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Ultrasound phantom AND cryogel

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https://www.readbyqxmd.com/read/28728780/detecting-regional-stiffness-changes-in-aortic-aneurysmal-geometries-using-pressure-normalized-strain
#1
Doran S Mix, Ling Yang, Camille C Johnson, Nathan Couper, Ben Zarras, Isaac Arabadjis, Lauren E Trakimas, Michael C Stoner, Steven W Day, Michael S Richards
Transabdominal ultrasound elasticity imaging could improve the assessment of rupture risk for abdominal aortic aneurysms by providing information on the mechanical properties and stress or strain states of vessel walls. We implemented a non-rigid image registration method to visualize the pressure-normalized strain within vascular tissues and adapted it to measure total strain over an entire cardiac cycle. We validated the algorithm's performance with both simulated ultrasound images with known principal strains and anatomically accurate heterogeneous polyvinyl alcohol cryogel vessel phantoms...
October 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28331886/effects-of-line-fiducial-parameters-and-beamforming-on-ultrasound-calibration
#2
Golafsoun Ameri, John S H Baxter, A Jonathan McLeod, Terry M Peters, Elvis C S Chen
Ultrasound (US)-guided interventions are often enhanced via integration with an augmented reality environment, a necessary component of which is US calibration. Calibration requires the segmentation of fiducials, i.e., a phantom, in US images. Fiducial localization error (FLE) can decrease US calibration accuracy, which fundamentally affects the total accuracy of the interventional guidance system. Here, we investigate the effects of US image reconstruction techniques as well as phantom material and geometry on US calibration...
January 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28114013/wall-less-flow-phantoms-with-tortuous-vascular-geometries-design-principles-and-a-patient-specific-model-fabrication-example
#3
Chung Kit Ho, Adrian J Y Chee, Billy Y S Yiu, Anderson C O Tsang, Kwok Wing Chow, Alfred C H Yu
Flow phantoms with anatomically realistic geometry and high acoustic compatibility are valuable investigative tools in vascular ultrasound studies. Here, we present a new framework to fabricate ultrasound-compatible flow phantoms to replicate human vasculature that is tortuous, non-planar and branching in nature. This framework is based upon the integration of rapid prototyping and investment casting principles. A pedagogical walkthrough of our engineering protocol is presented in this paper using a patient-specific cerebral aneurysm model as an exemplar demonstration...
December 6, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27959808/wall-less-flow-phantoms-with-tortuous-vascular-geometries-design-principles-and-a-patient-specific-model-fabrication-example
#4
Chung Kit Ho, Adrian J Y Chee, Billy Y S Yiu, Anderson C O Tsang, Kwok Wing Chow, Alfred C H Yu
Flow phantoms with anatomically realistic geometry and high acoustic compatibility are valuable investigative tools in vascular ultrasound studies. Here, we present a new framework to fabricate ultrasound-compatible flow phantoms to replicate human vasculature that is tortuous, nonplanar, and branching in nature. This framework is based upon the integration of rapid prototyping and investment casting principles. A pedagogical walkthrough of our engineering protocol is presented in this paper using a patient-specific cerebral aneurysm model as an exemplar demonstration...
January 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/26952900/contactless-remote-induction-of-shear-waves-in-soft-tissues-using-a-transcranial-magnetic-stimulation-device
#5
Pol Grasland-Mongrain, Erika Miller-Jolicoeur, An Tang, Stefan Catheline, Guy Cloutier
This study presents the first observation of shear waves induced remotely within soft tissues. It was performed through the combination of a transcranial magnetic stimulation device and a permanent magnet. A physical model based on Maxwell and Navier equations was developed. Experiments were performed on a cryogel phantom and a chicken breast sample. Using an ultrafast ultrasound scanner, shear waves of respective amplitudes of 5 and 0.5 μm were observed. Experimental and numerical results were in good agreement...
