Acoustic Imaging
Mostrando 13-24 de 24 artigos, teses e dissertações.
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13. Análise da voz e do comportamento do trato vocal suplaglótico por meio visual, perceptivo-auditivo e acústico em mulheres disfônicas com diferentes configurações glóticas / Analysis of voice and supraglottic vocal behavior using visual, perceptual and acoustic methods in dysphonic women whith different glottic configurations
Objective: To analyze voice and supraglottic vocal tract using imaging of the vocal tract, perceptual and acoustic methods in dysphonic women with different glottic configurations. Method: The studied sample comprised 31 women, aged 20 to 45 years, with vocal complaints and affections. Subjects underwent brief assessment of sensorial-motor-oral system, video
Publicado em: 2005
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14. A pulsatile flow model for in vitro quantitative evaluation of prosthetic valve regurgitation
A pulsatile pressure-flow model was developed for in vitro quantitative color Doppler flow mapping studies of valvular regurgitation. The flow through the system was generated by a piston which was driven by stepper motors controlled by a computer. The piston was connected to acrylic chambers designed to simulate "ventricular" and "atrial" heart chambers. In
Brazilian Journal of Medical and Biological Research. Publicado em: 2000-03
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15. Vibro-acoustography: An imaging modality based on ultrasound-stimulated acoustic emission
We describe theoretical principles of an imaging modality that uses the acoustic response of an object to a highly localized dynamic radiation force of an ultrasound field. In this method, named ultrasound-stimulated vibro-acoustography (USVA), ultrasound is used to exert a low-frequency (in kHz range) force on the object. In response, a portion of the objec
The National Academy of Sciences.
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16. Disruption of the neural response to rapid acoustic stimuli in dyslexia: Evidence from functional MRI
The biological basis for developmental dyslexia remains unknown. Research has suggested that a fundamental deficit in dyslexia is the inability to process sensory input that enters the nervous system rapidly and that deficits in processing rapid acoustic information are associated with impaired reading. Functional magnetic resonance imaging (fMRI) was u
The National Academy of Sciences.
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17. Microfluidics without microfabrication
Microfluidic devices create spatially defined, chemically controlled environments at microscopic dimensions. We demonstrate the formation and control of microscopic hydrodynamic and chemical environments by impinging a low-intensity acoustic oscillation on a cylindrical electrode. The interaction of small-amplitude (≤203 μm), low-frequency (≤515 Hz) flu
The National Academy of Sciences.
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18. Ultrasonic tagging of light: Theory
A theory is provided for the detection efficiency of diffuse light whose frequency is modulated by an acoustical wave. We derive expressions for the speckle pattern of the modulated light, as well as an expression for the signal-to-noise ratio for the detector. The aim is to develop a new imaging technology for detection of tumors in humans. The acoustic wav
The National Academy of Sciences.
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19. Dispersed activation in the left temporal cortex for speech-reading in congenitally deaf people.
Does the lateral temporal cortex require acoustic exposure in order to become specialized for speech processing? Six hearing participants and six congenitally deaf participants, all with spoken English as their first langugage, were scanned using functional magnetic resonance imaging while performing a simple speech-reading task. Focal activation of the left
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20. Assessing atherosclerotic plaque morphology: comparison of optical coherence tomography and high frequency intravascular ultrasound.
BACKGROUND: OCT can image plaque microstructure at a level of resolution not previously demonstrated with other imaging techniques because it uses infrared light rather than acoustic waves. OBJECTIVES: To compare optical coherence tomography (OCT) and intravascular ultrasound (IVUS) imaging of in vitro atherosclerotic plaques. METHODS: Segments of abdominal
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21. Coregistered three-dimensional ultrasound and photoacoustic imaging system for ovarian tissue characterization
Ovarian cancer has the highest mortality of all gynecologic cancers, with a five-year survival rate of only 30% or less. Current imaging techniques are limited in sensitivity and specificity in detecting early stage ovarian cancer prior to its widespread metastasis. New imaging techniques that can provide functional and molecular contrasts are needed to redu
Society of Photo-Optical Instrumentation Engineers.
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22. Non-invasive grading of aortic regurgitation by Doppler ultrasonography.
Doppler ultrasound without concomitant echocardiographic imaging was used to grade isolated aortic regurgitation in 21 patients. The severity of aortic regurgitation was subsequently graded (from 0 to IV) angiographically. A 2 MHz continuous wave Doppler transducer was placed over the apex of the heart and the beam was aimed parallel to the mitral flow by me
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23. Multiple matching scheme for broadband 0.72Pb(Mg1∕3Nb2∕3)O3−0.28PbTiO3 single crystal phased-array transducer
Lead magnesium niobate–lead titanate single crystal 0.72Pb(Mg1∕3Nb2∕3)O3−0.28PbTiO3 (abbreviated as PMN-PT) was used to fabricate high performance ultrasonic phased-array transducer as it exhibited excellent piezoelectric properties. In this paper, we focus on the design and fabrication of a low-loss and wide-band transducer for medical imaging appli
American Institute of Physics.
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24. Real-time measurement of renal blood flow in healthy subjects using contrast-enhanced ultrasound
Current methods for measuring renal blood flow (RBF) are time consuming and not widely available. Contrast-enhanced ultrasound (CEU) is a safe and noninvasive imaging technique suitable for assessment of tissue blood flow, which has been used clinically to assess myocardial blood flow. We tested the utility of CEU in monitoring changes in RBF in healthy volu
American Physiological Society.