Pub Date : 2024-04-03DOI: 10.1088/1361-6579/ad290b
Jacob McErlean, John Malik, Yu-Ting Lin, Ronen Talmon, Hau-Tieng Wu
Objective.We aimed to fuse the outputs of different electrocardiogram-derived respiration (EDR) algorithms to create one higher quality EDR signal.Methods.We viewed each EDR algorithm as a software sensor that recorded breathing activity from a different vantage point, identified high-quality software sensors based on the respiratory signal quality index, aligned the highest-quality EDRs with a phase synchronization technique based on the graph connection Laplacian, and finally fused those aligned, high-quality EDRs. We refer to the output as the sync-ensembled EDR signal. The proposed algorithm was evaluated on two large-scale databases of whole-night polysomnograms. We evaluated the performance of the proposed algorithm using three respiratory signals recorded from different hardware sensors, and compared it with other existing EDR algorithms. A sensitivity analysis was carried out for a total of five cases: fusion by taking the mean of EDR signals, and the four cases of EDR signal alignment without and with synchronization and without and with signal quality selection.Results.The sync-ensembled EDR algorithm outperforms existing EDR algorithms when evaluated by the synchronized correlation (γ-score), optimal transport (OT) distance, and estimated average respiratory rate score, all with statistical significance. The sensitivity analysis shows that the signal quality selection and EDR signal alignment are both critical for the performance, both with statistical significance.Conclusion.The sync-ensembled EDR provides robust respiratory information from electrocardiogram.Significance.Phase synchronization is not only theoretically rigorous but also practical to design a robust EDR.
{"title":"Unsupervised ensembling of multiple software sensors with phase synchronization: a robust approach for electrocardiogram-derived respiration.","authors":"Jacob McErlean, John Malik, Yu-Ting Lin, Ronen Talmon, Hau-Tieng Wu","doi":"10.1088/1361-6579/ad290b","DOIUrl":"10.1088/1361-6579/ad290b","url":null,"abstract":"<p><p><i>Objective.</i>We aimed to fuse the outputs of different electrocardiogram-derived respiration (EDR) algorithms to create one higher quality EDR signal.<i>Methods.</i>We viewed each EDR algorithm as a software sensor that recorded breathing activity from a different vantage point, identified high-quality software sensors based on the respiratory signal quality index, aligned the highest-quality EDRs with a phase synchronization technique based on the graph connection Laplacian, and finally fused those aligned, high-quality EDRs. We refer to the output as the sync-ensembled EDR signal. The proposed algorithm was evaluated on two large-scale databases of whole-night polysomnograms. We evaluated the performance of the proposed algorithm using three respiratory signals recorded from different hardware sensors, and compared it with other existing EDR algorithms. A sensitivity analysis was carried out for a total of five cases: fusion by taking the mean of EDR signals, and the four cases of EDR signal alignment without and with synchronization and without and with signal quality selection.<i>Results.</i>The sync-ensembled EDR algorithm outperforms existing EDR algorithms when evaluated by the synchronized correlation (γ-score), optimal transport (OT) distance, and estimated average respiratory rate score, all with statistical significance. The sensitivity analysis shows that the signal quality selection and EDR signal alignment are both critical for the performance, both with statistical significance.<i>Conclusion.</i>The sync-ensembled EDR provides robust respiratory information from electrocardiogram.<i>Significance.</i>Phase synchronization is not only theoretically rigorous but also practical to design a robust EDR.</p>","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139730296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-02DOI: 10.1088/1361-6579/ad39a2
Branko G. Celler, A. Argha
OBJECTIVES In this study, we test the hypothesis that if, as demonstrated in a previous study, brachial arteries exhibit hysteresis as the occluding cuff is deflated and fail to open until cuff pressure (CP) is well below true intra-arterial blood pressure (IAPB), estimating systolic (SBP) and diastolic blood pressure (DBP) from the presence of Korotkoff sounds as CP increases may eliminate these errors and give more accurate estimates of SBP and DBP relative to IABP readings. Approach. In 62 subjects of varying ages (45.1±19.8, range 20-6 - 75.8 years), including 44 men (45.3±19.4, range 20.6 - 75.8 years) and 18 women (44.4±21.4, range 20.9 - 75.3 years), we sequentially recorded SBP and DBP both during cuff inflation and cuff deflation using Korotkoff sounds. Results. There was a significant (p<0.0001) increase in SBP from 122.8±13.2 to 127.6±13.0 mmHg and a significant (p=0.0001) increase in DBP from 70.0±9.0 to 77.5±9.7 mmHg. Of the 62 subjects, 51 showed a positive increase in SBP (0 to 14 mmHg) and 11 subjects showed a reduction (-0.3 to -7 mmHg). The average differences for SBP and DBP estimates derived as the cuff inflates and those derived as the cuff deflates were 4.8±4.6 mmHg and 2.5±4.6mmHg, not dissimilar to the differences reported between IABP and NIBP measurements. Although we could not develop multiparameter linear or non-linear models to explain this phenomenon we have clearly demonstrated through ANOVA tests that both body mass index (BMI) and pulse wave velocity (PWV) are implicated, supporting the hypothesis that the phenomenon is associated with age, higher BMI and stiffer arteries. Significance. The implications of this study are that brachial sphygmomanometry carried out during cuff inflation could be more accurate than measurements carried out as the cuff deflates. Further research is required to validate these results with intra-arterial blood pressure measurements. .
