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ultra-fine tuning
摘要： Researchers from Xi’an University of Technology in China, alongside researchers from the ENSEIRB and the IERF in France, propose an auto-tuning network for a phased-array high intensity focused ultrasound (HIFU) system based on a variable synchronous switched capacitor. The novel system is capable of automatically compensating for the reactive power and impedance drifts, caused by temperature fluctuations and manufacturing errors, in circuit transducers and complies with magnetic resonance imaging (MRI) compatibility regulations.
关键词： phased-array,variable synchronous switched capacitor,high-intensity focused ultrasound,HIFU,Auto-tuning network,MRI compatibility
更新于2025-09-23 15:21:01
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Intravascular Photothermal Strain Imaging for Lipid Detection
摘要： Cardiovascular disease (CVD) is one of the major threats to humanity, accounting for one-third of the world’s deaths. For patients with high-risk CVD, plaque rupture can lead to critical condition. It is therefore important to determine the stability of the plaque and classify the patient’s risk level. Lipid content is an important determinant of plaque stability. However, conventional intravascular imaging methods have limitations in ?nding lipids. Therefore, new intravascular imaging techniques for plaque risk assessment are urgently needed. In this study, a novel photothermal strain imaging (pTSI) was applied to an intravascular imaging system for detecting lipids in plaques. As a combination of thermal strain imaging and laser-induced heating, pTSI differentiates lipids from other tissues based on changes in ultrasound (US) velocity with temperature change. We designed an optical pathway to an intravascular ultrasound catheter to deliver 1210-nm laser and US simultaneously. To establish the feasibility of the intravascular pTSI system, we experimented with a tissue-mimicking phantom made of fat and gelatin. Due to the difference in the strain during laser heating, we can clearly distinguish fat and gelatin in the phantom. The result demonstrates that pTSI could be used with conventional intravascular imaging methods to detect the plaque lipid.
关键词： photothermal strain imaging,intravascular ultrasound (IVUS),thermal strain imaging,lipid detection,unstable plaque,intravascular imaging,cardiovascular disease
更新于2025-09-23 15:21:01
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A Comparison of Intraoperative Metrics between the Infiniti with and the Centurion without Intelligent Phacoemulsification Systems
摘要： Purpose: To compare the efficiency and safety of two phacoemulsification systems, the Infiniti with intelligent phacoemulsification (IP) and the Centurion without IP, in terms of intraoperative metrics of phacoemulsification and the occurrences of adverse events and intraoperative tip obstruction. Design: Comparative case series. Methods: A consecutive series of 340 eyes (151 eyes with the Infiniti, 189 eyes with the Centurion) was evaluated. A 2.4 mm sclerocorneal incision was used with the Infiniti, and a 2.0 mm incision was used with the Centurion. Phacoemulsification of the nucleus was performed using the phaco chop technique, with the IP function of the Infiniti turned on and the IP mode of the Centurion turned off. From among the parameters displayed on the panels of both devices, ultrasound (US) time, cumulative dissipated energy (CDE), aspiration time, and estimated balanced salt solution (BSS) aspiration volume were investigated and compared between the devices. Results: A comparison of all subjects found significant differences between the two devices in mean CDE (p=0.02) and mean aspiration time (p=0.003), but not in mean US time (p=0.43) or mean estimated BSS aspiration volume (p=0.07). For grade 3 nuclei, all parameters of mean US time (p=0.0044), mean CDE (p ≤ 0.001), mean aspiration time (p<0.001), and mean estimated BSS aspiration volume (p=0.001) showed significant differences favoring the Centurion. Conclusions: Compared to the Infiniti with IP mode, cataract surgery with the Centurion without IP mode is likely to be performed with less phacoemulsification energy and higher efficiency.
关键词： Centurion,Intelligent Phacoemulsification Mode,Cumulative dissipated energy,Infiniti,Ultrasound time
更新于2025-09-23 15:21:01
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Photoacoustic Energy Sensor for Nanosecond Optical Pulse Measurement
摘要： We demonstrate a photoacoustic sensor capable of measuring high-energy nanosecond optical pulses in terms of temporal width and energy fluence per pulse. This was achieved by using a hybrid combination of a carbon nanotube-polydimethylsiloxane (CNT-PDMS)-based photoacoustic transmitter (i.e., light-to-sound converter) and a piezoelectric receiver (i.e., sound detector). In this photoacoustic energy sensor (PES), input pulsed optical energy is heavily absorbed by the CNT-PDMS composite film and then efficiently converted into an ultrasonic output. The output ultrasonic pulse is then measured and analyzed to retrieve the input optical characteristics. We quantitatively compared the PES performance with that of a commercial thermal energy meter. Due to the efficient energy transduction and sensing mechanism of the hybrid structure, the minimum-measurable pulsed optical energy was significantly lowered, ~157 nJ/cm2, corresponding to 1/760 of the reference pyroelectric detector. Moreover, despite the limited acoustic frequency bandwidth of the piezoelectric receiver, laser pulse widths over a range of 6–130 ns could be measured with a linear relationship to the ultrasound pulse width of 22–153 ns. As CNT has a wide electromagnetic absorption spectrum, the proposed pulsed sensor system can be extensively applied to high-energy pulse measurement over visible through terahertz spectral ranges.
