This study demonstrated the first air-coupled pMUT using sol-gel PZT thin film that could deliver ultrasonic waves to mid-air. First, the deposition conditions for making PZT thin film with high remanent polarization were determined. Then, air-coupled pMUTs with resonance frequencies close to 40 kHz were designed using the circular plate model. According to the design, pMUTs with radii measuring $600~mu $ m to $775~mu $ m were fabricated to evaluate the acoustic output pressure. Among these, the pMUT with the $725~mu $ m radius achieved a maximum sound pressure output of 4.42 Pa at 3 cm above when driven with 10 Vpp, and the resonance frequency was 40.48 kHz. Finally, the output pressure of a phased array consisting of sol-gel PZT-based pMUTs with a $725~mu $ m radius was calculated using the k-Wave toolbox. The output pressure of the $11times 11$ pMUT array reached 365.62 Pa when focused at 3 cm above it. This result revealed that the output pressure of the proposed pMUT array could fulfill the requirement for most mid-air ultrasound applications.
{"title":"Development of an Air-Coupled Piezoelectric Micromachined Ultrasonic Transducer Using Sol-Gel PZT Thin Film for Fast-Prototyping","authors":"Ya-Han Liu;Hsiao-Chi Lin;Chih-Ying Li;Chien-Lun Kao;Han-Jen Hsu;Yeong-Her Wang;Chih-Hsien Huang","doi":"10.1109/OJUFFC.2024.3397630","DOIUrl":"https://doi.org/10.1109/OJUFFC.2024.3397630","url":null,"abstract":"This study demonstrated the first air-coupled pMUT using sol-gel PZT thin film that could deliver ultrasonic waves to mid-air. First, the deposition conditions for making PZT thin film with high remanent polarization were determined. Then, air-coupled pMUTs with resonance frequencies close to 40 kHz were designed using the circular plate model. According to the design, pMUTs with radii measuring \u0000<inline-formula> <tex-math>$600~mu $ </tex-math></inline-formula>\u0000m to \u0000<inline-formula> <tex-math>$775~mu $ </tex-math></inline-formula>\u0000m were fabricated to evaluate the acoustic output pressure. Among these, the pMUT with the \u0000<inline-formula> <tex-math>$725~mu $ </tex-math></inline-formula>\u0000m radius achieved a maximum sound pressure output of 4.42 Pa at 3 cm above when driven with 10 Vpp, and the resonance frequency was 40.48 kHz. Finally, the output pressure of a phased array consisting of sol-gel PZT-based pMUTs with a \u0000<inline-formula> <tex-math>$725~mu $ </tex-math></inline-formula>\u0000m radius was calculated using the k-Wave toolbox. The output pressure of the \u0000<inline-formula> <tex-math>$11times 11$ </tex-math></inline-formula>\u0000 pMUT array reached 365.62 Pa when focused at 3 cm above it. This result revealed that the output pressure of the proposed pMUT array could fulfill the requirement for most mid-air ultrasound applications.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"4 ","pages":"27-36"},"PeriodicalIF":0.0,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10521570","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141084766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-29DOI: 10.1109/OJUFFC.2024.3371913
Martin Angerer;Jonas Welsch;Carlos D. Gerardo;Nicole V. Ruiter;Edmond Cretu;Robert Rohling
The objective of this work was to investigate changes in the acoustic characteristics of micromachined transducers caused by acoustic cross-coupling between cells. We used hexagonal, polymer-based capacitive micromachined ultrasonic transducers (polyCMUTs) consisting of 127 cells connected in parallel. The distances between the cells were varied, while the cell dimensions and number of cells remained constant. The resulting changes in characteristics were evaluated in terms of peak frequency $f_{pk}$ , fractional bandwidth $FBW$ , peak transmit sensitivity $S_{pk}$ and opening angle $Phi _{t}$ . The study relies on results from an analytic multicell model (MCM) which considers cross-coupling effects between cells through a mutual acoustic impedance matrix. The results are compared with finite element (FE) analyses and measurements on fabricated prototypes. The manufacturing processes used to produce the polyCMUT prototypes are explained in detail. We found significant changes in all acoustic characteristics: as cell spacing increases, $f_{pk}$ and $Phi _{t}$ decrease, while $S_{pk}$ gradually rises to about twice the initial value. The $FBW$ varies due to the change in $f_{pk}$ , peaking at small to intermediate cell-to-cell distances. While both modeling approaches cover the general effects, discrepancies in comparison to the measurements were identified. The FE model provided better fits than the analytic MCM, albeit at significantly higher computational costs. The effects on the acoustic characteristics were found strongest at lower frequencies and if many cells are in close proximity to each other. Hence, rotational symmetric or square transducers operating at lower frequencies are affected most. The results demonstrate that design approaches based on modeling single cells may lead to significant deviations from design goals. Both, analytic and FE models are suitable tools to estimate the effects of acoustic interactions and to predict the performance. This aids in meeting design requirements of micromachined ultrasound transducers consisting of multiple radiators.
