Cardiac shear wave elastography (SWE) is a non-invasive technique to assess myocardial stiffness, based on the speed of waves that travel through the heart after valve closure. The wave physics underlying natural SWE remains incompletely understood. Therefore, we investigated the impact of wave excitation sources on 3 wave propagation aspects – wave amplitude (determined as wave acceleration magnitude), temporal wave width and speed. SWE was applied to 17 patients with aortic stenosis (AS), 13 AS patients that underwent transcatheter aortic valve implantation (TAVI), 10 AS patients that underwent surgical aortic valve replacement (AVR) and 18 age-matched healthy volunteers (HV). Absolute wave acceleration was lower in AS, TAVI and AVR patients compared to HV (1.5±0.60 vs 2.8±1.1 m/s2; p=0.001; 1.6±0.78 vs 2.8±1.1 m/s2; p=0.010; 1.7±0.66 vs 2.8±1.1 m/s2; p=0.015). Wave acceleration amplitude (measured as negative peak acceleration of the tissue) correlated with wave speed (r=0.388; p=0.003), implying that absolute wave acceleration is smaller in a stiffer heart. Subgroup analysis showed that the correlation between wave peak acceleration and speed is less steep in AS patients vs. HV (slopes: 0.23 vs 0.47 s). This implies that stenotic valves generate a wave with a lower acceleration magnitude compared to native valves. Further, temporal wave width was lower in TAVI patients vs. HV (8.7±2.3 vs 12.5±3.0 ms; p=0.002) and there was no difference in wave speed after aortic valve closure (AVC) between the groups. To conclude, wave acceleration magnitude and width offer additional insights into SWE physics next to wave speed and should be verified in a larger cohort.
心脏剪切波弹性成像（SWE）是一种评估心肌硬度的无创技术，基于瓣膜关闭后穿过心脏的波的速度。自然SWE背后的波动物理仍未完全被理解。因此，我们研究了波激励源对波传播3个方面的影响——波幅（以波加速度大小确定）、时间波宽度和速度。SWE应用于17例主动脉瓣狭窄患者（AS）， 13例经导管主动脉瓣植入术（TAVI）的AS患者，10例手术主动脉瓣置换术（AVR）的AS患者和18例年龄匹配的健康志愿者（HV）。AS、TAVI和AVR患者的绝对波加速度较HV患者低(1.5±0.60 vs 2.8±1.1 m/s2；p = 0.001;1.6±0.78 vs 2.8±1.1 m/s2；p = 0.010;1.7±0.66 vs 2.8±1.1 m/s2；p = 0.015)。波加速度幅值（以组织负峰值加速度测量）与波速相关(r=0.388；P =0.003)，这意味着在较硬的心脏中，绝对波加速度较小。亚组分析显示，AS患者与HV患者相比，波峰加速度和速度之间的相关性不那么陡峭（斜率：0.23 vs 0.47 s）。这意味着狭窄瓣膜产生的波与原生瓣膜相比具有较低的加速度量级。此外，TAVI患者的颞波宽度低于HV患者（8.7±2.3 vs 12.5±3.0 ms）；p=0.002)，两组间主动脉瓣关闭（AVC）后的波速无差异。综上所述，波加速度的大小和宽度除了波速之外，还提供了对SWE物理的进一步了解，应该在更大的队列中进行验证。
{"title":"The Impact of Valve Stenosis and Replacement on Wave Characteristics in Cardiac Shear Wave Elastography","authors":"Laurine Wouters;Lennert Minten;Marta Orlowska;Annette Caenen;Jürgen Duchenne;Jens-Uwe Voigt;Jan D’Hooge","doi":"10.1109/OJUFFC.2025.3577142","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3577142","url":null,"abstract":"Cardiac shear wave elastography (SWE) is a non-invasive technique to assess myocardial stiffness, based on the speed of waves that travel through the heart after valve closure. The wave physics underlying natural SWE remains incompletely understood. Therefore, we investigated the impact of wave excitation sources on 3 wave propagation aspects – wave amplitude (determined as wave acceleration magnitude), temporal wave width and speed. SWE was applied to 17 patients with aortic stenosis (AS), 13 AS patients that underwent transcatheter aortic valve implantation (TAVI), 10 AS patients that underwent surgical aortic valve replacement (AVR) and 18 age-matched healthy volunteers (HV). Absolute wave acceleration was lower in AS, TAVI and AVR patients compared to HV (1.5±0.60 vs 2.8±1.1 m/s2; p=0.001; 1.6±0.78 vs 2.8±1.1 m/s2; p=0.010; 