{"title":"Measuring blood pressure from Korotkoff sounds as the brachial cuff inflates on average provides higher values than when the cuff deflates.","authors":"Branko G. Celler, A. Argha","doi":"10.1088/1361-6579/ad39a2","DOIUrl":"https://doi.org/10.1088/1361-6579/ad39a2","url":null,"abstract":"OBJECTIVES\u0000 In this study, we test the hypothesis that if, as demonstrated in a previous study, brachial arteries exhibit hysteresis as the occluding cuff is deflated and fail to open until cuff pressure (CP) is well below true intra-arterial blood pressure (IAPB), estimating systolic (SBP) and diastolic blood pressure (DBP) from the presence of Korotkoff sounds as CP increases may eliminate these errors and give more accurate estimates of SBP and DBP relative to IABP readings. Approach. In 62 subjects of varying ages (45.1±19.8, range 20-6 - 75.8 years), including 44 men (45.3±19.4, range 20.6 - 75.8 years) and 18 women (44.4±21.4, range 20.9 - 75.3 years), we sequentially recorded SBP and DBP both during cuff inflation and cuff deflation using Korotkoff sounds. Results. There was a significant (p<0.0001) increase in SBP from 122.8±13.2 to 127.6±13.0 mmHg and a significant (p=0.0001) increase in DBP from 70.0±9.0 to 77.5±9.7 mmHg. Of the 62 subjects, 51 showed a positive increase in SBP (0 to 14 mmHg) and 11 subjects showed a reduction (-0.3 to -7 mmHg). The average differences for SBP and DBP estimates derived as the cuff inflates and those derived as the cuff deflates were 4.8±4.6 mmHg and 2.5±4.6mmHg, not dissimilar to the differences reported between IABP and NIBP measurements. Although we could not develop multiparameter linear or non-linear models to explain this phenomenon we have clearly demonstrated through ANOVA tests that both body mass index (BMI) and pulse wave velocity (PWV) are implicated, supporting the hypothesis that the phenomenon is associated with age, higher BMI and stiffer arteries. Significance. The implications of this study are that brachial sphygmomanometry carried out during cuff inflation could be more accurate than measurements carried out as the cuff deflates. Further research is required to validate these results with intra-arterial blood pressure measurements. .","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140753711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-02DOI: 10.1088/1361-6579/ad39c2
Ayman A Ameen, Achim Sack, Thorsten Poeschel
In this paper, we present a novel data-driven approach for solving ill-posed inverse problems, such as Electrical Impedance Tomography (EIT). Our approach introduces a new layer architecture composed of three paths: spatial, spectral, and truncated spectral paths. The spatial path processes information locally, while the spectral and truncated spectral paths provide the network with a global receptive field. Such architecture helps eliminate the ill-posedness and nonlinearity of the inverse problem. The three paths are interconnected, allowing for information exchange on different receptive fields with different learning abilities. The network has a bottleneck architecture which enables it to recover signal information from noisy redundant measurements. We call our proposed model Truncated Spatial-Spectral Convolutional neural Network (TSSConvNet). The model overcomes the receptive field limitation of the most existing models which use only the local information in Euclidean space. We trained the network on a large dataset that covers various configurations with random parameters to ensure generalization over the training samples. Our model achieves superior accuracy with relatively high resolution on both simulation and experimental data.
