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}
Pub Date : 2023-07-06DOI: 10.1109/OJUFFC.2023.3263281
{"title":"IEEE OPEN JOURNAL OF ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL","authors":"","doi":"10.1109/OJUFFC.2023.3263281","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3263281","url":null,"abstract":"","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"C2-C2"},"PeriodicalIF":0.0,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9292640/10031625/10174839.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49959010","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 : 2023-01-30DOI: 10.1109/OJUFFC.2023.3240699
Marta Saccher;Shinnosuke Kawasaki;Johan H. Klootwijk;Rob Van Schaijk;Ronald Dekker
Recently, the applications of ultrasound transducers expanded from high-end diagnostic tools to point of care diagnostic devices and wireless power receivers for implantable devices. These new applications additionally require that the transducer technology must comply to biocompatibility and manufacturing scalability. In this respect, Capacitive Micromachined Ultrasound Transducers (CMUTs) have a strong advantage compared to the conventional PZT based transducers. However, current CMUTs require a large DC bias voltage for their operation, which limits the miniaturizability of these devices. In this study, we propose a pre-charged collapse-mode CMUT for immersive applications that can operate without an external bias by means of a charge trapping Al2O3 layer embedded in the dielectrics between the top and bottom electrodes. The built-in charge layer was analytically modeled and four layer stack combinations were investigated and characterized. The measurement results of the CMUTs were then used to fit the model and to quantify the amount and type of trapped charge. It was found that these devices polarize due to the ferroelectric-like behavior of the Al2O3, and the amount of charge stored in the charge-trapping layer was estimated to be approximately 0.02 C/m2. Their acoustic performance shows a transmit and receive sensitivity of 8.8 kPa/V and 13.1 V/MPa respectively. In addition, we show that increasing the charging temperature, the charging duration, and the charging voltage results in a higher amount of stored charge. Finally, results of ALT tests showed that these devices have a lifetime of more than 2.5 years at body temperature.
{"title":"Modeling and Characterization of Pre-Charged Collapse-Mode CMUTs","authors":"Marta Saccher;Shinnosuke Kawasaki;Johan H. Klootwijk;Rob Van Schaijk;Ronald Dekker","doi":"10.1109/OJUFFC.2023.3240699","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3240699","url":null,"abstract":"Recently, the applications of ultrasound transducers expanded from high-end diagnostic tools to point of care diagnostic devices and wireless power receivers for implantable devices. These new applications additionally require that the transducer technology must comply to biocompatibility and manufacturing scalability. In this respect, Capacitive Micromachined Ultrasound Transducers (CMUTs) have a strong advantage compared to the conventional PZT based transducers. However, current CMUTs require a large DC bias voltage for their operation, which limits the miniaturizability of these devices. In this study, we propose a pre-charged collapse-mode CMUT for immersive applications that can operate without an external bias by means of a charge trapping Al2O3 layer embedded in the dielectrics between the top and bottom electrodes. The built-in charge layer was analytically modeled and four layer stack combinations were investigated and characterized. The measurement results of the CMUTs were then used to fit the model and to quantify the amount and type of trapped charge. It was found that these devices polarize due to the ferroelectric-like behavior of the Al2O3, and the amount of charge stored in the charge-trapping layer was estimated to be approximately 0.02 C/m2. Their acoustic performance shows a transmit and receive sensitivity of 8.8 kPa/V and 13.1 V/MPa respectively. In addition, we show that increasing the charging temperature, the charging duration, and the charging voltage results in a higher amount of stored charge. Finally, results of ALT tests showed that these devices have a lifetime of more than 2.5 years at body temperature.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"14-28"},"PeriodicalIF":0.0,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9292640/10031625/10029911.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49959012","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 : 2023-01-01DOI: 10.1109/OJUFFC.2023.3284781
Miho Fujieda;Motohiro Kumagai
We have developed a fiber-optic frequency and timing transfer system. It has been installed to provide timing synchronization between NICT and a distant university site connected by a 58-km urban optical fiber link. The timing signal generated at the remote site is derived from a frequency source that is stabilized using the link, and it is synchronized by a transferred timing marker. A second, separate fiber link confirms a timing synchronization uncertainty of 5.7 ns and a 10-MHz frequency instability of less than $10^{-16}$ at $10^{5}$ s averaging time. We additionally demonstrate a timing marker delivery using a code-based signal, which combines nanosecond-level uncertainty with the simplicity and compactness suitable for a system that can be deployed for synchronization across numerous sites.