March 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/26773791/high-frame-rate-and-high-line-density-ultrasound-imaging-for-local-pulse-wave-velocity-estimation-using-motion-matching-a-feasibility-study-on-vessel-phantoms
#6
Fubing Li, Qiong He, Chengwu Huang, Ke Liu, Jinhua Shao, Jianwen Luo
Pulse wave imaging (PWI) is an ultrasound-based method to visualize the propagation of pulse wave and to quantitatively estimate regional pulse wave velocity (PWV) of the arteries within the imaging field of view (FOV). To guarantee the reliability of PWV measurement, high frame rate imaging is required, which can be achieved by reducing the line density of ultrasound imaging or transmitting plane wave at the expense of spatial resolution and/or signal-to-noise ratio (SNR). In this study, a composite, full-view imaging method using motion matching was proposed with both high temporal and spatial resolution...
April 2016: Ultrasonics
https://www.readbyqxmd.com/read/26736851/a-wall-less-poly-vinyl-alcohol-cryogel-flow-phantom-with-accurate-scattering-properties-for-transcranial-doppler-ultrasound-propagation-channels-analysis
#7
Alexander J Weir, Robin Sayer, Cheng-Xiang Wang, Stuart Parks
Medical phantoms are frequently required to verify image and signal processing systems, and are often used to support algorithm development for a wide range of imaging and blood flow assessments. A phantom with accurate scattering properties is a crucial requirement when assessing the effects of multi-path propagation channels during the development of complex signal processing techniques for Transcranial Doppler (TCD) ultrasound. The simulation of physiological blood flow in a phantom with tissue and blood equivalence can be achieved using a variety of techniques...
August 2015: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/24495438/endovascular-shear-strain-elastography-for-the-detection-and-characterization-of-the-severity-of-atherosclerotic-plaques-in-vitro-validation-and-in-vivo-evaluation
#8
Younes Majdouline, Jacques Ohayon, Zahra Keshavarz-Motamed, Marie-Hélène Roy Cardinal, Damien Garcia, Louise Allard, Sophie Lerouge, Frédéric Arsenault, Gilles Soulez, Guy Cloutier
This work explores the potential of shear strain elastograms to identify vulnerable atherosclerotic plaques. The Lagrangian speckle model estimator (LSME) elasticity imaging method was further developed to estimate shear strain elasticity (SSE). Three polyvinyl alcohol cryogel vessel phantoms were imaged with an intravascular ultrasound (IVUS) scanner. The estimated SSE maps were validated against finite-element results. Atherosclerosis was induced in carotid arteries of eight Sinclair mini-pigs using a combination of surgical techniques, diabetes and a high-fat diet...
May 2014: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/23366603/a-biventricular-multimodal-mri-ultrasound-cardiac-phantom
#9
Vahid Tavakoli, M J Negahdar, Michael Kendrick, Motaz Alshaher, Marcus Stoddard, Amir A Amini
A cardiac phantom can be of crucial importance in the development and validation of ultrasound and cardiac magnetic resonance (MR) imaging and image analysis methods. A biventricular multimodal cardiac phantom has been manufactured in-house that can simulate normal and pathologic hearts with different degrees of infarction. The two-chamber structure can simulate the asymmetric left ventricular motion. Poly Vinyl Alcohol (PVA) is utilized as the basic material since it can simulate the shape, elasticity, and MR and ultrasound properties of the heart...
2012: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/22643042/the-effects-of-fatty-deposits-on-the-accuracy-of-the-fibroscan%C3%A2-%C3%A2-liver-transient-elastography-ultrasound-system
#10
S Cournane, J E Browne, A J Fagan
A new generation of ultrasound transient elastography (TE) systems have emerged which exploit the well-known correlation between the liver's pathological and mechanical properties through measurements of the Young's elastic modulus; however, little work has been carried out to examine the effect that fatty deposits may have on the TE measurement accuracy. An investigation was carried out on the effects on the measurement accuracy of a TE ultrasound system, the Fibroscan®, caused by overlaying fat layers of varying thickness on healthy liver-mimicking phantoms, simulating in vivo conditions for obese patients...
