Dataset Information

Real-time Monitoring of Contrast-enhanced Ultrasound for Radio Frequency Ablation.

ABSTRACT: Background:This study compared the realtime monitoring effects of conventional ultrasound and contrast-enhanced ultrasound (CEUS) on evaluating radio frequency ablation (RFA) in a living swine liver model. Methodology:Liver RFA was performed on 10 young swine. Conventional ultrasound and CEUS were performed immediately. After the animals were sacrificed, ablation lesions were removed to histopathologically examine the range of the lesions. Ablation completeness based on three methods were compared using histopathology as the gold standard. Results:Forty-three ablation lesions were produced in the animals. The horizontal diameter, vertical diameter and ablation lesion area based on conventional ultrasound were all significantly smaller than those based on the gross sample, but no significant differences existed between the results of the CEUS and the gross sample. Histopathology showed that 30 lesions were incompletely ablated and 13 were completely ablated, while CEUS showed that 28 lesions were incompletely ablated and 15 were completely ablated. Compared with histopathology, CEUS had an accuracy of 81.4%, a sensitivity of 83.3%, and a specificity of 76.9%. No significant difference in ablation completeness judgment between CEUS and histopathology was observed. Conclusion:CEUS provides a real-time radiological foundation for evaluating RFA lesion ranges and completeness in a living swine liver model.

SUBMITTER: Liu J

PROVIDER: S-EPMC5757354 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Real-time Monitoring of Contrast-enhanced Ultrasound for Radio Frequency Ablation.

Liu Jiangwei J Liu Yan Y Huang Jianzhao J Huang Lei L Zhao Pengwei P

Open medicine (Warsaw, Poland) 20171229

<h4>Background</h4>This study compared the realtime monitoring effects of conventional ultrasound and contrast-enhanced ultrasound (CEUS) on evaluating radio frequency ablation (RFA) in a living swine liver model.<h4>Methodology</h4>Liver RFA was performed on 10 young swine. Conventional ultrasound and CEUS were performed immediately. After the animals were sacrificed, ablation lesions were removed to histopathologically examine the range of the lesions. Ablation completeness based on three meth ...[more]

PMID: 29318194

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Project description:PurposeTo examine the accuracy of the unenhanced zone at contrast material-enhanced ultrasonography (US) in predicting coagulative necrosis during and 21 days after radiofrequency (RF) ablation by using radiologic-pathologic comparison.Materials and methodsAnimal studies were approved by the Institutional Animal Care and Use Committee. The livers of 28 rats underwent US-guided RF ablation. In four animals, contrast-enhanced US was performed during ablation and 2 hours and 2, 7, 14, and 21 days after ablation. The unenhanced zone area on US images was measured. DiI-labeled microbubbles were administered during ablation at 2, 4, and 6 minutes or at 2 hours and 2, 7, 14, and 21 days after ablation in the remaining 24 animals (n = 3 at each time point). One minute later, the animal was euthanized, and the ablated liver was harvested. Tissue samples were imaged to quantify total fluorescence, and NADH staining was performed on the same slice. Hematoxylin-eosin staining was also performed. The findings on fluorescence images, NADH-stained images, and hematoxylin-eosin-stained images were compared. The areas of DiI bubble-negative zones, NADH-negative zones, and lightly NADH-staining zones were measured. Data were analyzed by using one-way analysis of variance.ResultsThe area of the unenhanced zone on contrast-enhanced US images increased during RF ablation and reached a maximum within 2 days after ablation. At histopathologic examination, a transition zone manifested adjacent to the coagulation zone until 2 days after ablation. The DiI-bubble negative zone on fluorescence images and the damaged zone (transition zone plus coagulation zone) on NADH-stained images increased rapidly within 2 hours after ablation, then slowly reached the maximum on day 2. The ratios of the mean areas of these two zones at hour 2 to those at day 2 were 94.6% and 95.6%, respectively. High uniformity between the damaged zone on NADH-stained images and the DiI bubble-negative zone on fluorescence images was noted at all time points.ConclusionThe temporary transition zone in NADH staining is partially damaged and should transition to nonviability 2 days after ablation. These results demonstrate that contrast-enhanced US can help delineate the maximum area of cell damage (to within 5% of the maximum) as early as 2 hours after ablation. Contrast-enhanced US may be a simple and accurate tool for monitoring the effects of RF ablation and quantifying the size of thermal damage after treatment.

