Ultrasound Monitoring of In Vitro Radio Frequency Ablation by Echo Decorrelation Imaging

Mast, T. Douglas; Pucke, Daniel P.; Subramanian, Shankar C.; Bowlus, William J.; Rudich, Steven M.; Buell, Joseph F.

doi:10.7863/jum.2008.27.12.1685

Cited by 56 publications

(94 citation statements)

References 36 publications

(51 reference statements)

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“…Optimal frequency bands for analysis of acoustic emissions (for example, choice of subharmonic or ultraharmonic bands to detect stable cavitation activity) will likely depend on the HIFU frequency and tissue path in the application of interest. Spatial selectivity in cavitation detection, achievable by passive cavitation imaging [44,50-52], may be useful, particularly in combination with pulse-echo methods for real-time detection of local heating, such as echo decorrelation imaging [53,54]. Optimal thresholds for emission detection would need to be determined more rigorously, with the goal of reducing hemorrhage likelihood to clinically acceptable levels.…”

Section: Discussionmentioning

confidence: 99%

Prediction and suppression of HIFU-induced vessel rupture using passive cavitation detection in an ex vivo model

et al. 2014

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BackgroundOcclusion of blood vessels using high-intensity focused ultrasound (HIFU) is a potential treatment for arteriovenous malformations and other neurovascular disorders. However, attempting HIFU-induced vessel occlusion can also cause vessel rupture, resulting in hemorrhage. Possible rupture mechanisms include mechanical effects of acoustic cavitation and heating of the vessel wall.MethodsHIFU exposures were performed on 18 ex vivo porcine femoral arteries with simultaneous passive cavitation detection. Vessels were insonified by a 3.3-MHz focused source with spatial-peak, temporal-peak focal intensity of 15,690–24,430 W/cm2 (peak negative-pressure range 10.92–12.52 MPa) and a 50% duty cycle for durations up to 5 min. Time-dependent acoustic emissions were recorded by an unfocused passive cavitation detector and quantified within low-frequency (10–30 kHz), broadband (0.3–1.1 MHz), and subharmonic (1.65 MHz) bands. Vessel rupture was detected by inline metering of saline flow, recorded throughout each treatment. Recorded emissions were grouped into ‘pre-rupture’ (0–10 s prior to measured point of vessel rupture) and ‘intact-vessel’ (>10 s prior to measured point of vessel rupture) emissions. Receiver operating characteristic curve analysis was used to assess the ability of emissions within each frequency band to predict vessel rupture.Based on these measurements associating acoustic emissions with vessel rupture, a real-time feedback control module was implemented to monitor acoustic emissions during HIFU treatment and adjust the ultrasound intensity, with the goal of maximizing acoustic power delivered to the vessel while avoiding rupture. This feedback control approach was tested on 10 paired HIFU exposures of porcine femoral and subclavian arteries, in which the focal intensity was stepwise increased from 9,117 W/cm2 spatial-peak temporal-peak (SPTP) to a maximum of 21,980 W/cm2, with power modulated based on the measured subharmonic emission amplitude. Time to rupture was compared between these feedback-controlled trials and paired controller-inactive trials using a paired Wilcoxon signed-rank test.ResultsSubharmonic emissions were found to be the most predictive of vessel rupture (areas under the receiver operating characteristic curve (AUROC) = 0.757, p < 10-16) compared to low-frequency (AUROC = 0.657, p < 10-11) and broadband (AUROC = 0.729, p < 10-16) emissions. An independent-sample t test comparing pre-rupture to intact-vessel emissions revealed a statistically significant difference between the two groups for broadband and subharmonic emissions (p < 10-3), but not for low-frequency emissions (p = 0.058).In a one-sided paired Wilcoxon signed-rank test, activation of the control module was shown to increase the time to vessel rupture (T- = 8, p = 0.0244, N = 10). In one-sided paired t tests, activation of the control module was shown to cause no significant difference in time-averaged focal intensity (t = 0.362, p = 0.363, N = 10), but was shown to cause delivery of significantly greater total acou...

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Section: Discussionmentioning

confidence: 99%

Prediction and suppression of HIFU-induced vessel rupture using passive cavitation detection in an ex vivo model

et al. 2014

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“…Echo decorrelation imaging is reported be more robust to tissue motion and bubble activity than thermal strain imaging, but at higher temperatures the images are qualitative, not quantitative. Initial application of this technique was for RF ablation, but the technique should be compatible with HIFU (147). …”

Section: Specific Strategies For Ultrasound Thermometry and Ablatimentioning

confidence: 99%

Thermometry and ablation monitoring with ultrasound

Lewis

Staruch

Chopra

2015

International Journal of Hyperthermia

146

102

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“…5(a) shows B-scans taken by a THX4A image-ablate array, before and after in vitro ablation of a VX2 tumor in rabbit liver. The post-treatment image shows vaporization visible as hyperechoic, transient image changes, suggesting that quantitative imaging of transient variations in tissue scattering [16] may be suitable for monitoring of treatments using these miniaturized image-ablate arrays.…”

Section: Resultsmentioning

confidence: 96%

In vivo treatment of rabbit VX2 tumor by miniaturized image-ablate ultrasound arrays

Mast

Barthé

Makin

et al. 2009

2009 IEEE International Ultrasonics Symposium

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In the preclinical studies reported here, VX2 cancer within rabbit liver has been treated by bulk ultrasound ablation employing miniaturized image-ablate arrays. Array probes were constructed with 32 elements in a 2.3×20 mm 2 aperture and employed for B-scan imaging as well as bulk ablation at 4.8 MHz. In a series of in vivo experiments, tumor ablation using these arrays was histologically confirmed, with complete ablation of tumor cross sections for exposures with delivery of >747 J acoustic energy. These results show feasibility for development of an image-guided, interstitial bulk ultrasound ablation approach for clinical liver cancer treatment.

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Ultrasound Monitoring of In Vitro Radio Frequency Ablation by Echo Decorrelation Imaging

Cited by 56 publications

References 36 publications

Prediction and suppression of HIFU-induced vessel rupture using passive cavitation detection in an ex vivo model

Prediction and suppression of HIFU-induced vessel rupture using passive cavitation detection in an ex vivo model

Thermometry and ablation monitoring with ultrasound

In vivo treatment of rabbit VX2 tumor by miniaturized image-ablate ultrasound arrays

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