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https://www.readbyqxmd.com/read/28808900/varying-ultrasound-power-level-to-distinguish-surgical-instruments-and-tissue
#1
Hongliang Ren, Banani Anuraj, Pierre E Dupont
We investigate a new framework of surgical instrument detection based on power-varying ultrasound images with simple and efficient pixel-wise intensity processing. Without using complicated feature extraction methods, we identified the instrument with an estimated optimal power level and by comparing pixel values of varying transducer power level images. The proposed framework exploits the physics of ultrasound imaging system by varying the transducer power level to effectively distinguish metallic surgical instruments from tissue...
August 15, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28805509/enhanced-cell-killing-and-apoptosis-of-oral-squamous-cell-carcinoma-cells-with-ultrasound-in-combination-with-cetuximab-coated-albumin-microbubbles
#2
Kyoichi Narihira, Akiko Watanabe, Hong Sheng, Hitomi Endo, Loreto B Feril, Yutaka Irie, Koichi Ogawa, Seyedeh Moosavi-Nejad, Seiji Kondo, Toshihiro Kikuta, Katsuro Tachibana
Targeted microbubbles has the potential to be used for ultrasound (US) therapy and diagnosis of various cancers. In the present study, US was irradiated to oral squamous cell carcinoma cells (HSC-2) in the presence of cetuximab coated albumin microbubbles (CCAM). Cell killing rate with ultrasound treatment at 0.9W/cm(2) and 1.0W/cm(2) in the presence of CCAM was greater compared to non-targeted albumin microbubbles (p < 0.05). On the other hand, selective cell killing was not observed in human myelomonocytic lymphoma cell line (U937) that had no affinity to cetuximab...
August 14, 2017: Journal of Drug Targeting
https://www.readbyqxmd.com/read/28795419/simultaneous-mr-thermometry-and-acoustic-radiation-force-imaging-using-interleaved-acquisition
#3
Joshua T de Bever, Henrik Odéen, Lorne W Hofstetter, Dennis L Parker
PURPOSE: A novel and practical method for simultaneously performing MR acoustic radiation force imaging (ARFI) and proton resonance frequency (PRF)-shift thermometry has been developed and tested. This could be an important tool for evaluating the success of MR-guided focused ultrasound procedures for which MR-thermometry measures temperature and thermal dose and MR-ARFI detects changes in tissue mechanical properties. METHODS: MR imaging was performed using a gradient recalled echo segmented echo-planar imaging pulse sequence with bipolar motion encoding gradients (MEG)...
August 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28792891/feasibility-and-validation-of-4-d-pulse-wave-imaging-in-phantoms-and-in-vivo
#4
Iason Z Apostolakis, Pierre Nauleau, Clement Papadacci, Matthew D McGarry, Elisa E Konofagou
Pulse wave Imaging (PWI) is a noninvasive technique for tracking the propagation of the pulse wave along the arterial wall. 3-D ultrasound imaging would aid in objectively estimating the PulseWave Velocity (PWV) vector. This study aims to introduce a novel PWV estimation method along the propagation direction, validate it in phantoms and test its feasibility in vivo. A silicone vessel phantom consisting of a stiff and a soft segment along the longitudinal axis and and a silicone vessel with a plaque were constructed...
August 3, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28792890/ultrafast-ultrasound-imaging-using-combined-transmissions-with-cross-coherence-based-reconstruction
#5
Yang Zhang, Yuexin Guo, Wei-Ning Lee
Plane-wave-based ultrafast imaging has become the prevalent technique for non-conventional ultrasound imaging. The image quality, especially in terms of the suppression of artifacts, is generally compromised by reducing the number of transmissions for a higher frame rate. We hereby propose a new ultrafast imaging framework that reduces not only the side lobe artifacts but also the axial lobe artifacts using combined transmissions with a new coherence-based factor. The results from simulations, in vitro wire phantoms, the ex vivo porcine artery, and the in vivo porcine heart show that our proposed methodology greatly reduced the axial lobe artifact by 25 ± 5 dB compared with coherent plane-wave compounding (CPWC), which was considered as the ultrafast imaging standard, and suppressed side lobe artifacts by 15 ± 5 dB compared with CPWC and coherent spherical-wave compounding (CSWC)...
