Stagg
- Wellcome Centre for Integrative Neuroimaging (WIN), Centre for Functional MRI of the Brain (FMRIB), University of Oxford, Nuffield Department of Clinical Neurosciences, Level 6, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Miriam Klein-Flügge
- Wellcome Centre for Integrative Neuroimaging (WIN), Centre for Functional MRI of the Brain (FMRIB), University of Oxford, Nuffield Department of Clinical Neurosciences, Level 6, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK; Wellcome Centre for Integrative Neuroimaging (WIN), Department of Experimental Psychology, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3TA, UK
| | - Lennart Verhagen
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 GD Nijmegen, the Netherlands
| | - Seung-Schik Yoo
- Brigham and Women's Hospital, Harvard Medical School, Department of Radiology, 75 Francis St., Boston, MA, USA
| | - Kim Butts Pauly
- Stanford University, Department of Radiology, Stanford CA, 94305, USA
| | - Jean-Francois Aubry
- Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS UMR8063, PSL University, Paris, France.
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24
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Menozzi L, Yang W, Feng W, Yao J. Sound out the impaired perfusion: Photoacoustic imaging in preclinical ischemic stroke. Front Neurosci 2022; 16:1055552. [PMID: 36532279 PMCID: PMC9751426 DOI: 10.3389/fnins.2022.1055552] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/17/2022] [Indexed: 09/19/2023] Open
Abstract
Acoustically detecting the optical absorption contrast, photoacoustic imaging (PAI) is a highly versatile imaging modality that can provide anatomical, functional, molecular, and metabolic information of biological tissues. PAI is highly scalable and can probe the same biological process at various length scales ranging from single cells (microscopic) to the whole organ (macroscopic). Using hemoglobin as the endogenous contrast, PAI is capable of label-free imaging of blood vessels in the brain and mapping hemodynamic functions such as blood oxygenation and blood flow. These imaging merits make PAI a great tool for studying ischemic stroke, particularly for probing into hemodynamic changes and impaired cerebral blood perfusion as a consequence of stroke. In this narrative review, we aim to summarize the scientific progresses in the past decade by using PAI to monitor cerebral blood vessel impairment and restoration after ischemic stroke, mostly in the preclinical setting. We also outline and discuss the major technological barriers and challenges that need to be overcome so that PAI can play a more significant role in preclinical stroke research, and more importantly, accelerate its translation to be a useful clinical diagnosis and management tool for human strokes.
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Affiliation(s)
- Luca Menozzi
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Wei Yang
- Multidisciplinary Brain Protection Program, Department of Anesthesiology, Duke University, Durham, NC, United States
| | - Wuwei Feng
- Department of Neurology, Duke University School of Medicine, Durham, NC, United States
| | - Junjie Yao
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
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25
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Murphy KR, Farrell JS, Gomez JL, Stedman QG, Li N, Leung SA, Good CH, Qiu Z, Firouzi K, Butts Pauly K, Khuri-Yakub BPT, Michaelides M, Soltesz I, de Lecea L. A tool for monitoring cell type-specific focused ultrasound neuromodulation and control of chronic epilepsy. Proc Natl Acad Sci U S A 2022; 119:e2206828119. [PMID: 36343238 PMCID: PMC9674244 DOI: 10.1073/pnas.2206828119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 09/16/2022] [Indexed: 11/09/2022] Open
Abstract
Focused ultrasound (FUS) is a powerful tool for noninvasive modulation of deep brain activity with promising therapeutic potential for refractory epilepsy; however, tools for examining FUS effects on specific cell types within the deep brain do not yet exist. Consequently, how cell types within heterogeneous networks can be modulated and whether parameters can be identified to bias these networks in the context of complex behaviors remains unknown. To address this, we developed a fiber Photometry Coupled focused Ultrasound System (PhoCUS) for simultaneously monitoring FUS effects on neural activity of subcortical genetically targeted cell types in freely behaving animals. We identified a parameter set that selectively increases activity of parvalbumin interneurons while suppressing excitatory neurons in the hippocampus. A net inhibitory effect localized to the hippocampus was further confirmed through whole brain metabolic imaging. Finally, these inhibitory selective parameters achieved significant spike suppression in the kainate model of chronic temporal lobe epilepsy, opening the door for future noninvasive therapies.
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Affiliation(s)
- Keith R. Murphy
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305
| | | | - Juan L. Gomez
- Biobehavioral Imaging and Molecular Neuropsychopharmacology Unit, National Institute on Drug Abuse, Baltimore, MD 21224
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Quintin G. Stedman
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305
| | - Ningrui Li
- Department of Radiology, Stanford University, Stanford, CA 94305
| | - Steven A. Leung
- Department of Radiology, Stanford University, Stanford, CA 94305
| | - Cameron H. Good
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60601
| | - Zhihai Qiu
- Department of Radiology, Stanford University, Stanford, CA 94305
| | - Kamyar Firouzi
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305
| | - Kim Butts Pauly
- Department of Radiology, Stanford University, Stanford, CA 94305
| | | | - Michael Michaelides
- Biobehavioral Imaging and Molecular Neuropsychopharmacology Unit, National Institute on Drug Abuse, Baltimore, MD 21224
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA 94305
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305
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26
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Cain JA, Visagan S, Monti MM. S.M.A.R.T. F.U.S: Surrogate Model of Attenuation and Refraction in Transcranial Focused Ultrasound. PLoS One 2022; 17:e0264101. [PMID: 36302034 PMCID: PMC9612531 DOI: 10.1371/journal.pone.0264101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 09/19/2022] [Indexed: 11/05/2022] Open
Abstract
Low-intensity focused ultrasound (LIFU) is an increasingly applied method for achieving non-invasive brain stimulation. However, transmission of ultrasound through the human skull can substantially affect focal point characteristics of LIFU, including dramatic attenuation in intensity and refraction of focal point location. These effects depend on a high-dimensional parameter space, making these effects difficult to estimate from previous work. Instead, focal point properties of LIFU experiments are often estimated using numerical simulation of LIFU sonication through skull. However, this procedure presents many entry barriers to even computationally savvy investigators and often requires expensive computational hardware, impeding LIFU research. We present a novel MATLAB toolbox (data: doi:10.5068/D1QD60; Matlab Scripts: https://doi.org/10.5281/zenodo.5811122) for rapidly estimating beam properties of LIFU transmitted through bone. Users provide specific values for frequency of LIFU, bone thickness, angle at which LIFU is applied, depth of the LIFU focal point, and diameter of the transducer used and receive an estimation of the degree of refraction/attenuation expected for the given parameters.
