Using acoustic vortex tweezers (AVTs) to spatially accumulate microbubbles (MBs) shows promise for enhancing drug delivery efficiency and reducing off-target effects. The strong echogenicity of accumulated MBs also improves diagnostics via conventional ultrasound (US) B-mode imaging. However, the annular high-pressure distribution of AVT inhibits MBs inflow at the inlet, reducing MBs collection. The spatial resolution of US B-mode imaging further limits theranostic applications of AVT-mediated MBs accumulation. To address these challenges, we integrated an AVT waveform with volumetric super-resolution imaging (VSRI) to monitor the dynamic growth of MBs cluster during accumulation. We used a 5-MHz 2-D array transducer for VSRI, employing plane wave pulses interleaved with accumulating pulses to retain MBs at a flow rate of 0.023–0.047 mL/s in a 3-mm vessel phantom. An asymmetrical AVT waveform (AVT $^{ast }$ ) was produced by modulating the pressure at the MBs inlet compared to the outlet. The effectiveness was validated in rat cerebral vessels for real-time volumetric tracking of MBs clusters. Microscopy observations showed that AVT $^{ast }$ could quickly gather flowing MBs into cluster without repelling them at a flow rate of 0.023 mL/s. Statistical results indicated that microscopic data correlated better with VSRI than with B-mode images, suggesting VSRI suffices to detect the dynamics of AVT $^{ast }$ -actuated MBs accumulation in real-time. Additionally, VSRI detected a significant increase in MBs cluster size over time during AVT $^{ast }$ in the superior sagittal sinus (SSS) of the rat brain. These findings demonstrate that the proposed strategy can accumulate the flowing MBs at a desired location and simultaneously observe this phenomenon.
{"title":"Super-Resolution Ultrasound Imaging for Analysis of Microbubbles Cluster by Acoustic Vortex Tweezers","authors":"Ching-Hsiang Fan;Wei-Chen Lo;Chung-Han Huang;Thi-Nhan Phan;Chih-Kuang Yeh","doi":"10.1109/TUFFC.2024.3466119","DOIUrl":"10.1109/TUFFC.2024.3466119","url":null,"abstract":"Using acoustic vortex tweezers (AVTs) to spatially accumulate microbubbles (MBs) shows promise for enhancing drug delivery efficiency and reducing off-target effects. The strong echogenicity of accumulated MBs also improves diagnostics via conventional ultrasound (US) B-mode imaging. However, the annular high-pressure distribution of AVT inhibits MBs inflow at the inlet, reducing MBs collection. The spatial resolution of US B-mode imaging further limits theranostic applications of AVT-mediated MBs accumulation. To address these challenges, we integrated an AVT waveform with volumetric super-resolution imaging (VSRI) to monitor the dynamic growth of MBs cluster during accumulation. We used a 5-MHz 2-D array transducer for VSRI, employing plane wave pulses interleaved with accumulating pulses to retain MBs at a flow rate of 0.023–0.047 mL/s in a 3-mm vessel phantom. An asymmetrical AVT waveform (AVT\u0000<inline-formula> <tex-math>$^{ast }$ </tex-math></inline-formula>\u0000) was produced by modulating the pressure at the MBs inlet compared to the outlet. The effectiveness was validated in rat cerebral vessels for real-time volumetric tracking of MBs clusters. Microscopy observations showed that AVT\u0000<inline-formula> <tex-math>$^{ast }$ </tex-math></inline-formula>\u0000 could quickly gather flowing MBs into cluster without repelling them at a flow rate of 0.023 mL/s. Statistical results indicated that microscopic data correlated better with VSRI than with B-mode images, suggesting VSRI suffices to detect the dynamics of AVT\u0000<inline-formula> <tex-math>$^{ast }$ </tex-math></inline-formula>\u0000-actuated MBs accumulation in real-time. Additionally, VSRI detected a significant increase in MBs cluster size over time during AVT\u0000<inline-formula> <tex-math>$^{ast }$ </tex-math></inline-formula>\u0000 in the superior sagittal sinus (SSS) of the rat brain. These findings demonstrate that the proposed strategy can accumulate the flowing MBs at a desired location and simultaneously observe this phenomenon.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 12: Breaking the Resolution Barrier in Ultrasound","pages":"1814-1822"},"PeriodicalIF":3.0,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-23DOI: 10.1109/TUFFC.2024.3466290
Ruud J. G. van Sloun
Ultrasound (US) has the unique potential to offer access to medical imaging to anyone, everywhere. Devices have become ultraportable and cost-effective, akin to the stethoscope. Nevertheless, and despite many advances, US image quality and diagnostic efficacy are still highly operator- and patient-dependent. In difficult-to-image patients, image quality is often insufficient for reliable diagnosis. In this article, we put forth the idea that US imaging systems can be recast as information-seeking agents that engage in reciprocal interactions with their anatomical environment. Such agents autonomously adapt their transmit-receive sequences to fully personalize imaging and actively maximize information gain in situ. To that end, we will show that the sequence of pulse-echo experiments that a US system performs can be interpreted as a perception-action loop: the action is the data acquisition, probing tissue with acoustic waves and recording reflections at the detection array, and perception is the inference of the anatomical and or functional state, potentially including associated diagnostic quantities. We then equip systems with a mechanism to actively reduce uncertainty and maximize diagnostic value across a sequence of experiments, treating action and perception jointly using Bayesian inference given generative models of the environment and action-conditional pulse-echo observations. Since the representation capacity of the generative models dictates both the quality of inferred anatomical states and the effectiveness of inferred sequences of future imaging actions, we will be greatly leveraging the enormous advances in deep generative modeling (generative AI), which are currently disrupting many fields and society at large. Finally, we show some examples of cognitive, closed-loop, US systems that perform active beamsteering and adaptive scanline selection based on deep generative models that track anatomical belief states.
