Introduction: This study proposes an algorithm for preprocessing VCG records to obtain a representative QRS loop. Methods: The proposed algorithm uses the following methods: Digital filtering to remove noise from the signal, wavelet-based detection of ECG fiducial points and isoelectric PQ intervals, spatial alignment of QRS loops, QRS time synchronization using root mean square error minimization and ectopic QRS elimination. The representative QRS loop is calculated as the average of all QRS loops in the VCG record. The algorithm is evaluated on 161 VCG records from a database of 58 healthy control subjects, 69 patients with myocardial infarction, and 34 patients with bundle branch block. The morphologic intra-individual beat-to-beat variability rate is calculated for each VCG record. Results and Discussion: The maximum relative deviation is 12.2% for healthy control subjects, 19.3% for patients with myocardial infarction, and 17.2% for patients with bundle branch block. The performance of the algorithm is assessed by measuring the morphologic variability before and after QRS time synchronization and ectopic QRS elimination. The variability is reduced by a factor of 0.36 for healthy control subjects, 0.38 for patients with myocardial infarction, and 0.41 for patients with bundle branch block. The proposed algorithm can be used to generate a representative QRS loop for each VCG record. This representative QRS loop can be used to visualize, compare, and further process VCG records for automatic VCG record classification.
- Publikační typ
- časopisecké články MeSH
This article presents an overview of existing approaches to perform vectorcardiographic (VCG) diagnostics of ischemic heart disease (IHD). Individual methodologies are divided into categories to create a comprehensive and clear overview of electrical cardiac activity measurement, signal pre-processing, features extraction and classification procedures. An emphasis is placed on methods describing the electrical heart space (EHS) by several features extraction techniques based on spatiotemporal characteristics or signal modelling and signal transformations. Performance of individual methodologies are compared depending on classification of extent of ischemia, acute forms - myocardial infarction (MI) and myocardial scars localization. Based on a comparison of imaging methods, the advantages of VCG over the standard 12-leads ECG such as providing a 3D orthogonal leads imaging, better performance, and appropriate computer processing are highlighted. The issues of electrical cardiac activity measurements on body surface, the lack of VKG databases supported by a more accurate imaging method, possibility of comparison with the physiology of individual cases are outlined as potential reserves for future research.
- MeSH
- elektrokardiografie metody MeSH
- infarkt myokardu * MeSH
- lidé MeSH
- myokard MeSH
- počítačové zpracování signálu MeSH
- srdce fyziologie MeSH
- vektorkardiografie * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Mechanical ventilation (MV) provides basic organ support for patients who have acute hypoxemic respiratory failure, with acute respiratory distress syndrome as the most severe form. The use of excessive ventilation forces can exacerbate the lung condition and lead to ventilator-induced lung injury (VILI); mechanical energy (ME) or power can characterize such forces applied during MV. The ME metric combines all MV parameters affecting the respiratory system (ie, lungs, chest, and airways) into a single value. Besides evaluating the overall ME, this parameter can be also related to patient-specific characteristics, such as lung compliance or patient weight, which can further improve the value of ME for characterizing the aggressiveness of lung ventilation. High ME is associated with poor outcomes and could be used as a prognostic parameter and indicator of the risk of VILI. ME is rarely determined in everyday practice because the calculations are complicated and based on multiple equations. Although low ME does not conclusively prevent the possibility of VILI (eg, due to the lung inhomogeneity and preexisting damage), individualization of MV settings considering ME appears to improve outcomes. This article aims to review the roles of bedside assessment of mechanical power, its relevance in mechanical ventilation, and its associations with treatment outcomes. In addition, we discuss methods for ME determination, aiming to propose the most suitable method for bedside application of the ME concept in everyday practice.