1.7±0.66 vs 2.8±1.1 m/s2; p=0.015). Wave acceleration amplitude (measured as negative peak acceleration of the tissue) correlated with wave speed (r=0.388; p=0.003), implying that absolute wave acceleration is smaller in a stiffer heart. Subgroup analysis showed that the correlation between wave peak acceleration and speed is less steep in AS patients vs. HV (slopes: 0.23 vs 0.47 s). This implies that stenotic valves generate a wave with a lower acceleration magnitude compared to native valves. Further, temporal wave width was lower in TAVI patients vs. HV (8.7±2.3 vs 12.5±3.0 ms; p=0.002) and there was no difference in wave speed after aortic valve closure (AVC) between the groups. To conclude, wave acceleration magnitude and width offer additional insights into SWE physics next to wave speed and should be verified in a larger cohort.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"114-118"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11027079","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144492373","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 : 2025-06-05DOI: 10.1109/OJUFFC.2025.3541756
{"title":"IEEE OPEN JOURNAL OF ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL","authors":"","doi":"10.1109/OJUFFC.2025.3541756","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3541756","url":null,"abstract":"","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"C2-C2"},"PeriodicalIF":0.0,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11026032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144219708","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 : 2025-06-04DOI: 10.1109/OJUFFC.2025.3576722
Håvard Kjellmo Arnestad;Andreas Austeng;Sven Peter Näsholm
A wide variety of transmit sequences can be employed in medical ultrasound, including plane waves, diverging waves, and focused beams. The choice of sequence often involves trade-offs between resolution, signal-to-noise ratio (SNR), frame rate, and harmonic imaging capabilities. However, the desirable mathematical property of orthogonality (i.e., absence of cross-talk) between transmits has generally received less attention. This property, often lacking, becomes particularly relevant for the recent REFoCUS (retrospective encoding for conventional ultrasound sequences) technique, which we in this work connect to the array signal processing technique called beamspace processing. Given an arbitrary transmit sequence, REFoCUS enables the recovery of signals from single-element transmissions (known as the multistatic dataset) thereby enhancing beamforming flexibility. In this context, the choice of transmit sequence influences the recovery process when using the intuitively appealing and computationally efficient adjoint-based method, which must be replaced by a regularized pseudoinverse for general applicability. In the current work, we derive the “closest” alternative to any chosen transmit sequence that makes the regularized and adjoint methods yield equal estimates of the multistatic dataset, and show via numerical experiments a reduction in beam and/or element cross-talk. The derivation is based on a matrix nearness problem of finding the nearest orthogonal (or unitary) matrix to the encoding matrix using singular value decomposition (SVD). The resulting transmit sequences offer a time-domain equivalent understanding of the regularized REFoCUS method, as well as a solution for optimizing the invertibility of ultrasound sequences.