{"title":"Studying the Effects of Mutual Acoustic Impedance on the Performance of Polymer-Based CMUTs","authors":"Martin Angerer;Jonas Welsch;Carlos D. Gerardo;Nicole V. Ruiter;Edmond Cretu;Robert Rohling","doi":"10.1109/OJUFFC.2024.3371913","DOIUrl":"https://doi.org/10.1109/OJUFFC.2024.3371913","url":null,"abstract":"The objective of this work was to investigate changes in the acoustic characteristics of micromachined transducers caused by acoustic cross-coupling between cells. We used hexagonal, polymer-based capacitive micromachined ultrasonic transducers (polyCMUTs) consisting of 127 cells connected in parallel. The distances between the cells were varied, while the cell dimensions and number of cells remained constant. The resulting changes in characteristics were evaluated in terms of peak frequency \u0000<inline-formula> <tex-math>$f_{pk}$ </tex-math></inline-formula>\u0000, fractional bandwidth \u0000<inline-formula> <tex-math>$FBW$ </tex-math></inline-formula>\u0000, peak transmit sensitivity \u0000<inline-formula> <tex-math>$S_{pk}$ </tex-math></inline-formula>\u0000 and opening angle \u0000<inline-formula> <tex-math>$Phi _{t}$ </tex-math></inline-formula>\u0000. The study relies on results from an analytic multicell model (MCM) which considers cross-coupling effects between cells through a mutual acoustic impedance matrix. The results are compared with finite element (FE) analyses and measurements on fabricated prototypes. The manufacturing processes used to produce the polyCMUT prototypes are explained in detail. We found significant changes in all acoustic characteristics: as cell spacing increases, \u0000<inline-formula> <tex-math>$f_{pk}$ </tex-math></inline-formula>\u0000 and \u0000<inline-formula> <tex-math>$Phi _{t}$ </tex-math></inline-formula>\u0000 decrease, while \u0000<inline-formula> <tex-math>$S_{pk}$ </tex-math></inline-formula>\u0000 gradually rises to about twice the initial value. The \u0000<inline-formula> <tex-math>$FBW$ </tex-math></inline-formula>\u0000 varies due to the change in \u0000<inline-formula> <tex-math>$f_{pk}$ </tex-math></inline-formula>\u0000, peaking at small to intermediate cell-to-cell distances. While both modeling approaches cover the general effects, discrepancies in comparison to the measurements were identified. The FE model provided better fits than the analytic MCM, albeit at significantly higher computational costs. The effects on the acoustic characteristics were found strongest at lower frequencies and if many cells are in close proximity to each other. Hence, rotational symmetric or square transducers operating at lower frequencies are affected most. The results demonstrate that design approaches based on modeling single cells may lead to significant deviations from design goals. Both, analytic and FE models are suitable tools to estimate the effects of acoustic interactions and to predict the performance. This aids in meeting design requirements of micromachined ultrasound transducers consisting of multiple radiators.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"4 ","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10453524","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140114040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-22DOI: 10.1109/OJUFFC.2023.3344372
Mohammad Mohajery;Sebastien Salles;Torvald Espeland;Solveig Fadnes;Lasse Lovstakken
The mechanical wave (MW) propagation velocity in the heart is related to the tissue stiffness and its measurement mainly relies on manual evaluation of the 1D wave projection. This study presents an automated method for 3D wave visualization and velocity estimation in the heart using 3D ultrasound imaging of the left ventricle (LV). High-quality (HQ, 19 vps) and high-frame-rate (HFR, 823 vps) volumes were acquired. Deep learning models automatically segmented the LV and extracted the apical standard views from the HQ data which were used to derive the anatomical M-lines and myocardial segmentation. The clutter filter wave imaging (CFWI) and tissue Doppler imaging (TDI) generated wave propagation maps from HFR data, and the aortic valve closure (AVC) and atrial