关键词： photoacoustic sensor,ultrasound sensor,nanosecond optical pulse,CNT-PDMS,optical energy meter
更新于2025-09-23 15:21:01
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Interventional Oncology (Principles and Practice of Image-Guided Cancer Therapy) || Principles of high-intensity focused ultrasound
摘要： High-intensity focused ultrasound (HIFU), also known as focused ultrasound (US), is a non-invasive image-guided therapy which has been primarily employed in the clinical realm for non-invasive thermal ablation of benign and malignant neoplasms. Real-time imaging guidance, treatment monitoring, and therapy control are achieved with either US or magnetic resonance imaging (MRI) guidance. HIFU clinical experience has been described in the treatment of leiomyomata (uterine fibroids), prostate (benign prostatic hypertrophy and cancer), breast, hepatic, renal, pancreatic, brain, and bone tumors, although for most of these tumors, relatively small numbers of treated patients have been described and widespread adoption of HIFU thermoablation remains limited. Ongoing technical challenges include the feasibility of treating large tumors within a finite treatment time, treating tumors prone to motion, and accessing targets when the acoustic window is restricted by intervening anatomy (e.g., ribs, bowel).
关键词： image-guided therapy,thermal ablation,HIFU,High-intensity focused ultrasound,non-invasive therapy
更新于2025-09-23 15:21:01
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Measurement of shallow defects using noncontact broadband leaky Lamb wave produced by pulsed laser with ultrasound microphone
摘要： In this study, we propose a convenient noncontact laser ultrasonic system to detect small cracks and estimate the wall-thinning defects of thin plates. The system uses an ultrasound microphone to detect the energy leaked from the broadband Lamb-wave propagation. The broadband characteristics of this wave, produced by a pulsed laser, are used to measure the wavenumber. The cumulative standing-wave energy (CSWE) method that uses a traveling wave is implemented to verify the feasibility of the ultrasound microphone. The excitation energy of the pulsed laser was insufficient compared with that of the continuous-wave contact actuator. Therefore, a modified local wavenumber estimation (LWE) method is proposed, which reconstructs several LWE images at various frequencies. These images are averaged to calculate thicknesses of the plate and defects, by using the wavenumber–thickness relationship. The method has an error of 2.84% and 7.7% for the thickness of the plate and defect area, respectively.
关键词： cumulative standing-wave energy (CSWE),ultrasound microphone,local wavenumber estimation (LWE),wall-thinning defects,noncontact laser ultrasonic system,broadband Lamb-wave propagation,small cracks
更新于2025-09-23 15:19:57
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In Vivo Confocal Imaging of Fluorescently Labelled Microbubbles: Implications for Ultrasound Localization Microscopy
摘要： We report the time kinetics of fluorescently labelled microbubbles in capillary-level microvasculature as measured via confocal microscopy and compare these results to ultrasound localization microscopy. The observed 19.4 ± 4.2 microbubbles per confocal field-of-view (212 μm x 212 μm) is in excellent agreement with the expected count of 19.1 microbubbles per frame. The estimated time to fully perfuse this capillary network was 193 seconds, which corroborates the values reported in literature. We then modeled the capillary network as an empirically determined discrete-time Markov chain with adjustable microbubble transition probabilities though individual capillaries. Monte Carlo random walk simulations found perfusion times ranging from 24.5 seconds for unbiased Markov chains up to 182 seconds for heterogeneous flow distributions. This pilot study confirms a probability-derived explanation for the long acquisition times required for super-resolution ultrasound localization microscopy.