June 21, 2012: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/22447435/validation-of-a-hybrid-doppler-ultrasound-vessel-based-registration-algorithm-for-neurosurgery
#11
Sean Jy-Shyang Chen, Ingerid Reinertsen, Pierrick Coupé, Charles X B Yan, Laurence Mercier, D Rolando Del Maestro, D Louis Collins
PURPOSE: We describe and validate a novel hybrid nonlinear vessel registration algorithm for intra-operative updating of preoperative magnetic resonance (MR) images using Doppler ultrasound (US) images acquired on the dura for the correction of brain-shift and registration inaccuracies. We also introduce an US vessel appearance simulator that generates vessel images similar in appearance to that acquired with US from MR angiography data. METHODS: Our registration uses the minimum amount of preprocessing to extract vessels from the raw volumetric images...
September 2012: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/22225325/an-anthropomorphic-polyvinyl-alcohol-brain-phantom-based-on-colin27-for-use-in-multimodal-imaging
#12
Sean Jy-Shyang Chen, Pierre Hellier, Maud Marchal, Jean-Yves Gauvrit, Romain Carpentier, Xavier Morandi, D Louis Collins
PURPOSE: In this paper, the method for the creation of an anatomically and mechanically realistic brain phantom from polyvinyl alcohol cryogel (PVA-C) is proposed for validation of image processing methods such as segmentation, reconstruction, registration, and denoising. PVA-C is material widely used in medical imaging phantoms because of its mechanical similarities to soft tissues. METHODS: The phantom was cast in a mold designed using the left hemisphere of the Colin27 brain dataset [C...
January 2012: Medical Physics
https://www.readbyqxmd.com/read/20879303/an-anthropomorphic-polyvinyl-alcohol-triple-modality-brain-phantom-based-on-colin27
#13
Sean Jy-Shyang Chen, Pierre Hellier, Jean-Yves Gauvrit, Maud Marchal, Xavier Morandi, D Louis Collins
We propose a method for the creation of an anatomically and mechanically realistic brain phantom from polyvinyl alcohol cryogel (PVA-C) for validation of image processing methods for segmentation, reconstruction, registration, and denoising. PVA-C is material widely used in medical imaging phantoms for its mechanical similarities to soft tissues. The phantom was cast in a mold designed using the left hemiphere of the Colin27 brain dataset and contains deep sulci, a complete insular region, and an anatomically accurate left ventricle...
2010: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/20858913/assessment-of-the-accuracy-of-an-ultrasound-elastography-liver-scanning-system-using-a-pva-cryogel-phantom-with-optimal-acoustic-and-mechanical-properties
#14
S Cournane, L Cannon, J E Browne, A J Fagan
The accuracy of a transient elastography liver-scanning ultrasound system was assessed using a novel application of PVA-cryogel as a tissue-mimicking material with acoustic and shear elasticity properties optimized to best represent those of liver tissue. Although the liver-scanning system has been shown to offer a safer alternative for diagnosing liver cirrhosis through stiffness measurement, as compared to the liver needle biopsy exam, the scanner's accuracy has not been fully established. Young's elastic modulus values of 5-6 wt% PVA-cryogel phantoms, also containing glycerol and 0...
October 7, 2010: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/20826899/on-the-potential-of-a-new-ivus-elasticity-modulus-imaging-approach-for-detecting-vulnerable-atherosclerotic-coronary-plaques-in-vitro-vessel-phantom-study
#15
Simon Le Floc'h, Guy Cloutier, Gérard Finet, Philippe Tracqui, Roderic I Pettigrew, Jacques Ohayon
Peak cap stress amplitude is recognized as a good indicator of vulnerable plaque (VP) rupture. However, such stress evaluation strongly relies on a precise, but still lacking, knowledge of the mechanical properties exhibited by the plaque components. As a first response to this limitation, our group recently developed, in a previous theoretical study, an original approach, called iMOD (imaging modulography), which reconstructs elasticity maps (or modulograms) of atheroma plaques from the estimation of strain fields...