{"title":"Fiber-Optic Frequency and Timing Transfer Over an Urban Optical Fiber Link","authors":"Miho Fujieda;Motohiro Kumagai","doi":"10.1109/OJUFFC.2023.3284781","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3284781","url":null,"abstract":"We have developed a fiber-optic frequency and timing transfer system. It has been installed to provide timing synchronization between NICT and a distant university site connected by a 58-km urban optical fiber link. The timing signal generated at the remote site is derived from a frequency source that is stabilized using the link, and it is synchronized by a transferred timing marker. A second, separate fiber link confirms a timing synchronization uncertainty of 5.7 ns and a 10-MHz frequency instability of less than <inline-formula> <tex-math notation=\"LaTeX\">$10^{-16}$ </tex-math></inline-formula> at <inline-formula> <tex-math notation=\"LaTeX\">$10^{5}$ </tex-math></inline-formula> s averaging time. We additionally demonstrate a timing marker delivery using a code-based signal, which combines nanosecond-level uncertainty with the simplicity and compactness suitable for a system that can be deployed for synchronization across numerous sites.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"70-76"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9292640/10031625/10147246.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49930448","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 : 2023-01-01DOI: 10.1109/OJUFFC.2023.3259941
Stefano Fiorentini;Erik Andreas Rye Berg;Hans Torp;Svend Aakhus;Jørgen Avdal
Valve regurgitation is a cardiac condition caused by the incomplete closure of a cardiac valve. Untreated, this condition may result in cardiac failure. Regular monitoring of this condition is essential in guiding the decision process for surgical intervention. Current guidelines recommend a multi-parametric assessment of valve regurgitation using echocardiography, which is both time consuming and heavily dependent on the experience of the examiner. Several methods have been proposed to provide quantitative markers to facilitate the assessment of valve regurgitation, most notably the Proximal Isovelocity Surface Area (PISA) method and methods based on the quantification of the total Regurgitant Volume (RVol) from the power of backscattered blood signal. In this work, we propose a framework based on trans-thoracic 3-D high frame-rate acquisitions for the simultaneous estimation of the jet cross-sectional area and jet velocity directly at the jet core, which are then combined to estimate the instantaneous flow rate and RVol patients with aortic or mitral insufficiency. We compare two methods for the segmentation of the jet cross-sectional area from the power Doppler signal. Validation on simulated data indicates good segmentation accuracy for the best method ($beta $ = 0.97, ${R}^{{2}}$ = 0.91). Validation on recordings from a flow phantom shows good agreement ($beta $ = 1.2, ${R}^{{2}}$ = 0.88) with an external flow rate meter. Clinical feasibility of the method is also shown in a patient with mitral regurgitation.
{"title":"Quantification of Flow Rates and Flow Volumes in Valve Regurgitation Using 3-D High Frame-Rate Ultrasound","authors":"Stefano Fiorentini;Erik Andreas Rye Berg;Hans Torp;Svend Aakhus;Jørgen Avdal","doi":"10.1109/OJUFFC.2023.3259941","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3259941","url":null,"abstract":"Valve regurgitation is a cardiac condition caused by the incomplete closure of a cardiac valve. Untreated, this condition may result in cardiac failure. Regular monitoring of this condition is essential in guiding the decision process for surgical intervention. Current guidelines recommend a multi-parametric assessment of valve regurgitation using echocardiography, which is both time consuming and heavily dependent on the experience of the examiner. Several methods have been proposed to provide quantitative markers to facilitate the assessment of valve regurgitation, most notably the Proximal Isovelocity Surface Area (PISA) method and methods based on the quantification of the total Regurgitant Volume (RVol) from the power of backscattered blood signal. In this work, we propose a framework based on trans-thoracic 3-D high frame-rate acquisitions for the simultaneous estimation of the jet cross-sectional area and jet velocity directly at the jet core, which are then combined to estimate the instantaneous flow rate and RVol patients with aortic or mitral insufficiency. We compare two methods for the segmentation of the jet cross-sectional area from the power Doppler signal. Validation on simulated data indicates good segmentation accuracy for the best method (<inline-formula> <tex-math notation=\"LaTeX\">$beta $ </tex-math></inline-formula> = 0.97, <inline-formula> <tex-math notation=\"LaTeX\">${R}^{{2}}$ </tex-math></inline-formula> = 0.91). Validation on recordings from a flow phantom shows good agreement (<inline-formula> <tex-math notation=\"LaTeX\">$beta $ </tex-math></inline-formula> = 1.2, <inline-formula> <tex-math notation=\"LaTeX\">${R}^{{2}}$ </tex-math></inline-formula> = 0.88) with an external flow rate meter. Clinical feasibility of the method is also shown in a patient with mitral regurgitation.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"29-40"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9292640/10031625/10077387.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49959009","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}