{"title":"Construction of Orthogonal Transmit Sequences Using the Nearest Orthogonal Matrix","authors":"Håvard Kjellmo Arnestad;Andreas Austeng;Sven Peter Näsholm","doi":"10.1109/OJUFFC.2025.3576722","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3576722","url":null,"abstract":"A wide variety of transmit sequences can be employed in medical ultrasound, including plane waves, diverging waves, and focused beams. The choice of sequence often involves trade-offs between resolution, signal-to-noise ratio (SNR), frame rate, and harmonic imaging capabilities. However, the desirable mathematical property of orthogonality (i.e., absence of cross-talk) between transmits has generally received less attention. This property, often lacking, becomes particularly relevant for the recent REFoCUS (retrospective encoding for conventional ultrasound sequences) technique, which we in this work connect to the array signal processing technique called beamspace processing. Given an arbitrary transmit sequence, REFoCUS enables the recovery of signals from single-element transmissions (known as the multistatic dataset) thereby enhancing beamforming flexibility. In this context, the choice of transmit sequence influences the recovery process when using the intuitively appealing and computationally efficient adjoint-based method, which must be replaced by a regularized pseudoinverse for general applicability. In the current work, we derive the “closest” alternative to any chosen transmit sequence that makes the regularized and adjoint methods yield equal estimates of the multistatic dataset, and show via numerical experiments a reduction in beam and/or element cross-talk. The derivation is based on a matrix nearness problem of finding the nearest orthogonal (or unitary) matrix to the encoding matrix using singular value decomposition (SVD). The resulting transmit sequences offer a time-domain equivalent understanding of the regularized REFoCUS method, as well as a solution for optimizing the invertibility of ultrasound sequences.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"103-107"},"PeriodicalIF":0.0,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11023854","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144264239","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 : 2025-04-30DOI: 10.1109/OJUFFC.2025.3566006
Hasti Rostamikhanghahi;Marcus Ingram;Brian G. Booth;Jan D’Hooge
Percutaneous Scaphoid Fixation is a minimally invasive technique used to treat fractures of the scaphoid, the most fractured bone in the wrist. A significant challenge in this procedure is managing complications due to scaphoid movement due to wrist motion. This study aims to enhance the effectiveness of the intervention by introducing a novel wearable ultrasound array capable of flexible adherence and real-time tracking. By accurately monitoring scaphoid movement throughout the surgery, this innovation seeks to improve the overall success of the treatment. In previous research, a wearable transducer was designed to track the scaphoid during Percutaneous Scaphoid Fixation. In this study, ultrasound data was collected from this transducer and streamed to MATLAB, where an in-house developed algorithm employed template matching methods to track the scaphoid, specifically by identifying image segments that match a predefined template. With this method, we were able to demonstrate online processing at a frame rate of 28 Hz, which aligns with most clinical scanners, indicating the potential of this scaphoid tracking method for deployment on a clinical scanner.
{"title":"Online Scaphoid Tracking Using a Wearable and Flexible Ultrasound Array: A First Proof of Concept","authors":"Hasti Rostamikhanghahi;Marcus Ingram;Brian G. Booth;Jan D’Hooge","doi":"10.1109/OJUFFC.2025.3566006","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3566006","url":null,"abstract":"Percutaneous Scaphoid Fixation is a minimally invasive technique used to treat fractures of the scaphoid, the most fractured bone in the wrist. A significant challenge in this procedure is managing complications due to scaphoid movement due to wrist motion. This study aims to enhance the effectiveness of the intervention by introducing a novel wearable ultrasound array capable of flexible adherence and real-time tracking. By accurately monitoring scaphoid movement throughout the surgery, this innovation seeks to improve the overall success of the treatment. In previous research, a wearable transducer was designed to track the scaphoid during Percutaneous Scaphoid Fixation. In this study, ultrasound data was collected from this transducer and streamed to MATLAB, where an in-house developed algorithm employed template matching methods to track the scaphoid, specifically by identifying image segments that match a predefined template. With this method, we were able to demonstrate online processing at a frame rate of 28 Hz, which aligns with most clinical scanners, indicating the potential of this scaphoid tracking method for deployment on a clinical scanner.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"58-61"},"PeriodicalIF":0.0,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10981429","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073254","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 : 2025-04-15DOI: 10.1109/OJUFFC.2025.3560938
Hasti Rostamikhanghahi;Marcus Ingram;Brian G. Booth;Jan D’Hooge
Scaphoid fractures, the most common of wrist bone fractures, are typically treated using Percutaneous Scaphoid Fixation (PSF). Incorporating ultrasound guidance into this technique could reduce reliance on fluoroscopy, thereby avoiding ionizing radiation and improving procedural accuracy. However, the scaphoid’s position can shift as a result of hand movement during PSF, adding complexity to the procedure. Real-time ultrasound motion tracking of the scaphoid during PSF could simplify the intervention, which would necessitate a flexible transducer array to maintain contact during wrist motion. Our previous research proposed a transducer design with two parallel flexible 1D arrays, enabling simultaneous acquisition of two parallel images. This study focuses on transitioning from theoretical design to practical application by evaluating the performance of the custom array in terms of image quality using phantoms. We assessed image quality using the generalized contrast-to-noise ratio (gCNR) on a cyst phantom and the full width at half maximum (FWHM) on a wire phantom. Results demonstrated gCNR values above 0.67 and FWHM values below 0.70 mm across all sequences. These measurements fall within the acceptable range for the phantoms. Since the primary goal of the array is to track the scaphoid bone during surgery, requiring relatively high image quality, the values observed in this study are suitable for this application.
