47 research outputs found

    Microwave ablation of primary and secondary liver tumours: ex vivo, in vivo, and clinical characterisation.

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    The aim of this study was to compare the performance of a microwave ablation (MWA) apparatus in preclinical and clinical settings.The same commercial 2.45 GHz MWA apparatus was used throughout this study. In total 108 ablations at powers ranging from 20 to 130 W and lasting from 3 to 30 min were obtained on ex vivo bovine liver; 28 ablations at 60 W, 80 W and 100 W lasting 5 and 10 min were then obtained in an in vivo swine model. Finally, 32 hepatocellular carcinomas (HCCs) and 19 liver metastases in 46 patients were treated percutaneously by administering 60 W for either 5 or 10 min. The treatment outcome was characterised in terms of maximum longitudinal and transversal axis of the induced ablation zone.Ex vivo ablation volumes increased linearly with deposited energy (rFor the selected MW ablation device, ex vivo data on bovine liver was more predictive of the actual clinical performance on liver malignancies than an in vivo porcine model. Equivalent MW treatments yielded a significantly different response for HCC and metastases at higher deposited energy, suggesting that outcomes are not only device-specific but must also be characterised on a tissue-by-tissue basis

    How to perform Contrast-Enhanced Ultrasound (CEUS)

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    "How to perform contrast-enhanced ultrasound (CEUS)" provides general advice on the use of ultrasound contrast agents (UCAs) for clinical decision-making and reviews technical parameters for optimal CEUS performance. CEUS techniques vary between centers, therefore, experts from EFSUMB, WFUMB and from the CEUS LI-RADS working group created a discussion forum to standardize the CEUS examination technique according to published evidence and best personal experience. The goal is to standardise the use and administration of UCAs to facilitate correct diagnoses and ultimately to improve the management and outcomes of patients

    Consensus guidelines for the definition of time-to-event end points in image-guided tumor ablation: results of the SIO and DATECAN initiative

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    International audienceThere is currently no consensus regarding preferred clinical outcome measures following image-guided tumor ablation or clear definitions of oncologic end points. This consensus document proposes standardized definitions for a broad range of oncologic outcome measures with recommendations on how to uniformly document, analyze, and report outcomes. The initiative was coordinated by the Society of Interventional Oncology in collaboration with the Definition for the Assessment of Time-to-Event End Points in Cancer Trials, or DATECAN, group. According to predefined criteria, based on experience with clinical trials, an international panel of 62 experts convened. Recommendations were developed using the validated three-step modified Delphi consensus method. Consensus was reached on when to assess outcomes per patient, per session, or per tumor; on starting and ending time and survival time definitions; and on time-to-event end points. Although no consensus was reached on the preferred classification system to report complications, quality of life, and health economics issues, the panel did agree on using the most recent version of a validated patient-reported outcome questionnaire. This article provides a framework of key opinion leader recommendations with the intent to facilitate a clear interpretation of results and standardize worldwide communication. Widespread adoption will improve reproducibility, allow for accurate comparisons, and avoid misinterpretations in the field of interventional oncology research. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Liddell in this issue

    Contrast-enhanced ultrasonography of the liver using SonoVue

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    This review focuses on the use of contrast-enhanced ultrasonography (CEUS) with SonoVue (Bracco Imaging) for the diagnosis of focal liver lesions (FLLs), guidance during ablative treatment, and follow-up of liver tumors. Multicenter trials have shown that the performance of CEUS for the characterization of FLLs is similar to that of contrast-enhanced computed tomography or contrast-enhanced magnetic resonance imaging. CEUS with SonoVue has been effectively used for guiding the percutaneous treatment of malignant liver tumors that are invisible or poorly visualized in traditional gray-scale ultrasonography. Postprocedural CEUS may be used to detect and retreat residual viable tissue in the same ablative session. The use of CEUS for the assessment of diffuse liver disease is also discussed

    Loco-regional treatment of hepatocellular carcinoma: Role of contrast-enhanced ultrasonography

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    Hepatocellular carcinoma (HCC) is one of the few cancers for which locoregional treatments (LRTs) are included in international guidelines and are considered as a valid alternative to conventional surgery. According to Barcelona Clinic Liver Cancer classification, percutaneous treatments such as percutaneous ethanol injection, radiofrequency ablation and microwave ablation are the therapy of choice among curative treatments in patients categorized as very early and early stage, while transcatheter arterial chemoembolization is considered the better option for intermediate stage HCC. A precise assessment of treatment efficacy and surveillance is essential to optimize survival rate, whereas residual tumor requires additional treatment. Imaging modalities play a key role in this task. Currently, contrast-enhanced computed tomography/magnetic resonance imaging are considered the standard imaging modalities for this purpose. Contrast enhanced ultrasound (CEUS), using second generation contrast agents, plays an increasingly important role in detecting residual disease after LRTs. CEUS is a straightforward to perform, repeatable and cost-effective imaging modality for patients with renal failure or iodine allergies. Due to the ability to focus on single regions, CEUS can also provide high temporal resolution. Moreover, several studies have reported the same or better diagnostic accuracy as contrast-enhanced computed tomography for assessing tumor vascularity 1 mo after LRTs, and recently three-dimensional (3D)-CEUS has been reported as a promising technique to improve the evaluation of tumor response to therapy. Furthermore, CEUS could be used early after procedures in monitoring HCC treatments, but nowadays this indication is still debated, and data from literature are conflicting, especially after transcatheter arterial chemoembolization procedure