关键词： Super-resolution,Ultrasound Microvessel Imaging,Microbubble tracking,Microvasculature
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Advanced Computer Science and information Systems (ICACSIS) - Bali, Indonesia (2019.10.12-2019.10.13)] 2019 International Conference on Advanced Computer Science and information Systems (ICACSIS) - Wavelength Selection of Persimmon Leafusing Decision Tree Method in Visible Near-Infrared Imaging
摘要： The intima-media thickness (IMT) of the common carotid artery (CCA) is an established indicator of cardiovascular disease (CVD). There have been reports about the difference between the left and the right sides of the CCA IMT and their relation with CVD. In this paper, we propose an automated system based on image normalization, speckle reduction ?ltering, and snakes segmentation, for segmenting the CCA, perform IMT measurements, and provide the differences between the left and the right sides. The study was performed on 1104 longitudinal-section ultrasound images acquired from 568 men and 536 women out of which 125 had cardiovascular symptoms (CVD). A cardiovascular expert manually delineated the IMT for the normal and the CVD groups. The corresponding (normal versus CVD) IMT mean ± standard deviation values for the left and the right sides were 0.74 ± 0.24 versus 0.87 ± 0.24 mm and 0.70 ± 0.17 versus 0.80 ± 0.18 mm, respectively. The main ?ndings of this paper can be summarized as follows: 1) there was no signi?cant difference between the CCA left side IMT and the right side IMT. These ?ndings suggest that the measurement of the CCA IMT on one side only is needed for the normal group (and this is in agreement with other studies); 2) there were statistical signi?cant differences for the IMT measurements between the normal group and the CVD group for both the left and the right sides; 3) there was an increasing linear relationship of the left and the right IMT measurements with age for the normal group; and to a lesser extend for the CVD group; 4) no statistical signi?cant differences were found between the manual and the automated IMT measurements for both sides; and 5) the best result for classi?cation disease modeling, using support vector machines, to discriminate between the normal and the CVD groups was a 64% ± 3.5% correct classi?cations score when using both the left and the right IMT automated measurements. Further research is required for estimating differences and similarities between left and right intima media complex structure and morphology and their variability with texture features for differentiating between the normal and the CVD group.
关键词： B-mode,IMT,common carotid artery,cardiovascular disease,ultrasound imaging,intima media thickness
更新于2025-09-23 15:19:57
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Coa??Integration of Single Mode Waveguides and Embedded Electrical Interconnects for High Bandwidth Communications
摘要： Valid characterization of carotid atherosclerosis (CA) is a crucial public health issue, which would limit the major risks held by CA for both patient safety and state economies. This paper investigated the unexplored potential of kinematic features in assisting the diagnostic decision for CA in the framework of a computer-aided diagnosis (CAD) tool. To this end, 15 CAD schemes were designed and were fed with a wide variety of kinematic features of the atherosclerotic plaque and the arterial wall adjacent to the plaque for 56 patients from two different hospitals. The CAD schemes were benchmarked in terms of their ability to discriminate between symptomatic and asymptomatic patients and the combination of the Fisher discriminant ratio, as a feature-selection strategy, and support vector machines, in the classification module, was revealed as the optimal motion-based CAD tool. The particular CAD tool was evaluated with several cross-validation strategies and yielded higher than 88% classification accuracy; the texture-based CAD performance in the same dataset was 80%. The incorporation of kinematic features of the arterial wall in CAD seems to have a particularly favorable impact on the performance of image-data-driven diagnosis for CA, which remains to be further elucidated in future prospective studies on large datasets.
关键词： motion analysis,Carotid atherosclerosis (CA),kinematic features,ultrasound (US),computer-aided diagnosis (CAD)
更新于2025-09-23 15:19:57
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Cavitation inception pressure and bubble cloud formation due to the backscattering of high-intensity focused ultrasound from a laser-induced bubble
摘要： Cavitation bubble cloud formation due to the backscattering of high-intensity focused ultrasound (HIFU) from a laser-induced bubble in various water temperatures and dissolved oxygen (DO) has been investigated. A laser-induced bubble generated near the geometrical focus of HIFU is utilized to yield intense negative pressure by the backscattering. Optical observation with a high-speed video camera and pressure measurement with a fiber-optic probe hydrophone are conducted simultaneously to understand the forming process of a bubble cloud and corresponding pressure field by the backscattering. Optical observation shows that a bubble cloud grows stepwise forming multiple layers composed of tiny cavitation bubbles, and the cavitation inception position is consistent with the local minimum pressure position simulated with the ghost fluid method. The bubble cloud grows larger in the opposite direction of HIFU propagation, and the absolute value of the cavitation inception pressure decreases with an increase in water temperature. The linear correlation between cavitation inception pressure and water temperature agrees with that given by Vlaisavljevich, Xu, Maxwell, Mancia, Zhang, Lin, Duryea, Sukovich, Hall, Johnsen, and Cain [IEEE Trans. Ultrason. Ferroelectr. Freq. Control 63, 1064–1077 (2016)]. However DO has minor dependence on the cavitation inception pressure when DO is degassed sufficiently. Furthermore, the gas nucleus size that might exist in the experiment has been estimated by using bubble dynamics.
关键词： Dissolved oxygen,Water temperature,Bubble cloud formation,Cavitation inception pressure,Laser-induced bubble,High-intensity focused ultrasound,Cavitation
更新于2025-09-23 15:19:57