October 7, 2010: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/20643765/ability-of-ultrasound-imaging-to-detect-erosions-in-a-bone-phantom-model
#16
Juhani M Koski, Eeva Alasaarela, Irma Soini, Kari Kemppainen, Ullamari Hakulinen, Jari O Heikkinen, Mikko S Laasanen, Simo Saarakkala
OBJECTIVES: The authors examined the validity, interobserver reliability and interscanner variation in detecting bone erosions with ultrasonography using a custom-made phantom. METHODS: 21 bovine bones were used. Artificial erosions were made into 15 bones and six bones were left as controls. In the processed bones the numbers of erosions, their depths and widths varied between 1-7, 1-4 and 1.5-5 mm, respectively. Each bone was coated with polyvinyl alcohol cryogel to mimic overlying soft tissue and to hide the erosions...
September 2010: Annals of the Rheumatic Diseases
https://www.readbyqxmd.com/read/20483680/model-fitting-using-ransac-for-surgical-tool-localization-in-3-d-ultrasound-images
#17
Marián Uhercík, Jan Kybic, Hervé Liebgott, Christian Cachard
Ultrasound guidance is used for many surgical interventions such as biopsy and electrode insertion. We present a method to localize a thin surgical tool such as a biopsy needle or a microelectrode in a 3-D ultrasound image. The proposed method starts with thresholding and model fitting using random sample consensus for robust localization of the axis. Subsequent local optimization refines its position. Two different tool image models are presented: one is simple and fast and the second uses learned a priori information about the tool's voxel intensities and the background...
August 2010: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/20459201/deformable-mock-stenotic-artery-with-a-lipid-pool
#18
V Pazos, R Mongrain, J C Tardif
The comparison, evaluation, and optimization of new techniques, models, or algorithms often require the use of realistic deformable test phantoms. The purpose of this paper is to present a multilayer deformable test specimen mimicking an atherosclerotic coronary artery, suitable for mechanical testing and intravascular imaging. Mock arteries were constructed in three phases using two molds: building a first layer of polyvinyl alcohol (PVA) cryogel, adding a lipid pool and building a second layer of PVA cryogel...
March 2010: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/20201771/robotic-brachytherapy-of-the-prostate
#19
REVIEW
Kyle J Wilson
Recent applications of robotics in the field of prostate brachytherapy are seeding the future and could potentially lead to a fully automated prostate brachytherapy surgery. Currently, a typical prostate brachytherapy surgery involves the implantation of upwards of 100 radioactive I-125 seeds by a surgeon. This review supplies background information on prostate biology, brachytherapy of the prostate, robotic brachytherapy, and transrectal ultrasound. Subsequently, it examines the physics involved in ultrasound, radiation from an I-125 source, dosimetry, and robotics...
2009: Critical Reviews in Biomedical Engineering
https://www.readbyqxmd.com/read/19292007/investigation-of-pva-cryogel-young-s-modulus-stability-with-time-controlled-by-a-simple-reliable-technique
#20
François Duboeuf, Adrian Basarab, Hervé Liebgott, Elisabeth Brusseau, Philippe Delachartre, Didier Vray
We describe a quasistatic method for mechanical characterization of tissue-mimicking material used in elastography. We demonstrate that it is possible to assess the elasticity modulus with a reasonable reproducibility using simple and easy tools and methods. Possessing a simple relevant technique with evaluated relative error to assess Young's modulus of these phantoms could deeply improve the quality of the research in the field of elastography. The method was tested and validated with four samples of polyvinyl alcohol (PVA) cryogel with different elasticity values corresponding to those of stiffer soft biological tissues...
February 2009: Medical Physics
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