contraction/kick (AK) waves were automatically detected. LV segmentation and anatomical M-lines were used for 3D wave propagation extraction and its 1D projection, respectively. The 1D wave propagation velocity was determined through automatic slope detection, while the 3D velocity map was derived from the gradient of the time-of-flight (TOF) map. Results showed varying 1D velocity across views and myocardial regions, with the AVC propagation velocity surpassing that of the AK wave. The pipeline remained stable and generated results consistent with expert measurements. Comparing 3D and 1D propagation highlighted errors from 1D projection and demonstrated the benefits of the 3D method in assessing regional velocities and the validity of the 1D approach. This study demonstrated an automatic evaluation of 3D MW propagation velocities in the entire LV, leading to improved accuracy and standardized measurements of myocardial tissue properties.
心脏中的机械波（MW）传播速度与组织硬度有关，其测量主要依靠人工评估一维波的投影。本研究提出了一种利用左心室三维超声成像进行心脏三维波可视化和速度估算的自动化方法。研究人员采集了高质量（HQ，19 vps）和高帧频（HFR，823 vps）容积。深度学习模型自动分割左心室，并从 HQ 数据中提取心尖标准视图，用于推导解剖 M 线和心肌分割。杂波滤波成像（CFWI）和组织多普勒成像（TDI）从 HFR 数据中生成波传播图，并自动检测主动脉瓣关闭波（AVC）和心房收缩/踢波（AK）。左心室分割和解剖 M 线分别用于三维波传播提取和一维投影。一维波传播速度是通过自动斜率检测确定的，而三维速度图则来自飞行时间（TOF）图的梯度。结果显示，不同视图和心肌区域的一维速度各不相同，AVC 波的传播速度超过了 AK 波。管道保持稳定，生成的结果与专家测量结果一致。对比三维和一维传播，突出了一维投影的误差，证明了三维方法在评估区域速度方面的优势和一维方法的有效性。这项研究证明了三维 MW 传播速度在整个左心室的自动评估，从而提高了心肌组织特性测量的准确性和标准化。
{"title":"Automated 3D Velocity Estimation of Natural Mechanical Wave Propagation in the Myocardium","authors":"Mohammad Mohajery;Sebastien Salles;Torvald Espeland;Solveig Fadnes;Lasse Lovstakken","doi":"10.1109/OJUFFC.2023.3344372","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3344372","url":null,"abstract":"The mechanical wave (MW) propagation velocity in the heart is related to the tissue stiffness and its measurement mainly relies on manual evaluation of the 1D wave projection. This study presents an automated method for 3D wave visualization and velocity estimation in the heart using 3D ultrasound imaging of the left ventricle (LV). High-quality (HQ, 19 vps) and high-frame-rate (HFR, 823 vps) volumes were acquired. Deep learning models automatically segmented the LV and extracted the apical standard views from the HQ data which were used to derive the anatomical M-lines and myocardial segmentation. The clutter filter wave imaging (CFWI) and tissue Doppler imaging (TDI) generated wave propagation maps from HFR data, and the aortic valve closure (AVC) and atrial contraction/kick (AK) waves were automatically detected. LV segmentation and anatomical M-lines were used for 3D wave propagation extraction and its 1D projection, respectively. The 1D wave propagation velocity was determined through automatic slope detection, while the 3D velocity map was derived from the gradient of the time-of-flight (TOF) map. Results showed varying 1D velocity across views and myocardial regions, with the AVC propagation velocity surpassing that of the AK wave. The pipeline remained stable and generated results consistent with expert measurements. Comparing 3D and 1D propagation highlighted errors from 1D projection and demonstrated the benefits of the 3D method in assessing regional velocities and the validity of the 1D approach. This study demonstrated an automatic evaluation of 3D MW propagation velocities in the entire LV, leading to improved accuracy and standardized measurements of myocardial tissue properties.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"210-222"},"PeriodicalIF":0.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10372587","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139676159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.1109/OJUFFC.2023.3342751
Arthur Chavignon;Baptiste Heiles;Vincent Hingot;Cyrille Orset;Denis Vivien;Olivier Couture