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Affiliation(s)
- Joshua A. Cain
- Department of Psychology, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
| | - Shakthi Visagan
- Department of Neurology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Martin M. Monti
- Department of Psychology, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, California, United States of America
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27
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Cudeiro-Blanco J, Cueto C, Bates O, Strong G, Robins T, Toulemonde M, Warner M, Tang MX, Agudo OC, Guasch L. Design and Construction of a Low-Frequency Ultrasound Acquisition Device for 2-D Brain Imaging Using Full-Waveform Inversion. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:1995-2008. [PMID: 35902276 DOI: 10.1016/j.ultrasmedbio.2022.05.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/28/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
The main techniques used to image the brain and obtain structural data are magnetic resonance imaging and X-ray computed tomography. These techniques produce images with high spatial resolution, but with the disadvantage of requiring very large equipment with special installation needs. In addition, X-ray tomography uses ionizing radiation, which limits their use. Ultrasound imaging is a safe technology that is delivered using compact and mobile devices. However, conventional ultrasound reconstruction techniques have failed to obtain images of the brain because of, fundamentally, the presence of the skull and the distortion that it produces on ultrasound. Recent studies have indicated that full-waveform inversion, a computational technique originally from Earth science, has the potential to generate accurate 3-D images of the brain. This technology can overcome the limitations of conventional ultrasound imaging, but a prototype for transcranial applications does not yet exist. Here, we investigate different designs of an annular array of ultrasound transducers to optimize the number of elements and rotations needed to conduct transcranial imaging with full-waveform inversion. This device uses small-diameter, low-frequency transducers that readily propagate ultrasound through the skull with good signal-to-noise ratios. It also incorporates the use of rotations to produce a high-density coverage of the target and acquire redundant traces that are beneficial for full-waveform inversion. We have built a ring of 40 transducers to illustrate that this design is capable of reconstructing images of the brain, retrieving its anatomy and acoustic properties with millimeter resolution. Laboratory results reveal the ability of this device to successfully image a 2.5-D brain- and skull-mimicking phantom using full-waveform inversion. To our knowledge, this is the first prototype ever used for transcranial-like imaging. The importance of these findings and their implications for the design of a 3-D reconstruction system with possible clinical applications are discussed.
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Affiliation(s)
- Javier Cudeiro-Blanco
- Department of Earth Science and Engineering, Imperial College London, London, UK; Department of Bioengineering, Imperial College London, London, UK.
| | - Carlos Cueto
- Department of Bioengineering, Imperial College London, London, UK
| | - Oscar Bates
- Department of Bioengineering, Imperial College London, London, UK
| | - George Strong
- Department of Earth Science and Engineering, Imperial College London, London, UK
| | - Tom Robins
- Department of Bioengineering, Imperial College London, London, UK
| | | | - Mike Warner
- Department of Earth Science and Engineering, Imperial College London, London, UK
| | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, UK
| | - Oscar Calderón Agudo
- Department of Earth Science and Engineering, Imperial College London, London, UK
| | - Lluis Guasch
- Department of Earth Science and Engineering, Imperial College London, London, UK
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28
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Huang L, Kang J, Chen G, Ye W, Meng X, Du Q, Feng Z. Low-intensity focused ultrasound attenuates early traumatic brain injury by OX-A/NF-κB/NLRP3 signaling pathway. Aging (Albany NY) 2022; 14:7455-7469. [PMID: 36126193 PMCID: PMC9550253 DOI: 10.18632/aging.204290] [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: 05/20/2022] [Accepted: 08/03/2022] [Indexed: 11/25/2022]
Abstract
Background: Traumatic brain injury (TBI) is a serious hazard to human health and is characterized by high rates of disability and mortality. It is necessary to explore new effective treatment methods to reduce the impact of TBI on individuals and society. As an emerging neuromodulation technique, ultrasound is used to treat some neurological diseases, but the neuroprotective mechanism of low-intensity focused ultrasound (LIFUS) in TBI remains unclear. We aimed to investigate the protective effects and potential mechanisms of LIFUS in TBI. Methods: A rat model of TBI was established using the free-fall method. After establishing the TBI model, the hypothalamus region was covered with LIFUS radiation, and an orexin receptor 1 (OXR1) antagonist (SB334867) was injected intraperitoneally. Neurobehavioral examination, Nissl staining, hematoxylin and eosin staining of the brain tissue, and brain water content, were performed 3 days later. Western blotting, quantitative real-time polymerase chain reaction, immunofluorescence staining, and immunohistochemical staining, were used to evaluate the neuroprotective mechanisms of LIFUS. Results: LIFUS improved tissue damage, neurological deficits, and brain edema. LIFUS can increase the expression of orexin-A (OX-A) and OXR1, significantly inhibit the activation of nuclear factor-κB (NF-κB) protein and nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome after TBI, and reduce the release of pro-inflammatory factors after TBI; however, SB334867 can reverse this effect. Conclusions: This study suggests that LIFUS may play a neuroprotective role by promoting the release of OX-A from the hypothalamus and inhibiting the inflammatory response after TBI through the OX-A /NF-κB/NLRP3 pathway.