{"title":"Evaluation of a Dual Linear Flexible Ultrasound Array for Surgical Interventional Guidance","authors":"Hasti Rostamikhanghahi;Marcus Ingram;Brian G. Booth;Jan D’Hooge","doi":"10.1109/OJUFFC.2025.3560938","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3560938","url":null,"abstract":"Scaphoid fractures, the most common of wrist bone fractures, are typically treated using Percutaneous Scaphoid Fixation (PSF). Incorporating ultrasound guidance into this technique could reduce reliance on fluoroscopy, thereby avoiding ionizing radiation and improving procedural accuracy. However, the scaphoid’s position can shift as a result of hand movement during PSF, adding complexity to the procedure. Real-time ultrasound motion tracking of the scaphoid during PSF could simplify the intervention, which would necessitate a flexible transducer array to maintain contact during wrist motion. Our previous research proposed a transducer design with two parallel flexible 1D arrays, enabling simultaneous acquisition of two parallel images. This study focuses on transitioning from theoretical design to practical application by evaluating the performance of the custom array in terms of image quality using phantoms. We assessed image quality using the generalized contrast-to-noise ratio (gCNR) on a cyst phantom and the full width at half maximum (FWHM) on a wire phantom. Results demonstrated gCNR values above 0.67 and FWHM values below 0.70 mm across all sequences. These measurements fall within the acceptable range for the phantoms. Since the primary goal of the array is to track the scaphoid bone during surgery, requiring relatively high image quality, the values observed in this study are suitable for this application.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"43-47"},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10965791","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892434","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}
Conventional camera modules are characterized by a substantial size, thickness, and weight. This is a consequence of the need for multiple lens elements to achieve the required level of image quality. However, as portable electronic devices continue to undergo miniaturization, there is a growing demand for smaller and thinner camera modules. In this paper, the optical characteristics of an ultrasound gel lens were evaluated quantitatively by expanding the wavefront of the transmitted light in terms of the Zernike polynomial. It was possible to control the focal length of the lens by changing its surface profile through the acoustic radiation force generated by ultrasonic vibration. The effects of ultrasound excitation on spherical aberration, coma aberrations, and astigmatisms were investigated. It was observed that spherical and coma aberrations increased with voltage amplitude, while astigmatism exhibited a reduction in magnitude.
