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1

Wyznaczanie czasu propagacji Fali tętna w oparciu o sygnały EKG i PPG

100%

Sieczkowski K. , Dobrowolski A. P. , Sondej T. , Olszewski R.

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2019

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tom R. 95, nr 11

101--104

PL

W artykule przedstawiono nowatorską metodę pozwalającą na wyznaczanie czasów propagacji fali tętna, która bazuje na jednoczesnym pomiarze sygnałów EKG i PPG. Kluczowa dla proponowanego algorytmu dokładność wyznaczenia początkowego i końcowego punktu pomiarowego danego sygnału, silnie zależy od procedur wstępnego przetwarzania. Proponowane rozwiązanie opiera się na rozwijanej przez autorów metodzie korelacji aktualizowanego na bieżąco wzorca sygnału z aktualnie analizowanym fragmentem sygnału.

EN

In this article was presented a novel method for determining a pulse transit time, which is based on simultaneous measurement of ECG and PPG signals. The key to the proposed algorithm, the accuracy of determining the starting and ending measuring point of a given signal, strongly depends on the pre-processing procedures. The proposed solution is based on the method of correlation of the currently updated signal pattern with the currently analyzed fragment of signal, developed by the authors.

2

Simultaneous multi-site measurement system for the assessment of pulse wave delays

100%

Sondej T. , Sieczkowski K. , Olszewski R. , Dobrowolski A.

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tom Vol. 39, no. 2

488--502

EN

A precise, multi-track system for the simultaneous, real-time measurement of electrocardiographic (ECG) and many photopletysmographic (PPG) signals is described. This system allows the calculation of pulse wave delay parameters such as pulse arrival time (PAT) and pulse transit time (PTT). The measurement system was built on a custom, real-time embedded system with multiple specific analogue-front-end devices. Signals were recorded on-line and data were processed off-line in the Matlab software. Testing of human subjects was carried out on a group of 16 volunteers. The system was capable of taking a measurement of one 24-bit ECG and eight 22-bit PPG tracks with high precision (input-referred noise 1.4 mV for ECG and about 20 pA for PPG). All signals are sampled simultaneously (phase shift between ECG and PPG is only 1.5 ms for 250 Hz frequency sampling). Significant differences in pulse wave delays were found for the 16 subjects studied (e.g. about 100 ms for PAT on a right toe, 40 ms for differential PAT on left-right toes and about 100 ms for PTT calculated for forehead-right toe pulse wave). The proposed system provides a simultaneous and continuous evaluation of pulse wave delays for the entire arterial bed. The proposed measurement methods are comfortable and can be used for a long time. Simultaneous measurements of pulse wave delays at various sites increase the reliability of measurement and create new possibilities for medical diagnosis.

3

Comparison of Acoustocerebrography Measurement and Magnetic Resonance Imaging Methods in the Assessment of White Matter Lesions in Patients with Atrial Fibrillation

75%

Dobkowska-Chudon W. , Wrobel M. , Frankowska E. , Zegadlo A. , Krupienicz A. , Nowicki A. , Olszewski R.

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tom Vol. 45, No. 3

445--452

EN

The brain is subject to damage, due to ageing, physiological processes and/or disease. Some of the damage is acute in nature, such as strokes; some is more subtle, like white matter lesions. White matter lesions or hyperintensities (WMH) can be one of the first signs of micro brain damage. We implemented the Acoustocerebrography (ACG) as an easy to use method designed to capture differing states of human brain tissue and the respective changes. Aim: The purpose of the study is to compare the efficacy of ACG and Magnetic Resonance Imaging (MRI) to detect WMH in patients with clinically silent atrial fibrillation (AF). Methods and results: The study included 97 patients (age 66.26 ± 6.54 years) with AF. CHA2DS2-VASc score (2.5 ±1.3) and HAS BLED (1.65 ± 0.9). According to MRI data, the patients were assigned into four groups depending on the number of lesions: L0 – 0 to 4 lesions, L5 – 5 to 9 lesions, L10 – 10 to 29 lesions, and L30 – 30 or more lesions. Authors found that the ACG method clearly differentiates the groups L0 (with 0-4 lesions) and L30 (with more than 30 lesions) of WMH patients. Fisher’s Exact Test shows that this correlation is highly significant (p < 0.001). Conclusion: ACG is a new, easy and cost-effective method for detecting WMH in patients with atrial fibrillation. The ACG measurement methodology should become increasingly useful for the assessment of WMH.

4

Validation of a new device for photoplethysmographic measurement of multi-site arterial pulse wave velocity

75%

Sondej T. , Jannasz I. , Sieczkowski K. , Dobrowolski A. , Obiała K. , Targowski T. , Olszewski R.