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Affiliation(s)
- Lianghua Huang
- Department of Rehabilitation Medicine, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
| | - Junwei Kang
- Department of Rehabilitation Medicine, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
| | - Gengfa Chen
- Department of Rehabilitation Medicine, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
| | - Wen Ye
- Department of Rehabilitation Medicine, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
| | - Xiangqiang Meng
- Department of Rehabilitation Medicine, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
| | - Qing Du
- Department of Rehabilitation Medicine, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
| | - Zhen Feng
- Department of Rehabilitation Medicine, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
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29
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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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30
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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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31
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Baek H, Lockwood D, Mason EJ, Obusez E, Poturalski M, Rammo R, Nagel SJ, Jones SE. Clinical Intervention Using Focused Ultrasound (FUS) Stimulation of the Brain in Diverse Neurological Disorders. Front Neurol 2022; 13:880814. [PMID: 35614924 PMCID: PMC9124976 DOI: 10.3389/fneur.2022.880814] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/07/2022] [Indexed: 12/02/2022] Open
Abstract
Various surgical techniques and pharmaceutical treatments have been developed to improve the current technologies of treating brain diseases. Focused ultrasound (FUS) is a new brain stimulation modality that can exert a therapeutic effect on diseased brain cells, with this effect ranging from permanent ablation of the pathological neural circuit to transient excitatory/inhibitory modulation of the neural activity depending on the acoustic energy of choice. With the development of intraoperative imaging technology, FUS has become a clinically available noninvasive neurosurgical option with visual feedback. Over the past 10 years, FUS has shown enormous potential. It can deliver acoustic energy through the physical barrier of the brain and eliminate abnormal brain cells to treat patients with Parkinson's disease and essential tremor. In addition, FUS can help introduce potentially beneficial therapeutics at the exact brain region where they need to be, bypassing the brain's function barrier, which can be applied for a wide range of central nervous system disorders. In this review, we introduce the current FDA-approved clinical applications of FUS, ranging from thermal ablation to blood barrier opening, as well as the emerging applications of FUS in the context of pain control, epilepsy, and neuromodulation. We also discuss the expansion of future applications and challenges. Broadening FUS technologies requires a deep understanding of the effect of ultrasound when targeting various brain structures in diverse disease conditions in the context of skull interface, anatomical structure inside the brain, and pathology.
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Affiliation(s)
- Hongchae Baek
- Cleveland Clinic, Imaging Institute, Cleveland, OH, United States
- Center for Neurological Restoration, Cleveland Clinic, Neurological Institute, Cleveland, OH, United States
| | - Daniel Lockwood
- Cleveland Clinic, Imaging Institute, Cleveland, OH, United States
| | | | - Emmanuel Obusez
- Cleveland Clinic, Imaging Institute, Cleveland, OH, United States
| | | | - Richard Rammo
- Center for Neurological Restoration, Cleveland Clinic, Neurological Institute, Cleveland, OH, United States
| | - Sean J. Nagel
- Center for Neurological Restoration, Cleveland Clinic, Neurological Institute, Cleveland, OH, United States
| | - Stephen E. Jones
- Cleveland Clinic, Imaging Institute, Cleveland, OH, United States
- *Correspondence: Stephen E. Jones
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32
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Deng L, Yang SD, O’Reilly MA, Jones RM, Hynynen K. An Ultrasound-Guided Hemispherical Phased Array for Microbubble-Mediated Ultrasound Therapy. IEEE Trans Biomed Eng 2022; 69:1776-1787. [PMID: 34855582 PMCID: PMC9092225 DOI: 10.1109/tbme.2021.3132014] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
GOAL To develop a low-cost magnetic resonance imaging (MRI)-free transcranial focused ultrasound (FUS) system for microbubble-mediated therapy. METHODS A 128-element 11 MHz array for skull localization was integrated within a 256-module multi-frequency (306/612/1224 kHz) dual-mode phased array. The system's transcranial transmit and receive performance was evaluated with ex-vivo human skullcaps using phase aberration corrections calculated from computed tomography (CT)-based simulations via ultrasound-based (USCT) and landmark-based (LMCT) registrations, and a gold-standard fixed source emitter (FSE)-based method. RESULTS Displacement and rotation registration errors of 1.4 ± 0.4 mm and 2.1 ± 0.2 ° were obtained using USCT, resulting in sub-millimeter transmit targeting errors driven at 306 kHz (0.9 ± 0.2 mm) and 612 kHz (0.9 ± 0.3 mm), and source localization errors of 1.0 ± 0.3 mm and 0.6 ± 0.2 mm at receive frequencies of 306 kHz and 612 kHz, respectively (mean ± SD). Similar errors were obtained using LMCT and no significant differences between these two approaches were found on either transmit (p = 0.64/0.99) or receive (p = 0.45/0.36) at 306 kHz/612kHz. During volumetric multi-point exposures, approximately 70% and 60% of the transmit frames in which microbubble activity was detected via FSE were recovered using USCT when imaging at the second-harmonic and half-harmonic, respectively, compared to 60% and 69% using LMCT. CONCLUSION This low-cost ultrasound-guided transcranial FUS system affords USCT skull registration with accuracy comparable to LMCT methods. SIGNIFICANCE Such systems have great potential to advance the adoption of microbubble-mediated FUS brain therapy by improving access to the technology.
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Affiliation(s)
| | - Steven D. Yang
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Meaghan A. O’Reilly
- Physical Sciences Platform, Sunnybrook Research Institute and the Department of Medical Biophysics, University of Toronto, ON, Canada
| | - Ryan M. Jones
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Kullervo Hynynen
- Physical Sciences Platform, Sunnybrook Research Institute, the Department of Medical Biophysics, and the Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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33
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Mozaffarzadeh M, Verschuur E, Verweij MD, Daeichin V, De Jong N, Renaud G. Refraction-Corrected Transcranial Ultrasound Imaging Through the Human Temporal Window Using a Single Probe. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:1191-1203. [PMID: 35100111 DOI: 10.1109/tuffc.2022.3148121] [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
Transcranial ultrasound imaging (TUI) is a diagnostic modality with numerous applications, but unfortunately, it is hindered by phase aberration caused by the skull. In this article, we propose to reconstruct a transcranial B-mode image with a refraction-corrected synthetic aperture imaging (SAI) scheme. First, the compressional sound velocity of the aberrator (i.e., the skull) is estimated using the bidirectional headwave technique. The medium is described with four layers (i.e., lens, water, skull, and water), and a fast marching method calculates the travel times between individual array elements and image pixels. Finally, a delay-and-sum algorithm is used for image reconstruction with coherent compounding. The point spread function (PSF) in a wire phantom image and reconstructed with the conventional technique (using a constant sound speed throughout the medium), and the proposed method was quantified with numerical synthetic data and experiments with a bone-mimicking plate and a human skull, compared with the PSF achieved in a ground truth image of the medium without the aberrator (i.e., the bone plate or skull). A phased-array transducer (P4-1, ATL/Philips, 2.5 MHz, 96 elements, pitch = 0.295 mm) was used for the experiments. The results with the synthetic signals, the bone-mimicking plate, and the skull indicated that the proposed method reconstructs the scatterers with an average lateral/axial localization error of 0.06/0.14 mm, 0.11/0.13 mm, and 1.0/0.32 mm, respectively. With the human skull, an average contrast ratio (CR) and full-width-half-maximum (FWHM) of 37.1 dB and 1.75 mm were obtained with the proposed approach, respectively. This corresponds to an improvement of CR and FWHM by 7.1 dB and 36% compared with the conventional method, respectively. These numbers were 12.7 dB and 41% with the bone-mimicking plate.