August 4, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28783919/training-in-endoscopy-endoscopic-ultrasound
#6
REVIEW
Chang Min Cho
Endoscopic ultrasound (EUS) has been recently established as an indispensable modality for the diagnosis and management of pancreatobiliary and gastrointestinal (GI) disorders. EUS proficiency requires both cognitive and technical abilities, including an understanding of the appropriate indications, the performance of appropriate evaluations before and after the procedure, and the management of procedure-related complications. An increasing demand for skills to handle a growing range of interventional EUS procedures and a continual shortage of EUS training programs are two major obstacles for EUS training...
July 2017: Clinical Endoscopy
https://www.readbyqxmd.com/read/28783627/post-hoc-analysis-of-passive-cavitation-imaging-for-classification-of-histotripsy-induced-liquefaction-in-vitro
#7
Kenneth B Bader, Kevin J Haworth, Adam D Maxwell, Christy K Holland
Histotripsy utilizes focused ultrasound to generate bubble clouds for transcutaneous tissue liquefaction. Image guidance of histotripsy pulses is required to provide spatially resolved monitoring of treatment progress. The aim of this study was to investigate the feasibility of plane wave B-mode and passive cavitation images to be used as binary classifiers of histotripsy-induced liquefaction. Prostate tissue phantoms were exposed to mechanically ablative histotripsy pulses over a range of pulse durations (5 - 20 μs) and peak negative pressures (12 - 23 MPa)...
August 2, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28782129/volumetric-mri-thermometry-using-a-three-dimensional-stack-of-stars-echo-planar-imaging-pulse-sequence
#8
Sumeeth V Jonathan, William A Grissom
PURPOSE: To measure temperature over a large brain volume with fine spatiotemporal resolution. METHODS: A three-dimensional stack-of-stars echo-planar imaging sequence combining echo-planar imaging and radial sampling with golden angle spacing was implemented at 3T for proton resonance frequency-shift temperature imaging. The sequence acquires a 188x188x43 image matrix with 1.5x1.5x2.75 mm(3) spatial resolution. Temperature maps were reconstructed using sensitivity encoding (SENSE) image reconstruction followed by the image domain hybrid method, and using the k-space hybrid method...
August 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28779957/toward-a-standardization-of-ultrasound-scanners-for-dynamic-contrast-enhanced-ultrasonography-methodology-and-phantoms
#9
Stéphanie Pitre-Champagnat, Bénédicte Coiffier, Laurène Jourdain, Baya Benatsou, Ingrid Leguerney, Nathalie Lassau
The standardization of ultrasound scanners for dynamic contrast-enhanced ultrasonography (DCE-US) is mandatory for evaluation of clinical multicenter studies. We propose a robust method using a phantom for measuring the variation of the harmonic signal intensity obtained from the area under the time-intensity curve versus various contrast-agent concentrations. The slope of this measured curve is the calibration parameter. We tested our method on two devices from the same manufacturer (AplioXV and Aplio500, Toshiba, Tokyo, Japan) using the same settings as defined for a French multicenter study...
August 2, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28763461/effect-of-ultrasound-frequency-on-the-nakagami-statistics-of-human-liver-tissues
#10
Po-Hsiang Tsui, Zhuhuang Zhou, Ying-Hsiu Lin, Chieh-Ming Hung, Shih-Jou Chung, Yung-Liang Wan
The analysis of the backscattered statistics using the Nakagami parameter is an emerging ultrasound technique for assessing hepatic steatosis and fibrosis. Previous studies indicated that the echo amplitude distribution of a normal liver follows the Rayleigh distribution (the Nakagami parameter m is close to 1). However, using different frequencies may change the backscattered statistics of normal livers. This study explored the frequency dependence of the backscattered statistics in human livers and then discussed the sources of ultrasound scattering in the liver...