{"title":"Active Inference and Deep Generative Modeling for Cognitive Ultrasound","authors":"Ruud J. G. van Sloun","doi":"10.1109/TUFFC.2024.3466290","DOIUrl":"10.1109/TUFFC.2024.3466290","url":null,"abstract":"Ultrasound (US) has the unique potential to offer access to medical imaging to anyone, everywhere. Devices have become ultraportable and cost-effective, akin to the stethoscope. Nevertheless, and despite many advances, US image quality and diagnostic efficacy are still highly operator- and patient-dependent. In difficult-to-image patients, image quality is often insufficient for reliable diagnosis. In this article, we put forth the idea that US imaging systems can be recast as information-seeking agents that engage in reciprocal interactions with their anatomical environment. Such agents autonomously adapt their transmit-receive sequences to fully personalize imaging and actively maximize information gain in situ. To that end, we will show that the sequence of pulse-echo experiments that a US system performs can be interpreted as a perception-action loop: the action is the data acquisition, probing tissue with acoustic waves and recording reflections at the detection array, and perception is the inference of the anatomical and or functional state, potentially including associated diagnostic quantities. We then equip systems with a mechanism to actively reduce uncertainty and maximize diagnostic value across a sequence of experiments, treating action and perception jointly using Bayesian inference given generative models of the environment and action-conditional pulse-echo observations. Since the representation capacity of the generative models dictates both the quality of inferred anatomical states and the effectiveness of inferred sequences of future imaging actions, we will be greatly leveraging the enormous advances in deep generative modeling (generative AI), which are currently disrupting many fields and society at large. Finally, we show some examples of cognitive, closed-loop, US systems that perform active beamsteering and adaptive scanline selection based on deep generative models that track anatomical belief states.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 11","pages":"1478-1490"},"PeriodicalIF":3.0,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-23DOI: 10.1109/TUFFC.2024.3465589
Sanjog Vilas Joshi;Sina Sadeghpour;Michael Kraft
This article reports a $30times 12$ row-column (RC) addressed flexible piezoelectric micromachined ultrasound transducer (PMUT) array with a top-down fabrication process. The fabrication uses a temporary carrier wafer from which the array device is released by deep reactive ion etching (DRIE). About 0.8- $mu $ m-thick sol-gel processed lead zirconate titanate (PZT) thin film acts as the active piezoelectric. The flexible PMUT membrane includes the PZT film and a 14- $mu $ m polyimide as a passive layer. A sidewall made of polyimide measuring $21~mu $ m in thickness with a cavity of $100~mu $ m in diameter is realized by reactive ion etching (RIE). Laser Doppler vibrometer (LDV) characterization of the PMUT indicates 2.7 and 2.1 MHz as the resonance frequency in-air and underwater, respectively. Excitation of a single PMUT element coupled with 5-V direct current (dc) bias results in 1.2-nm/V sensitivity in-air, whereas when the same is excited along with 10-V dc bias, a pressure response of 40 Pa/V at 1 cm is measured underwater using a hydrophone. The presented results under bending to an 8-mm bending radius show the potential for wearable applications in shallow-depth regions subject to further optimization.
