975 research outputs found

    Automatic evolutionary medical image segmentation using deformable models

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    International audienceThis paper describes a hybrid level set approach to medical image segmentation. The method combines region-and edge-based information with the prior shape knowledge introduced using deformable registration. A parameter tuning mechanism, based on Genetic Algorithms, provides the ability to automatically adapt the level set to different segmentation tasks. Provided with a set of examples, the GA learns the correct weights for each image feature used in the segmentation. The algorithm has been tested over four different medical datasets across three image modalities. Our approach has shown significantly more accurate results in comparison with six state-of-the-art segmentation methods. The contributions of both the image registration and the parameter learning steps to the overall performance of the method have also been analyzed

    Radiofrequency catheter ablation of frequent premature ventricular contractions using ARRAY multi-electrode balloon catheter

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    Background: The noncontact mapping system facilitates the mapping of premature ventricular contractions (PVCs) and ventricular tachycardia (VT) using a 64-electrode expandable balloon catheter (ARRAY, St. Jude Medical). The aim of this study is to analyze the results and follow-up of the PVC ablation using this system. Methods and results: Prospective and consecutive patients with frequent PVCs (6,000 or more) or monomorphic VT, suspected to be originated on the right ventricular outflow tract (RVOT), were included. The balloon catheter was positioned in the RVOT. Eighteen patients, 9 women, mean age 48 years (youngest/oldest 19–65) were included. Sixteen patients presented no structural heart disease. The origin of the arrhythmia was RVOT (n = 15), right ventricular inflow tract (n = 1), and left ventricular outflow tract (n = 2). Acute success was achieved in 15 patients; in 2 patients radiofrequency was not applied due to security reasons (origin site close to left coronary artery origin). The mean follow-up was 15 months (min. 4, max. 26); 13 patients presented abolition of the arrhythmia without drugs and 1 patient required antiarrhythmic drugs for arrhythmia control (previously ineffective). As an only complication, a femoral artery-venous fistula was observed. Conclusions: The noncontact mapping system using a multielectrode balloon allows right ventricular arrhythmia treatment with a high rate of efficacy and safety

    Evidence evaluation in craniofacial superimposition using likelihood ratios

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    Craniofacial Superimposition is a forensic identification technique that supports decision-making when skeletal remains are involved. It is based on the analysis of the overlapping of a post-mortem skull with antemortem facial photographs. Despite its importance and wide applicability, the process remains complex and challenging. To address this, computerized methods have been proposed, but subjectivity and qualitative reporting persist in decision-making. This study introduces an evidence evaluation system proposal based on Likelihood Ratios, previously used in other forensic fields, such as DNA, voice, fingerprint, and facial comparison. We present a novel application of this framework to Craniofacial Superimposition. Our work comprises three experiments in which our LR system is trained and tested under distinct conditions concerning facial images: the first utilizes frontal facial photographs; the second employs lateral facial photographs; and the last one integrates both frontal and lateral facial photographs. In the three experiments, the proposed LR system stands out in terms of calibration and discriminating power, providing practitioners with a quantitative tool for evidence evaluation and integration. However, the lack of massive actual data obliged us to focus our study on synthetic data only. Therefore, it should be considered a proof of concept. Nevertheless, the resulting likelihood-ratio system offers objective decision support in Craniofacial Superimposition. Further studies are required to validate in a real scenario the conclusions achieved.R&D project CONFIA (grant PID2021-122916NB-I00), funded by MICIU/AEI/10.13039/ 501100011033 and by ERDF/EU - ‘‘ERDF A way of making Europe’’Grant FORAGE (B-TIC-456-UGR20) funded by Consejería de Universidad, Investigación e Innovación and by ‘‘ERDF A way of making Europe’’Miss Martínez-Moreno is supported by grant PRE2022-102029 funded by MICIU/AEI/10.13039/501100011033 and the FSE+Dr. Valsecchi’s work is supported by Red.es under grant Skeleton-ID2.0 (2021/C005/00141299)Dr. Ibáñez’s work is funded by the Spanish Ministry of Science, Innovation and Universities under grant RYC2020-029454-I and by Xunta de Galicia, Spain by grant ED431F 2022/21Funding for open access charge: Universidad de Granada / CBU

    Pacemaker-detected severe sleep apnea predicts new-onset atrial fibrillation

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    Sleep apnea (SA) diagnosed on overnight polysomnography is a risk factor for atrial fibrillation (AF). Advanced pacemakers are now able to monitor intrathoracic impedance for automatic detection of SA events

    Ventricular Dyssynchrony: 12-month Evaluation In Ischemic Versus Nonischemic CRT Patients

