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https://www.readbyqxmd.com/read/28231487/detecting-changes-in-ultrasound-backscattered-statistics-by-using-nakagami-parameters-comparisons-of-moment-based-and-maximum-likelihood-estimators
#1
Jen-Jen Lin, Jung-Yu Cheng, Li-Fei Huang, Ying-Hsiu Lin, Yung-Liang Wan, Po-Hsiang Tsui
The Nakagami distribution is an approximation useful to the statistics of ultrasound backscattered signals for tissue characterization. Various estimators may affect the Nakagami parameter in the detection of changes in backscattered statistics. In particular, the moment-based estimator (MBE) and maximum likelihood estimator (MLE) are two primary methods used to estimate the Nakagami parameters of ultrasound signals. This study explored the effects of the MBE and different MLE approximations on Nakagami parameter estimations...
February 9, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28231337/4d-dose-simulation-in-volumetric-arc-therapy-accuracy-and-affecting-parameters
#2
Thilo Sothmann, Tobias Gauer, René Werner
Radiotherapy of lung and liver lesions has changed from normofractioned 3D-CRT to stereotactic treatment in a single or few fractions, often employing volumetric arc therapy (VMAT)-based techniques. Potential unintended interference of respiratory target motion and dynamically changing beam parameters during VMAT dose delivery motivates establishing 4D quality assurance (4D QA) procedures to assess appropriateness of generated VMAT treatment plans when taking into account patient-specific motion characteristics...
2017: PloS One
https://www.readbyqxmd.com/read/28228823/recognising-small-image-quality-differences-for-ultrasound-probes-and-the-potential-of-misdiagnosis-due-to-undetected-side-lobes
#3
Georg Doblhoff, Jaroslav Satrapa, Philip Coulthard
BACKGROUND: Ultrasonic imaging is an integral and routine procedure in many medical applications. An increased awareness of the need for quality assurance in this field has led to numerous tests being proposed. Due to the complexity of the problem, the tests directly measuring the important parameters of resolution and contrast of low-echoic structures are not unified, often more qualitative than quantitative, and are performed at large periodic intervals. Uniform sensitivity of an array transducer is a necessary but insufficient requirement for imaging quality of an ultrasound probe...
February 2017: Ultrasound: Journal of the British Medical Ultrasound Society
https://www.readbyqxmd.com/read/28228820/temperature-elevation-measured-in-a-tissue-mimicking-phantom-for-transvaginal-ultrasound-at-clinical-settings
#4
Piero Miloro, Eleanor Martin, Adam Shaw
INTRODUCTION: This paper reports the results of an audit to assess the possible thermal hazard associated with the clinical use of ultrasound scanners in UK Hospitals for transvaginal ultrasound imaging. METHODS: An anatomically relevant phantom composed of a block of agar-based tissue mimicking material with embedded thermal sensors was developed. Seventeen hospitals around the UK were visited and a total of 64 configurations were tested. A representative typical scanning protocol was adopted, which primarily used B-mode with 30 s periods of colour-flow and pulsed Doppler modes for both gynaecology and obstetrics pre-sets...
February 2017: Ultrasound: Journal of the British Medical Ultrasound Society
https://www.readbyqxmd.com/read/28227991/mr-conditional-safety-assessment-of-implanted-medical-devices-advantages-of-computational-human-phantoms
#5
James E Brown, Rui Qiang, Paul J Stadnik, Larry J Stotts, Jeffrey A Von Arx, James E Brown, Rui Qiang, Paul J Stadnik, Larry J Stotts, Jeffrey A Von Arx, Rui Qiang, Paul J Stadnik, Larry J Stotts, Jeffrey A Von Arx, James E Brown
Until recently, patients with active implantable medical devices (AIMDs) have been contraindicated for magnetic resonance imaging (MRI). Current efforts to demonstrate safety of these devices separate the interaction of the device and MRI into several hazards. For several of these hazards, computational human phantoms (CHPs) are used to provide conservative conditions for a risk-based analysis. This use of CHPs for the identification of conservative conditions provides a substantial benefit to the assessment of MR conditional safety over experimental techniques, as the evaluation of millions of test cases is possible in simulation, but impractical (due to economic constraints) and, in some cases, unethical for an experimental effort...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227990/using-computational-phantoms-to-improve-delivery-of-tumor-treating-fields-ttfields-to-patients
#6
Ze'ev Bomzon, Hadas Sara Hershkovich, Noa Urman, Aafia Chaudhry, Dario Garcia-Carracedo, Anders R Korshoej, Uri Weinberg, Cornelia Wenger, Pedro Miranda, Yoram Wasserman, Eilon D Kirson, Yoram, Ze'ev Bomzon, Hadas Sara Hershkovich, Noa Urman, Aafia Chaudhry, Dario Garcia-Carracedo, Anders R Korshoej, Uri Weinberg, Cornelia Wenger, Pedro Miranda, Yoram Wasserman, Eilon D Kirson, Yoram, Uri Weinberg, Cornelia Wenger, Noa Urman, Hadas Sara Hershkovich, Yoram Wasserman, Anders R Korshoej, Eilon D Kirson, Dario Garcia-Carracedo, Pedro Miranda, Aafia Chaudhry, Zeev Bomzon, Yoram