Ultrasound Localization Microscopy (ULM) enables imaging microvessels in the brain with a resolution of a few tens of micrometers in-vivo. The planar architecture of arterioles and venules was revealed with a 2D ultrasound scanner in the cortex of the rat brain. However, deeper in the brain, where the vascularization becomes tri-dimensional, 2D imaging remains limited by the elevation projection. In this study, volumetric ultrasound imaging was performed in the craniotomized rat brain to yield 3D ULM in vivo within 7.5 min of acquisition with a commercial system. For instance, it highlighted the thalamus or the circle of Willis with small vessels down to $21 ~mu text{m}$ . Microbubbles tracking also gave access to the 3D velocity vector of blood flow allowing to distinguish flow directions. Volumetric ULM resolved deep complex tri-dimensional vascular structures and was compared to 2D ULM. It is a safe, simple and repeatable system to image wide field of view in the brain.
{"title":"Deep and Complex Vascular Anatomy in the Rat Brain Described With Ultrasound Localization Microscopy in 3D","authors":"Arthur Chavignon;Baptiste Heiles;Vincent Hingot;Cyrille Orset;Denis Vivien;Olivier Couture","doi":"10.1109/OJUFFC.2023.3342751","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3342751","url":null,"abstract":"Ultrasound Localization Microscopy (ULM) enables imaging microvessels in the brain with a resolution of a few tens of micrometers in-vivo. The planar architecture of arterioles and venules was revealed with a 2D ultrasound scanner in the cortex of the rat brain. However, deeper in the brain, where the vascularization becomes tri-dimensional, 2D imaging remains limited by the elevation projection. In this study, volumetric ultrasound imaging was performed in the craniotomized rat brain to yield 3D ULM in vivo within 7.5 min of acquisition with a commercial system. For instance, it highlighted the thalamus or the circle of Willis with small vessels down to \u0000<inline-formula> <tex-math>$21 ~mu text{m}$ </tex-math></inline-formula>\u0000. Microbubbles tracking also gave access to the 3D velocity vector of blood flow allowing to distinguish flow directions. Volumetric ULM resolved deep complex tri-dimensional vascular structures and was compared to 2D ULM. It is a safe, simple and repeatable system to image wide field of view in the brain.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"203-209"},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10368081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139034310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-04DOI: 10.1109/OJUFFC.2023.3338570
Stefano Fiorentini;Svein-Erik Måsøy;Jørgen Avdal
In medical ultrasound, aberration is a phenomenon that causes distortion of the ultrasound wavefront as it travels through an inhomogeneous medium. Aberration has been investigated since the 1960s and is known as a major cause of image quality loss in several applications, such as abdominal, breast, transcranial, and cardiac imaging. In the attempt to improve image quality in the presence of aberration, research has focused on two fronts: to provide deeper understanding of the physics behind aberration, and to develop robust methods for aberration correction based on such knowledge. However, most of the work found in the literature is focused towards improving BMode image quality, whereas little attention is given to other modalities. The aim of this work is to investigate the effects of aberration on two established blood flow imaging and quantification modalities, Pulsed Wave (PW) Doppler and Color Flow. The study was carried out on phantom and in-vivo recordings, using acquisitions and aberration conditions commonly encountered in cardiac imaging. In this work, aberration was modeled as a near-field phase screen, allowing for easier design and manufacturing compared to more realistic models. The results indicate that, as in BMode imaging, aberration degrades signal-to-noise ratio and resolution. Moreover, the increased sample volume size can significantly affect mean velocity and variance estimates in Color Flow, especially in the presence of strong velocity gradients occurring laterally to the beam direction. Similar effects were observed in PW Doppler. The conclusion is that blood flow imaging and quantification modalities in cardiac applications can potentially benefit from the development of aberration correction methods.