{"title":"Flexible PZT-Based Row-Column Addressed 2-D PMUT Array","authors":"Sanjog Vilas Joshi;Sina Sadeghpour;Michael Kraft","doi":"10.1109/TUFFC.2024.3465589","DOIUrl":"10.1109/TUFFC.2024.3465589","url":null,"abstract":"This article reports a \u0000<inline-formula> <tex-math>$30times 12$ </tex-math></inline-formula>\u0000 row-column (RC) addressed flexible piezoelectric micromachined ultrasound transducer (PMUT) array with a top-down fabrication process. The fabrication uses a temporary carrier wafer from which the array device is released by deep reactive ion etching (DRIE). About 0.8-\u0000<inline-formula> <tex-math>$mu $ </tex-math></inline-formula>\u0000m-thick sol-gel processed lead zirconate titanate (PZT) thin film acts as the active piezoelectric. The flexible PMUT membrane includes the PZT film and a 14-\u0000<inline-formula> <tex-math>$mu $ </tex-math></inline-formula>\u0000m polyimide as a passive layer. A sidewall made of polyimide measuring \u0000<inline-formula> <tex-math>$21~mu $ </tex-math></inline-formula>\u0000m in thickness with a cavity of \u0000<inline-formula> <tex-math>$100~mu $ </tex-math></inline-formula>\u0000m in diameter is realized by reactive ion etching (RIE). Laser Doppler vibrometer (LDV) characterization of the PMUT indicates 2.7 and 2.1 MHz as the resonance frequency in-air and underwater, respectively. Excitation of a single PMUT element coupled with 5-V direct current (dc) bias results in 1.2-nm/V sensitivity in-air, whereas when the same is excited along with 10-V dc bias, a pressure response of 40 Pa/V at 1 cm is measured underwater using a hydrophone. The presented results under bending to an 8-mm bending radius show the potential for wearable applications in shallow-depth regions subject to further optimization.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 11","pages":"1616-1626"},"PeriodicalIF":3.0,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1109/TUFFC.2024.3465214
Yimeng Dou;Fangzhou Mu;Yin Li;Tomy Varghese
Three-dimensional ultrasound (3-D US) imaging with freehand scanning is utilized in cardiac, obstetric, abdominal, and vascular examinations. While 3-D US using either a “wobbler” or “matrix” transducer suffers from a small field of view and low acquisition rates, freehand scanning offers significant advantages due to its ease of use. However, current 3-D US volumetric reconstruction methods with freehand sweeps are limited by imaging plane shifts along the scanning path, i.e., out-of-plane (OOP) motion. Prior studies have incorporated motion sensors attached to the transducer, which is cumbersome and inconvenient in a clinical setting. Recent work has introduced deep neural networks (DNNs) with 3-D convolutions to estimate the position of imaging planes from a series of input frames. These approaches, however, fall short for estimating OOP motion. The goal of this article is to bridge the gap by designing a novel, physics-inspired DNN for freehand 3-D US reconstruction without motion sensors, aiming to improve the reconstruction quality and, at the same time, to reduce computational resources needed for training and inference. To this end, we present our physics-guided learning-based prediction of pose information (PLPPI) model for 3-D freehand US reconstruction without 3-D convolution. PLPPI yields significantly more accurate reconstructions and offers a major reduction in computation time. It attains a performance increase in the double digits in terms of mean percentage error, with up to 106% speedup and 131% reduction in graphic processing unit (GPU) memory usage, when compared to the latest deep learning methods.