- MeSH
- agrese MeSH
- dýchání MeSH
- hrudník MeSH
- lidé MeSH
- poškození plic mechanickou ventilací * MeSH
- syndrom dechové tísně * MeSH
- umělé dýchání MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Data o zdravotní péči ve správě státem řízených organizací jsou pro společnost cenným nehmotným aktivem. Jejich využití by mělo být pro jejich správce a stát prioritou. Zcela paternalistický přístup správců a státu je nežádoucí, jakkoliv má za cíl ochranu práva na soukromí osob registrovaných v databázích. V souladu s evropskou politikou a celosvětovým trendem by však tato opatření neměla převážit společenský benefit, který z analýzy těchto údajů vyplývá, existují-li technické možnosti práva osob na soukromí dostatečně chránit. Česká společnost vede k tématu intenzivní diskusi, která se však podle autorů jen nedostatečně opírá o fakta a postrádá jasně artikulovaná stanoviska odborné veřejnosti. Cílem tohoto článku je tyto mezery zacelit. Techniky anonymizace údajů představují řešení, jak chránit práva jednotlivců na soukromí a zároveň zachovat vědeckou hodnotu údajů. Riziko ztotožnění jednotlivců v anonymizovaných souborech údajů je škálovatelné a lze ho minimalizovat v závislosti na typu a obsahu údajů a jejich použití konkrétním žadatelem. Nalezení optimální formy a rozsahu deidentifikovaných údajů vyžaduje kompetence a znalosti jak na straně žadatele, tak na straně správce. Je v zájmu žadatele, správce i chráněných osob v databázích, aby obě strany projevily ochotu a měly schopnost a odborné znalosti komunikovat v průběhu žádosti a jejího zpracování.
Healthcare data held by state-run organisations is a valuable intangible asset for society. Its use should be a priority for its administrators and the state. A completely paternalistic approach by administrators and the state is undesirable, however much it aims to protect the privacy rights of persons registered in databases. In line with European policies and the global trend, these measures should not outweigh the social benefit that arises from the analysis of these data if the technical possibilities exist to sufficiently protect the privacy rights of individuals. Czech society is having an intense discussion on the topic, but according to the authors, it is insufficiently based on facts and lacks clearly articulated opinions of the expert public. The aim of this article is to fill these gaps. Data anonymization techniques provide a solution to protect individuals' privacy rights while preserving the scientific value of the data. The risk of identifying individuals in anonymised data sets is scalable and can be minimised depending on the type and content of the data and its use by the specific applicant. Finding the optimal form and scope of deidentified data requires competence and knowledge on the part of both the applicant and the administrator. It is in the interest of the applicant, the administrator, as well as the protected persons in the databases that both parties show willingness and have the ability and expertise to communicate during the application and its processing.
Ultrasound power delivery can be considered a convenient technique for charging implantable medical devices. In this work, an intra-body system has been modeled to characterize the phenomenon of ultrasound power transmission. The proposed system comprises a Langevin transducer as transmitter and an AlN-based square piezoelectric micro-machined ultrasonic transducer as receiver. The medium layers, in which elastic waves propagate, were made by polydimethylsiloxane to mimic human tissue and stainless steel to replace the case of the implantable device. To characterize the behavior of the transducers, measurements of impedance and phase, velocity and displacement, and acoustic pressure field were carried out in the experimental activity. Then, voltage and power output were measured to analyze the performance of the ultrasound power delivery system. For a root mean square voltage input of approximately 35 V, the power density resulted in 21.6 μW cm-2. Such a result corresponds to the data obtained with simulation through a one-dimensional lumped parameter transmission line model. The methodology proposed to develop the ultrasound power delivery (UPD) system, as well as the use of non-toxic materials for the fabrication of the intra-body elements, are a valid design approach to raise awareness of using wireless power transfer techniques for charging implantable devices.