{"title":"Analysis of Aberration Effects on Flow Imaging and Quantification in Echocardiography","authors":"Stefano Fiorentini;Svein-Erik Måsøy;Jørgen Avdal","doi":"10.1109/OJUFFC.2023.3338570","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3338570","url":null,"abstract":"In medical ultrasound, aberration is a phenomenon that causes distortion of the ultrasound wavefront as it travels through an inhomogeneous medium. Aberration has been investigated since the 1960s and is known as a major cause of image quality loss in several applications, such as abdominal, breast, transcranial, and cardiac imaging. In the attempt to improve image quality in the presence of aberration, research has focused on two fronts: to provide deeper understanding of the physics behind aberration, and to develop robust methods for aberration correction based on such knowledge. However, most of the work found in the literature is focused towards improving BMode image quality, whereas little attention is given to other modalities. The aim of this work is to investigate the effects of aberration on two established blood flow imaging and quantification modalities, Pulsed Wave (PW) Doppler and Color Flow. The study was carried out on phantom and in-vivo recordings, using acquisitions and aberration conditions commonly encountered in cardiac imaging. In this work, aberration was modeled as a near-field phase screen, allowing for easier design and manufacturing compared to more realistic models. The results indicate that, as in BMode imaging, aberration degrades signal-to-noise ratio and resolution. Moreover, the increased sample volume size can significantly affect mean velocity and variance estimates in Color Flow, especially in the presence of strong velocity gradients occurring laterally to the beam direction. Similar effects were observed in PW Doppler. The conclusion is that blood flow imaging and quantification modalities in cardiac applications can potentially benefit from the development of aberration correction methods.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"194-202"},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10341282","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138577996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transmission through a phononic crystal of metallic rods in a viscous environment is numerically calculated. The cross-section of the rods is selected to be asymmetric to provide very different transmission in opposite directions along a given crystallographic line. Difference in transmission contains the reciprocal part, caused by asymmetry of the scatterers, and the truly nonreciprocal part, related to nonequal viscous losses for sound waves propagating in opposite directions. The rectification ratio for different levels of asymmetry is evaluated and optimized over its value at a fixed frequency, with various machine learning models. The possibility of using asymmetric phononic crystals as acoustic diodes is discussed.