采用自由手持扫描的三维超声（3D US）成像技术可用于心脏、产科、腹部和血管检查。使用 "摇摆 "或 "矩阵 "传感器的三维 US 存在视野小和采集率低的问题，而徒手扫描因其易于使用而具有显著的优势。然而，目前采用徒手扫描的三维超声容积重建方法受到成像平面沿扫描路径移动（即平面外运动）的限制。之前的研究将运动传感器连接到传感器上，这在临床环境中既麻烦又不方便。最近的研究引入了具有三维卷积功能的深度神经网络（DNN），以便从一系列输入帧中估计成像平面的位置。然而，这些方法在估计 OOP 运动方面存在不足。本文的目标是通过设计一种新颖的、受物理学启发的 DNN 来弥合这一差距，该 DNN 适用于无运动传感器的徒手三维 US 重建，旨在提高重建质量，同时减少训练和推理所需的计算资源。为此，我们提出了基于物理引导学习的姿势信息预测模型（PLPPI），用于无三维卷积的三维徒手 US 重建。PLPPI 模型能大大提高重建的精确度，并显著减少计算时间。与最新的深度学习方法相比，它在平均百分比误差方面实现了两位数的性能提升，速度提高了106%，图形处理器（GPU）内存使用量减少了131%。
{"title":"Sensorless End-to-End Freehand 3-D Ultrasound Reconstruction With Physics-Guided Deep Learning","authors":"Yimeng Dou;Fangzhou Mu;Yin Li;Tomy Varghese","doi":"10.1109/TUFFC.2024.3465214","DOIUrl":"10.1109/TUFFC.2024.3465214","url":null,"abstract":"Three-dimensional ultrasound (3-D US) imaging with freehand scanning is utilized in cardiac, obstetric, abdominal, and vascular examinations. While 3-D US using either a “wobbler” or “matrix” transducer suffers from a small field of view and low acquisition rates, freehand scanning offers significant advantages due to its ease of use. However, current 3-D US volumetric reconstruction methods with freehand sweeps are limited by imaging plane shifts along the scanning path, i.e., out-of-plane (OOP) motion. Prior studies have incorporated motion sensors attached to the transducer, which is cumbersome and inconvenient in a clinical setting. Recent work has introduced deep neural networks (DNNs) with 3-D convolutions to estimate the position of imaging planes from a series of input frames. These approaches, however, fall short for estimating OOP motion. The goal of this article is to bridge the gap by designing a novel, physics-inspired DNN for freehand 3-D US reconstruction without motion sensors, aiming to improve the reconstruction quality and, at the same time, to reduce computational resources needed for training and inference. To this end, we present our physics-guided learning-based prediction of pose information (PLPPI) model for 3-D freehand US reconstruction without 3-D convolution. PLPPI yields significantly more accurate reconstructions and offers a major reduction in computation time. It attains a performance increase in the double digits in terms of mean percentage error, with up to 106% speedup and 131% reduction in graphic processing unit (GPU) memory usage, when compared to the latest deep learning methods.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 11","pages":"1514-1525"},"PeriodicalIF":3.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142286107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1109/TUFFC.2024.3465268
Lukas Holzapfel;Vasiliki Giagka
Traditionally, implants are powered by batteries, which have to be recharged by an inductive power link. In the recent years, ultrasonic power links are being investigated, promising more available power for deeply implanted miniaturized devices. These implants often need to transfer back information. For ultrasonically powered implants, this is usually achieved with on-off keying (OOK) based on backscatter modulation, or active driving of a secondary transducer. In this article, we propose to superimpose subcarriers, effectively leveraging frequency-shift keying (FSK), which increases the robustness of the link against interference and fading. It also allows for simultaneous powering and communication, and inherently provides the possibility of frequency domain multiplexing for implant networks. The modulation scheme can be implemented in miniaturized application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and microcontrollers. We have validated this modulation scheme in a water tank during continuous ultrasound and movement. We achieved symbol rates of up to 104 kBd, and were able to transfer data through 20 cm of water and through a 5 cm tissue phantom with additional misalignment and during movements. This approach could provide a robust uplink for miniaturized implants that are located deep inside the body and need continuous ultrasonic powering.
{"title":"A Robust Backscatter Modulation Scheme for Uninterrupted Ultrasonic Powering and Back-Communication of Deep Implants","authors":"Lukas Holzapfel;Vasiliki Giagka","doi":"10.1109/TUFFC.2024.3465268","DOIUrl":"10.1109/TUFFC.2024.3465268","url":null,"abstract":"Traditionally, implants are powered by batteries, which have to be recharged by an inductive power link. In the recent years, ultrasonic power links are being investigated, promising more available power for deeply implanted miniaturized devices. These implants often need to transfer back information. For ultrasonically powered implants, this is usually achieved with on-off keying (OOK) based on backscatter modulation, or active driving of a secondary transducer. In this article, we propose to superimpose subcarriers, effectively leveraging frequency-shift keying (FSK), which increases the robustness of the link against interference and fading. It also allows for simultaneous powering and communication, and inherently provides the possibility of frequency domain multiplexing for implant networks. The modulation scheme can be implemented in miniaturized application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and microcontrollers. We have validated this modulation scheme in a water tank during continuous ultrasound and movement. We achieved symbol rates of up to 104 kBd, and were able to transfer data through 20 cm of water and through a 5 cm tissue phantom with additional misalignment and during movements. This approach could provide a robust uplink for miniaturized implants that are located deep inside the body and need continuous ultrasonic powering.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 12: Breaking the Resolution Barrier in Ultrasound","pages":"1897-1905"},"PeriodicalIF":3.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142286056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1109/TUFFC.2024.3464330
Phuong T. Vu;Stephan Strassle Rojas;Caroline C. Ott;Brooks D. Lindsey
Large vessel occlusion (LVO) stroke, in which major cerebral arteries such as the internal carotid and middle cerebral arteries supplying the brain are occluded, is the most debilitating form of acute ischemic stroke (AIS). The current gold standard treatment for LVO stroke is mechanical thrombectomy; however, initial attempts to recanalize these large, proximal arteries supplying the brain fail in up to 75% of cases, leading to repeated passes that decrease the likelihood of success and affect patient outcomes. We report the design, fabrication, and testing of a $3times 3$ mm forward-treating ultrasound (US) transducer with an acoustic metamaterial lens to dissolve blood clots recalcitrant to first-pass mechanical thrombectomy in LVO stroke. Due to the lens with microscale features, the device was able to produce a $2.3times $ increase in peak negative pressure (PNP) (4.3 versus 1.8 MPa) and $2.4times $ increase in blood clot dissolution rate ( $5.43~pm ~0.89$ versus $2.23~pm ~0.41$ mg/min) with 90% mass reduction after 30 min of treatment. In this small endovascular form factor, the acoustic metamaterial lens increased the acoustic output from the transducer while minimizing the US energy delivered to the surrounding areas outside of the treatment volume.
