scholarly journals Development Of A Nonlinear Frequency Compounding Method With Applications In Ultrasound Imaging And Thermometry

2021 ◽  
Author(s):  
Tyler Hornsby
Keyword(s):  
Ultrasound Imaging ◽  
Focused Ultrasound ◽  
Ex Vivo ◽  
Signal To Noise Ratio ◽  
Single Frequency ◽  
Temperature Sensitive ◽  
Nonlinear Frequency ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Temperature Maps

<div>Frequency compounding is an ultrasound imaging technique used to reduce artifacts and improve signal-to-noise-ratio (SNR). In this work a new nonlinear frequency compounding (NLFC) method was introduced, and its application in B-mode imaging and noninvasive thermometry was investigated. NLFC input frequencies were optimized to maximize speckle-signal-to-noise-ratio (SSNR) in a tissue mimicking phantom, and the method was then used to produce maps of the temperature sensitive change in backscattered energy of acoustic harmonics (<i>h</i>CBE) during heating of ex vivo porcine tissue with a focused ultrasound transducer. A <i>h</i>CBE-to-temperature calibration was also performed and temperature maps produced. Lastly, a comparative study of the NLFC and previously used nonlinear single frequency (NLSF) method was completed. By using the NLFC method it was concluded that SSNR of B-mode and backscattered energy images, SNR of <i>h</i>CBE maps, and temperature map agreement with a theoretical COMSOL based model were improved over the previously used NLSF method.</div>

scholarly journals Development Of A Nonlinear Frequency Compounding Method With Applications In Ultrasound Imaging And Thermometry

2021 ◽  
Author(s):  
Tyler Hornsby
Keyword(s):  
Ultrasound Imaging ◽  
Focused Ultrasound ◽  
Ex Vivo ◽  
Signal To Noise Ratio ◽  
Single Frequency ◽  
Temperature Sensitive ◽  
Nonlinear Frequency ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Temperature Maps

<div>Frequency compounding is an ultrasound imaging technique used to reduce artifacts and improve signal-to-noise-ratio (SNR). In this work a new nonlinear frequency compounding (NLFC) method was introduced, and its application in B-mode imaging and noninvasive thermometry was investigated. NLFC input frequencies were optimized to maximize speckle-signal-to-noise-ratio (SSNR) in a tissue mimicking phantom, and the method was then used to produce maps of the temperature sensitive change in backscattered energy of acoustic harmonics (<i>h</i>CBE) during heating of ex vivo porcine tissue with a focused ultrasound transducer. A <i>h</i>CBE-to-temperature calibration was also performed and temperature maps produced. Lastly, a comparative study of the NLFC and previously used nonlinear single frequency (NLSF) method was completed. By using the NLFC method it was concluded that SSNR of B-mode and backscattered energy images, SNR of <i>h</i>CBE maps, and temperature map agreement with a theoretical COMSOL based model were improved over the previously used NLSF method.</div>

scholarly journals Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging

2015 ◽  
Vol 60 (21) ◽  
pp. 8549-8566 ◽  
Author(s):  
Elodie Tiran ◽  
Thomas Deffieux ◽  
Mafalda Correia ◽  
David Maresca ◽  
Bruno-Felix Osmanski ◽  
...  
Keyword(s):  
Ultrasound Imaging ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Wave Imaging ◽  
Noise Ratio

scholarly journals An Investigation of Binary Coded Excitation Methods Using Golay Code Pairs for High Frequency Ultrasound Imaging

2021 ◽  
Author(s):  
Xuegang Su
Keyword(s):  
Ultrasound Imaging ◽  
High Frequency ◽  
Signal To Noise Ratio ◽  
High Frequency Ultrasound ◽  
Golay Code ◽  
Signal To Noise ◽  
Coded Excitation ◽  
High Frequency Ultrasound Imaging ◽  
Noise Ratio ◽  
Frequency Ultrasound