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Kang KC, Kim YH, Kim JN, Kabir M, Zhang Y, Ghanouni P, Park KK, Firouzi K, Khuri-Yakub BT. Increasing the transmission efficiency of transcranial ultrasound using a dual-mode conversion technique based on Lamb waves. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:2159. [PMID: 35364946 PMCID: PMC8957390 DOI: 10.1121/10.0009849] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 02/24/2022] [Accepted: 03/05/2022] [Indexed: 06/14/2023]
Abstract
Transcranial focused ultrasound (FUS) is a noninvasive treatment for brain tumors and neuromodulation. Based on normal incidence, conventional FUS techniques use a focused or an array of ultrasonic transducers to overcome the attenuation and absorption of ultrasound in the skull; however, this remains the main limitation of using FUS. A dual-mode conversion technique based on Lamb waves is proposed to achieve high transmission efficiency. This concept was validated using the finite element analysis (FEA) and experiments based on changes in the incident angle. Aluminum, plexiglass, and a human skull were used as materials with different attenuations. The transmission loss was calculated for each material, and the results were compared with the reflectance function of the Lamb waves. Oblique incidence based on dual-mode conversion exhibited a better transmission efficiency than that of a normal incidence for all of the specimens. The total transmission losses for the materials were 13.7, 15.46, and 3.91 dB less than those associated with the normal incidence. A wedge transducer was designed and fabricated to implement the proposed method. The results demonstrated the potential applicability of the dual-mode conversion technique for the human skull.
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Affiliation(s)
- Ki Chang Kang
- Mechanical Convergence Engineering, Hanyang University, Seoul, Republic of Korea
| | - Young Hun Kim
- Mechanical Convergence Engineering, Hanyang University, Seoul, Republic of Korea
| | - Jeong Nyeon Kim
- E. L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Minoo Kabir
- E. L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Yichi Zhang
- E. L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Pejman Ghanouni
- Department of Radiology, Stanford University, Stanford, California 94305, USA
| | - Kwan Kyu Park
- Mechanical Convergence Engineering, Hanyang University, Seoul, Republic of Korea
| | - Kamyar Firouzi
- E. L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Burtus T Khuri-Yakub
- E. L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
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Zhuang X, He J, Wu J, Ji X, Chen Y, Yuan M, Zeng L. A Spatial Multitarget Ultrasound Neuromodulation System Using High-Powered 2-D Array Transducer. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:998-1007. [PMID: 34990356 DOI: 10.1109/tuffc.2022.3140889] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Transcranial focused ultrasound (tFUS) is increasingly used in experimental neuroscience due to its neuromodulatory effectiveness in animal studies. However, achieving multitarget tFUS in small animals is typically limited by transducer size, energy transfer efficiency, and brain volume. The objective of this work was to construct an ultrasound system for multitarget neuromodulation in small animals. First, a miniaturized high-powered 2-D array transducer was developed. The phase delay of each array element was calculated based on the multifocal time-reversal method, generating multiple foci simultaneously in a 3-D field. The effects of the axial focal length, interfocus spacing (lateral distance between the two focal centers), and the number of foci on the focal properties of the pressure field were examined through numerical simulations. In-vitro ultrasonic measurements and transcranial simulations on a rat skull were conducted. The minimum interfocus spacing separating two -6-dB foci and the peak full-width at half-maximum were positively correlated with axial focal length; the relative relationship between the interfocus spacing and pressure field properties was similar for each axial focal length. The maximum acoustic pressure and spatial average intensity at focus in deionized water were 2.21 MPa and 133 W/cm2, respectively. The simulated and experimental results were compared, demonstrating agreement in both peak position and focus shape. The ultrasound system can provide a neuroscientific platform for evaluating the feasibility of multitarget ultrasound stimulation treatment protocols, thus improving the understanding of functional neuroanatomy.
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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.