- Publikační typ
- časopisecké články MeSH
The analysis and segmentation of articular cartilage magnetic resonance (MR) images belongs to one of the most commonly routine tasks in diagnostics of the musculoskeletal system of the knee area. Conventional regional segmentation methods, which are based either on the histogram partitioning (e.g., Otsu method) or clustering methods (e.g., K-means), have been frequently used for the task of regional segmentation. Such methods are well known as fast and well working in the environment, where cartilage image features are reliably recognizable. The well-known fact is that the performance of these methods is prone to the image noise and artefacts. In this context, regional segmentation strategies, driven by either genetic algorithms or selected evolutionary computing strategies, have the potential to overcome these traditional methods such as Otsu thresholding or K-means in the context of their performance. These optimization strategies consecutively generate a pyramid of a possible set of histogram thresholds, of which the quality is evaluated by using the fitness function based on Kapur's entropy maximization to find the most optimal combination of thresholds for articular cartilage segmentation. On the other hand, such optimization strategies are often computationally demanding, which is a limitation of using such methods for a stack of MR images. In this study, we publish a comprehensive analysis of the optimization methods based on fuzzy soft segmentation, driven by artificial bee colony (ABC), particle swarm optimization (PSO), Darwinian particle swarm optimization (DPSO), and a genetic algorithm for an optimal thresholding selection against the routine segmentations Otsu and K-means for analysis and the features extraction of articular cartilage from MR images. This study objectively analyzes the performance of the segmentation strategies upon variable noise with dynamic intensities to report a segmentation's robustness in various image conditions for a various number of segmentation classes (4, 7, and 10), cartilage features (area, perimeter, and skeleton) extraction preciseness against the routine segmentation strategies, and lastly the computing time, which represents an important factor of segmentation performance. We use the same settings on individual optimization strategies: 100 iterations and 50 population. This study suggests that the combination of fuzzy thresholding with an ABC algorithm gives the best performance in the comparison with other methods as from the view of the segmentation influence of additive dynamic noise influence, also for cartilage features extraction. On the other hand, using genetic algorithms for cartilage segmentation in some cases does not give a good performance. In most cases, the analyzed optimization strategies significantly overcome the routine segmentation methods except for the computing time, which is normally lower for the routine algorithms. We also publish statistical tests of significance, showing differences in the performance of individual optimization strategies against Otsu and K-means method. Lastly, as a part of this study, we publish a software environment, integrating all the methods from this study.
The article deals with an overview of acute extremity compartment syndrome with a focus on the option of non-invasive detection of the syndrome. Acute extremity compartment syndrome (ECS) is an urgent complication that occurs most often in fractures or high-energy injuries. There is still no reliable method for detecting ECS. The only objective measurement method used in clinical practice is an invasive measurement of intramuscular pressure (IMP). The purpose of this paper is to summarize the current state of research into non-invasive measurement methods that could allow simple and reliable continuous monitoring of patients at risk of developing ECS. Clinical trials are currently underway to verify the suitability of the most studied method, near-infrared spectroscopy (NIRS), which is a method for measuring the local oxygenation of muscle compartments. Less explored methods include the use of ultrasound, ultrasound elastography, bioimpedance measurements, and quantitative tissue hardness measurements. Finding a suitable method for continuous non-invasive monitoring of the syndrome would greatly improve the quality of care for patients at risk. ECS must be diagnosed quickly and accurately to prevent irreversible tissue damage that can occur within hours of syndrome onset and may even warrant amputation if neglected.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Wavelet transform (WT) is a commonly used method for noise suppression and feature extraction from biomedical images. The selection of WT system settings significantly affects the efficiency of denoising procedure. This comparative study analyzed the efficacy of the proposed WT system on real 292 ultrasound images from several areas of interest. The study investigates the performance of the system for different scaling functions of two basic wavelet bases, Daubechies and Symlets, and their efficiency on images artificially corrupted by three kinds of noise. To evaluate our extensive analysis, we used objective metrics, namely structural similarity index (SSIM), correlation coefficient, mean squared error (MSE), peak signal-to-noise ratio (PSNR) and universal image quality index (Q-index). Moreover, this study includes clinical insights on selected filtration outcomes provided by clinical experts. The results show that the efficiency of the filtration strongly depends on the specific wavelet system setting, type of ultrasound data, and the noise present. The findings presented may provide a useful guideline for researchers, software developers, and clinical professionals to obtain high quality images.