{"title":"Optimization of Nonreciprocal Transmission Through Dissipative Phononic Crystals With Machine Learning Techniques","authors":"Dmitrii Shymkiv;Arnav Mazumder;Jesús Arriaga;Arkadii Krokhin","doi":"10.1109/OJUFFC.2023.3334234","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3334234","url":null,"abstract":"Transmission through a phononic crystal of metallic rods in a viscous environment is numerically calculated. The cross-section of the rods is selected to be asymmetric to provide very different transmission in opposite directions along a given crystallographic line. Difference in transmission contains the reciprocal part, caused by asymmetry of the scatterers, and the truly nonreciprocal part, related to nonequal viscous losses for sound waves propagating in opposite directions. The rectification ratio for different levels of asymmetry is evaluated and optimized over its value at a fixed frequency, with various machine learning models. The possibility of using asymmetric phononic crystals as acoustic diodes is discussed.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"186-193"},"PeriodicalIF":0.0,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10322727","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138570758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-25DOI: 10.1109/OJUFFC.2023.3318560
Michelle K. Sigona;Thomas J. Manuel;M. Anthony Phipps;Kianoush Banaie Boroujeni;Robert Louie Treuting;Thilo Womelsdorf;Charles F. Caskey
Optical tracking is a real-time transducer positioning method for transcranial focused ultrasound (tFUS) procedures, but the predicted focus from optical tracking typically does not incorporate subject-specific skull information. Acoustic simulations can estimate the pressure field when propagating through the cranium but rely on accurately replicating the positioning of the transducer and skull in a simulated space. Here, we develop and characterize the accuracy of a workflow that creates simulation grids based on optical tracking information in a neuronavigated phantom with and without transmission through an ex vivo skull cap. The software pipeline could replicate the geometry of the tFUS procedure within the limits of the optical tracking system (transcranial target registration error (TRE): 3.9 ± 0.7 mm). The simulated focus and the free-field focus predicted by optical tracking had low Euclidean distance errors of 0.5 ± 0.1 and 1.2 ± 0.4 mm for phantom and skull cap, respectively, and some skull-specific effects were captured by the simulation. However, the TRE of simulation informed by optical tracking was 4.6 ± 0.2, which is as large or greater than the focal spot size used by many tFUS systems. By updating the position of the transducer using the original TRE offset, we reduced the simulated TRE to 1.1 ± 0.4 mm. Our study describes a software pipeline for treatment planning, evaluates its accuracy, and demonstrates an approach using MR-acoustic radiation force imaging as a method to improve dosimetry. Overall, our software pipeline helps estimate acoustic exposure, and our study highlights the need for image feedback to increase the accuracy of tFUS dosimetry.
{"title":"Generating Patient-Specific Acoustic Simulations for Transcranial Focused Ultrasound Procedures Based on Optical Tracking Information","authors":"Michelle K. Sigona;Thomas J. Manuel;M. Anthony Phipps;Kianoush Banaie Boroujeni;Robert Louie Treuting;Thilo Womelsdorf;Charles F. Caskey","doi":"10.1109/OJUFFC.2023.3318560","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3318560","url":null,"abstract":"Optical tracking is a real-time transducer positioning method for transcranial focused ultrasound (tFUS) procedures, but the predicted focus from optical tracking typically does not incorporate subject-specific skull information. Acoustic simulations can estimate the pressure field when propagating through the cranium but rely on accurately replicating the positioning of the transducer and skull in a simulated space. Here, we develop and characterize the accuracy of a workflow that creates simulation grids based on optical tracking information in a neuronavigated phantom with and without transmission through an ex vivo skull cap. The software pipeline could replicate the geometry of the tFUS procedure within the limits of the optical tracking system (transcranial target registration error (TRE): 3.9 ± 0.7 mm). The simulated focus and the free-field focus predicted by optical tracking had low Euclidean distance errors of 0.5 ± 0.1 and 1.2 ± 0.4 mm for phantom and skull cap, respectively, and some skull-specific effects were captured by the simulation. However, the TRE of simulation informed by optical tracking was 4.6 ± 0.2, which is as large or greater than the focal spot size used by many tFUS systems. By updating the position of the transducer using the original TRE offset, we reduced the simulated TRE to 1.1 ± 0.4 mm. Our study describes a software pipeline for treatment planning, evaluates its accuracy, and demonstrates an approach using MR-acoustic radiation force imaging as a method to improve dosimetry. Overall, our software pipeline helps estimate acoustic exposure, and our study highlights the need for image feedback to increase the accuracy of tFUS dosimetry.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"146-156"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9292640/10031625/10262121.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49930455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.1109/OJUFFC.2023.3317363
S. R. Sandeep Kumar;Vineeth P. Ramachandran;Krishnan Balasubramaniam;Prabhu Rajagopal
Cylindrical or circular rod-type waveguides are of much interest in applications such as measurement of flow, temperature, material properties in harsh environments, and also in medical diagnostics. However, multiple waveguide modes exist in such systems, out of which only some are of interest to certain applications. For example, L(0,3) longitudinal mode excitation can optimally transmit elastic waves into the test specimen and help in better sensing and measurement when compared to other modes within the family of longitudinal guided waves. This paper demonstrates the up-conversion of longitudinal modes within the family of guided ultrasonic rod waves (from L(0,2) to L(0,3)), which is of interest to certain waveguide transducer applications. The mode up-conversion is demonstrated using numerical simulations and experiments. An analysis is used to bring more insights and guide the design of the metamaterial in this process.