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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
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Numerical Evaluation of the Effects of Transducer Displacement on Transcranial Focused Ultrasound in the Rat Brain. Brain Sci 2022; 12:brainsci12020216. [PMID: 35203979 PMCID: PMC8870101 DOI: 10.3390/brainsci12020216] [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: 12/14/2021] [Revised: 01/15/2022] [Accepted: 02/03/2022] [Indexed: 02/04/2023] Open
Abstract
Focused ultrasound is a promising therapeutic technique, as it involves the focusing of an ultrasonic beam with sufficient acoustic energy into a target brain region with high precision. Low-intensity ultrasound transmission by a single-element transducer is mostly established for neuromodulation applications and blood–brain barrier disruption for drug delivery. However, transducer positioning errors can occur without fine control over the sonication, which can affect repeatability and lead to reliability problems. The objective of this study was to determine whether the target brain region would be stable under small displacement (0.5 mm) of the transducer based on numerical simulations. Computed-tomography-derived three-dimensional models of a rat head were constructed to investigate the effects of transducer displacement in the caudate putamen (CP) and thalamus (TH). Using three different frequencies (1.1, 0.69, and 0.25 MHz), the transducer was displaced by 0.5 mm in each of the following six directions: superior, interior, anterior, posterior, left, and right. The maximum value of the intracranial pressure field was calculated, and the targeting errors were determined by the full-width-at-half-maximum (FWHM) overlap between the free water space (FWHMwater) and transcranial transmission (FWHMbase). When the transducer was positioned directly above the target region, a clear distinction between the target regions was observed, resulting in 88.3%, 81.5%, and 84.5% FWHMwater for the CP and 65.6%, 76.3%, and 64.4% FWHMwater for the TH at 1.1, 0.69, and 0.25 MHz, respectively. Small transducer displacements induced both enhancement and reduction of the peak pressure and targeting errors, compared with when the transducer was displaced in water. Small transducer displacement to the left resulted in the lowest stability, with 34.8% and 55.0% targeting accuracy (FWHMwater) at 1.1 and 0.69 MHz in the TH, respectively. In addition, the maximum pressure was reduced by up to 11% by the transducer displacement. This work provides the targeting errors induced by transducer displacements through a preclinical study and recommends that attention be paid to determining the initial sonication foci in the transverse plane in the cases of small animals.
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Riis TS, Webb TD, Kubanek J. Acoustic properties across the human skull. ULTRASONICS 2022; 119:106591. [PMID: 34717144 PMCID: PMC8642838 DOI: 10.1016/j.ultras.2021.106591] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 08/05/2021] [Accepted: 09/16/2021] [Indexed: 05/11/2023]
Abstract
Transcranial ultrasound is emerging as a noninvasive tool for targeted treatments of brain disorders. Transcranial ultrasound has been used for remotely mediated surgeries, transient opening of the blood-brain barrier, local drug delivery, and neuromodulation. However, all applications have been limited by the severe attenuation and phase distortion of ultrasound by the skull. Here, we characterized the dependence of the aberrations on specific anatomical segments of the skull. In particular, we measured ultrasound propagation properties throughout the perimeter of intact human skulls at 500 kHz. We found that the parietal bone provides substantially higher transmission (average pressure transmission 31 ± 7%) and smaller phase distortion (242 ± 44 degrees) than frontal (13 ± 2%, 425 ± 47 degrees) and occipital bone regions (16 ± 4%, 416 ± 35 degrees). In addition, we found that across skull regions, transmission strongly anti-correlated (R=-0.79) and phase distortion correlated (R=0.85) with skull thickness. This information guides the design, positioning, and skull correction functionality of next-generation devices for effective, safe, and reproducible transcranial focused ultrasound therapies.
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Affiliation(s)
- Thomas S Riis
- Department of Biomedical Engineering, University of Utah, Salt Lake City, 84112, UT, United States.
| | - Taylor D Webb
- Department of Biomedical Engineering, University of Utah, Salt Lake City, 84112, UT, United States.
| | - Jan Kubanek
- Department of Biomedical Engineering, University of Utah, Salt Lake City, 84112, UT, United States.
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Ahmed AK, Guo S, Kelm N, Clanton R, Melhem ER, Gullapalli RP, Ksendzovsky A, Eisenberg HM, Miller TR, Gandhi D. Technical Comparison of Treatment Efficiency of Magnetic Resonance-Guided Focused Ultrasound Thalamotomy and Pallidotomy in Skull Density Ratio-Matched Patient Cohorts. Front Neurol 2022; 12:808810. [PMID: 35126300 PMCID: PMC8813961 DOI: 10.3389/fneur.2021.808810] [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: 11/04/2021] [Accepted: 12/17/2021] [Indexed: 11/24/2022] Open
Abstract
Objective MR-guided focused ultrasound (MRgFUS) is increasingly being used to treat patients with essential tremor (ET) and Parkinson's disease (PD) with thalamotomy and pallidotomy, respectively. Pallidotomy is performed off-center within the cranium compared to thalamotomy and may present challenges to therapeutic lesioning due to this location. However, the impact of target location on treatment efficiency and ability to create therapeutic lesions has not been studied. This study aimed to compare the physical efficiency of MRgFUS thalamotomy and pallidotomy. Methods Treatment characteristics were compared between patients treated with thalamotomy (n = 20) or pallidotomy (n = 20), matched by skull density ratios (SDR). Aspects of treatment efficiency were compared between these groups. Demographic and comparative statistics were conducted to assess these differences. Acoustic field simulations were performed to compare and validate the simulated temperature profile for VIM and GPi ablation. Results Lower SDR values were associated with greater energy requirement for thalamotomy (R2 = 0.197, p = 0.049) and pallidotomy (R2 = 0.342, p = 0.007). The impact of low SDR on efficiency reduction was greater for pallidotomy, approaching significance (p = 0.061). A nearly two-fold increase in energy was needed to reach 50°C in pallidotomy (10.9kJ) than in thalamotomy (5.7kJ), (p = 0.002). Despite lower energy requirement, the maximum average temperature reached was higher in thalamotomy (56.7°C) than in pallidotomy (55.0°C), (p = 0.017). Mean incident angle of acoustic beams was lesser in thalamotomy (12.7°) than in pallidotomy (18.6°), (p < 0.001). For all patients, a lesser mean incident angle correlated with a higher maximum average temperature reached (R2 = 0.124, p = 0.026), and less energy needed to reach 50°C (R2=0.134, p = 0.020). Greater skull thickness was associated with a higher maximum energy for a single sonication for thalamotomy (R2 = 0.206, p = 0.045) and pallidotomy (R2 = 0.403, p = 0.003). An acoustic and temperature field simulation validated similar findings for thalamotomy and pallidotomy in a single patient. Conclusion The centrally located VIM offers a more efficient location for therapeutic lesioning compared to GPi pallidotomy in SDR matched cohort of patients. The impact on therapeutic lesioning with lower SDR may be greater for pallidotomy patients. As newer off-center targets are investigated, these findings can inform patient selection and treatment requirements for lesion production.
