scholarly journals Real-time QRS detection using integrated variance for ECG gated cardiac MRI

2016 ◽  
Vol 2 (1) ◽  
pp. 255-258 ◽  
Author(s):  
Marcus Schmidt ◽  
Johannes W. Krug ◽  
Georg Rose
Keyword(s):  
Real Time ◽  
Cardiac Mri ◽  
Vital Signs ◽  
Peak Detection ◽  
Resonance Imaging ◽  
Qrs Detection ◽  
Ecg Signals ◽  
Integrated Variance ◽  
Magnetic Resonance Imaging Mri ◽  
Electrocardiogram Ecg

AbstractDuring magnetic resonance imaging (MRI), a patient’s vital signs are required for different purposes. In cardiac MRI (CMR), an electrocardiogram (ECG) of the patient is required for triggering the image acquisition process. However, a reliable QRS detection of an ECG signal acquired inside an MRI scanner is a challenging task due to the magnetohydrodynamic (MHD) effect which interferes with the ECG. The aim of this work was to develop a reliable QRS detector usable inside the MRI which also fulfills the standards for medical devices (IEC 60601-2-27). Therefore, a novel real-time QRS detector based on integrated variance measurements is presented. The algorithm was trained on ANSI/AAMI EC13 test waveforms and was then applied to two databases with 12-lead ECG signals recorded inside and outside an MRI scanner. Reliable results for both databases were achieved for the ECG signals recorded inside (DBMRI: sensitivity Se = 99.94%, positive predictive value +P = 99.84%) and outside (DBInCarT: Se = 99.29%, +P = 99.72%) the MRI. Due to the accurate R-peak detection in real-time this can be used for monitoring and triggering in MRI exams.

scholarly journals Estimation of a respiratory signal from a single-lead ECG using the 4th order central moments

2015 ◽  
Vol 1 (1) ◽  
pp. 61-64 ◽  
Author(s):  
Marcus Schmidt ◽  
Johannes W Krug ◽  
Andy Schumann ◽  
Karl-Jürgen Bär ◽  
Georg Rose
Keyword(s):  
Respiratory Activity ◽  
Vital Signs ◽  
Daily Routine ◽  
Impedance Change ◽  
Resonance Imaging ◽  
Central Moments ◽  
Ecg Signals ◽  
Respiratory Signal ◽  
Magnetic Resonance Imaging Mri ◽  
Electrocardiogram Ecg

AbstractFor a variety of clinical applications like magnetic resonance imaging (MRI) the monitoring of vital signs is a common standard in clinical daily routine. Besides the electrocardiogram (ECG), the respiratory activity is an important vital parameter and might reveal pathological changes. Thoracic movement and the resulting impedance change between ECG electrodes enable the estimation of the respiratory signal from the ECG. This ECG-derived respiration (EDR) can be used to calculate the breathing rate without the need for additional devices or monitoring modules. In this paper a new method is presented to estimate the respiratory signal from a single-lead ECG. The 4th order central moments was used to estimate the EDR signal exploiting the change of the R-wave slopes induced by respiration. This method was compared with two approaches by analyzing the Fantasia database from www.physionet.org. Furthermore, the ECG signals of 24 healthy subjects placed in an 3 T MR-scanner were acquired.

A REAL-TIME QT INTERVAL DETECTION ALGORITHM

2008 ◽  
Vol 08 (02) ◽  
pp. 251-263 ◽  
Author(s):  
Z. E. HADJ SLIMANE ◽  
F. BEREKSI REGUIG
Keyword(s):  
Real Time ◽  
Qt Interval ◽  
Detection Algorithm ◽  
Qrs Detection ◽  
Signal To Noise ◽  
Ecg Signals ◽  
Wave Detection ◽  
T Wave ◽  
Electrocardiogram Ecg ◽  
Ventricular Depolarization