Biocybernetics and Biomedical Engineering

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2021

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tom Vol. 41, no. 4

1664--1684

EN

Pulse wave velocity (PWV) is commonly used for assessing arterial stiffness and it is a useful and accurate cardiovascular mortality predictor. Currently, many techniques and devices for PWV measurement are known, but they are usually expensive and require operator experience. One possible solution for PWV measurement is photoplethysmography (PPG), which is convenient, inexpensive and provides continuous PWV results. The aim of this paper is validation of a new device for PPG sensor-based measurement of multisite arterial PWV using a SphygmoCor XCEL (as the reference device) according to the recommendations of the Artery Society Guidelines (ASG). In this study, 108 subjects (56 men and 52 women, 20–91 years in 3 required age groups) were enrolled. The multi-site PWV was simultaneous measured by 7 PPG sensors commonly used in pulse oximetry in clinical settings. These sensors were placed on the forehead, and right and left earlobes, fingers and toes. Pulse transit time (PTT) was measured offline as the difference of time delay between two onsets of the pulse wave determined by the intersecting tangent method. The PWV was calculated by dividing the distance between PPG sensors by PTT. During PPG signals measurement, reference carotid to femoral PWV (cfPWV) was performed with a SphygmoCor XCEL system. The Pearson correlation coefficient (r) between the obtained PWV results was calculated. The Bland-Altman method was used to establish the level of agreement between the two devices. Mean difference (md) and standard deviation (SD) were also calculated. The multi-site PWV was highly correlated with accuracy at the ASG-defined level of ‘‘Acceptable” (md < 1.0 m/s and SD ≤ 1.5 m/s) with cfPWV: forehead - right toe (r = 0.75, md = 0.20, SD = 0.97), forehead - left toe (r = 0.79, md = 0.18, SD = 0.91), right ear - right toe (r = 0.79, md = 0.11, SD = 0.96), left ear - left toe (r = 0.75, md = 0.43, SD = 0.99), right ear - left toe (r = 0.78, md = 0.40, SD = 0.93), left ear - right toe (r = 0.78, md = 0.11, SD = 0.96), right finger - right toe (r = 0.66, md = 0.95, SD = 1.29), left finger - lefttoe (r = 0.67, md = 0.68, SD = 1.35). This study showed that PWV measured with the multisite PPG system, in relation to the obtained numerical values, correlated very well with that measured using the commonly known applanation tonometry method. However, it should be noted, that the measured PWV concerns the central and muscular part of the arterial tree while the cfPWV is only for the central one. The best results were obtained when the proximal PPG sensor was placed on the head (ear or forehead) and the distal PPG sensor on the toe. PPG sensors can be placed in many sites at the same time, which provides greater freedom of their configuration. Multi-site photoplethysmography is an alternative method for PWV measurement and creates new possibilities for the diagnostics of cardiovascular diseases.

5

Assessment of High Frequency Imaging and Doppler System for the Measurements of the Radial Artery Flow-Mediated Dilation

75%

Nowicki A. , Gambin B. , Secomski W. , Trawiński Z. , Szubielski M. , Tymkiewicz R. , Olszewski R.

Archives of Acoustics

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2019

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tom Vol. 44, No. 4

637--644

EN

Objectives: In the article we describe the new, high frequency, 20 MHz scanning/Doppler probe designed to measure the flow mediated dilation (FMD) and shear rate (SR) close to the radial artery wall. Methods: We compare two US scanning systems, standard vascular modality working below 12 MHz and high frequency 20 MHz system designed for FMD and SR measurements. Axial resolutions of both systems were compared by imaging of two closely spaced food plastic foils immersed in water and by measuring systolic/diastolic diameter changes in the radial artery. The sensitivities of Doppler modalities were also determined. The diagnostic potential of a high frequency system in measurements of FMD and SR was studied in vivo, in two groups of subjects, 12 healthy volunteers and 14 patients with stable coronary artery disease (CAD). Results: Over three times better axial resolution was demonstrated for a high frequency system. Also, the sensitivity of the external single transducer 20 MHz pulse Doppler proved to be over 20 dB better (in terms of a signal-to-noise ratio) than the pulse Doppler incorporated into the linear array. Statistically significant differences in FMD and FMD/SR values for healthy volunteers and CAD patients were confirmed, p-values < 0:05. The areas under Receiver Operating Characteristic (ROC) curves for FMD and FMD/SR for the prediction CAD had the values of 0.99 and 0.97, respectively. Conclusions: These results justify the usefulness of the designed high-frequency scanning system to determine the FMD and SR in the radial artery as predictors of coronary arterial disease.