{"title":"TSS-ConvNet for electrical impedance tomography image reconstruction.","authors":"Ayman A Ameen, Achim Sack, Thorsten Poeschel","doi":"10.1088/1361-6579/ad39c2","DOIUrl":"https://doi.org/10.1088/1361-6579/ad39c2","url":null,"abstract":"In this paper, we present a novel data-driven approach for solving ill-posed inverse problems, such as Electrical Impedance Tomography (EIT). Our approach introduces a new layer architecture composed of three paths: spatial, spectral, and truncated spectral paths. The spatial path processes information locally, while the spectral and truncated spectral paths provide the network with a global receptive field. Such architecture helps eliminate the ill-posedness and nonlinearity of the inverse problem. The three paths are interconnected, allowing for information exchange on different receptive fields with different learning abilities. The network has a bottleneck architecture which enables it to recover signal information from noisy redundant measurements. We call our proposed model Truncated Spatial-Spectral Convolutional neural Network (TSSConvNet). The model overcomes the receptive field limitation of the most existing models which use only the local information in Euclidean space. We trained the network on a large dataset that covers various configurations with random parameters to ensure generalization over the training samples. Our model achieves superior accuracy with relatively high resolution on both simulation and experimental data.","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140753040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.1088/1361-6579/ad3a2d
Andrew E Toader, Mitsuhiro Fukuda, Alberto L Vazquez
Abstract Objective. The continuous delivery of oxygen is critical to sustain brain function, and therefore, measuring brain oxygen consumption can provide vital physiological insight. In this work, we examine the impact of calibration and cerebral blood flow (CBF) measurements on the computation of the relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2) from hemoglobin-sensitive intrinsic optical imaging data. Using these data, we calculate rCMRO2, and calibrate the model using an isometabolic stimulus. Approach. We used awake head-fixed rodents to obtain hemoglobin-sensitive optical imaging data to test different calibrated and uncalibrated rCMRO2 models. Hypercapnia was used for calibration and whisker stimulation was used to test the impact of calibration. Main results. We found that typical uncalibrated models can provide reasonable estimates of rCMRO2 with differences as small as 7%–9% compared to their calibrated models. However, calibrated models showed lower variability and less dependence on baseline hemoglobin concentrations. Lastly, we found that supplying the model with measurements of CBF significantly reduced error and variability in rCMRO2 change calculations. Significance. The effect of calibration on rCMRO2 calculations remains understudied, and we systematically evaluated different rCMRO2 calculation scenarios that consider including different measurement combinations. This study provides a quantitative comparison of these scenarios to evaluate trade-offs that can be vital to the design of blood oxygenation sensitive imaging experiments for rCMRO2 calculation.
