Temperature dependence of acoustic harmonics generated by nonlinear ultrasound beam propagation in<i>ex vivo</i>tissue and tissue-mimicking phantoms

Maraghechi, B.; Kolios, Michael C.; Tavakkoli, Jahan

doi:10.3109/02656736.2015.1052856

Cited by 21 publications

(23 citation statements)

References 31 publications

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“…The variability was reduced by using higher harmonics (CBE 2 and CBE 3 ). Figures 4, 5, 7 and 8 also demonstrate that higher harmonics have higher sensitivity to temperature which is in agreement with our previous findings [31]. Figures 6 and 9 demonstrate that the gradient map obtained using the conventional echo-shift technique shows the heated region in the sample only in the case where the measurement was not affected by vibrations.…”

Section: Methodssupporting

confidence: 90%

“…Envelope values were squared to calculate the backscattered energy at each data point on the RF signal. More details can be found in ref [31]. Figure 2.…”

Section: Methodsmentioning

confidence: 99%

“…The temperature range used in this study was from 26 C to 46 C which was based on our previous work [31]. However in hyperthermia the tissue temperature increases from 37 to 45 C. Therefore, in order to show the sensitivity of harmonics within this more relevant clinical temperature range, the maps of CBE 1 , CBE 2 and CBE 3 in the gel phantom and tissue sample were plotted in Figures 12 and 13 in which the base level temperature was set to 38 C and the temperature increases to 46 C.…”

Section: Methodsmentioning

confidence: 99%

“…Our group previously showed that the pressure amplitude and the backscattered energy of the fundamental frequency (p 1 and BE 1 ), the second (p 2 and BE 2 ) and the third (p 3 and BE 3 ) harmonics in tissue-mimicking gel phantoms and ex vivo bovine muscle tissues are temperature dependent and that this temperature dependence could be considered as a basis for an ultrasound-based method for noninvasive thermometry [31]. It was shown that the average BE 1 , BE 2 and BE 3 increased by 163%, 281% and 2257%, respectively in tissue samples as the temperature was uniformly elevated from 26 to 46 C. In gel phantoms, the average BE 1 , BE 2 and BE 3 increased by 42%, 121% and 470%, respectively in the same temperature range [31]. The tissue samples and the gel phantoms were uniformly heated and the ultrasound beam had a transmit frequency of 13 MHz.…”

Section: Introductionmentioning

confidence: 99%

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Feasibility of detecting change in backscattered energy of acoustic harmonics in locally heated tissues

Maraghechi

Kolios

Tavakkoli

2019

International Journal of Hyperthermia

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Purpose: A real-time noninvasive thermometry technique is required to estimate the temperature distribution during hyperthermia to monitor and control the treatment. The main objective of this study is to demonstrate the possibility of detecting change in backscatter energy (CBE) of acoustic harmonics in tissue-mimicking gel phantoms and ex vivo bovine muscle tissues in which the temperature was locally increased within the hyperthermia regime. Materials and Methods: A peristaltic pump was used to circulate hot water through a needle inserted inside the samples to locally increase the temperature from 26 C to 46 C. The CBE of acoustic harmonics were used to identify the location of temperature changes in the samples. A conventional echo-shift technique was also implemented for comparison. Data collection was performed for two conditions to investigate the effect of motion on both techniques by: (1) inducing vibration in the sample through the peristatic pump and, (2) subsequently with no sample vibration while the pump was off. Results: Harmonics were able to determine the location of temperature rise in the presence and absence of vibration. In gel phantom, the mean contrast to noise ratio (CNR) in CBE maps reduced by a factor of 0.86 due to vibration whereas in gradient maps the CNR reduced by a factor of 8.3. Conclusions: The findings of this study suggest that the change in backscatter energy of acoustic harmonics can potentially be used to develop a noninvasive ultrasound-based thermometry technique with lower susceptibility to motion artifacts compared to the echo-shift method.

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Section: Methodssupporting

confidence: 90%

“…Envelope values were squared to calculate the backscattered energy at each data point on the RF signal. More details can be found in ref [31]. Figure 2.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Feasibility of detecting change in backscattered energy of acoustic harmonics in locally heated tissues

Maraghechi

Kolios

Tavakkoli

2019

International Journal of Hyperthermia

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“…We have recently shown that the pressure amplitude and the energy content of the backscattered fundamental frequency, the second and the third harmonics generated by nonlinear ultrasound propagation in tissue-mimicking gel phantoms, and ex vivo bovine muscle tissues are highly sensitive to temperature, when the acoustic harmonics were generated by transmitting a 13-MHz pulse using a highfrequency ultrasound imaging scanner. 11 It was also demonstrated that higher harmonics have a higher sensitivity to temperature.…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of acoustic harmonics generated by nonlinear ultrasound wave propagation in water at various frequencies

Maraghechi

Hasani

Kolios

et al. 2016

The Journal of the Acoustical Society of America

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Ultrasound-based thermometry requires a temperature-sensitive acoustic parameter that can be used to estimate the temperature by tracking changes in that parameter during heating. The objective of this study is to investigate the temperature dependence of acoustic harmonics generated by nonlinear ultrasound wave propagation in water at various pulse transmit frequencies from 1 to 20 MHz. Simulations were conducted using an expanded form of the Khokhlov-Zabolotskaya-Kuznetsov nonlinear acoustic wave propagation model in which temperature dependence of the medium parameters was included. Measurements were performed using single-element transducers at two different transmit frequencies of 3.3 and 13 MHz which are within the range of frequencies simulated. The acoustic pressure signals were measured by a calibrated needle hydrophone along the axes of the transducers. The water temperature was uniformly increased from 26 °C to 46 °C in increments of 5 °C. The results show that the temperature dependence of the harmonic generation is different at various frequencies which is due to the interplay between the mechanisms of absorption, nonlinearity, and focusing gain. At the transmit frequencies of 1 and 3.3 MHz, the harmonic amplitudes decrease with increasing the temperature, while the opposite temperature dependence is observed at 13 and 20 MHz.

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Measuring Tissue Temperature with Ultrasound

Shaswary,

Tavakkoli

2023

The Application of Heat in Oncology

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Temperature dependence of acoustic harmonics generated by nonlinear ultrasound beam propagation inex vivotissue and tissue-mimicking phantoms

Abstract: The findings suggest that the harmonics generated due to nonlinear ultrasound beam propagation are highly sensitive to temperature and could potentially be used for noninvasive ultrasound tissue thermometry.

Cited by 21 publications

References 31 publications

Feasibility of detecting change in backscattered energy of acoustic harmonics in locally heated tissues

Feasibility of detecting change in backscattered energy of acoustic harmonics in locally heated tissues

Temperature dependence of acoustic harmonics generated by nonlinear ultrasound wave propagation in water at various frequencies

Measuring Tissue Temperature with Ultrasound

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