{"title":"Graded Elastic Waveguide Metamaterial Rod for Up-Conversion of Longitudinal Axisymmetric Guided Ultrasonic Wave Modes","authors":"S. R. Sandeep Kumar;Vineeth P. Ramachandran;Krishnan Balasubramaniam;Prabhu Rajagopal","doi":"10.1109/OJUFFC.2023.3317363","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3317363","url":null,"abstract":"Cylindrical or circular rod-type waveguides are of much interest in applications such as measurement of flow, temperature, material properties in harsh environments, and also in medical diagnostics. However, multiple waveguide modes exist in such systems, out of which only some are of interest to certain applications. For example, L(0,3) longitudinal mode excitation can optimally transmit elastic waves into the test specimen and help in better sensing and measurement when compared to other modes within the family of longitudinal guided waves. This paper demonstrates the up-conversion of longitudinal modes within the family of guided ultrasonic rod waves (from L(0,2) to L(0,3)), which is of interest to certain waveguide transducer applications. The mode up-conversion is demonstrated using numerical simulations and experiments. An analysis is used to bring more insights and guide the design of the metamaterial in this process.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"157-165"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9292640/10031625/10256115.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49930456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-12DOI: 10.1109/OJUFFC.2023.3314396
Kunqi Huang;Yuanyuan Li;Yun Lai;Xiaozhou Liu
Phononic crystals are artificial periodic structural composites. With the introduction of nonlinearity, nonlinear phononic crystals(NPCs) have shown some novel properties beyond their linear counterparts and thus attracted significant interest recently. Among these novel properties, the second harmonic characteristics have potential applications in the fields of acoustic frequency conversion, non-reciprocal propagation, and nondestructive testing. Therefore, how to accurately manipulate the second harmonic band structure is a main challenge for the design of NPCs. Traditional design methods are based on parametric analysis and continuous trials, leading to low design efficiency and poor performance. Here, we construct the convolutional neural networks(CNNs) and the generalized regression neural networks(GRNNs) to inversely design the physical and geometric parameters of NPCs using the information of harmonic transmission curves. The results show that the inverse design method based on neural networks is effective in designing the NPCs. In addition, the CNNs have better prediction accuracy while the GRNNs have a shorter training time. These methods also can be applied to the design of higher-order harmonic band structures. This work confirms the feasibility of neural networks for designing the NPCs efficiently according to target harmonic band structures and provides a useful reference for inverse design of metamaterials.