2017: PloS One
https://www.readbyqxmd.com/read/28761393/a-combined-intravascular-mri-endoscope-and-intravascular-ultrasound-ivus-transducer-for-high-resolution-image-guided-ablation
#11
Xiaoyang Liu, Nicholas Ellens, Emery Williams, Everette Clif Burdette, Parag Karmarkar, Paul Bottomley
An intravascular MRI (IMRI) loopless antenna is combined for the first time with an intravascular water-cooled ultrasound ablation transducer as a possible tool for providing high-resolution MRI-guided ablations of pathological tissue via intravascular access. High resolution anatomical MRI, and real-time MRI thermometry were used to monitor ablation delivery in phantoms and tissue specimens. Results show that IMRI can guide IVUS-mediated directional ablation with minimal image artifacts. This permits the monitoring of thermal dose and therapy titration while minimizing potential thermal damage to the vessel wall...
April 2017: Proceedings of the International Society for Magnetic Resonance in Medicine ... Scientific Meeting and Exhibition
https://www.readbyqxmd.com/read/28760576/performances-and-limitations-of-several-ultrasound-based-elastography-techniques-a-phantom-study
#12
Stéphanie Franchi-Abella, Caroline Elie, Jean-Michel Correas
The objective of this study is to assess strain and shear wave (SW) elastography performance in terms of accuracy by performing in vitro measurements on a calibrated elastography phantom. Acquisitions were done on a phantom containing 4 inclusions (12-74 kPa) embedded in a homogeneous background material (30 kPa). We performed qualitative assessment on elastograms, semiquantitative assessment with strain or elasticity ratios between each inclusion and the background and quantitative evaluation with SW acquisitions...
July 28, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28750944/vector-and-doppler-ultrasound-velocities-evaluated-in-a-flow-phantom-and-the-femoropopliteal-vein
#13
Thor Bechsgaard, Kristoffer Lindskov Hansen, Andreas Hjelm Brandt, Simon Holbek, Julie Lyng Forman, Charlotte Strandberg, Lars Lönn, Niels Bækgaard, Jørgen Arendt Jensen, Michael Bachmann Nielsen
Ultrasound is used for evaluating the veins of the lower extremities. Operator and angle dependency limit spectral Doppler ultrasound (SDUS). The aim of the study was to compare peak velocity measurements in a flow phantom and the femoropopliteal vein of 20 volunteers with the angle-independent vector velocity technique vector flow imaging (VFI) and SDUS. In the flow phantom, VFI underestimated velocity (p = 0.01), with a lower accuracy of 5.5% (p = 0.01) and with no difference in precision, that is, error factor, compared with SDUS (VFI: 1...
July 24, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28749348/fast-simulation-of-dynamic-ultrasound-images-using-the-gpu
#14
Sigurd Storve, Hans Torp
Simulated ultrasound data is a valuable tool for development and validation of quantitative image analysis methods in echocardiography. Unfortunately, simulation time can become prohibitive for phantoms consisting of a large number of point-scatterers. The COLE algorithm by Gao et al. is a fast convolution-based simulator that trades simulation accuracy for improved speed. We present highly efficient parallelized CPU- and GPU-implementations of the COLE algorithm with an emphasis on dynamic simulations involving moving pointscatterers...
July 25, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28749342/broadband-vibration-detection-in-tissue-phantoms-using-a-fiber-fabry-perot-cavity
#15
Jack Barnes, Sijia Li, Apoorv Goyal, Purang Abolmaesumi, Parvin Mousavi, Hans-Peter Loock
A fiber optic vibration sensor is developed and characterized with an ultra-wide dynamic sensing range, from less than 1 Hz to clinical ultrasound frequencies near 6 MHz. The vibration sensor consists of a matched pair of fiber Bragg gratings coupled to a custom-built signal processing circuit. The wavelength of a laser diode is locked to one of the many cavity resonances using the Pound-Drever-Hall scheme. A calibrated piezoelectric vibration element was used to characterize the sensor's strain, temperature, and noise responses...