This paper reviews the state-of-the-art in simulation-based studies of Tumor Treating Fields (TTFields) and highlights major aspects of TTFields in which simulation-based studies could affect clinical outcomes. A major challenge is how to simulate multiple scenarios rapidly for TTFields delivery. Overcoming this challenge will enable a better understanding of how TTFields distribution is correlated with disease progression, leading to better transducer array designs and field optimization procedures, ultimately improving patient outcomes...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227984/preliminary-study-on-the-automated-skull-fracture-detection-in-ct-images-using-black-hat-transform
#7
Ayumi Yamada, Atsushi Teramoto, Tomoko Otsuka, Kohei Kudo, Hirofumi Anno, Hiroshi Fujita, Ayumi Yamada, Atsushi Teramoto, Tomoko Otsuka, Kohei Kudo, Hirofumi Anno, Hiroshi Fujita, Tomoko Otsuka, Hiroshi Fujita, Ayumi Yamada, Kohei Kudo, Hirofumi Anno, Atsushi Teramoto
Linear skull fracture, following head trauma, may reach major blood vessels, such as the middle meningeal artery or sinus venosus, and may cause epidural hematoma. However, hematoma is likely to be missed in the initial interpretation because it spreads only gradually. In addition, the fracture lines that run along the scan slice plane are often missed during initial interpretation. In this study, we develop a novel method for automated detection of the linear skull fracture using head computed tomography (CT) images and conduct a basic evaluation using digital phantom and head phantom that enclose genuine human bones...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227941/a-three-element-1-h-31-p-dual-tuned-array-for-magnetic-resonance-spectroscopy-at-4-7-t
#8
Matthew D Wilcox, Romina Del Bosque, Kurt Parizek, Jeremy Sia, Edwin D Eigenbrodt, Mary P McDougall, Matthew D Wilcox, Romina Del Bosque, Kurt Parizek, Jeremy Sia, Edwin D Eigenbrodt, Mary P McDougall, Jeremy Sia, Romina Del Bosque, Kurt Parizek, Mary P McDougall, Matthew D Wilcox, Edwin D Eigenbrodt
This work describes the construction and testing of a three-element, double-tuned receive array and transmit coils for (31)P-(1)H spectroscopy and imaging. The receive coils were geometrically-decoupled, single-loop surface coils and the transmit coils were concentric saddle coils. The coils were used to examine a physiologically-modeled CNC-milled phantom. The receive coil array was able to improve SNR while also providing gross localization of the (1)H and (31)P signals.
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227938/integrated-rf-shim-coil-allowing-two-degrees-of-freedom-shim-current
#9
Jiazheng Zhou, Ying-Hua Chu, Yi-Cheng Hsu, Pu-Yeh Wu, Jason P Stockmann, Fa-Hsuan Lin, Jiazheng Zhou, Ying-Hua Chu, Yi-Cheng Hsu, Pu-Yeh Wu, Jason P Stockmann, Fa-Hsuan Lin, Pu-Yeh Wu, Jason P Stockmann, Fa-Hsuan Lin, Jiazheng Zhou, Ying-Hua Chu, Yi-Cheng Hsu
High-quality magnetic resonance imaging and spectroscopic measurements require a highly homogeneous magnetic field. Different from global shimming, localized off-resonance can be corrected by using multi-coil shimming. Previously, integrated RF and shimming coils have been used to implement multi-coil shimming. Such coils share the same conductor for RF signal reception and shim field generation. Here we propose a new design of the integrated RF-shim coil at 3-tesla, where two independent shim current paths are allowed in each coil...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227937/effects-of-tuning-conditions-on-near-field-of-mri-transmit-birdcage-coil-at-64-mhz
#10
Mikhail Kozlov, Elena Lucano, Leonardo M Angelone, Mikhail Kozlov, Elena Lucano, Leonardo M Angelone, Elena Lucano, Leonardo M Angelone, Mikhail Kozlov
This study investigates how the tuning conditions of a 64 MHz / 1.5 T radio frequency (RF) birdcage coil modeled with an RF circuit and 3D electromagnetic co-simulation affect the electric and magnetic near-field distribution. Four models were implemented with different tuning conditions and difference between numerical results and measurements was evaluated. The results show that the simulated near-field depends significantly on coil tuning conditions, especially in volumes close to the ASTM phantom walls...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227882/development-and-application-of-human-breast-phantoms-in-microwave-diagnostic-and-therapeutic-technologies
#11
Luz Maria Neira, R Owen Mays, Susan C Hagness, Luz Maria Neira, R Owen Mays, Susan C Hagness, Luz Maria Neira, Susan C Hagness, R Owen Mays
We highlight recent progress in the development of high-fidelity numerical and physical breast phantoms. These phantoms mimic the anatomical structure and physical properties that are relevant to accurately portraying microwave interactions with the human breast. The phantoms are currently being used in numerous laboratory studies of microwave diagnostic and therapeutic technologies for a variety of potential clinical applications in breast health and disease management.