Project description:The purpose of these clinical studies was to validate a Tissue Change Monitoring (TCM) algorithm in vivo. TCM is a quantitative tool for the real-time assessment of HIFU dose. TCM provides quantitative analysis of the backscatter pulse echo signals (pre and immediately post HIFU) for each individual ablative site, using ultrasonic tissue characterization as a surrogate for monitoring tissue temperature. Real-time analysis generates an energy difference parameter (?E in dB) that is proportional to tissue temperature.Post in vitro studies, two clinical studies were conducted to validate the TCM algorithm on the Sonablate® device. Studies enrolled histologically confirmed, organ confined prostate cancer patients. The first clinical study was conducted in two phases for whole gland ablation. First eight patients' data were used to measure the algorithm performance followed by 89 additional patients for long term outcome. The second clinical study enrolled five patients; four patients with focal cancer had hemi-ablation only and one had whole gland ablation. Four 3 Fr. needles containing three thermocouples each were placed transperineally in the prostate to record tissue temperatures in the focal zone, posterior to the focal zone and on the lateral gland where no HIFU was applied. Tissue temperatures from the focal zone were correlated to the ?E parameter.In the first clinical study, the average TCM rate was 86%. Pre and 6 months post HIFU, median PSA was 7.64 and 0.025 ng/ml respectively and 97% patients had negative biopsy. For the second clinical study, the measured prostate tissue temperatures (Average, Max, and Min) in the ablation zones were 84°, 114° and 60 °C and the corresponding ?E (dB/10) parameters were 1.05, 2.6 and 0.4 resulting in 83% of temperatures in the range of 75°-100 °C and 17% in the 60°-74 °C range. Outside the focal zone, the average temperature was 50 °C and in the lateral lobe where no HIFU was applied, peak temperature was 40.7 °C.The TCM algorithm is able to estimate tissue changes reliably during the HIFU procedure for prostate tissue ablation in real-time and can be used as a guide for HIFU dose delivery and tissue ablation control.

Project description:BackgroundThe aim of modern medicine is to safely classify diseases for successful therapy without invasive measures. Sonography, computed tomography (CT), and magnetic resonance imaging (MRI) are potent imaging techniques. However, without contrast medium, the informative value of the 3 native methods is limited. The advantages of sonography are: no radiation exposure or previously known physically harmful interactions with tissue, proportionate disappearance of a contrast agent risk, no (probably irreversible) contrast agent deposits, and no risk of renal insufficiency. But, is that enough to compete with of even exceed CT and MRI?SummaryIn this review, the state of the art of contrast-enhanced ultrasound (CEUS) in the abdominal cavity is presented. The remarkable diagnostic possibilities can unfortunately only be demonstrated here in a small number of impressive, typical case studies underpinned by the literature, so that, from one's own perspective, the full spectrum of CEUS can be used by oneself or initiated. Within the limits of physics, the real-time dynamics of CEUS enable conclusions to be drawn, so that with the current technology, sonography, including expansion by contrast, can be considered superior to other imaging methods. It is not uncommon for CEUS to have the value of a control and reference method.Key messagesSonography very often enables reliable diagnostics. The introduction of a contrast agent in sonography has led to a quantum leap similar to that of other imaging techniques. Already natively, the real-time representation of dynamic events leads to a certain superiority, i.e., complete observation of the inflow and outflow phases of the contrast medium and the resulting diagnostic; tissue-specific differentiation options provide a unique selling point. Further advantages of the first-choice imaging diagnostic method are: a lack of radiation exposure, repeatability of the examination at any time, local independence, a negligible allergy rate compared to the contrast agents of other methods, and a lack of kidney and thyroid exposure or excluded deposits.

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Real-time Monitoring of Contrast-enhanced Ultrasound for Radio Frequency Ablation.

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Real-time Monitoring of Contrast-enhanced Ultrasound for Radio Frequency Ablation.

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