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    Objective: Few data exist about the potential differences in the dyssynchrony status of cardiac resynchronization therapy (CRT) candidates stratified by etiology of heart failure, and about the evolution of dyssynchrony at long-term follow-up. We provided a description of intra-ventricular dyssynchrony at baseline, 6 months and 12 months in ischemic and nonischemic CRT patients.Methods: Tissue Doppler Imaging was performed in 35 CRT candidates (18 ischemic, 17 nonischemic) at baseline, and at 6-month and 12-month follow-up. A group of 11 healthy subjects was considered for comparison.Results: At baseline, the standard deviation and the maximum activation delay between any 2 segments were significantly greater in ischemic (38±33ms, 94±76ms) and nonischemic (38±24ms, 96±62ms) patients versus controls (9±7ms, 22±15ms) (all p<0.05). The average time to activation for posterior and lateral wall was significantly higher in nonischemic patients, while the anterior septum activated later in ischemic patients. At 6-month follow-up, standard deviation and maximum delay did not vary in nonischemic while decreased in ischemic group. All changes persisted at 12 months.Conclusions No baseline differences were observed between ischemic and nonischemic patients using studied indices. At 6- and 12-month follow-up, only ischemic patients presented a significant reduction in dyssynchrony values, although in both groups CRT did not lead to a complete normalization of LV synchronism

    Uncoupling protein 2 G(-866)A polymorphism: a new gene polymorphism associated with C-reactive protein in type 2 diabetic patients C-reactive protein in type 2 diabetic patients

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    <p>Abstract</p> <p>Background</p> <p>This study evaluated the relationship between the G(-866)A polymorphism of the uncoupling protein 2 (UCP2) gene and high-sensitivity C reactive protein (hs-CRP) plasma levels in diabetic patients.</p> <p>Methods</p> <p>We studied 383 unrelated people with type 2 diabetes aged 40-70 years. Anthropometry, fasting lipids, glucose, HbA1c, and hs-CRP were measured. Participants were genotyped for the G (-866)A polymorphism of the uncoupling protein 2 gene.</p> <p>Results</p> <p>Hs-CRP (mg/L) increased progressively across the three genotype groups AA, AG, or GG, being respectively 3.0 ± 3.2, 3.6 ± 5.0, and 4.8 ± 5.3 (p for trend = 0.03). Since hs-CRP values were not significantly different between AA and AG genotype, these two groups were pooled for further analyses. Compared to participants with the AA/AG genotypes, homozygotes for the G allele (GG genotype) had significantly higher hs-CRP levels (4.8 ± 5.3 vs 3.5 ± 4.7 mg/L, p = 0.01) and a larger proportion (53.9% vs 46.1%, p = 0.013) of elevated hs-CRP (> 2 mg/L). This was not explained by major confounders such as age, gender, BMI, waist circumference, HbA1c, smoking, or medications use which were comparable in the two genotype groups.</p> <p>Conclusions</p> <p>The study shows for the first time, in type 2 diabetic patients, a significant association of hs-CRP levels with the G(-866)A polymorphism of UCP2 beyond the effect of major confounders.</p

    The "Defibrillation Testing, Why Not?" survey. Testing of subcutaneous and transvenous defibrillators in the Italian clinical practice

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    Background: Defibrillation testing (DT) can be omitted in patients undergoing transvenous implantable cardioverter-defibrillator (T-ICD) implantation, but it is still recommended for patients at risk for a high defibrillation threshold and for ICD generator changes. Moreover, DT is still recommended on implantation of subcutaneous ICD (S-ICD). The aim of the present survey was to analyze the current practice of DT during T-ICD and S-ICD implantations.Methods: In March 2021, an ad hoc questionnaire on the current performance of DT and the standard practice adopted during testing was completed at 72 Italian centers implanting S-ICD and T-ICD.Results: 48 (67%) operators reported never performing DT during de-novo T-ICD implantations, while no operators perform it systematically. The remaining respondents perform it for patients at risk for a high defibrillation threshold. DT is never performed at T-ICD generator change. At the time of de-novo S-ICD implantation, DT is never performed by 9 (13%) operators and performed systematically by 48 (66%). The remaining operators frequently omit DT in patients with more severe systolic dysfunction. DT is not performed at S-ICD generator change by 92% of operators. DT is conducted by delivering a first shock energy of 65 J by 60% of operators, while the remaining 40% test lower energy values.Conclusions: In current clinical practice, most operators omit DT at T-ICD implantation, even when still recommended in the guidelines. DT is also frequently omitted at S-ICD implantation, and a wide variability exists among operators in the procedures followed during DT
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