The QT interval is the electrocardiographic representation of the duration of ventricular depolarization and repolarization. In this paper, we have developed a new real-time QT interval detection algorithm for automatically locating the onset of QRS and the end of the T wave. The algorithm consists of several steps: signal-to-noise enhancement, QRS detection, QRS onset, and T-wave end definition. The detection algorithm is tested on electrocardiogram (ECG) signals from the universal MIT-BIH Arrhythmia Database. The resulting QRS detection algorithm has a sensitivity of 99.79% and a specificity of 99.72%. The QRS onset and T-wave detection algorithm is tested using several data records from the MIT/BIH Arrhythmia Database. The results obtained are shown to be highly satisfactory.

scholarly journals A Real Time QRS Detection Algorithm Based on ET and PD Controlled Threshold Strategy

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4003 ◽  
Author(s):  
Aiyun Chen ◽  
Yidan Zhang ◽  
Mengxin Zhang ◽  
Wenhan Liu ◽  
Sheng Chang ◽  
...  
Keyword(s):  
Real Time ◽  
Detection Algorithm ◽  
Qrs Detection ◽  
Threshold Strategy ◽  
Pd Control ◽  
Ecg Signals ◽  
Field Programmable ◽  
Exponential Transform ◽  
Current Threshold ◽  
Basic Characteristics

As one of the important components of electrocardiogram (ECG) signals, QRS signal represents the basic characteristics of ECG signals. The detection of QRS waves is also an essential step for ECG signal analysis. In order to further meet the clinical needs for the accuracy and real-time detection of QRS waves, a simple, fast, reliable, and hardware-friendly algorithm for real-time QRS detection is proposed. The exponential transform (ET) and proportional-derivative (PD) control-based adaptive threshold are designed to detect QRS-complex. The proposed ET can effectively narrow the magnitude difference of QRS peaks, and the PD control-based method can adaptively adjust the current threshold for QRS detection according to thresholds of previous two windows and predefined minimal threshold. The ECG signals from MIT-BIH databases are used to evaluate the performance of the proposed algorithm. The overall sensitivity, positive predictivity, and accuracy for QRS detection are 99.90%, 99.92%, and 99.82%, respectively. It is also implemented on Altera Cyclone V 5CSEMA5F31C6 Field Programmable Gate Array (FPGA). The time consumed for a 30-min ECG record is approximately 1.3 s. It indicates that the proposed algorithm can be used for wearable heart rate monitoring and automatic ECG analysis.

SU-GG-J-164: Real-Time Magnetic Resonance Imaging (MRI) Guidance and Thermal Modeling to Focus Hyperthermia Delivery

2008 ◽  
Vol 35 (6Part8) ◽  
pp. 2717-2717
Author(s):  
V Stakhursky ◽  
K Cheng ◽  
J MacFall ◽  
P Maccarini ◽  
P Stauffer ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Real Time ◽  
Thermal Modeling ◽  
Resonance Imaging ◽  
Mri Guidance ◽  
Magnetic Resonance Imaging Mri

Basic Neuronavigation Options for Cortical and Subcortical Brain Lesions Surgery

2018 ◽  
Vol 11 (2) ◽  
pp. 141-149
Author(s):  
Milan N. Mladenovski ◽  
Nikolay V. Vasilev ◽  
Mladen E. Ovcharov ◽  
Iliya V. Valkov
Keyword(s):  
Real Time ◽  
Brain Lesions ◽  
Neurosurgical Procedures ◽  
Cortical Lesions ◽  
Resonance Imaging ◽  
Anatomical Structures ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain ◽  
Real Time Ultrasonography

Summary Craniometric points are essential for orienting neurosurgeons in their practice. Understanding the correlations of these points help to manage any pathological lesion located on the cortical surface and subcortically. The brain sulci and gyri should be identified before craniotomy. It is difficult to identify these anatomical structures intraoperatively (after craniotomy) with precision. The main purpose of this study was to collect as much information as possible from the literature and our clinical practice in order to facilitate the placement of craniotomies without using modern neuronavigation systems. Operative reports from the last five years on cranial operations for cortical and subcortical lesions were reviewed. All the craniotomies had been planned, using four methods: detection of craniometric points, computed tomography (CT) scans/topograms, magnetic resonance imaging (MRI) scans/topograms, and intraoperative real-time ultrasonography (USG). Retrospectively, we analyzed 295 cranial operations. Our analysis showed that operating on for cortical lesions, we had frequently used the first and the second method mentioned above (118 patients), while in cases of subcortical lesions, we had used craniometric points, MRI scans/topograms and intraoperative real-time USG as methods of neuronavigation (177 patients). These results show that craniometric points are essential in both neurosurgical procedures.