Měření mnoha důležitých psychologických konceptů jako jsou kvalita života související se zdravím, spokojenost s různými typy veřejných a soukromých služeb, osobnost nebo postoje, se nejčastěji opírá o různé dotazníky. Tyto dotazníkové metody jsou však založeny na subjektivním svědectví jednotlivce o jeho vlastnostech, pocitech, postojích atd. Relevantní odpovědi poskytují pouze tehdy, mají-li respondenti dobře vyvinutou introspekci, důvod otevřít se, vyjádřit se a poskytnout adekvátní a relevantní odpovědi. Projektivní metody představují alternativní možnost měření psychologických konceptů s potenciálním snížením vědomé či nevědomé zaujatosti. Metoda asociace barev (The Colour Association Method; CA) je pokročilá projektivní technika, inspirovaná Lüscherovým testem barev a slovních asociací, která využívá objektivního vyhodnocení počítačových dat a překonává tak jednu z hlavních slabin projektivních metod. Cílem studie je prozkoumat schopnost standardního dotazníku a metody CA v zachycení reakce lidí na různé podněty s emočním nábojem. K tomuto účelu bude do studie zařazen vzorek 101 jedinců, kdy každý z nich bude vystaven 145 různým předem definovaným podnětům. Bude provedeno srovnání fyziologických odpovědí (průtok krve mozkem, elektrická aktivita mozku, variabilita srdeční frekvence a kožní impedance) na tyto podněty a vnímání podnětů měřených dotazníkem a metodou CA s cílem zjistit, která metoda poskytuje přesnější informace o skutečném emočním vnímání podnětů. Tato zjištění mohou mít důležité důsledky pro použití dotazníku a metody CA k měření různých psychologických konceptů.
Measurement of many important psychological concepts, such as health-related quality of life, satisfaction with different types of public and private services, personality, or attitudes, is most often based on various questionnaires. Nevertheless, this method is based on the subjective testimony of an individual about his/her features, feelings, attitudes, etc. It provides relevant responses only when respondents have well developed introspection, a reason to open up, express themselves, and provide adequate and relevant answers. Projective methods represent an alternative option to measure psychological concepts with the potential reduction of conscious or unconscious bias. The Colour Association Method (CA method) is an advanced projective technique, based on principles of the Lüscher colour test and word associations, which uses an objective computer data evaluation and thus overcomes one of the main weaknesses of projective methods. The study aims to investigate the ability of standard questionnaire and CA method to capture the responses of humans to different stimuli with emotional charge. A sample of 101 individuals will be used for this purpose, where each of them will be exposed to 145 different predefined stimuli. Comparison of physiological responses (cerebral blood flow, electrical activity of the brain, heart rate variability, and skin conductance response) to these stimuli and the perception of the stimuli measured by the questionnaire and CA method will be performed to determine which method provides a more accurate information on the real perception of the stimuli. These findings may have important consequences for the use of the questionnaire and the CA method to measure different psychological concepts.
- Klíčová slova
- kožní impedance, metoda asociace barev,
- MeSH
- emoce * fyziologie MeSH
- klinická studie jako téma MeSH
- lidé MeSH
- mozkový krevní oběh MeSH
- průzkumy a dotazníky MeSH
- psychometrie * metody MeSH
- srdeční frekvence MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Background: Here we aimed to evaluate the respiratory and cardiac-induced motion of a ICD lead used as surrogate in the heart during stereotactic body radiotherapy (SBRT) of ventricular tachycardia (VT). Data provides insight regarding motion and motion variations during treatment. Materials and methods: We analyzed the log files of surrogate motion during SBRT of ventricular tachycardia performed in 20 patients. Evaluated parameters included the ICD lead motion amplitudes; intrafraction amplitude variability; correlation error between the ICD lead and external markers; and margin expansion in the superior-inferior (SI), latero-lateral (LL), and anterior-posterior (AP) directions to cover 90% or 95% of all amplitudes. Results: In the SI, LL, and AP directions, respectively, the mean motion amplitudes were 5.0 ± 2.6, 3.4. ± 1.9, and 3.1 ± 1.6 mm. The mean intrafraction amplitude variability was 2.6 ± 0.9, 1.9 ± 1.3, and 1.6 ± 0.8 mm in the SI, LL, and AP directions, respectively. The margins required to cover 95% of ICD lead motion amplitudes were 9.5, 6.7, and 5.5 mm in the SI, LL, and AP directions, respectively. The mean correlation error was 2.2 ± 0.9 mm. Conclusions: Data from online tracking indicated motion irregularities and correlation errors, necessitating an increased CTV-PTV margin of 3 mm. In 35% of cases, the motion variability exceeded 3 mm in one or more directions. We recommend verifying the correlation between CTV and surrogate individually for every patient, especially for targets with posterobasal localization where we observed the highest difference between the lead and CTV motion.
- Publikační typ
- časopisecké články MeSH