{"title":"A 9-Fr Endovascular Therapy Transducer With an Acoustic Metamaterial Lens for Rapid Stroke Thrombectomy","authors":"Phuong T. Vu;Stephan Strassle Rojas;Caroline C. Ott;Brooks D. Lindsey","doi":"10.1109/TUFFC.2024.3464330","DOIUrl":"10.1109/TUFFC.2024.3464330","url":null,"abstract":"Large vessel occlusion (LVO) stroke, in which major cerebral arteries such as the internal carotid and middle cerebral arteries supplying the brain are occluded, is the most debilitating form of acute ischemic stroke (AIS). The current gold standard treatment for LVO stroke is mechanical thrombectomy; however, initial attempts to recanalize these large, proximal arteries supplying the brain fail in up to 75% of cases, leading to repeated passes that decrease the likelihood of success and affect patient outcomes. We report the design, fabrication, and testing of a \u0000<inline-formula> <tex-math>$3times 3$ </tex-math></inline-formula>\u0000 mm forward-treating ultrasound (US) transducer with an acoustic metamaterial lens to dissolve blood clots recalcitrant to first-pass mechanical thrombectomy in LVO stroke. Due to the lens with microscale features, the device was able to produce a \u0000<inline-formula> <tex-math>$2.3times $ </tex-math></inline-formula>\u0000 increase in peak negative pressure (PNP) (4.3 versus 1.8 MPa) and \u0000<inline-formula> <tex-math>$2.4times $ </tex-math></inline-formula>\u0000 increase in blood clot dissolution rate (\u0000<inline-formula> <tex-math>$5.43~pm ~0.89$ </tex-math></inline-formula>\u0000 versus \u0000<inline-formula> <tex-math>$2.23~pm ~0.41$ </tex-math></inline-formula>\u0000 mg/min) with 90% mass reduction after 30 min of treatment. In this small endovascular form factor, the acoustic metamaterial lens increased the acoustic output from the transducer while minimizing the US energy delivered to the surrounding areas outside of the treatment volume.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 11","pages":"1627-1640"},"PeriodicalIF":3.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142286055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1109/TUFFC.2024.3463188
Junjin Yu;Yang Cai;Zhili Zeng;Kailiang Xu
Accurate assessment of spinal cord vasculature is important for the urgent diagnosis of injury and subsequent treatment. Ultrasound localization microscopy (ULM) offers super-resolution imaging of microvasculature by localizing and tracking individual microbubbles (MBs) across multiple frames. However, a long data acquisition often involves significant motion artifacts caused by breathing and heartbeat, which further impairs the resolution of ULM. This effect is particularly pronounced in spinal cord imaging due to respiratory movement. We propose a VoxelMorph-based deep learning (DL) motion correction method to enhance the ULM performance in spinal cord imaging. Simulations were conducted to demonstrate the motion estimation accuracy of the proposed method, achieving a mean absolute error of $8~mu $ m. Results from in vivo experiments show that the proposed method efficiently compensates for rigid and nonrigid motion, providing improved resolution with smaller vascular diameters and enhanced microvessel reconstruction after motion correction. Nonrigid deformation fields with varying displacement magnitudes were applied to in vivo data for assessing the robustness of the algorithm.