We are investigating the feasibility of binary coded excitation methods using Golay code pairs for high frequency ultrasound imaging as a way to increase the signal to noise ratio. I present some theoretical models used to simulate the coded excitation method and results generated from the models. A new coded excitation high frequency ultrasound prototype system was built to verify the simulation results. Both the simulation and the experimental results show that binary coded excitation can improve the signal to noise ratio in high frequency ultrasound backscatter signals. These results are confirmed in phantoms and excised bovine liver. If just white noise is considered, the encoding gain is 15dB for a Golay pair of length 4. We find the system to be very sensitive to motion (i.e. phase shift) and frequency dependent (FD) attenuation, creating sidelobes and degrading axial resolution and encoding gain. Methods to address these issues are discussed.

scholarly journals Single-molecule optical absorption imaging by nanomechanical photothermal sensing

2018 ◽  
Vol 115 (44) ◽  
pp. 11150-11155 ◽  
Author(s):  
Miao-Hsuan Chien ◽  
Mario Brameshuber ◽  
Benedikt K. Rossboth ◽  
Gerhard J. Schütz ◽  
Silvan Schmid
Keyword(s):  
Single Molecule ◽  
Shot Noise ◽  
Signal To Noise Ratio ◽  
Local Heating ◽  
Single Molecules ◽  
High Sensitivity ◽  
Temperature Sensitive ◽  
Signal To Noise ◽  
Promising Alternative ◽  
Noise Ratio

Absorption microscopy is a promising alternative to fluorescence microscopy for single-molecule imaging. So far, molecular absorption has been probed optically via the attenuation of a probing laser or via photothermal effects. The sensitivity of optical probing is not only restricted by background scattering but it is fundamentally limited by laser shot noise, which minimizes the achievable single-molecule signal-to-noise ratio. Here, we present nanomechanical photothermal microscopy, which overcomes the scattering and shot-noise limit by detecting the photothermal heating of the sample directly with a temperature-sensitive substrate. We use nanomechanical silicon nitride drums, whose resonant frequency detunes with local heating. Individual Au nanoparticles with diameters from 10 to 200 nm and single molecules (Atto 633) are scanned with a heating laser with a peak irradiance of 354 ± 45 µW/µm2 using 50× long-working-distance objective. With a stress-optimized drum we reach a sensitivity of 16 fW/Hz1/2 at room temperature, resulting in a single-molecule signal-to-noise ratio of >70. The high sensitivity combined with the inherent wavelength independence of the nanomechanical sensor presents a competitive alternative to established tools for the analysis and localization of nonfluorescent single molecules and nanoparticles.

scholarly journals Converting Coherence to Signal-to-noise Ratio for Enhancement of Adaptive Ultrasound Imaging

2019 ◽  
Vol 42 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Hideyuki Hasegawa ◽  
Ryo Nagaoka
Keyword(s):  
Ultrasound Imaging ◽  
Spatial Resolution ◽  
Signal To Noise Ratio ◽  
Frame Rate ◽  
Signal To Noise ◽  
High Frame Rate ◽  
Ultrasonic Echo ◽  
Wave Imaging ◽  
Noise Ratio ◽  
Phantom Experiments

High-frame-rate ultrasound is an emerging technique for functional ultrasound imaging. However, the lateral spatial resolution and contrast in high-frame-rate ultrasound with an unfocused transmit beam are inherently lower than those in conventional ultrasonic imaging based on the line-by-line acquisition using a focused ultrasonic beam because of the low directivity of the transmit beam. Coherence-based beamforming methods were introduced in ultrasound imaging for improvement of image quality. Such methods improve the lateral spatial resolution using the coherence among ultrasonic echo signals received by individual transducer elements. In this study, a new method based on the signal-to-noise ratio (SNR) among the element echo signals was developed for enhancement of the effect of the coherence factor (CF), which was previously developed for improvement in spatial resolution and contrast. In the proposed method, a new factor, namely, SNR factor, was introduced, and the relationship between the previously developed CF and SNR factor was discussed. The proposed method was implemented in plane wave imaging, and the performance was evaluated by simulated and phantom experiments. In simulation, the lateral spatial resolution and contrast obtained with the conventional CF were 0.23 mm and 47.0 dB, respectively, which were significantly better than 0.39 mm and 15.3 dB obtained by conventional delay-and-sum (DAS) beamforming. Using the proposed method, the lateral spatial resolution and contrast were further improved to 0.12 mm and 69.8 dB, respectively. Similar trends were found also in phantom experiments.

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