{"title":"Optical Characteristics of an Ultrasound Gel Lens","authors":"Haruto Miki;Fumiko Taniguchi;Kosuke Nakamura;Yuki Harada;Mami Matsukawa;Daisuke Koyama","doi":"10.1109/OJUFFC.2025.3561101","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3561101","url":null,"abstract":"Conventional camera modules are characterized by a substantial size, thickness, and weight. This is a consequence of the need for multiple lens elements to achieve the required level of image quality. However, as portable electronic devices continue to undergo miniaturization, there is a growing demand for smaller and thinner camera modules. In this paper, the optical characteristics of an ultrasound gel lens were evaluated quantitatively by expanding the wavefront of the transmitted light in terms of the Zernike polynomial. It was possible to control the focal length of the lens by changing its surface profile through the acoustic radiation force generated by ultrasonic vibration. The effects of ultrasound excitation on spherical aberration, coma aberrations, and astigmatisms were investigated. It was observed that spherical and coma aberrations increased with voltage amplitude, while astigmatism exhibited a reduction in magnitude.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"48-52"},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10965713","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892532","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 : 2025-04-14DOI: 10.1109/OJUFFC.2025.3560585
Anna V. Phillips;Cherie M. Kuzmiak;Gabriela Torres;Caterina M. Gallippi
Ultrasound elastography is increasingly being used alongside mammography for breast cancer diagnosis, particularly in women with radiographically dense breasts. The elastogram-to-B-Mode ratio (E/B), which compares lesion sizes in B-Mode and stiffness images, has been shown to differentiate malignant (E/B >1) from benign (E/B <1)>1 in malignant lesions and <1 in benign lesions) to those observed in stiffness images. Additionally, E/B values calculated from RE alone, RV alone, or a combination of RE and RV achieved 4-16% higher AUCs for discriminating malignant lesions compared to E/B derived solely from Acoustic Radiation Force Impulse (ARFI) peak displacement. These results suggest that incorporating VisR-derived viscosity and elasticity metrics into E/B calculations could significantly improve diagnostic accuracy for breast cancer detection.
{"title":"VisR Ultrasound Improves Diagnosis of Breast Cancer by the Elastogram-to-B-Mode Ratio in a Blinded Reader Study","authors":"Anna V. Phillips;Cherie M. Kuzmiak;Gabriela Torres;Caterina M. Gallippi","doi":"10.1109/OJUFFC.2025.3560585","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3560585","url":null,"abstract":"Ultrasound elastography is increasingly being used alongside mammography for breast cancer diagnosis, particularly in women with radiographically dense breasts. The elastogram-to-B-Mode ratio (E/B), which compares lesion sizes in B-Mode and stiffness images, has been shown to differentiate malignant (E/B >1) from benign (E/B <1)>1 in malignant lesions and <1 in benign lesions) to those observed in stiffness images. Additionally, E/B values calculated from RE alone, RV alone, or a combination of RE and RV achieved 4-16% higher AUCs for discriminating malignant lesions compared to E/B derived solely from Acoustic Radiation Force Impulse (ARFI) peak displacement. These results suggest that incorporating VisR-derived viscosity and elasticity metrics into E/B calculations could significantly improve diagnostic accuracy for breast cancer detection.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"67-76"},"PeriodicalIF":0.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10964276","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090710","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 : 2025-04-01DOI: 10.1109/OJUFFC.2025.3556974
Ambuj K. Gautam;Ching-Chung Yin;Bishakh Bhattacharya
The fundamental shear horizontal (SH0) modes exhibit conversion behaviors to higher mode (SH1) influenced by the symmetric and anti-symmetric defects within a plate. Specifically, reflected SH0 modes remain unaffected by symmetrically oriented defects while transitioning to SH1 mode in the presence of anti-symmetrically oriented defects. This prompts inquiry into the effects when defects lie between symmetric and anti-symmetric positions within the plate thickness. In order to quantify the impact of mode conversion resulting from diverse defect orientations, a thorough analysis has been conducted, and a methodology has been proposed to assess the defect’s position using mode conversion of shear horizontal (SH) guided waves. Particularly, as defects move from symmetric to anti-symmetric positions, the energy of the reflected wave is notably influenced by the defect’s orientation. This indicates that defects located close to symmetric orientations yield minimal reflected energy in the converted SH1 mode, whereas those approaching anti-symmetric orientations exhibit significant reflected energy in the converted SH1 mode. To precisely identify the defect’s position, an assessment of the Reflective Correlation Indexing (RCI) of the converted mode has been conducted. Numerical simulations have been performed to investigate these phenomena and validated with an experimental result using chevron EMAT.
