Ultrasound monitoring of temperature change during radiofrequency ablation: preliminary in-vivo results

Varghese, Tomy; Zagzebski, James A.; Chen, Quan; Techavipoo, Udomchai; Frank, Gary R.; Johnson, Chris; Wright, Andrew S.; Lee, F.T

doi:10.1016/s0301-5629(01)00519-1

Cited by 139 publications

(121 citation statements)

References 45 publications

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“…For a short HIFU-induced heating pulse applied at time t = 0, the resulting temperature distribution along the transverse direction r after the HIFU pulse has been turned off is modeled by eqn 14. Previously, it has been demonstrated (Simon et al 1998;Varghese et al 2002;Pernot et al 2004) that the temperature-induced strain (ε) measured from the ultrasound radio-frequency (RF) backscatter signal, for small temperature rises above ambient temperature, is directly proportional to the induced temperature change T(r,t) (15) where k is a scalar constant.…”

Section: Estimation Of Thermal Diffusivity Using Backscattered Ultrasmentioning

confidence: 99%

“…The parameter estimation technique is based on visualizing the spatiotemporal variation of temperature induced strain (Miller et al 2002(Miller et al , 2004 estimated from the raw ultrasound backscatter data after a short focused ultrasound heating pulse is applied at subablative intensities. The temperature induced strain is caused by changes in the local sound speed of the medium and thermal expansion (Maass-Moreno et al 1996;Simon et al 1998;Varghese et al 2002). The maximum induced temperature rise is less than 10°C to avoid any permanent changes in tissue.…”

Section: Introductionmentioning

confidence: 99%

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Noninvasive Measurement of Local Thermal Diffusivity Using Backscattered Ultrasound and Focused Ultrasound Heating

Anand

Kaczkowski

2008

Ultrasound in Medicine & Biology

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Previously, noninvasive methods of estimating local tissue thermal and acoustic properties using backscattered ultrasound have been proposed in the literature. In this article, a noninvasive method of estimating local thermal diffusivity in situ during focused ultrasound heating using beamformed acoustic backscatter data and applying novel signal processing techniques is developed. A high intensity focused ultrasound (HIFU) transducer operating at subablative intensities is employed to create a brief local temperature rise of no more than 10°C. Beamformed radio-frequency (RF) data are collected during heating and cooling using a clinical ultrasound scanner. Measurements of the time-varying "acoustic strain", that is, spatiotemporal variations in the RF echo shifts induced by the temperature related sound speed changes, are related to a solution of the heat transfer equation to estimate the thermal diffusivity in the heated zone. Numerical simulations and experiments performed in vitro in tissue mimicking phantoms and excised turkey breast muscle tissue demonstrate agreement between the ultrasound derived thermal diffusivity estimates and independent estimates made by a traditional hot-wire technique. The new noninvasive ultrasonic method has potential applications in thermal therapy planning and monitoring, physiological monitoring and as a means of noninvasive tissue characterization.

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Section: Estimation Of Thermal Diffusivity Using Backscattered Ultrasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Noninvasive Measurement of Local Thermal Diffusivity Using Backscattered Ultrasound and Focused Ultrasound Heating

Anand

Kaczkowski

2008

Ultrasound in Medicine & Biology

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“…Temperature estimation using these effects is based on measuring displacements in the direction of propagation z, which can be related to changes in temperature iT(z) according to [39,55,56,62] ÁT ðzÞ ¼ c 0 =2ð À Þ Â tðzÞ=z ð1Þ…”

