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101.
Extraction of artefactual MRS patterns from a large database using non-negative matrix factorization
Yanisleydis Hernández-Villegas Sandra Ortega-Martorell Carles Arús Alfredo Vellido Margarida Julià-Sapé 《NMR in biomedicine》2022,35(4):e4193
Despite the success of automated pattern recognition methods in problems of human brain tumor diagnostic classification, limited attention has been paid to the issue of automated data quality assessment in the field of MRS for neuro-oncology. Beyond some early attempts to address this issue, the current standard in practice is MRS quality control through human (expert-based) assessment. One aspect of automatic quality control is the problem of detecting artefacts in MRS data. Artefacts, whose variety has already been reviewed in some detail and some of which may even escape human quality control, have a negative influence in pattern recognition methods attempting to assist tumor characterization. The automatic detection of MRS artefacts should be beneficial for radiology as it guarantees more reliable tumor characterizations, as well as the development of more robust pattern recognition-based tumor classifiers and more trustable MRS data processing and analysis pipelines. Feature extraction methods have previously been used to help distinguishing between good and bad quality spectra to apply subsequent supervised pattern recognition techniques. In this study, we apply feature extraction differently and use a variant of a method for blind source separation, namely Convex Non-Negative Matrix Factorization, to unveil MRS signal sources in a completely unsupervised way. We hypothesize that, while most sources will correspond to the different tumor patterns, some of them will reflect signal artefacts. The experimental work reported in this paper, analyzing a combined short and long echo time 1H-MRS database of more than 2000 spectra acquired at 1.5T and corresponding to different tumor types and other anomalous masses, provides a first proof of concept that points to the possible validity of this approach. 相似文献
102.
Alfredo Bardají Judit Rodriguez-López Mauricio Torres-Sánchez 《World journal of cardiology》2014,6(7):621-629
Over the last two decades,there has been increasing interest in new techniques for the percutaneous treatment of coronary chronic total occlusions(CTO),which have a success rate that is much higher than that of a few years ago.The rise in percutaneous treatment for these lesions is due to its ability to improve the symptoms and prognosis of patients in the chronic and stable phase of coronary disease.Current data suggest that successful percutaneous coronary intervention for CTO is associated with improvement in patient symptoms,quality of life,left ventricular function,and survival,compared with those with unsuccessful CTO PCI.However,all the scientific evidence supporting this treatment comes from observational studies,and no randomized study comparing percutaneous treatment with medical treatment has yet been published.A major limitation of these studies is their observational design,with limited information with regard to potential baseline differences between the successful vs unsuccessful cohorts.Pending randomized studies,patients should be selected very carefully,especially if they are asymptomatic or very few symptoms,and the benefits obtained in terms of complications during the procedure,the quality of life obtained and further ischemic events avoided should be evaluated systematically.In this review,we will consider the available information supporting percutaneous treatment for chronic occlusions,as well as the areas of uncertainty where more research projects are required. 相似文献
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Luiz Alberto Forgiarini Gustavo Grün Nélson Alexandre Kretzmann Gustavo Alfredo Ochs de Muñoz Antonino de Almeida Luiz Felipe Forgiarini Cristiano Feijó Andrade 《The Journal of surgical research》2013,179(1):168-174
ObjectiveTo verify the impact of ischemic time on lung cell viability in an experimental model of lung ischemia–reperfusion (IR) injury and its repercussion on lung performance after reperfusion.MethodsTwenty-four animals were subjected to selective clamping of the left pulmonary artery and divided into four groups (n = 6) according to ischemic time: 15 (IR15), 30 (IR30), 45 (IR45), and 60 min (IR60). All animals were observed for 120 min after reperfusion. The hemodynamics, arterial blood gases measurements, and histologic changes were analyzed. Immunofluorescence assays for caspase 3 and annexin V were performed. Lipid peroxidation was assessed by thiobarbituric acid–reactive substances, and caspase 3 activity was assessed by colorimetric extract.ResultsThe partial pressure of arterial oxygen significantly decreased at the end of the observation period in the IR30, IR45, and IR60 groups (P < 0.05). The final mean arterial pressure significantly decreased in the IR60 group (P < 0.05). We observed a significant increase in caspase 3 activity and caspase 3–positive cells by immunofluorescence in the IR45 group compared with the other groups (P < 0.05). Additionally, there was an increase in necrotic cells assessed by annexin V in the IR60 group. The histologic score did not show differences among the different groups.ConclusionsThe degree of cell damage had a negative impact on lung performance. Sixty minutes of lung ischemia and posterior reperfusion resulted in an increased number of necrotic cells, suggesting that these cells may not be able to reverse the effects of the IR injury because of the lack of viable cells. 相似文献
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106.