Abstract 15088: Scar Pattern in Chagas Heart Disease

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Mahmoud I Traina ◽  
Mariam Thomas ◽  
Jason Bradfield ◽  
Salvador Hernandez ◽  
Alvaro J Altamirano Ufion ◽  
...  
Keyword(s):  
Heart Disease ◽  
Resonance Imaging ◽  
Chagas Heart Disease ◽  
Group 3 ◽  
Vt Ablation ◽  
Group 2 ◽  
Magnetic Resonance Imaging Mri ◽  
Electrocardiogram Ecg ◽  
Epicardial Access ◽  
Group 1

Introduction: Scar in Chagas heart disease (CHD) is thought to be predominantly epicardial and requires epicardial access for ventricular tachycardia (VT) ablation. However, little data exists on scar patterns in this population. We evaluated the patterns of scar in patients who underwent magnetic resonance imaging (MRI) with delayed enhancement (DE). Methods: 19 patients were enrolled who had evidence of DE by MRI: 4 (21.0%) patients with normal electrocardiogram (ECG) and normal echocardiogram (echo) (group 1); 3 (15.8%) patients with abnormal ECG and normal echo (group 2); and 12 (63.2%) patients with abnormal ECG and echo (group 3). Results: In the 19 patients, there were 110 segments (34.1%) with DE identified using a 17-segment model. Pattern of involvement is as follows: endocardial 30 (27.3%), mid-myocardial 22 (20.0%), epicardial 2 (1.8%) and transmural 56 (50.9%). Most common territories of involvement are as follows (% of patients with segment involved): Basal inferolateral (78.9%), basal anterolateral (68.4%), mid inferolateral (63.2%), mid anterolateral (52.6%), apical lateral (52.6%) and apex (42.1%). The pattern of involvement also varied by group. In group 1, mid-myocardial 7 (50%), endocardial 6 (42.9%), transmural 1 (7.1%). In group 2, mid-myocardial 2 (18.2%), endocardial 6 (54.5%), transmural 3 (27.3%). In group 3, mid-myocardial 13 (15.3%), endocardial 18 (21.2%), transmural 52 (61.2%), epicardial 2 (2.4%). Conclusion: DE tends to occur most commonly in the basal and mid lateral segments. At earlier stages of disease, myocardial scar pattern tends to involve mid-myocardium and endocardium, and progress to transmural in later stages. Isolated epicardial scar was rare in this patient population, which is has potential implications for VT ablation strategies.

ALGORITHM FOR AUTOMATIC DETECTION OF ECG WAVES

2011 ◽  
Vol 11 (01) ◽  
pp. 15-29 ◽  
Author(s):  
DIB. NABIL ◽  
F. BEREKSI-REGUIG
Keyword(s):  
Detection Accuracy ◽  
Ecg Signal ◽  
Qrs Complex ◽  
Qrs Detection ◽  
Accurate Identification ◽  
Ecg Signals ◽  
Good Ability ◽  
Noisy Conditions ◽  
Electrocardiogram Ecg ◽  
T Waves

An accurate measurement of the different electrocardiogram (ECG) intervals is dependent on the accurate identification of the beginning and the end of the P, QRS, and T waves. Available commercial systems provide a good QRS detection accuracy. However, the detection of the P and T waves remains a serious challenge due to their widely differing morphologies in normal and abnormal beats. In this paper, a new algorithm for the detection of the QRS complex as well as for P and T waves identification is provided. The proposed algorithm is based on different approaches and methods such as derivations, thresholding, and surface indicator. The proposed algorithm is tested and evaluated on ECG signals from the universal MIT-BIH database. It shows a good ability to detect P, QRS, and T waves for different cases of ECG signal even in very noisy conditions. The obtained QRS, sensitivity and positive predictivity are respectively 95.39% and 98.19%. The developed algorithm is also able to separate the overlapping P and T waves.

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