Tissue shrinkage in microwave ablation of liver: an ex vivo predictive model

The aim of this study was to develop a predictive model of the shrinkage of liver tissues in microwave ablation.Thirty-seven cuboid specimens of ex vivo bovine liver of size ranging from 2 cm to 8 cm were heated exploiting different techniques: 1) using a microwave oven (2.45 GHz) operated at 420 W, 500 W and 700 W for 8 to 20 min, achieving complete carbonisation of the specimens, 2) using a radiofrequency ablation apparatus (450 kHz) operated at 70 W for a time ranging from 6 to 7.5 min obtaining white coagulation of the specimens, and 3) using a microwave (2.45 GHz) ablation apparatus operated at 60 W for 10 min. Measurements of specimen dimensions, carbonised and coagulated regions were performed using a ruler with an accuracy of 1 mm. Based on the results of the first two experiments a predictive model for the contraction of liver tissue from microwave ablation was constructed and compared to the result of the third experiment.For carbonised tissue, a linear contraction of 31 ± 6% was obtained independently of the heating source, power and operation time. Radiofrequency experiments determined that the average percentage linear contraction of white coagulated tissue was 12 ± 5%. The average accuracy of our model was determined to be 3 mm (5%).The proposed model allows the prediction of the shrinkage of liver tissues upon microwave ablation given the extension of the carbonised and coagulated zones. This may be useful in helping to predict whether sufficient tissue volume is ablated in clinical practice

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

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

An ex vivo study on the shrinkage occurring in bovine liver during microwave thermal ablation: carbonized vs coagulated tissue

This work aims at deepening the comprehension of this phenomenon, proposing two novel set ups for the characterization of the tissue contraction in correlation with the physical status of the ablated tissue, i.e. to its temperature

The role of FDG PET/CT or PET/MRI in assessing response to neoadjuvant therapy for patients with borderline or resectable pancreatic cancer: a systematic literature review

The aim of the present systematic review is to examine the role of fluorodeoxyglucose (FDG) positron emission tomography (PET) associated with computed tomography (CT) or magnetic resonance imaging (MRI) in assessing response to preoperative chemotherapy or chemoradiotherapy (CRT) for patients with borderline and resectable pancreatic ductal adenocarcinoma (PDAC). Three researchers ran a database query in PubMed, Web of Science and EMBASE. The total number of patients considered was 488. The most often used parameters of response to therapy were the reductions in the maximum standardized uptake value (SUVmax) or the peak standardized uptake lean mass (SULpeak). Patients whose SUVs were higher at the baseline (before CRT) were associated with a better response to therapy and a better overall survival. SUVs remaining high after neoadjuvant therapy correlated with a poor prognosis. Available data indicate that FDG PET/CT or PET/MRI can be useful for predicting and assessing response to CRT in patients with resectable or borderline PDAC

Monitoring of Thermal-Induced Changes in Liver Stiffness During Controlled Hyperthermia and Microwave Ablation in an Ex Vivo Bovine Model Using Point Shear Wave Elastography

To investigate liver stiffness changes-evaluated by point shear wave elastography (pSWE)-in controlled hyperthermia and microwave ablation (MWA) in an ex vivo animal model

Tissue shrinkage in microwave ablation of liver: an <i>ex vivo</i> predictive model

<p><b>Purpose:</b> The aim of this study was to develop a predictive model of the shrinkage of liver tissues in microwave ablation.</p> <p><b>Methods:</b> Thirty-seven cuboid specimens of <i>ex vivo</i> bovine liver of size ranging from 2 cm to 8 cm were heated exploiting different techniques: 1) using a microwave oven (2.45 GHz) operated at 420 W, 500 W and 700 W for 8 to 20 min, achieving complete carbonisation of the specimens, 2) using a radiofrequency ablation apparatus (450 kHz) operated at 70 W for a time ranging from 6 to 7.5 min obtaining white coagulation of the specimens, and 3) using a microwave (2.45 GHz) ablation apparatus operated at 60 W for 10 min. Measurements of specimen dimensions, carbonised and coagulated regions were performed using a ruler with an accuracy of 1 mm. Based on the results of the first two experiments a predictive model for the contraction of liver tissue from microwave ablation was constructed and compared to the result of the third experiment.</p> <p><b>Results:</b> For carbonised tissue, a linear contraction of 31 ± 6% was obtained independently of the heating source, power and operation time. Radiofrequency experiments determined that the average percentage linear contraction of white coagulated tissue was 12 ± 5%. The average accuracy of our model was determined to be 3 mm (5%).</p> <p><b>Conclusions:</b> The proposed model allows the prediction of the shrinkage of liver tissues upon microwave ablation given the extension of the carbonised and coagulated zones. This may be useful in helping to predict whether sufficient tissue volume is ablated in clinical practice.</p

Divergence Between Clinical Trial Evidence and Actual Practice in Use of Dual Antiplatelet Therapy After Transient Ischemic Attack and Minor Stroke

Background: Randomized controlled trials (RCTs) proved that short-term (21-90 days) dual antiplatelet therapy (DAPT) reduces the risk of early ischemic recurrences after a noncardioembolic minor stroke or high-risk transient ischemic attack (TIA) without substantially increasing the hemorrhagic risk. We aimed at understanding whether and how real-world use of DAPT differs from RCTs. Methods: READAPT (Real-Life Study on Short-Term Dual Antiplatelet Treatment in Patients With Ischemic Stroke or TIA) is a prospective cohort study including &gt;18-year-old patients treated with DAPT after a noncardioembolic minor ischemic stroke or high-risk TIA from 51 Italian centers. The study comprises a 90-day follow-up from symptom onset. In the present work, we reported descriptive statistics of baseline data of patients recruited up to July 31, 2022, and proportions of patients who would have been excluded from RCTs. We compared categorical data through the χ² test. Results: We evaluated 1070 patients, who had 72 (interquartile range, 62-79) years median age, were mostly Caucasian (1045; 97.7%), and were men (711; 66.4%). Among the 726 (67.9%) patients with ischemic stroke, 226 (31.1%) did not meet the RCT inclusion criteria because of National Institutes of Health Stroke Scale score &gt;3 and 50 (6.9%) because of National Institutes of Health Stroke Scale score &gt;5. Among the 344 (32.1%) patients with TIA, 69 (19.7%) did not meet the RCT criteria because of age, blood pressure, clinical features, duration of TIA, presence of diabetes score &lt;4 and 252 (74.7%) because of age, blood pressure, clinical features, duration of TIA, presence of diabetes score &lt;6 and no symptomatic arterial stenosis. Additionally, 144 (13.5%) patients would have been excluded because of revascularization procedures. Three hundred forty-five patients (32.2%) did not follow the RCT procedures because of late (&gt;24 hours) DAPT initiation; 776 (72.5%) and 676 (63.2%) patients did not take loading doses of aspirin and clopidogrel, respectively. Overall, 84 (7.8%) patients met the RCT inclusion/exclusion criteria. Conclusions: The real-world use of DAPT is broader than RCTs. Most patients did not meet the RCT criteria because of the severity of ischemic stroke, lower risk of TIA, late DAPT start, or lack of antiplatelet loading dose. Registration: URL: https://www. Clinicaltrials: gov; Unique identifier: NCT05476081