Analysis of HR Variability from Multi Channels PPG

Import 03/11/2016Variabilita srdečního rytmu (heart rate variability, HRV) je parametr, popisující a sledující kolísání intervalů mezi jednotlivými srdečními systolami. Bakalářská práce je zaměřena na měření signálů PPG a EKG multikanálovým fotopletysmografem, ze kterých je následně HRV analyzována. Práce se věnuje vhodnému zpracování signálů tak, aby bylo možno dostatečně přesně zhodnotit výsledky měření HRV, a zabývá se změnami HRV v důsledku některých vlivů. Cílem práce je zhodnotit přesnost měření z PPG ve srovnání s EKG, jelikož v praxi se této metody ještě nevyužívá, a analyzovat některé vlivy, působící na změny HRV během dne.Heart rate variability (HRV) is a parameter of heart activity which is used to describe fluctuation of intervals between two consecutive heart beats. This work focuses on the analysis of HRV from PPG and ECG signals derived from Multi channels PPG. The suitable methods of preprocessing of signals are described in order to obtain the accurate results of the HRV analysis and several effect causing changes in HRV are evaluated. The object of work is to evaluate accuracy of the measurement from PPG beside EKG because this method is not used in common practice and analyse the change of HRV during day.450 - Katedra kybernetiky a biomedicínského inženýrstvívýborn

Modular Processing System for Biological Signals

Biologický signál je signálem velmi křehkým, proto jsou stále hledány nové a zlepšovány již objevené metody jeho zpracování. Diplomová práce se tímto zpracováním biologických signálů zabývá, klasifikuje jejich způsoby měření, problematiku rušení a metody zpracování, kdy vychází z poznatků současné literatury. Náplní práce je návrh softwaru pro zpracování nejčastěji využívaných biologických signálů v diagnostice (EKG, EEG, EMG, PPG, FKG) a jeho implementace v Matlabu. Sofware je vytvořen s cílem pojmout co největší oblast zpracování biologických signálů tak, aby bylo možné provést základní úpravy, popř. analýzu jakéhokoli jednorozměrného biologického signálu.A biological signal is a weak signal, so it is necessary to find new or improve methods of its processing. The diploma thesis deals with the processing of biological signals and classifies the ways of their measurement, problems of their interference and methods of processing, based on the contemporary literature. The content of the paper is the design of software for processing the most commonly used biological signals in diagnostics (ECG, EEG, EMG, PPG, PCG) and its implementation in Matlab. The software is designed to ensure the greatest possible area of the biological signal processing so that basic modifications or analysis of any one-dimensional biological signal can be made.450 - Katedra kybernetiky a biomedicínského inženýrstvívýborn

Methods of power line interference elimination in EMG signals

Electromyogram (EMG) recordings are often corrupted by the wide range of artifacts, which one of them is power line interference (PLI). The study focuses on some of the well-known signal processing approaches used to eliminate or attenuate PLI from EMG signal. The results are compared using signal-to-noise ratio (SNR), correlation coefficients and Bland-Altman analysis for each tested method: notch filter, adaptive noise canceller (ANC) and wavelet transform (WT). Thus, the power of the remaining noise and shape of the output signal are analysed. The results show that the ANC method gives the best output SNR and lowest shape distortion compared to the other methods.Web of Science40706

Fiber-optic cardiorespiratory monitoring and triggering in magnetic resonance imaging

During the past decades, fiber-optic technology has become a very popular tool for vital signs monitoring. Thanks to its advantageous properties, such as noninvasiveness, biocompatibility, and resistance to electromagnetic interferences, this methodology started to be explored under the conditions of a magnetic resonance (MR) environment. This review article presents the motivation and possibilities of using fiber-optic sensors (FOSs) in MR environment and summarizes the studies dealing with experimental validation of their compatibility with MR. Several aspects of the presented issue are highlighted and discussed, such as suitability of the fiber-optic approach for MR triggering, precision of vital sign detection, development of sensor designs, and its application to patient's body. From the literature review, it can be concluded that FOSs have promising future in the field of cardiorespiratory monitoring in MR environment. This is mainly due to their advantages originating from sensing mechanical signals instead of electrical ones, which makes them resistant to MR interference and extrasystoles. Moreover, these sensors are easy to use, reusable, and suitable for combined monitoring. However, there are several shortcomings that should be solved in future research before introducing them to clinical practice, namely, signal's delay or optimal placement of sensors.Web of Science71art. no. 400531

