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Accelerometer-Based Method for Extracting Respiratory and Cardiac Gating Information for Dual Gating during Nuclear Medicine Imaging.

Jafari Tadi M, Koivisto T, Pänkäälä M, Paasio A - Int J Biomed Imaging (2014)

Bottom Line: Both respiratory and cardiac motions reduce the quality and consistency of medical imaging specifically in nuclear medicine imaging.The correct information about the status of ventricles and atria helps us to create an improved estimate for quiescent phases within a cardiac cycle.The correlation of ADR signals with the reference respiration belt was investigated using Pearson correlation.

View Article: PubMed Central - PubMed

Affiliation: Technology Research Center, Brahea Center, University of Turku, 20520 Turku, Finland ; Department of Clinical Physiology and Nuclear Medicine, Faculty of Medicine, University of Turku, 20520 Turku, Finland.

ABSTRACT
Both respiratory and cardiac motions reduce the quality and consistency of medical imaging specifically in nuclear medicine imaging. Motion artifacts can be eliminated by gating the image acquisition based on the respiratory phase and cardiac contractions throughout the medical imaging procedure. Electrocardiography (ECG), 3-axis accelerometer, and respiration belt data were processed and analyzed from ten healthy volunteers. Seismocardiography (SCG) is a noninvasive accelerometer-based method that measures accelerations caused by respiration and myocardial movements. This study was conducted to investigate the feasibility of the accelerometer-based method in dual gating technique. The SCG provides accelerometer-derived respiratory (ADR) data and accurate information about quiescent phases within the cardiac cycle. The correct information about the status of ventricles and atria helps us to create an improved estimate for quiescent phases within a cardiac cycle. The correlation of ADR signals with the reference respiration belt was investigated using Pearson correlation. High linear correlation was observed between accelerometer-based measurement and reference measurement methods (ECG and Respiration belt). Above all, due to the simplicity of the proposed method, the technique has high potential to be applied in dual gating in clinical cardiac positron emission tomography (PET) to obtain motion-free images in the future.

No MeSH data available.


Related in: MedlinePlus

Demonstration of filtered ECG signal and accelerometer signals from different axes.
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fig4: Demonstration of filtered ECG signal and accelerometer signals from different axes.

Mentions: All of the acquired data were normalized and zero averaged according to the signals' standard deviation to be formulated for direct assessment. All the three acceleration signals extracted from each axis plus ECG were filtered using a fast Fourier transform (FFT) filtering method. The FFT band-pass filter was designed with the cut-off frequencies of 20 Hz and 40 Hz, respectively. The ECG signal was filtered with the cut-off frequencies of 1 Hz and 40 Hz, respectively. The FFT filter was used to remove high frequency noises caused by various sources of noise. Figure 4 indicates ECG signal associated with three axes of SCG data extracted from the measuring system. Unlike ECG, the SCG is affected by the anatomical characteristics so that there are significant differences in the acquired data. According to Figure 4, the z-axis has less distortion in comparison with the ECG which has made it a sufficient signal to investigate the cardiac cycles. As can be seen from this figure, the locations of the z-axis peaks were much closer to the R peaks of QRS complex than y- and x-axes. Furthermore, z-axis components have higher amplitude in comparison with components of the two other axes. As demonstrated earlier by Figure 1, the z-axis is coaxial with the lungs movement and the heart. Thus, because of locating the accelerometer in this position (coaxial with the lungs and heart), the z-axis has acquired the cardiac microvibrations better than the other axes.


Accelerometer-Based Method for Extracting Respiratory and Cardiac Gating Information for Dual Gating during Nuclear Medicine Imaging.

Jafari Tadi M, Koivisto T, Pänkäälä M, Paasio A - Int J Biomed Imaging (2014)

Demonstration of filtered ECG signal and accelerometer signals from different axes.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4120481&req=5

fig4: Demonstration of filtered ECG signal and accelerometer signals from different axes.
Mentions: All of the acquired data were normalized and zero averaged according to the signals' standard deviation to be formulated for direct assessment. All the three acceleration signals extracted from each axis plus ECG were filtered using a fast Fourier transform (FFT) filtering method. The FFT band-pass filter was designed with the cut-off frequencies of 20 Hz and 40 Hz, respectively. The ECG signal was filtered with the cut-off frequencies of 1 Hz and 40 Hz, respectively. The FFT filter was used to remove high frequency noises caused by various sources of noise. Figure 4 indicates ECG signal associated with three axes of SCG data extracted from the measuring system. Unlike ECG, the SCG is affected by the anatomical characteristics so that there are significant differences in the acquired data. According to Figure 4, the z-axis has less distortion in comparison with the ECG which has made it a sufficient signal to investigate the cardiac cycles. As can be seen from this figure, the locations of the z-axis peaks were much closer to the R peaks of QRS complex than y- and x-axes. Furthermore, z-axis components have higher amplitude in comparison with components of the two other axes. As demonstrated earlier by Figure 1, the z-axis is coaxial with the lungs movement and the heart. Thus, because of locating the accelerometer in this position (coaxial with the lungs and heart), the z-axis has acquired the cardiac microvibrations better than the other axes.

Bottom Line: Both respiratory and cardiac motions reduce the quality and consistency of medical imaging specifically in nuclear medicine imaging.The correct information about the status of ventricles and atria helps us to create an improved estimate for quiescent phases within a cardiac cycle.The correlation of ADR signals with the reference respiration belt was investigated using Pearson correlation.

View Article: PubMed Central - PubMed

Affiliation: Technology Research Center, Brahea Center, University of Turku, 20520 Turku, Finland ; Department of Clinical Physiology and Nuclear Medicine, Faculty of Medicine, University of Turku, 20520 Turku, Finland.

ABSTRACT
Both respiratory and cardiac motions reduce the quality and consistency of medical imaging specifically in nuclear medicine imaging. Motion artifacts can be eliminated by gating the image acquisition based on the respiratory phase and cardiac contractions throughout the medical imaging procedure. Electrocardiography (ECG), 3-axis accelerometer, and respiration belt data were processed and analyzed from ten healthy volunteers. Seismocardiography (SCG) is a noninvasive accelerometer-based method that measures accelerations caused by respiration and myocardial movements. This study was conducted to investigate the feasibility of the accelerometer-based method in dual gating technique. The SCG provides accelerometer-derived respiratory (ADR) data and accurate information about quiescent phases within the cardiac cycle. The correct information about the status of ventricles and atria helps us to create an improved estimate for quiescent phases within a cardiac cycle. The correlation of ADR signals with the reference respiration belt was investigated using Pearson correlation. High linear correlation was observed between accelerometer-based measurement and reference measurement methods (ECG and Respiration belt). Above all, due to the simplicity of the proposed method, the technique has high potential to be applied in dual gating in clinical cardiac positron emission tomography (PET) to obtain motion-free images in the future.

No MeSH data available.


Related in: MedlinePlus