{"title":"VoxelMorph-Based Deep Learning Motion Correction for Ultrasound Localization Microscopy of Spinal Cord","authors":"Junjin Yu;Yang Cai;Zhili Zeng;Kailiang Xu","doi":"10.1109/TUFFC.2024.3463188","DOIUrl":"10.1109/TUFFC.2024.3463188","url":null,"abstract":"Accurate assessment of spinal cord vasculature is important for the urgent diagnosis of injury and subsequent treatment. Ultrasound localization microscopy (ULM) offers super-resolution imaging of microvasculature by localizing and tracking individual microbubbles (MBs) across multiple frames. However, a long data acquisition often involves significant motion artifacts caused by breathing and heartbeat, which further impairs the resolution of ULM. This effect is particularly pronounced in spinal cord imaging due to respiratory movement. We propose a VoxelMorph-based deep learning (DL) motion correction method to enhance the ULM performance in spinal cord imaging. Simulations were conducted to demonstrate the motion estimation accuracy of the proposed method, achieving a mean absolute error of \u0000<inline-formula> <tex-math>$8~mu $ </tex-math></inline-formula>\u0000m. Results from in vivo experiments show that the proposed method efficiently compensates for rigid and nonrigid motion, providing improved resolution with smaller vascular diameters and enhanced microvessel reconstruction after motion correction. Nonrigid deformation fields with varying displacement magnitudes were applied to in vivo data for assessing the robustness of the algorithm.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 12: Breaking the Resolution Barrier in Ultrasound","pages":"1752-1764"},"PeriodicalIF":3.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142286110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1109/TUFFC.2024.3462299
Brice Rauby;Paul Xing;Maxime Gasse;Jean Provost
Ultrasound localization microscopy (ULM) is a novel super-resolution imaging technique that can image the vasculature in vivo at depth with resolution far beyond the conventional limit of diffraction. By relying on the localization and tracking of clinically approved microbubbles injected in the blood stream, ULM can provide not only anatomical visualization but also hemodynamic quantification of the microvasculature. Several deep learning approaches have been proposed to address challenges in ULM including denoising, improving microbubble localization, estimating blood flow velocity, or performing aberration correction. Proposed deep learning methods often outperform their conventional counterparts by improving image quality and reducing processing time. In addition, their robustness to high concentrations of microbubbles can lead to reduced acquisition times in ULM, addressing a major hindrance to ULM clinical application. Herein, we propose a comprehensive review of the diversity of deep learning applications in ULM focusing on approaches assuming a sparse microbubble distribution. We first provide an overview of how existing studies vary in the constitution of their datasets or in the tasks targeted by the deep learning model. We also take a deeper look into the numerous approaches that have been proposed to improve the localization of microbubbles since they differ highly in their formulation of the optimization problem, their evaluation, or their network architectures. We finally discuss the current limitations and challenges of these methods, as well as the promises and potential of deep learning for ULM in the future.
{"title":"Deep Learning in Ultrasound Localization Microscopy: Applications and Perspectives","authors":"Brice Rauby;Paul Xing;Maxime Gasse;Jean Provost","doi":"10.1109/TUFFC.2024.3462299","DOIUrl":"10.1109/TUFFC.2024.3462299","url":null,"abstract":"Ultrasound localization microscopy (ULM) is a novel super-resolution imaging technique that can image the vasculature in vivo at depth with resolution far beyond the conventional limit of diffraction. By relying on the localization and tracking of clinically approved microbubbles injected in the blood stream, ULM can provide not only anatomical visualization but also hemodynamic quantification of the microvasculature. Several deep learning approaches have been proposed to address challenges in ULM including denoising, improving microbubble localization, estimating blood flow velocity, or performing aberration correction. Proposed deep learning methods often outperform their conventional counterparts by improving image quality and reducing processing time. In addition, their robustness to high concentrations of microbubbles can lead to reduced acquisition times in ULM, addressing a major hindrance to ULM clinical application. Herein, we propose a comprehensive review of the diversity of deep learning applications in ULM focusing on approaches assuming a sparse microbubble distribution. We first provide an overview of how existing studies vary in the constitution of their datasets or in the tasks targeted by the deep learning model. We also take a deeper look into the numerous approaches that have been proposed to improve the localization of microbubbles since they differ highly in their formulation of the optimization problem, their evaluation, or their network architectures. We finally discuss the current limitations and challenges of these methods, as well as the promises and potential of deep learning for ULM in the future.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 12: Breaking the Resolution Barrier in Ultrasound","pages":"1765-1784"},"PeriodicalIF":3.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142286058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-13DOI: 10.1109/TUFFC.2024.3460688