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Affiliation(s)
- Abdul-Kareem Ahmed
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, United States
- *Correspondence: Abdul-Kareem Ahmed
| | - Sijia Guo
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | | | | | - Elias R. Melhem
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Rao P. Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Alexander Ksendzovsky
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Howard M. Eisenberg
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Timothy R. Miller
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Dheeraj Gandhi
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
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Bancel T, Tiennot T, Aubry JF. Adaptive Ultrasound Focusing Through the Cranial Bone for Non-invasive Treatment of Brain Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1364:397-409. [DOI: 10.1007/978-3-030-91979-5_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Guided Waves in the Skull. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1364:411-422. [DOI: 10.1007/978-3-030-91979-5_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Schoen S, Kilinc MS, Lee H, Guo Y, Degertekin FL, Woodworth GF, Arvanitis C. Towards controlled drug delivery in brain tumors with microbubble-enhanced focused ultrasound. Adv Drug Deliv Rev 2022; 180:114043. [PMID: 34801617 PMCID: PMC8724442 DOI: 10.1016/j.addr.2021.114043] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 09/27/2021] [Accepted: 11/04/2021] [Indexed: 02/06/2023]
Abstract
Brain tumors are particularly challenging malignancies, due to their location in a structurally and functionally distinct part of the human body - the central nervous system (CNS). The CNS is separated and protected by a unique system of brain and blood vessel cells which together prevent most bloodborne therapeutics from entering the brain tumor microenvironment (TME). Recently, great strides have been made through microbubble (MB) ultrasound contrast agents in conjunction with ultrasound energy to locally increase the permeability of brain vessels and modulate the brain TME. As we elaborate in this review, this physical method can effectively deliver a wide range of anticancer agents, including chemotherapeutics, antibodies, and nanoparticle drug conjugates across a range of preclinical brain tumors, including high grade glioma (glioblastoma), diffuse intrinsic pontine gliomas, and brain metastasis. Moreover, recent evidence suggests that this technology can promote the effective delivery of novel immunotherapeutic agents, including immune check-point inhibitors and chimeric antigen receptor T cells, among others. With early clinical studies demonstrating safety, and several Phase I/II trials testing the preclinical findings underway, this technology is making firm steps towards shaping the future treatments of primary and metastatic brain cancer. By elaborating on its key components, including ultrasound systems and MB technology, along with methods for closed-loop spatial and temporal control of MB activity, we highlight how this technology can be tuned to enable new, personalized treatment strategies for primary brain malignancies and brain metastases.
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Affiliation(s)
- Scott Schoen
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - M. Sait Kilinc
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hohyun Lee
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Yutong Guo
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - F. Levent Degertekin
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Graeme F. Woodworth
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA,Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, College Park, MD 20742, USA,Fischell Department of Bioengineering A. James Clarke School of Engineering, University of Maryland
| | - Costas Arvanitis
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA,Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
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Hu Z, Xu L, Chien CY, Yang Y, Gong Y, Ye D, Pacia CP, Chen H. 3-D Transcranial Microbubble Cavitation Localization by Four Sensors. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:3336-3346. [PMID: 34166187 PMCID: PMC8808337 DOI: 10.1109/tuffc.2021.3091950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cavitation is the fundamental physical mechanism of various focused ultrasound (FUS)-mediated therapies in the brain. Accurately knowing the three-dimensional (3-D) location of cavitation in real-time can improve the targeting accuracy and avoid off-target tissue damage. Existing techniques for 3-D passive transcranial cavitation detection require the use of expensive and complicated hemispherical phased arrays with 128 or 256 elements. The objective of this study was to investigate the feasibility of using four sensors for transcranial 3-D localization of cavitation. Differential microbubble cavitation detection combined with the time difference of arrival algorithm was developed for the localization using the four sensors. Numerical simulation using k-Wave toolbox was performed to validate the proposed method for transcranial cavitation source localization. The sensors with a center frequency of 2.25 MHz and a 6 dB bandwidth of 1.39 MHz were used to locate cavitation generated by FUS (500 kHz) sonication of microbubbles that were injected into a tube positioned inside an ex vivo human skullcap. Cavitation emissions from the microbubbles were detected transcranially using the four sensors. Both simulation and experimental studies found that the proposed method achieved accurate 3-D cavitation localization. When the cavitation source was located within 30 mm from the geometric center of the sensor network, the accuracy of the localization method with the skull was measured to be 1.9±1.0 mm, which was not significantly different from that without the skull (1.7 ± 0.5 mm). The accuracy decreased as the cavitation source was away from the geometric center of the sensor network. It also decreased as the pulse length increased. Its accuracy was not significantly affected by the sensor position relative to the skull. In summary, four sensors combined with the proposed localization algorithm offer a simple approach for 3-D transcranial cavitation localization.
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Verification of Blood-Brain Barrier Disruption Based on the Clinical Validation Platform Using a Rat Model with Human Skull. Brain Sci 2021; 11:brainsci11111429. [PMID: 34827428 PMCID: PMC8615862 DOI: 10.3390/brainsci11111429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 12/22/2022] Open
Abstract
Methods to improve drug delivery efficiency through blood-brain barrier disruption (BBBD) based on microbubbles and focused ultrasound (FUS) are continuously being studied. However, most studies are being conducted in preclinical trial environments using small animals. The use of the human skull shows differences between the clinical and preclinical trials. BBBD results from preclinical trials are difficult to represent in clinical trials because various distortions of ultrasound by the human skull are excluded in the former. Therefore, in our study, a clinical validation platform based on a preclinical trial environment, using a human skull fragment and a rat model, was developed to induce BBBD under conditions similar to clinical trials. For this, a human skull fragment was inserted between the rat head and a 250 kHz FUS transducer, and optimal ultrasound parameters for the free field (without human skull fragment) and human skull (with human skull fragment) were derived by 300 mVpp and 700 mVpp, respectively. BBBD was analyzed according to each case using magnetic resonance images, Evans blue dye, cavitation, and histology. Although it was confirmed using magnetic resonance images and Evans blue dye that a BBB opening was induced in each case, multiple BBB openings were observed in the brain tissues. This phenomenon was analyzed by numerical simulation, and it was confirmed to be due to standing waves owing to the small skull size of the rat model. The stable cavitation doses (SCDh and SCDu) in the human skull decreased by 13.6- and 5.3-fold, respectively, compared to those in the free field. Additionally, the inertial cavitation dose in the human skull decreased by 1.05-fold compared to that of the free field. For the histological analysis, although some extravasated red blood cells were observed in each case, it was evaluated as recoverable based on our previous study results. Therefore, our proposed platform can help deduct optimal ultrasound parameters and BBBD results for clinical trials in the preclinical trials with small animals because it considers variables relevant to the human skull.