Carlos A. Jiménez Ruiz Daniel Buljubasich Juan Antonio Riesco Miranda Agustín Acuña Izcaray José Ignacio de Granda Orive José Miguel Chatkin Gustavo Zabert Alfredo Guerreros Benavides Nelson Paez Espinel Valeri Noé Efraín Sánchez-Angarita Ingrid Núñez-Sánchez Raúl H. Sansores Alejandro Casas Andrés Palomar Lever Inmaculada Alfageme Michavila 《Archivos de bronconeumología》2017,53(11):622-628
The ALAT and SEPAR Treatment and Control of Smoking Groups have collaborated in the preparation of this document which attempts to answer, by way of PICO methodology, different questions on health interventions for helping COPD patients to stop smoking.The main recommendations are: (i) moderate-quality evidence and strong recommendation for performing spirometry in COPD patients and in smokers with a high risk of developing the disease, as a motivational tool (particularly for showing evidence of lung age), a diagnostic tool, and for active case-finding; (ii) high-quality evidence and strong recommendation for using intensive dedicated behavioral counselling and drug treatment for helping COPD patients to stop smoking; (iii) high-quality evidence and strong recommendation for initiating interventions for helping COPD patients to stop smoking during hospitalization with improvement when the intervention is prolonged after discharge, and (iv) high-quality evidence and strong recommendation for funding treatment of smoking in COPD patients, in view of the impact on health and health economics. 相似文献
107.
Piccoli M Trambaiolo P Salustri A Cerquetani E Posteraro A Pastena G Amici E Papetti F Marincola E La Carruba S Gambelli G 《Chest》2005,128(5):3413-3420
OBJECTIVES: The aim of this study was to assess the potential value of hand-carried ultrasound (HCU) devices in the diagnosis and follow-up of patients with pleural effusion (PE) after cardiac surgery. METHODS: Seventy consecutive patients were evaluated at bedside early after cardiac surgery, in the upright sitting position, using an HCU device on hospital admission and every 3 days until hospital discharge. The posterior chest wall was scanned along the paravertebral, scapular, and posterior axillary lines. For each hemithorax, an effusion index was derived as the sum of the intercostal spaces between the lower and upper limits of the PE along the lines of scanning, divided by 3. A standard chest radiograph was performed in all patients on hospital admission and at hospital discharge, and was qualitatively scored (0, absent; 1, small; 2, large PE). The findings of the HCU device and radiograph were compared using kappa statistics and the Kruskal-Wallis test. RESULTS: A chest ultrasound was feasible in all patients (mean [+/- SD] time, 5 +/- 2 min). Compared with the chest ultrasound, a physical examination showed a sensitivity of 69% and a specificity of 77%. On hospital admission, the HCU device detected a PE in 72 of 140 hemithoraxes. Agreement with the finding of the radiograph was 76% (kappa = 0.52). In 15 hemithoraxes, the HCU device revealed a PE that had not been diagnosed using the radiograph. Conversely, in 18 hemithoraxes a PE that had been diagnosed with a radiograph was not confirmed by the HCU device. The correlation between ultrasound and radiographic scores was statistically significant (p < 0.001). At hospital discharge, a PE was present in 31 of 140 hemithoraxes according to the findings of the HCU device, and in 38 of 140 hemithoraxes according to the findings of the radiograph (agreement, 78%; kappa = 0.44). CONCLUSIONS: In patients early after cardiac surgery, HCU devices allow rapid PE detection and improve the clinical diagnosis. Compared to a radiograph, this method offers the unique advantage of the bedside evaluation of patients without the need for radiation exposure. 相似文献
108.
109.
Locatelli F Gauly A Czekalski S Hannedouche T Jacobson SH Loureiro A Martin-Malo A Papadimitriou M Passlick-Deetjen J Ronco C Vanholder R Wizemann V;Membrane Permeability Outcome 《Blood purification》2008,26(1):100-104
Although results from observational and epidemiological studies suggested a survival benefit associated with high-flux hemodialysis, conclusive evidence from prospective randomized clinical trials has been lacking. Both the HEMO Study in the USA and the Membrane Permeability Outcome Study (MPO Study) in Europe are randomized studies investigating the effect of high- and low-flux hemodialysis on patient outcomes, even though there were some significant differences in the design of the two studies. An earlier randomized clinical trial could not show differences on patient survival between patient groups being treated with membranes of different material and permeability, but this trial was not designed specifically to examine this particular endpoint. Based on these previous experiences, the MPO Study addressed a hemodialysis patient population which was considered to be more susceptible to the intervention with high-flux dialysis. To identify these patients with an elevated risk, low serum albumin levels were chosen as an indicator; low serum albumin is associated with malnutrition, inflammation, atherosclerosis, and with increased risk of morbidity and mortality. Together with low serum albumin, patients had to be new to dialysis to be selected for the MPO Study. These particular considerations on patient selection, together with additional methodological refinements in the study design allow the conclusion that the MPO Study is valid on its own rather than being a European version of the HEMO Study. 相似文献
110.