Doyoung Jang;Heechul Yoon;Gi-Duck Kim;Jae Hee Song;Tai-Kyong Song
A sparse array offers a significant reduction in the complexity of ultrasonic imaging systems by decreasing the number of active elements and associated electrical circuits needed to form a focused beam. Consequently, for 1-D arrays, it has been adopted in the development of miniaturized systems such as portable, handheld, or smartphone-based systems. Previously, we developed an analytic method that can design a pair of 1-D periodic sparse arrays (PSAs) satisfying three specific constraints, which are the array size, desired grating lobe level, and sparseness factor (SF). In this study, we further developed our method by incorporating aperture weighting functions, which take the form of tapered rectangular functions to introduce null points on the beam pattern. These null points effectively suppress grating lobes generated by a matching pair of arrays. The design process commences with determining transmit and receive PSA patterns, followed by deriving corresponding aperture weighting functions. First, aperture functions of a base and weighting arrays are convolved, which is then upsampled to the targeted array size. Finally, the upsampled aperture is convolved to an aperture function of a subarray, resulting in weighted PSAs (wPSAs). Pulsed wave (PW) simulation confirmed improved grating lobe suppression with wPSAs compared to PSAs. Phantom imaging experiments using a 1-D phased array validated the enhanced contrast due to suppressed grating lobes but at the cost of small degradation in lateral resolution. The signal-to-noise ratio (SNR) also gradually declined with the greater SFs, but no significant difference in SNR was observed between wPSAs and PSAs. Finally, in vivo echocardiography imaging highlighted the clinical potential of wPSAs, particularly with high SFs. Overall, these results suggest that wPSAs can effectively enhance contrast compared to PSAs under the given SF or, alternatively, wPSA with greater SFs can achieve comparable image quality to PSAs with lower SFs. In conclusion, the wPSA approach holds promise for further reducing the complexity of ultrasound imaging systems.
稀疏阵列通过减少形成聚焦声束所需的有源元件和相关电路的数量，大大降低了超声波成像系统的复杂性。因此，对于一维阵列，它已被用于开发微型系统，如便携式、手持式或基于智能手机的系统。此前，我们开发了一种分析方法，可以设计出一对满足三个特定约束条件的一维周期性稀疏阵列（PSA），这三个约束条件是阵列尺寸、所需光栅叶水平和稀疏因子（SF）。在本研究中，我们进一步发展了我们的方法，加入了孔径加权函数，该函数采用锥形矩形函数的形式，在光束图案上引入了空点。这些空点能有效抑制一对匹配阵列产生的光栅裂片。设计过程首先是确定发射和接收 PSA 图案，然后推导出相应的孔径加权函数。首先，对基准阵列和加权阵列的孔径函数进行卷积，然后根据目标阵列尺寸进行上采样。最后，将上采样孔径与子阵列的孔径函数进行卷积，得出加权 PSAs（wPSAs）。脉冲波模拟证实，与 PSA 相比，wPSA 能更好地抑制光栅叶。使用一维相控阵进行的幻影成像实验证实，光栅叶被抑制后，对比度得到了增强，但横向分辨率略有下降。信噪比（SNR）也随着 SF 的增大而逐渐下降，但 wPSAs 和 PSAs 之间的信噪比没有明显差异。最后，活体超声心动图成像凸显了 wPSAs 的临床潜力，尤其是在高 SFs 的情况下。总之，这些结果表明，与 PSA 相比，在给定 SF 的情况下，wPSA 可以有效增强对比度，或者说，SF 较高的 wPSA 可以获得与 SF 较低的 PSA 相当的图像质量。总之，wPSA 方法有望进一步降低超声成像系统的复杂性。
{"title":"Design and Evaluation of a Weighted Periodic Sparse Array for Low-Complexity 1-D Phased Array Ultrasound Imaging Systems","authors":"Doyoung Jang;Heechul Yoon;Gi-Duck Kim;Jae Hee Song;Tai-Kyong Song","doi":"10.1109/TUFFC.2024.3460688","DOIUrl":"10.1109/TUFFC.2024.3460688","url":null,"abstract":"A sparse array offers a significant reduction in the complexity of ultrasonic imaging systems by decreasing the number of active elements and associated electrical circuits needed to form a focused beam. Consequently, for 1-D arrays, it has been adopted in the development of miniaturized systems such as portable, handheld, or smartphone-based systems. Previously, we developed an analytic method that can design a pair of 1-D periodic sparse arrays (PSAs) satisfying three specific constraints, which are the array size, desired grating lobe level, and sparseness factor (SF). In this study, we further developed our method by incorporating aperture weighting functions, which take the form of tapered rectangular functions to introduce null points on the beam pattern. These null points effectively suppress grating lobes generated by a matching pair of arrays. The design process commences with determining transmit and receive PSA patterns, followed by deriving corresponding aperture weighting functions. First, aperture functions of a base and weighting arrays are convolved, which is then upsampled to the targeted array size. Finally, the upsampled aperture is convolved to an aperture function of