{"title":"Defect Orientation Evaluation in Structural Plates Using Reflective Correlation Indexing","authors":"Ambuj K. Gautam;Ching-Chung Yin;Bishakh Bhattacharya","doi":"10.1109/OJUFFC.2025.3556974","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3556974","url":null,"abstract":"The fundamental shear horizontal (SH0) modes exhibit conversion behaviors to higher mode (SH1) influenced by the symmetric and anti-symmetric defects within a plate. Specifically, reflected SH0 modes remain unaffected by symmetrically oriented defects while transitioning to SH1 mode in the presence of anti-symmetrically oriented defects. This prompts inquiry into the effects when defects lie between symmetric and anti-symmetric positions within the plate thickness. In order to quantify the impact of mode conversion resulting from diverse defect orientations, a thorough analysis has been conducted, and a methodology has been proposed to assess the defect’s position using mode conversion of shear horizontal (SH) guided waves. Particularly, as defects move from symmetric to anti-symmetric positions, the energy of the reflected wave is notably influenced by the defect’s orientation. This indicates that defects located close to symmetric orientations yield minimal reflected energy in the converted SH1 mode, whereas those approaching anti-symmetric orientations exhibit significant reflected energy in the converted SH1 mode. To precisely identify the defect’s position, an assessment of the Reflective Correlation Indexing (RCI) of the converted mode has been conducted. Numerical simulations have been performed to investigate these phenomena and validated with an experimental result using chevron EMAT.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"38-42"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10947017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143830541","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 : 2025-03-20DOI: 10.1109/OJUFFC.2025.3571698
Eric B. Dew;Shayan Khorassany;Mahyar Ghavami;Mohammad Rahim Sobhani;Mohammad Maadi;Roger J. Zemp
Capacitive micromachined ultrasound transducers (CMUTs) are typically designed with many small membranes per linear array element. However, these membranes can operate out of phase or collapse at different voltages, leading to suboptimal transmit performance and unreliable operation. To avoid these problems, we recently proposed a CMUT architecture with a single large rectangular membrane per element and novel insulated electrode post structures. These single-membrane CMUTs outperformed comparable piezoelectric transducers by almost 3-fold in terms of output pressure and demonstrated electromechanical efficiency values as high as 0.95. In this paper, we present an analytical model which can be used to simulate and optimize single-membrane rectangular CMUTs with or without post structures. Our approach relies on a polynomial deflection model, which was used to derive lumped element model parameters. Using this method, we developed expressions to model both electrostatic and pre-collapse small-signal dynamic CMUT behavior. This modeling framework was incorporated into a MATLAB program. We validated our approach using finite element method (FEM) simulations and experimental results in both air and immersion media. Model predictions for collapse voltage and operating frequency are within 4% of FEM results in both air and immersion. However, the runtime of our MATLAB program was 6 orders of magnitude faster than the corresponding FEM simulations. Compared with experiment, collapse voltage predictions were within 8%, and operating frequency predictions were within 5% in air and 18% in soybean oil. Our results indicate that that rectangular CMUTs may be optimized much further, potentially enabling even greater improvements over piezoelectric transducers.