Section: Echo Shiftsmentioning

confidence: 99%

Non-invasive estimation of hyperthermia temperatures with ultrasound

Arthur

Straube

Trobaugh

et al. 2005

International Journal of Hyperthermia

206

134

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Ultrasound is an attractive modality for temperature monitoring because it is non-ionizing, convenient, inexpensive and has relatively simple signal processing requirements. This modality may be useful for temperature estimation if a temperature-dependent ultrasonic parameter can be identified, measured and calibrated. The most prominent methods for using ultrasound as a non-invasive thermometer exploit either (1) echo shifts due to changes in tissue thermal expansion and speed of sound (SOS), (2) variation in the attenuation coefficient or (3) change in backscattered energy from tissue inhomogeneities. The use of echo shifts has received the most attention in the last decade. By tracking scattering volumes and measuring the time shift of received echoes, investigators have been able to predict the temperature from a region of interest both theoretically and experimentally in phantoms, in isolated tissue regions in vitro and preliminary in vivo studies. A limitation of this method for general temperature monitoring is that prior knowledge of both SOS and thermalexpansion coefficients is necessary. Acoustic attenuation is dependent on temperature, but with significant changes occurring only at temperatures above 50 C, which may lead to its use in thermal ablation therapies. Minimal change in attenuation, however, below this temperature range reduces its attractiveness for use in clinical hyperthermia. Models and measurements of the change in backscattered energy suggest that, over the clinical hyperthermia temperature range, changes in backscattered energy are dependent on the properties of individual scatterers or scattering regions. Calibration of the backscattered energy from different tissue regions is an important goal of this approach. All methods must be able to cope with motion of the image features on which temperature estimates are based. A crucial step in identifying a viable ultrasonic approach to temperature estimation is its performance during in vivo tests.

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“…To quantify the relationship between the externally induced temperature change and the observed thermal induced strain in the PVA phantom and arterial tissue sample, the calibration experiments were needed. Others have previously demonstrated water-bath experiments to generate a calibration curve for liver, muscle, kidney and prostate tissues Varghese and Daniels 2004;Varghese et al 2002). We performed similar calibration for polyvinyl alcohol and the arterial tissue.…”

Section: E Temperature Calibration and Noise Analysismentioning

confidence: 99%

“…Ultrasound has been used as a means to determine temperature changes in biological tissues. Several parameters have been investigated to utilize ultrasound for temperature estimation including measurement of change in speed of sound (Bowen et al 1979;Nasoni and Bowen 1989;Rajagopalan et al 1979), attenuation coefficient (Bush et al 1993;Damianou et al 1997;Ribault et al 1998;Varghese et al 2002), ultrasound echo-shift (Maass-Moreno andDamianou 1996;Seip et al 1996;Shi et al 2005b;Varghese et al 2002;Zohdy et al 2006) and backscatter energy (Straube and Arthur 1994). In this work, we utilize the ultrasound-based strain estimates of temperature change as a method to determine thermal effects during photoacoustic imaging.…”

Section: Introductionmentioning

confidence: 99%

Remote Temperature Estimation in Intravascular Photoacoustic Imaging

Sethuraman

Aglyamov

Smalling

et al. 2008

Ultrasound in Medicine & Biology

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Intravascular photoacoustic (IVPA) imaging is based on the detection of laser-induced acoustic waves generated within the arterial tissue under pulsed laser irradiation. Generally, laser radiant energy levels are kept low (20 mJ/cm 2 ) during photoacoustic imaging to conform to general standards for safe use of lasers on biological tissues. However, safety standards in intravascular photoacoustic imaging are not yet fully established. Consequently, monitoring spatio-temporal temperature changes associated with laser-tissue interaction is important to address thermal safety of IVPA imaging. In this study we utilize the IVUS based strain measurements to estimate the laser induced temperature increase. Temporal changes in temperature were estimated in a phantom modeling a vessel with an inclusion. A cross-correlation based time delay estimator was used to assess temperature induced strains produced by different laser radiant energies. The IVUS based remote measurements revealed temperature increases of 0.7±0.3°C, 2.9±0.2 °C and 5.0±0.2 °C, for the laser radiant energies of 30 mJ/cm 2 , 60 mJ/cm 2 and 85 mJ/cm 2 respectively. The technique was then used in imaging of ex vivo samples of a normal rabbit aorta. For arterial tissues, a temperature elevation of 1.1°C was observed for a laser fluence of 60 mJ/cm 2 and lesser than 1°C for lower energy levels normally associated with IVPA imaging. Therefore, the developed ultrasound technique can be used to monitor temperature during IVPA imaging. Furthermore, the analysis based on the Arrhenius thermal damage model indicates no thermal injury in the arterial tissue; suggesting the safety of IVPA imaging

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Ultrasound monitoring of temperature change during radiofrequency ablation: preliminary in-vivo results

Cited by 139 publications

References 45 publications

Noninvasive Measurement of Local Thermal Diffusivity Using Backscattered Ultrasound and Focused Ultrasound Heating

Noninvasive Measurement of Local Thermal Diffusivity Using Backscattered Ultrasound and Focused Ultrasound Heating

Non-invasive estimation of hyperthermia temperatures with ultrasound

Remote Temperature Estimation in Intravascular Photoacoustic Imaging

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