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Kim HC, Lee W, Kunes J, Yoon K, Lee JE, Foley L, Kowsari K, Yoo SS. Transcranial focused ultrasound modulates cortical and thalamic motor activity in awake sheep. Sci Rep 2021; 11:19274. [PMID: 34588588 PMCID: PMC8481295 DOI: 10.1038/s41598-021-98920-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 09/08/2021] [Indexed: 11/09/2022] Open
Abstract
Transcranial application of pulsed low-intensity focused ultrasound (FUS) modulates the excitability of region-specific brain areas, and anesthetic confounders on brain activity warrant the evaluation of the technique in awake animals. We examined the neuromodulatory effects of FUS in unanesthetized sheep by developing a custom-fit headgear capable of reproducibly placing an acoustic focus on the unilateral motor cortex (M1) and corresponding thalamic area. The efferent responses to sonication, based on the acoustic parameters previously identified in anesthetized sheep, were measured using electromyography (EMG) from both hind limbs across three experimental conditions: on-target sonication, off-target sonication, and without sonication. Excitatory sonication yielded greater amplitude of EMG signals obtained from the hind limb contralateral to sonication than that from the ipsilateral limb. Spurious appearance of motion-related EMG signals limited the amount of analyzed data (~ 10% selection of acquired data) during excitatory sonication, and the averaged EMG response rates elicited by the M1 and thalamic stimulations were 7.5 ± 1.4% and 6.7 ± 1.5%, respectively. Suppressive sonication, while sheep walked on the treadmill, temporarily reduced the EMG amplitude from the limb contralateral to sonication. No significant change was found in the EMG amplitudes during the off-target sonication. Behavioral observation throughout the study and histological analysis showed no sign of brain tissue damage caused by the acoustic stimulation. Marginal response rates observed during excitatory sonication call for technical refinement to reduce motion artifacts during EMG acquisitions as well as acoustic aberration correction schemes to improve spatial accuracy of sonication. Yet, our results indicate that low-intensity FUS modulated the excitability of regional brain tissues reversibly and safely in awake sheep, supporting its potential in theragnostic applications.
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Affiliation(s)
- Hyun-Chul Kim
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Wonhye Lee
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Jennifer Kunes
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Kyungho Yoon
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Ji Eun Lee
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Lori Foley
- Translational Discovery Laboratory, Brigham and Women's Hospital, Boston, MA, USA
| | - Kavin Kowsari
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Seung-Schik Yoo
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
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Tseng HA, Sherman J, Bortz E, Mohammed A, Gritton HJ, Bensussen S, Tang RP, Zemel D, Szabo T, Han X. Region-specific effects of ultrasound on individual neurons in the awake mammalian brain. iScience 2021; 24:102955. [PMID: 34458703 PMCID: PMC8379692 DOI: 10.1016/j.isci.2021.102955] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 03/31/2021] [Accepted: 08/03/2021] [Indexed: 12/24/2022] Open
Abstract
Ultrasound modulates brain activity. However, it remains unclear how ultrasound affects individual neurons in the brain, where neural circuit architecture is intact and different brain regions exhibit distinct tissue properties. Using a high-resolution calcium imaging technique, we characterized the effect of ultrasound stimulation on thousands of individual neurons in the hippocampus and the motor cortex of awake mice. We found that brief 100-ms-long ultrasound pulses increase intracellular calcium in a large fraction of individual neurons in both brain regions. Ultrasound-evoked calcium response in hippocampal neurons exhibits a rapid onset with a latency shorter than 50 ms. The evoked response in the hippocampus is shorter in duration and smaller in magnitude than that in the motor cortex. These results demonstrate that noninvasive ultrasound stimulation transiently increases intracellular calcium in individual neurons in awake mice, and the evoked response profiles are brain region specific.
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Affiliation(s)
- Hua-an Tseng
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Jack Sherman
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
- Department of Pharmacology and Experimental Therapeutics, Boston University, Boston, MA 02215, USA
| | - Emma Bortz
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Ali Mohammed
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Howard J. Gritton
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
- Department of Comparative Biosciences at the University of Illinois at Urbana Champaign, Urbana, IL 61802, USA
| | - Seth Bensussen
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Rockwell P. Tang
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Dana Zemel
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Thomas Szabo
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Xue Han
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
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Jing B, Lindsey BD. Effect of Skull Porous Trabecular Structure on Transcranial Ultrasound Imaging in the Presence of Elastic Wave Mode Conversion at Varying Incidence Angle. ULTRASOUND IN MEDICINE & BIOLOGY 2021; 47:2734-2748. [PMID: 34140169 DOI: 10.1016/j.ultrasmedbio.2021.05.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 05/04/2021] [Accepted: 05/07/2021] [Indexed: 06/12/2023]
Abstract
With the advancement of aberration correction techniques, transcranial ultrasound imaging has exhibited great potential in applications such as imaging neurological function and guiding therapeutic ultrasound. However, the feasibility of transcranial imaging varies among individuals because of the differences in skull acoustic properties. To better understand the fundamental mechanisms underlying the variation in imaging performance, the effect of the structure of the porous trabecular bone on transcranial imaging performance (i.e., target localization errors and resolution) was investigated for the first time through the use of elastic wave simulations and experiments. Simulation studies using high-resolution computed tomography data from ex vivo skull samples revealed that imaging at large incidence angles reduced the target localization error for skulls having low porosity; however, as skull porosity increased, large angles of incidence resulted in degradation of resolution and increased target localization errors. Experimental results indicate that imaging at normal incidence introduced a localization error of 1.85 ± 0.10 mm, while imaging at a large incidence angle (40°) resulted in an increased localization error of 6.54 ± 1.33 mm and caused a single point target to no longer appear as a single, coherent target in the resulting image, which is consistent with simulation results. This first investigation of the effects of skull microstructure on transcranial ultrasound imaging indicates that imaging performance is highly dependent on the porosity of the skull, particularly at non-normal angles of incidence.