Advanced bioelectrical signal processing methods: Past, present and future approach - Part III: Other biosignals

Analysis of biomedical signals is a very challenging task involving implementation of various advanced signal processing methods. This area is rapidly developing. This paper is a Part III paper, where the most popular and efficient digital signal processing methods are presented. This paper covers the following bioelectrical signals and their processing methods: electromyography (EMG), electroneurography (ENG), electrogastrography (EGG), electrooculography (EOG), electroretinography (ERG), and electrohysterography (EHG).Web of Science2118art. no. 606

A comparison of alternative approaches to MR cardiac triggering: A pilot study at 3 Tesla

This pilot comparative study evaluates the usability of the alternative approaches to magnetic resonance (MR) cardiac triggering based on ballistocardiography (BCG): fiber-optic sensor (O-BCG) and pneumatic sensor (P-BCG). The comparison includes both the objective and subjective assessment of the proposed sensors in comparison with a gold standard of ECG-based triggering. The objective evaluation included several image quality assessment (IQA) parameters, whereas the subjective analysis was performed by 10 experts rating the diagnostic quality (scale 1 - 3, 1 corresponding to the best image quality and 3 the worst one). Moreover, for each examination, we provided the examination time and comfort rating (scale 1 - 3). The study was performed on 10 healthy subjects. All data were acquired on a 3 T SIEMENS MAGNETOM Prisma. In image quality analysis, all approaches reached comparable results, with ECG slightly outperforming the BCG-based methods, especially according to the objective metrics. The subjective evaluation proved the best quality of ECG (average score of 1.68) and higher performance of P-BCG (1.97) than O-BCG (2.03). In terms of the comfort rating and total examination time, the ECG method achieved the worst results, i.e. the highest score and the longest examination time: 2.6 and 10:49 s, respectively. The BCG-based alternatives achieved comparable results (P-BCG 1.5 and 8:06 s; OBCG 1.9, 9:08 s). This study confirmed that the proposed BCG-based alternative approaches to MR cardiac triggering offer comparable quality of resulting images with the benefits of reduced examination time and increased patient comfort.Web of Science2662605259

A low-cost system for seismocardiography-based cardiac triggering: A practical solution for cardiovascular magnetic resonance imaging at 3 tesla

This study describes a pilot clinical validation of a new low-cost system for the continuous monitoring of the human body's cardiorespiratory activities within the magnetic resonance examination area. This study primarily focuses on monitoring cardiac activity and the related cardiac triggering. The patented system tested by the authors is based on seismocardiography (SCG). The study was conducted on 18 subjects on a Siemens Prisma 3T MR scanner. Standard anatomical and diffusion sequences were used to test cardiac activity monitoring. A wide range of commonly used diagnostic sequences were used to test imaging of the heart by means of cardiac triggering. System functionality was verified against a commercially available electrocardiography (ECG) system. Monitoring of cardiac activity (detection of the R-R interval in ECG and the AO-AO interval in SCG) was objectively evaluated by determining the overall probability of correct detection (ACC), sensitivity (SE), positive predictive value (PPV), and harmonic mean between SE and PPV, i.e. F1. Imaging quality control using Cardiac Triggering was performed by subjective evaluation of images by the physicians. The study conducted clearly confirmed the functionality of the system in terms of continuous cardiac activity monitoring. In all 18 subjects, a mean PPV > 99% was achieved; F1 > 99 %; SE > 99 %; ACC > 98 %; 1.96 sigma < 3.5 bpm. Also, Cardiac Triggering functionality was confirmed by the physicians on the basis of analyzing cardiac images using the T1/T2 balanced echo sequences and the T1 flash sequence measured natively.Web of Science711862911860