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227857/light-source-depth-estimation-in-porcine-skin-using-spatially-resolved-diffuse-imaging
#12
Kieran A Brennan, Bryan P Ruddy, Poul M F Nielsen, Andrew J Taberner, Kieran A Brennan, Bryan P Ruddy, Poul M F Nielsen, Andrew J Taberner, Bryan P Ruddy, Andrew J Taberner, Poul M F Nielsen, Kieran A Brennan
We present an inexpensive imaging system for measuring the diffuse surface radiance profile produced by a light source within a turbid medium. The diffusion model of light propagation in multiple scattering media is used to estimate the optical properties of a sample and subsequently approximate the depth of an optical source. The system is shown to accurately estimate the relative changes in source depth in a homogeneous phantom. The absolute depth estimate may be improved with a better estimate of the optical parameters...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227855/simultaneous-reconstruction-and-segmentation-with-the-mumford-shah-functional-for-electron-tomography
#13
Li Shen, Eric Todd Quinto, Shiqiang Wang, Ming Jiang, Li Shen, Eric Todd Quinto, Shiqiang Wang, Ming Jiang, Ming Jiang, Eric Todd Quinto, Shiqiang Wang, Li Shen
Electron micrography (EM) is an important method for determining the three-dimensional (3D) structure of macromolecular complexes and biological specimens. But there are several limitations such as poor signal-to-noise, limitation on range of tilt angles and sub-region subject to electron exposure, unintentional movements of the specimen, with EM systems that make the reconstruction procedure a severely ill-posed problem. A different choice of reconstruction method may lead to different results and create different additional artifacts in reconstructed images...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227765/distribution-aware-estimation-of-the-minimum-achievable-uncertainty-in-diffusion-tensor-imaging-dti
#14
Andrea Duggento, Marco Giannelli, Carlo Tessa, Simona Lanzafame, Maria Guerrisi, Nicola Toschi, Andrea Duggento, Marco Giannelli, Carlo Tessa, Simona Lanzafame, Maria Guerrisi, Nicola Toschi, Nicola Toschi, Maria Guerrisi, Marco Giannelli, Carlo Tessa, Simona Lanzafame, Andrea Duggento
Diffusion tensor imaging (DTI) provides exquisite sensitivity to structural and microstructural characteristics of brain tissue, and is routinely employed in advanced neuroimaging applications. DTI is commonly performed using intrinsically noisy echo-planar imaging techniques and poses high demands both on scanner performance and on in-scanner subject time, which in turn is directly related to the number of diffusion-weighting direction one requires. While DTI-derived indices such as fractional anisotropy (FA), diffusion tensor trace and anisotropy mode have proven extremely useful in characterizing disease-related aberrations, their estimation is commonly performed using fitting routines that do not properly take into account MRI noise distribution...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227744/classification-of-non-weight-bearing-lower-limb-movements-towards-a-potential-treatment-for-phantom-limb-pain-based-on-myoelectric-pattern-recognition
#15
Eva Lendaro, Max Ortiz-Catalan, Eva Lendaro, Max Ortiz-Catalan, Max Ortiz-Catalan, Eva Lendaro
Research in myoelectric pattern recognition (MPR) for the prediction of motor volition has primarily focused on the upper limbs. Recent studies in the lower limbs have mainly concentrated on prosthetic control, while MPR for lower limb rehabilitation purposes has received little attention. In this work we investigated the viability of a MPR system for the prediction of four degrees of freedom controlled in a near natural or physiologically appropriate fashion. We explored three different electrode configurations for acquiring electromyographic (EMG) signals: two targeted (bipolar and monopolar) and one untargeted (electrodes equally spaced axially)...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227683/artsens-%C3%A2-mobile-a-portable-image-free-platform-for-automated-evaluation-of-vascular-stiffness
#16
Malay Ilesh Shah, Jayaraj Joseph, T Aryasree, Mohanasankar Sivaprakasam, Malay Ilesh Shah, Jayaraj Joseph, T Aryasree, Mohanasankar Sivaprakasam, T Aryasree, Mohanasankar Sivaprakasam, Jayaraj Joseph, Malay Ilesh Shah