    Nanostructured Ni/CeO₂-ZrO₂ Catalysts for CO₂ Conversion into Synthetic Natural Gas

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    NiO-CeO₂-ZrO₂ mixed oxides, with Ni/(Ce + Zr) = 1 mol/mol and different Ce/Zr molar ratios, were prepared by the soft-template method. The chemical composition, texture, structure, and redox features of the synthesized systems were investigated by different techniques. All samples were nanocrystalline (NiO nanocrystal average size 4 nm) and had high surface area and quite an ordered mesoporous system. The catalytic performances in the CO₂ conversion into methane were studied at atmospheric pressure, 300 °C, and stoichiometric H₂/CO₂ molar ratio. Prior to reaction the catalysts were submitted to a mild reduction pretreatment (H₂ at 400 °C for 1 h). XRD analysis of the samples after pretreatment showed the presence of small Ni crystals (4-7 nm) on all the samples as well as of some unreduced NiO nanocrystals on the systems with high Zr content, in accordance with H₂-TPR experiments, which indicated that NiO reduction is promoted by CeO₂ but hindered by ZrO₂. The catalytic tests were performed at two different space velocities (72000 and 900000 cm³ h-1 g-1cat) on a series of Ni-based catalysts supported on CeO₂-ZrO₂ systems with different Ce/Zr ratios, including the two pure oxides. CO₂ conversion and selectivity to CH₄ (which was always close to 100 mol%) were constant throughout the 6-hour runs. CO₂ conversion resulted to increase with CeO₂ content in the catalyst, thus indicating the role of the CeO₂ component of the support in activating CO₂, whereas H₂ is activated on the Ni nanoparticles

    CO and CO2 Co-Methanation on Ni/CeO2-ZrO2 Soft-Templated Catalysts

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    Supported nickel catalysts were synthesized, characterized, and employed in the carbon oxides co-methanation process. Five NiO/CeO2-ZrO2 mixed oxides, with the same Ni content and different Ce/Zr molar ratios, were prepared by the soft-template method. They were characterized through ICP-AES, N2 adsorption, XRD, and TPR. Reduced Ni/CeO2-ZrO2 catalysts were obtained by submitting the oxide systems to reduction treatment in H2 at 400 ◦C. They were characterized by XRD, H2-TPD, and CO2 adsorption microcalorimetry and their catalytic performances in the carbon oxides co-methanation were investigated. Catalytic tests were performed in a fixed-bed continuous-flow microreactor at atmospheric pressure. The effect of experimental conditions (reaction temperature, space velocity, reactants molar ratio) was also studied. Almost complete CO conversion was obtained on any catalyst, whereas CO2 conversion was much lower and increased with Ce content, at least up to Ce/Zr = 1. The beneficial effect of the Ce content could be related to the increased NiO reducibility and to the higher ability to adsorb and activate CO2. However, at high Ce/Zr ratios, it is probably counterbalanced by an interplay of reactions involving CO and CO2

    Sulfonic acid-functionalized mesoporous silicas: Microcalorimetric characterization and catalytic performance toward biodiesel synthesis

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    In this work the synthesis of two sulfonic acid-functionalized mesoporous silica-based materials (SBA-15-propyl-SO3H and SBA-15-phenyl-SO 3H) through a co-condensation method is reported. The samples were characterized by means of SAXS, N2-adsorption/desorption isotherms, FTIR spectroscopy and thermogravimetric analysis. In addition, the surface acidity of the samples was investigated through ammonia adsorption microcalorimetry. We found that both the number and the strength of acid sites of SBA-15-phenyl-SO3H catalyst are higher than those of SBA-15-propyl-SO3H. The total number of acid sites was 808 μmol/g and 122 μmol/g for SBA-15-phenyl-SO3H and SBA-15-propyl-SO 3H, respectively. The two materials were then used as acid heterogeneous catalysts for the interesterification of extra virgin olive oil with ethyl acetate to produce biodiesel. We found a higher catalytic activity of SBA-15-phenyl-SO3H respect to SBA-15-propyl-SO3H in agreement with the microcalorimetric acidity measurements. Phenyl-sulfonic acid-functionalized SBA-15 seems to be a promising acid heterogenous catalyst for the preparation of biodiesel through the interesterification of triglycerides with ethyl acetate

    A Review of the Appropriateness of the Current Italian Guidelines for Noninvasive Imaging Assessment of Focal Liver Lesions

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    In 2007 the Italian National Institute of Health issued Guidelines for the use of diagnostic imaging techniques in the detection and the characterization of focal liver lesions. Since the publication of these guidelines in 2008, several studies relating to this topic have been published. Thus, we felt the need to assess whether interval research and new advancements in diagnostic imaging have yielded new evidence that should modify the recommendations that were previously issued. The literature search confirmed the appropriateness of the current guidelines. Although most modalities did not show substantial changes, interval introduction of DW-MRI is a valuable technique with a high diagnostic accuracy in the detection and characterization of FLLs, and its sensitivity is higher when combined with MRI
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