July 24, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28744328/ultrasonographic-imaging-and-anti-inflammatory-therapy-of-muscle-and-tendon-injuries-using-polymer-nanoparticles
#16
Gi-Wook Kim, Changsun Kang, Young-Bin Oh, Myoung-Hwan Ko, Jeong-Hwan Seo, Dongwon Lee
Ultrasonography is a reliable diagnostic modality for muscle and tendon injuries, but it has been challenging to find right diagnosis of minor musculoskeletal injuries by conventional ultrasonographic imaging. A large amount of hydrogen peroxide (H2O2) are known to be generated during tissue damages such as mechanical injury and therefore H2O2 holds great potential as a diagnostic and therapeutic marker for mechanical injuries in the musculoskeletal system. We previously developed poly(vanillyl alcohol-co-oxalate) (PVAX), which rapidly scavenges H2O2 and exerts antioxidant and anti-inflammatory activity in H2O2-associated diseases...
2017: Theranostics
https://www.readbyqxmd.com/read/28742032/architecture-of-an-ultrasound-system-for-continuous-real-time-high-frame-rate-imaging
#17
Enrico Boni, Luca Bassi, Alessandro Dallai, Valentino Meacci, Alessandro Ramalli, Monica Scaringella, Francesco Guidi, Stefano Ricci, Piero Tortoli
High frame rate (HFR) imaging methods based on the transmission of defocused or plane waves rather than focused beams are increasingly popular. However, the production of HFR images poses severe requirements both in the transmission and the reception sections of ultrasound scanners. In particular, major technical difficulties arise if the images must be continuously produced in real-time, i.e. without any acquisition interruption nor loss of data. This paper presents the implementation of the real-time HFR compounded imaging application in the ULA-OP 256 research platform...
July 20, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28741596/the-response-of-mri-contrast-parameters-in-in-vitro-tissues-and-tissue-mimicking-phantoms-to-fractionation-by-histotripsy
#18
Steven P Allen, Eli Vlaisavljevich, Jiaqi Shi, Luis Hernandez-Garcia, Charles A Cain, Zhen Xu, Timothy L Hall
Histotripsy is a non-invasive, focused ultrasound lesioning technique that can ablate precise volumes of soft tissue using a novel mechanical fractionation mechanism. Previous research suggests that magnetic resonance imaging (MRI) may be a sensitive image-based feedback mechanism for histotripsy. However, there are insufficient data to form some unified understanding of the response of the MR contrast mechanisms in tissues to histotripsy. In this paper, we investigate the response of the MR contrast parameters R1, R2, and the apparent diffusion coefficient (ADC) to various treatment levels of histotripsy in in vitro porcine liver, kidney, muscle, and blood clot as well in formulations of bovine red blood cells suspended in agar gel...
August 18, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28739379/ultrasound-induced-bubble-clusters-in-tissue-mimicking-agar%C3%A2-phantoms
#19
Pooya Movahed, Wayne Kreider, Adam D Maxwell, Barbrina Dunmire, Jonathan B Freund
Therapeutic ultrasound can drive bubble activity that damages soft tissues. To study the potential mechanisms of such injury, transparent agar tissue-mimicking phantoms were subjected to multiple pressure wave bursts of the kind being considered specifically for burst wave lithotripsy. A high-speed camera recorded bubble activity during each pulse. Various agar concentrations were used to alter the phantom's mechanical properties, especially its stiffness, which was varied by a factor of 3.5. However, the maximum observed bubble radius was insensitive to stiffness...
October 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28736982/understanding-the-influence-of-flow-velocity-wall-motion-filter-pulse-repetition-frequency-and-aliasing-on-power-doppler-image-quantification
#20
Maricy R Martins, Wellington P Martins, Carlos A M Soares, Andre H Miyague, Marek J Kudla, Theo Z Pavan
OBJECTIVES: Although power Doppler imaging has been used to quantify tissue and organ vascularity, many studies showed that limitations in defining adequate ultrasound machine settings and attenuation make such measurements complex to be achieved. However, most of these studies were conducted by using the output of proprietary software, such as Virtual Organ computer-aided analysis (GE Healthcare, Kretz, Zipf, Austria); therefore, many conclusions may not be generalizable because of unknown settings and parameters used by the software...
July 24, 2017: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
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