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Affiliation(s)
- Bowen Jing
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | - Brooks D Lindsey
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA; School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
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Top CB. A Generalized Split-Step Angular Spectrum Method for Efficient Simulation of Wave Propagation in Heterogeneous Media. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:2687-2696. [PMID: 33891551 DOI: 10.1109/tuffc.2021.3075367] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Angular spectrum (AS) methods enable efficient calculation of wave propagation from one plane to another inside homogeneous media. For wave propagation in heterogeneous media such as biological tissues, AS methods cannot be applied directly. Split-stepping techniques decompose the heterogeneous domain into homogeneous and perturbation parts, and provide a solution for forward wave propagation by propagating the incident wave in both frequency-space and frequency-wavenumber domains. Recently, a split-step hybrid angular spectrum (HAS) method was proposed for plane wave propagation of focused ultrasound beams. In this study, we extend these methods to enable simulation of acoustic pressure field for an arbitrary source distribution, by decomposing the source and reflection spectra into orthogonal propagation direction components, propagating each component separately, and summing all components to get the total field. We show that our method can efficiently simulate the pressure field of arbitrary sources in heterogeneous media. The accuracy of the method was analyzed comparing the resultant pressure field with pseudospectral time domain (PSTD) solution for breast tomography and hemispherical transcranial-focused ultrasound simulation models. Eighty times acceleration was achieved for a 3-D breast simulation model compared to PSTD solution with 0.005 normalized root mean-squared difference (NRMSD) between two solutions. For the hemispherical phased array, aberrations due to skull were accurately calculated in a single simulation run as evidenced by the resultant-focused ultrasound beam simulations, which had 0.001 NRMSD with 40 times acceleration factor compared to the PSTD method.
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Na S, Wang LV. Photoacoustic computed tomography for functional human brain imaging [Invited]. BIOMEDICAL OPTICS EXPRESS 2021; 12:4056-4083. [PMID: 34457399 PMCID: PMC8367226 DOI: 10.1364/boe.423707] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/05/2021] [Accepted: 06/08/2021] [Indexed: 05/02/2023]
Abstract
The successes of magnetic resonance imaging and modern optical imaging of human brain function have stimulated the development of complementary modalities that offer molecular specificity, fine spatiotemporal resolution, and sufficient penetration simultaneously. By virtue of its rich optical contrast, acoustic resolution, and imaging depth far beyond the optical transport mean free path (∼1 mm in biological tissues), photoacoustic computed tomography (PACT) offers a promising complementary modality. In this article, PACT for functional human brain imaging is reviewed in its hardware, reconstruction algorithms, in vivo demonstration, and potential roadmap.
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Affiliation(s)
- Shuai Na
- Caltech Optical Imaging Laboratory, Andrew
and Peggy Cherng Department of Medical Engineering,
California Institute of Technology, 1200
East California Boulevard, Pasadena, CA 91125, USA
| | - Lihong V. Wang
- Caltech Optical Imaging Laboratory, Andrew
and Peggy Cherng Department of Medical Engineering,
California Institute of Technology, 1200
East California Boulevard, Pasadena, CA 91125, USA
- Caltech Optical Imaging Laboratory,
Department of Electrical Engineering, California
Institute of Technology, 1200 East California Boulevard,
Pasadena, CA 91125, USA
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Graham MT, Dunne RA, Bell MAL. Comparison of compressional and elastic wave simulations for patient-specific planning prior to transcranial photoacoustic-guided neurosurgery. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210071R. [PMID: 34272841 PMCID: PMC8283302 DOI: 10.1117/1.jbo.26.7.076006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Simulations have the potential to be a powerful tool when planning the placement of photoacoustic imaging system components for surgical guidance. While elastic simulations (which include both compressional and shear waves) are expected to more accurately represent the physical transcranial acoustic wave propagation process, these simulations are more time-consuming and memory-intensive than the compressional-wave-only simulations that our group previously used to identify optimal acoustic windows for transcranial photoacoustic imaging. AIM We present qualitative and quantitative comparisons of compressional and elastic wave simulations to determine which option is more suitable for preoperative surgical planning. APPROACH Compressional and elastic photoacoustic k-Wave simulations were performed based on a computed tomography volume of a human cadaver head. Photoacoustic sources were placed in the locations of the internal carotid arteries and likely positions of neurosurgical instrument tips. Transducers received signals from three previously identified optimal acoustic windows (i.e., the ocular, nasal, and temporal regions). Target detectability, image-based target size estimates, and target-to-instrument distances were measured using the generalized contrast-to-noise ratio (gCNR), resolution, and relative source distances, respectively, for each simulation method. RESULTS The gCNR was equivalent between compressional and elastic simulations. The areas of the -6 dB contours of point spread functions utilized to measure resolution differed by 0.33 to 3.35 mm2. Target-to-instrument distance measurements were within 1.24 mm of the true distances. CONCLUSIONS These results indicate that it is likely sufficient to utilize the less time-consuming, less memory-intensive compressional wave simulations for presurgical planning.
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Affiliation(s)
- Michelle T. Graham
- Johns Hopkins University, Department of Electrical and Computer Engineering, Baltimore, Maryland, United States
| | - Reese A. Dunne
- Mississippi State University, Department of Mechanical Engineering, Mississippi State, Mississippi, United States
| | - Muyinatu A. Lediju Bell
- Johns Hopkins University, Department of Electrical and Computer Engineering, Baltimore, Maryland, United States
- Johns Hopkins University, Department of Biomedical Engineering, Baltimore, Maryland, United States
- Johns Hopkins University, Department of Computer Science, Baltimore, Maryland, United States
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