{"title":"Neural Network-Based Inverse Design of Nonlinear Phononic Crystals","authors":"Kunqi Huang;Yuanyuan Li;Yun Lai;Xiaozhou Liu","doi":"10.1109/OJUFFC.2023.3314396","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3314396","url":null,"abstract":"Phononic crystals are artificial periodic structural composites. With the introduction of nonlinearity, nonlinear phononic crystals(NPCs) have shown some novel properties beyond their linear counterparts and thus attracted significant interest recently. Among these novel properties, the second harmonic characteristics have potential applications in the fields of acoustic frequency conversion, non-reciprocal propagation, and nondestructive testing. Therefore, how to accurately manipulate the second harmonic band structure is a main challenge for the design of NPCs. Traditional design methods are based on parametric analysis and continuous trials, leading to low design efficiency and poor performance. Here, we construct the convolutional neural networks(CNNs) and the generalized regression neural networks(GRNNs) to inversely design the physical and geometric parameters of NPCs using the information of harmonic transmission curves. The results show that the inverse design method based on neural networks is effective in designing the NPCs. In addition, the CNNs have better prediction accuracy while the GRNNs have a shorter training time. These methods also can be applied to the design of higher-order harmonic band structures. This work confirms the feasibility of neural networks for designing the NPCs efficiently according to target harmonic band structures and provides a useful reference for inverse design of metamaterials.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"166-175"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9292640/10031625/10247576.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49930457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-21DOI: 10.1109/OJUFFC.2023.3307085
Kangfu Liu;Yaoqing Lu;Sheng Wu;Xinxin Li;Tao Wu
This work proposes the piezoelectric micromachined ultrasonic transducer (pMUT) design using high-order mode. Analytical models are established and used to estimate the performance of pMUT in ${n} ^{text {th}}$ -order axisymmetric mode. To prove the concept, a comprehensive analysis is conducted on the $3^{text {rd}}$ -order pMUT by finite element method (FEM). The analytical models give guidance for the design of electrode configuration and geometric dimensions, which are verified by FEM. With optimized electrode configuration and thickness, the proposed pMUT design shows extraordinary performance improvement in transmitting and round-trip sensitivity. Approximately $10.2times $ and $4.12times $ improvements in transmitting sensitivity and round-trip sensitivity have been achieved compared to the traditional $1^{text {st}}$ -order pMUT in the same radius, while there is an $8.6times $ improvement of the receiving voltage in the pulse-echo analysis. The high frequency, round-trip sensitivity, and directivity features of the proposed high-order pMUT design shown in FEM make it very promising for forming a high-frequency large-scale pMUT array.
{"title":"Design of Piezoelectric Micromachined Ultrasonic Transducers Using High-Order Mode With High Performance and High Frequency","authors":"Kangfu Liu;Yaoqing Lu;Sheng Wu;Xinxin Li;Tao Wu","doi":"10.1109/OJUFFC.2023.3307085","DOIUrl":"10.1109/OJUFFC.2023.3307085","url":null,"abstract":"This work proposes the piezoelectric micromachined ultrasonic transducer (pMUT) design using high-order mode. Analytical models are established and used to estimate the performance of pMUT in \u0000<inline-formula> <tex-math>${n} ^{text {th}}$ </tex-math></inline-formula>\u0000-order axisymmetric mode. To prove the concept, a comprehensive analysis is conducted on the \u0000<inline-formula> <tex-math>$3^{text {rd}}$ </tex-math></inline-formula>\u0000-order pMUT by finite element method (FEM). The analytical models give guidance for the design of electrode configuration and geometric dimensions, which are verified by FEM. With optimized electrode configuration and thickness, the proposed pMUT design shows extraordinary performance improvement in transmitting and round-trip sensitivity. Approximately \u0000<inline-formula> <tex-math>$10.2times $ </tex-math></inline-formula>\u0000 and \u0000<inline-formula> <tex-math>$4.12times $ </tex-math></inline-formula>\u0000 improvements in transmitting sensitivity and round-trip sensitivity have been achieved compared to the traditional \u0000<inline-formula> <tex-math>$1^{text {st}}$ </tex-math></inline-formula>\u0000-order pMUT in the same radius, while there is an \u0000<inline-formula> <tex-math>$8.6times $ </tex-math></inline-formula>\u0000 improvement of the receiving voltage in the pulse-echo analysis. The high frequency, round-trip sensitivity, and directivity features of the proposed high-order pMUT design shown in FEM make it very promising for forming a high-frequency large-scale pMUT array.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"176-185"},"PeriodicalIF":0.0,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10225593","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62908847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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