Microwave ablation of liver tumors: degree of tissue contraction as compared to RF ablation

Lee, Jeong Kyong; Siripongsakun, Surachate; Bahrami, Simin; Raman, Steven S.; Sayre, James W.; Lu, David

doi:10.1007/s00261-016-0725-8

Cited by 35 publications

(30 citation statements)

References 18 publications

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“…Thus, we surmise that greater water vaporization during microwave ablation was primarily responsible for the strain differences observed in this study. Even though only one setting of RF ablation was performed in this study, the significant tissue contraction difference between RF and microwave ablation was commensurate with other studies that measured and compared RF and microwave contraction using different techniques . The present study, as well as the other previous studies, demonstrates that tissue contraction during microwave ablation may have a more critical influence on the treatment outcome compared to RF ablation.…”

Section: Discussionsupporting

confidence: 86%

Evaluation of tissue deformation during radiofrequency and microwave ablation procedures: Influence of output energy delivery

Liu

Brace

2019

Medical Physics

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Purpose The purpose of this study was to quantitatively analyze tissue deformation during radiofrequency (RF) and microwave ablation for varying output energy levels. Methods A total of 46 fiducial markers which were classified into outer, middle, and inner lines were positioned into a single plane around an RF or microwave ablation applicator in each ex vivo bovine liver sample (8 cm × 6 cm × 4 cm, n = 18). Radiofrequency (500 kHz; ~35 W average) or microwave (2.4 GHz; 50–100 W output, ~35–70 W delivered) ablation was performed for 10 min (n = 4–6 each setting). CT images were acquired over the entire liver volume every 15 s. Principle strain magnitude and direction were determined from fiducial marker displacement. Normal and shear strain were then calculated such that negative strain denoted contraction and positive strain denoted expansion. Temporal variations, the final magnitudes, and angles of the strain were compared across energy delivery settings, using one‐way ANOVA with post hoc Tukey's tests. Results On average, tissue strain rates peak at around 1 min and decayed exponentially over time. No evidence of tissue expansion was observed. The tissue strains from RF and 50 W, 75 W, and 100 W microwave ablation at 10 min were −8.5%, −38.9%, −54.4%, and −65.7%, respectively, from the inner region and −3.6%, −23.7%, −41.8%, and −44.3%, respectively, from the outer region. Negative strain magnitude was positively correlated to energy delivery in the inner region (Spearman’s ρ = −0.99). Microwaves at higher powers (75–100 W) induced significantly more strain than at lower power (50 W) or after RF ablation (P < 0.01). Principal strain angles ranged from 0.8° to −8.1°, indicating that tissue deformed more in the direction transverse to the applicator than along the direction of the applicator. Conclusions The influence of output energy on tissue deformation during RF and microwave ablation was analyzed. Microwave ablation created significantly greater contraction than RF ablation with similar energy delivery. During microwave ablation, more contraction was noted at higher power levels and in proximity to the antenna. Contraction primarily transverse to the antenna produces ablation zones that are more elongated than the original tissue volume.

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Section: Discussionsupporting

confidence: 86%

Evaluation of tissue deformation during radiofrequency and microwave ablation procedures: Influence of output energy delivery

Liu

Brace

2019

Medical Physics

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“…This will allow the model to obtain relationships between different ablation therapies and the degree of tissue contraction, thus providing useful information during intervention planning. It will be especially useful to investigate tissue expansion observed in post clinical intervention of tumour organs [15].…”

Section: Discussionmentioning

confidence: 99%

“…Two independent studies on renal tumours reported tissue diameter contractions of -10 to 50% [13,14]. MWA and RFA on liver tumours have also reported both tissue contraction and expansion, the latter being observed more frequently during RFA [15].…”

Section: Introductionmentioning

confidence: 99%

A thermoelastic deformation model of tissue contraction during thermal ablation

Park

Liu

Hall

et al. 2017

International Journal of Hyperthermia

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“…Because of cirrhosis and tumour pseudocapsules, the surrounding fibrotic liver of HCC acts as an oven, creating higher temperatures and prolonged cytotoxic temperatures (204). MWA produces more tissue and tumour contraction compared with RFA, something that needs to be accounted for during pre-procedural planning and when assessing treatment response (205).…”

Section: Microwave Versus Radiofrequency Ablationmentioning

confidence: 99%

Stereotactic CT-Guided Percutaneous Microwave Ablation of Liver Tumors With the Use of High-Frequency Jet Ventilation: An Accuracy and Procedural Safety Study

Engstrand

Toporek

Harbut

et al. 2017

American Journal of Roentgenology

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Microwave ablation of liver tumors: degree of tissue contraction as compared to RF ablation

Abstract: MW ablation of hepatic tumors produced significantly more contraction of tumor and ablated hepatic tissue compared to RF ablation. Tissue contraction should be taken into account during pre-procedural planning and assessing treatment response by comparing pre- and post-ablation images.

Cited by 35 publications

References 18 publications

Evaluation of tissue deformation during radiofrequency and microwave ablation procedures: Influence of output energy delivery

Evaluation of tissue deformation during radiofrequency and microwave ablation procedures: Influence of output energy delivery

A thermoelastic deformation model of tissue contraction during thermal ablation

Stereotactic CT-Guided Percutaneous Microwave Ablation of Liver Tumors With the Use of High-Frequency Jet Ventilation: An Accuracy and Procedural Safety Study

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