a subarray, resulting in weighted PSAs (wPSAs). Pulsed wave (PW) simulation confirmed improved grating lobe suppression with wPSAs compared to PSAs. Phantom imaging experiments using a 1-D phased array validated the enhanced contrast due to suppressed grating lobes but at the cost of small degradation in lateral resolution. The signal-to-noise ratio (SNR) also gradually declined with the greater SFs, but no significant difference in SNR was observed between wPSAs and PSAs. Finally, in vivo echocardiography imaging highlighted the clinical potential of wPSAs, particularly with high SFs. Overall, these results suggest that wPSAs can effectively enhance contrast compared to PSAs under the given SF or, alternatively, wPSA with greater SFs can achieve comparable image quality to PSAs with lower SFs. In conclusion, the wPSA approach holds promise for further reducing the complexity of ultrasound imaging systems.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 10","pages":"1255-1268"},"PeriodicalIF":3.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10680100","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142286059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1109/TUFFC.2024.3459593
Qinwen Xu;Jie Zhou;Shashidhara Acharya;Jianwei Chai;Mingsheng Zhang;Chengliang Sun;Kui Yao
Piezoelectric films including coatings are widely employed in various electromechanical devices. Precise measurement for piezoelectric film properties is crucial for both piezoelectric material development and design of the piezoelectric devices. However, substrate constraint on the deformation of piezoelectric films could cause significant impacts on the reliability and accuracy of the piezoelectric coefficient measurement. Through both theoretical finite element analysis (FEA) and experimental validation, here we have identified three important factors that strongly affect the measurement results: ratio of Young’s modulus of substrate to piezoelectric film, ratio of electrode size to substrate thickness, and test frequency. Our investigations show that a relatively smaller substrate’s Young’s modulus to film, and a larger ratio of electrode size to substrate thickness would cause a larger substrate bending effect and thus potentially more significant measurement errors. Moreover, intense transversal displacement fluctuation can be excited at excessively high frequencies, leading to unreliable measurements. Various well-established piezoelectric measurement methods are compared with outstanding measurement issues identified for those commonly used piezoelectric films and substrates. We further establish the guidelines for piezoelectric coefficient measurements to achieve high reliability and accuracy, thus important to the wide technical community with interests in electromechanical active materials and devices.
{"title":"Analysis and Guideline for Determining Piezoelectric Coefficient for Films With Substrate Constraint","authors":"Qinwen Xu;Jie Zhou;Shashidhara Acharya;Jianwei Chai;Mingsheng Zhang;Chengliang Sun;Kui Yao","doi":"10.1109/TUFFC.2024.3459593","DOIUrl":"10.1109/TUFFC.2024.3459593","url":null,"abstract":"Piezoelectric films including coatings are widely employed in various electromechanical devices. Precise measurement for piezoelectric film properties is crucial for both piezoelectric material development and design of the piezoelectric devices. However, substrate constraint on the deformation of piezoelectric films could cause significant impacts on the reliability and accuracy of the piezoelectric coefficient measurement. Through both theoretical finite element analysis (FEA) and experimental validation, here we have identified three important factors that strongly affect the measurement results: ratio of Young’s modulus of substrate to piezoelectric film, ratio of electrode size to substrate thickness, and test frequency. Our investigations show that a relatively smaller substrate’s Young’s modulus to film, and a larger ratio of electrode size to substrate thickness would cause a larger substrate bending effect and thus potentially more significant measurement errors. Moreover, intense transversal displacement fluctuation can be excited at excessively high frequencies, leading to unreliable measurements. Various well-established piezoelectric measurement methods are compared with outstanding measurement issues identified for those commonly used piezoelectric films and substrates. We further establish the guidelines for piezoelectric coefficient measurements to achieve high reliability and accuracy, thus important to the wide technical community with interests in electromechanical active materials and devices.","PeriodicalId":13322,"journal":{"name":"IEEE transactions on ultrasonics, ferroelectrics, and frequency control","volume":"71 10","pages":"1335-1344"},"PeriodicalIF":3.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142286057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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