Vascular stiffness is a key physiological marker significant in screening and early diagnosis of vascular disease. However, state of art techniques for vascular stiffness evaluation are not suited for field deployment. We present ARTSENS(®) Mobile, a portable, image-free ultrasound technology platform for automated evaluation of carotid artery stiffness, amenable for field deployment. The technology utilises a single element ultrasound transducer operated in pulse echo modality to investigate arterial wall dynamics, assisted by intelligent algorithms for wall identification and motion tracking to completely automate the measurement...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227662/towards-synergistic-control-of-hands-on-needle-insertion-with-automated-needle-steering-for-mri-guided-prostate-interventions
#17
Marek Wartenberg, Niravkumar Patel, Gang Li, Gregory S Fischer, Marek Wartenberg, Niravkumar Patel, Gang Li, Gregory S Fischer, Niravkumar Patel, Marek Wartenberg, Gregory S Fischer, Gang Li
A significant hurdle of accurate needle tip placement in percutaneous needle-based prostate interventions is unmodeled needle deflection and tissue deformation during insertion. This paper introduces a robotic platform for developing synergistic, cooperatively controlled needle insertion algorithms decoupled from closed-loop image-guided needle steering. Shared control of the surgical workspace through human-robot synergy creates a balance between the accuracy of robotic autonomy while still providing ultimate control of the procedure to the physician...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227660/robot-assisted-retinal-vein-cannulation-with-force-based-puncture-detection-micron-vs-the-steady-hand-eye-robot
#18
Berk Gonenc, Nhat Tran, Peter Gehlbach, Russell H Taylor, Iulian Iordachita, Berk Gonenc, Nhat Tran, Peter Gehlbach, Russell H Taylor, Iulian Iordachita, Nhat Tran, Russell H Taylor, Iulian Iordachita, Berk Gonenc, Peter Gehlbach
Retinal vein cannulation is a demanding procedure where therapeutic agents are injected into occluded retina veins. The feasibility of this treatment is limited due to challenges in identifying the moment of venous puncture, achieving cannulation and maintaining it throughout the drug delivery period. In this study, we integrate a force-sensing microneedle with two distinct robotic systems: the handheld micromanipulator Micron, and the cooperatively controlled Steady-Hand Eye Robot (SHER). The sensed tool-to-tissue interaction forces are used to detect venous puncture and extend the robots' standard control schemes with a new position holding mode (PHM) that assists the operator hold the needle position fixed and maintain cannulation for a longer time with less trauma on the vasculature...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227452/single-source-photoplethysmograph-transducer-for-local-pulse-wave-velocity-measurement
#19
P M Nabeel, Jayaraj Joseph, Vartika Awasthi, Mohanasankar Sivaprakasam, P M Nabeel, Jayaraj Joseph, Vartika Awasthi, Mohanasankar Sivaprakasam, P M Nabeel, Mohanasankar Sivaprakasam, Vartika Awasthi, Jayaraj Joseph
Cuffless evaluation of arterial blood pressure (BP) using pulse wave velocity (PWV) has received attraction over the years. Local PWV based techniques for cuffless BP measurement has more potential in accurate estimation of BP parameters. In this work, we present the design and experimental validation of a novel single-source Photoplethysmograph (PPG) transducer for arterial blood pulse detection and cycle-to-cycle local PWV measurement. The ability of the transducer to continuously measure local PWV was verified using arterial flow phantom as well as by conducting an in-vivo study on 17 volunteers...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227430/a-method-for-coronary-bifurcation-centerline-reconstruction-from-angiographic-images-based-on-focalization-optimization
#20
E Montin, S Migliori, C Chiastra, C Credi, R Fedele, C Aurigemma, M Levi, F Burzotta, F Migliavacca, L T Mainardi, E Montin, S Migliori, C Chiastra, C Credi, R Fedele, C Aurigemma, M Levi, F Burzotta, F Migliavacca, L T Mainardi, L T Mainardi, C Chiastra, E Montin, S Migliori, F Burzotta, C Credi, R Fedele, M Levi, C Aurigemma, F Migliavacca
A method for the reconstruction of a vessel centerline from angiographic images is outlined in this work. A typical coronary artery segment with bifurcations was emulated with a 3D printed static phantom and several angiograms were acquired at various angular positions on the C-Arm. The effectiveness of the reconstruction turned out to be largely influenced by the intrinsic parameters of the angiographic system, particularly the homogeneous coordinates system scaling factor λ. Therefore, recourse was made to a heuristic optimization method to estimate the optimal value of λ for each view...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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