Sparse array designs are a promising approach to improve the beam pattern and imaging quality, especially for applications, where hardware resources are severely limited. In particular, spiral sunflower arrays become increasingly popular due to their excellent point-spread-function (PSF) characteristics and their simple, deterministic and scalable design. Therefore, several sunflower modifications for further improvement have been investigated, e.g. density tapering based on window functions adapted from apodization techniques. In this article, we introduce a two-scale spiral array design concept, which exploits the specific PSF structure of the sunflower geometry, instead of relying on window functions. The modification proposed combines two nested sunflower sub-arrays featuring two different spatial element densities such that the locations of their respective main, side and grating lobe zones differ, resulting in a balanced and improved composite one-way PSF in terms of main lobe width (MLW) and maximum side lobe level (MSLL) under far-field and narrow-band conditions. First, we provide an analysis of the unmodified classic sunflower geometry, describe its PSF zones and show how their locations in the PSF can be estimated based on the array design parameters, which finally leads to the two-scale concept. Second, we examine a specific well-matching combination of nested sub-arrays to discuss the advantages and limitations of the resulting PSF. Third, we benchmark the respective optimum arrays of the classic sunflower and density tapering strategies with the two-scale method, where the latter shows an improved performance of the one-way PSF in terms of MLW and MSLL. Fourth, the two-scale design strategy is validated using a real-world 64-element prototype for narrow-band ultrasound imaging in air. We conduct two experiments to analyze the resulting PSF and angular resolution. Overall, the results demonstrate that the proposed flexible four-parameter concept is particularly valuable for high frame rate imaging as well as for transmit-only and receive-only applications.
{"title":"Two-Scale Sparse Spiral Array Design for 3D Ultrasound Imaging in Air","authors":"Gianni Allevato;Christoph Haugwitz;Matthias Rutsch;Raphael Müller;Marius Pesavento;Mario Kupnik","doi":"10.1109/OJUFFC.2023.3303132","DOIUrl":"https://doi.org/10.1109/OJUFFC.2023.3303132","url":null,"abstract":"Sparse array designs are a promising approach to improve the beam pattern and imaging quality, especially for applications, where hardware resources are severely limited. In particular, spiral sunflower arrays become increasingly popular due to their excellent point-spread-function (PSF) characteristics and their simple, deterministic and scalable design. Therefore, several sunflower modifications for further improvement have been investigated, e.g. density tapering based on window functions adapted from apodization techniques. In this article, we introduce a two-scale spiral array design concept, which exploits the specific PSF structure of the sunflower geometry, instead of relying on window functions. The modification proposed combines two nested sunflower sub-arrays featuring two different spatial element densities such that the locations of their respective main, side and grating lobe zones differ, resulting in a balanced and improved composite one-way PSF in terms of main lobe width (MLW) and maximum side lobe level (MSLL) under far-field and narrow-band conditions. First, we provide an analysis of the unmodified classic sunflower geometry, describe its PSF zones and show how their locations in the PSF can be estimated based on the array design parameters, which finally leads to the two-scale concept. Second, we examine a specific well-matching combination of nested sub-arrays to discuss the advantages and limitations of the resulting PSF. Third, we benchmark the respective optimum arrays of the classic sunflower and density tapering strategies with the two-scale method, where the latter shows an improved performance of the one-way PSF in terms of MLW and MSLL. Fourth, the two-scale design strategy is validated using a real-world 64-element prototype for narrow-band ultrasound imaging in air. We conduct two experiments to analyze the resulting PSF and angular resolution. Overall, the results demonstrate that the proposed flexible four-parameter concept is particularly valuable for high frame rate imaging as well as for transmit-only and receive-only applications.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"3 ","pages":"113-127"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9292640/10031625/10210599.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49930452","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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