{"title":"Small-Signal Equivalent Circuit Model of Long Rectangular CMUT Membranes","authors":"Eric B. Dew;Shayan Khorassany;Mahyar Ghavami;Mohammad Rahim Sobhani;Mohammad Maadi;Roger J. Zemp","doi":"10.1109/OJUFFC.2025.3571698","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3571698","url":null,"abstract":"Capacitive micromachined ultrasound transducers (CMUTs) are typically designed with many small membranes per linear array element. However, these membranes can operate out of phase or collapse at different voltages, leading to suboptimal transmit performance and unreliable operation. To avoid these problems, we recently proposed a CMUT architecture with a single large rectangular membrane per element and novel insulated electrode post structures. These single-membrane CMUTs outperformed comparable piezoelectric transducers by almost 3-fold in terms of output pressure and demonstrated electromechanical efficiency values as high as 0.95. In this paper, we present an analytical model which can be used to simulate and optimize single-membrane rectangular CMUTs with or without post structures. Our approach relies on a polynomial deflection model, which was used to derive lumped element model parameters. Using this method, we developed expressions to model both electrostatic and pre-collapse small-signal dynamic CMUT behavior. This modeling framework was incorporated into a MATLAB program. We validated our approach using finite element method (FEM) simulations and experimental results in both air and immersion media. Model predictions for collapse voltage and operating frequency are within 4% of FEM results in both air and immersion. However, the runtime of our MATLAB program was 6 orders of magnitude faster than the corresponding FEM simulations. Compared with experiment, collapse voltage predictions were within 8%, and operating frequency predictions were within 5% in air and 18% in soybean oil. Our results indicate that that rectangular CMUTs may be optimized much further, potentially enabling even greater improvements over piezoelectric transducers.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"82-102"},"PeriodicalIF":0.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11007609","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170989","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 : 2025-03-17DOI: 10.1109/OJUFFC.2025.3552048
Geng-Shi Jeng;Sheng Chen;Le-Tung Hsieh;Men-Tzung Lo
Accurate and contactless respiratory monitoring is essential for both clinical diagnostics and home healthcare, offering the potential for continuous, non-invasive observation. Ultrasound-based systems, particularly when integrated into home smart devices, provide a cost-effective solution. However, existing approaches are limited by poor directivity, inadequate clothing penetration, reliance on averaged respiratory rates without waveform details, and the inability to measure range due to continuous-wave Doppler techniques. To address these challenges, this study develops a novel 18-kHz, 16-channel two-dimensional (2-D) ultrasound array system employing adaptive beamforming to enhance sensitivity and accuracy in respiratory waveform detection. The system integrates pulsed and frequency-modulated continuous-wave (FMCW) excitation to improve the signal-to-noise ratio (SNR) by 20 dB, while the 2-D beamforming technique directly estimates delays from respiratory movements, boosting SNR by an additional 8.5 dB and eliminating the need for time-intensive volumetric scanning. Experimental results demonstrate sub-millimeter displacement accuracy in motor-controlled plate tests, surpassing wearable inertial measurement devices, and human trials reveal an average respiratory rate error of 0.13 breaths per minute across various clothing types and distances. The proposed system not only advances remote respiratory monitoring but also paves the way for enhanced health diagnostics in both clinical and home settings.
{"title":"Contactless Respiratory Waveform Estimation Using Ultrasound Planar Array","authors":"Geng-Shi Jeng;Sheng Chen;Le-Tung Hsieh;Men-Tzung Lo","doi":"10.1109/OJUFFC.2025.3552048","DOIUrl":"https://doi.org/10.1109/OJUFFC.2025.3552048","url":null,"abstract":"Accurate and contactless respiratory monitoring is essential for both clinical diagnostics and home healthcare, offering the potential for continuous, non-invasive observation. Ultrasound-based systems, particularly when integrated into home smart devices, provide a cost-effective solution. However, existing approaches are limited by poor directivity, inadequate clothing penetration, reliance on averaged respiratory rates without waveform details, and the inability to measure range due to continuous-wave Doppler techniques. To address these challenges, this study develops a novel 18-kHz, 16-channel two-dimensional (2-D) ultrasound array system employing adaptive beamforming to enhance sensitivity and accuracy in respiratory waveform detection. The system integrates pulsed and frequency-modulated continuous-wave (FMCW) excitation to improve the signal-to-noise ratio (SNR) by 20 dB, while the 2-D beamforming technique directly estimates delays from respiratory movements, boosting SNR by an additional 8.5 dB and eliminating the need for time-intensive volumetric scanning. Experimental results demonstrate sub-millimeter displacement accuracy in motor-controlled plate tests, surpassing wearable inertial measurement devices, and human trials reveal an average respiratory rate error of 0.13 breaths per minute across various clothing types and distances. The proposed system not only advances remote respiratory monitoring but also paves the way for enhanced health diagnostics in both clinical and home settings.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"5 ","pages":"23-32"},"PeriodicalIF":0.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10929036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706647","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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