{"title":"Evaluation of calibrated and uncalibrated optical imaging approaches for relative cerebral oxygen metabolism measurements in awake mice","authors":"Andrew E Toader, Mitsuhiro Fukuda, Alberto L Vazquez","doi":"10.1088/1361-6579/ad3a2d","DOIUrl":"https://doi.org/10.1088/1361-6579/ad3a2d","url":null,"abstract":"Abstract Objective. The continuous delivery of oxygen is critical to sustain brain function, and therefore, measuring brain oxygen consumption can provide vital physiological insight. In this work, we examine the impact of calibration and cerebral blood flow (CBF) measurements on the computation of the relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2) from hemoglobin-sensitive intrinsic optical imaging data. Using these data, we calculate rCMRO2, and calibrate the model using an isometabolic stimulus. Approach. We used awake head-fixed rodents to obtain hemoglobin-sensitive optical imaging data to test different calibrated and uncalibrated rCMRO2 models. Hypercapnia was used for calibration and whisker stimulation was used to test the impact of calibration. Main results. We found that typical uncalibrated models can provide reasonable estimates of rCMRO2 with differences as small as 7%–9% compared to their calibrated models. However, calibrated models showed lower variability and less dependence on baseline hemoglobin concentrations. Lastly, we found that supplying the model with measurements of CBF significantly reduced error and variability in rCMRO2 change calculations. Significance. The effect of calibration on rCMRO2 calculations remains understudied, and we systematically evaluated different rCMRO2 calculation scenarios that consider including different measurement combinations. This study provides a quantitative comparison of these scenarios to evaluate trade-offs that can be vital to the design of blood oxygenation sensitive imaging experiments for rCMRO2 calculation.","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140757554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-29DOI: 10.1088/1361-6579/ad2eb5
Fabian Mueller-Graf, Paul Frenkel, Jonas Merz, Susanne Reuter, Brigitte Vollmar, Gerardo Tusman, Sven Pulletz, Stephan H Böhm, Amelie Zitzmann, Daniel A Reuter, Andy Adler
Objective. Since pulse wave transit time (PWTT) shortens as pulmonary artery pressure (PAP) increases it was suggested as a potential non-invasive surrogate for PAP. The state of tidal lung filling is also known to affect PWTT independently of PAP. The aim of this retrospective analysis was to test whether respiratory gating improved the correlation coefficient between PWTT and PAP.Approach. In each one of five anesthetized and mechanically ventilated pigs two high-fidelity pressure catheters were placed, one directly behind the pulmonary valve, and the second one in a distal branch of the pulmonary artery. PAP was raised using the thromboxane A2 analogue U46619 and animals were ventilated in a pressure controlled mode (I:E ratio 1:2, respiratory rate 12/min, tidal volume of 6 ml kg-1). All signals were recorded using the multi-channel platform PowerLab®. The arrival of the pulse wave at each catheter tip was determined using a MATLAB-based modified hyperbolic tangent algorithm and PWTT calculated as the time interval between these arrivals.Main results. Correlation coefficient for PWTT and mean PAP wasr= 0.932 for thromboxane. This correlation coefficient increased considerably when heart beats either at end-inspiration (r= 0.978) or at end-expiration (r= 0.985) were selected (=respiratory gating).Significance. The estimation of mean PAP from PWTT improved significantly when taking the respiratory cycle into account. Respiratory gating is suggested to improve for the estimation of PAP by PWTT.
由于脉搏波转运时间(PWTT)会随着肺动脉压(PAP)的增加而缩短,因此被认为是肺动脉压的潜在无创替代指标。众所周知,潮气肺充盈状态也会影响 PWTT,而与 PAP 无关。这项回顾性分析的目的是检验呼吸门控是否改善了 PWTT 和 PAP 之间的相关系数。在五头麻醉和机械通气的猪身上分别放置了两根高保真压力导管,一根直接位于肺动脉瓣后方,另一根位于肺动脉远端分支。使用血栓素 A2 类似物 U46619 提高血压,并以压力控制模式(I:E 比为 1:2,呼吸频率为 12/分钟,潮气量为 6 毫升/千克)对动物进行通气。所有信号均使用多通道平台 PowerLab® 进行记录。使用基于 MATLAB 的修正双曲正切算法确定脉搏波到达每个导管尖端的时间,并将 PWTT 计算为这些到达之间的时间间隔。对于血栓素,PWTT 与平均 PAP 的相关系数为 r = 0.932。当选择呼气末(r = 0.978)或呼气末(r = 0.985)的心脏搏动时(= 呼吸门控),该相关系数显著增加。因此,在考虑呼吸周期的情况下,通过脉搏波速度来估算平均肺活量的效果显著提高。建议呼吸门控可改善脉搏波速度测试法对 PAP 的估计。
{"title":"Respiratory gating improves correlation between pulse wave transit time and pulmonary artery pressure in experimental pulmonary hypertension.","authors":"Fabian Mueller-Graf, Paul Frenkel, Jonas Merz, Susanne Reuter, Brigitte Vollmar, Gerardo Tusman, Sven Pulletz, Stephan H Böhm, Amelie Zitzmann, Daniel A Reuter, Andy Adler","doi":"10.1088/1361-6579/ad2eb5","DOIUrl":"10.1088/1361-6579/ad2eb5","url":null,"abstract":"<p><p><i>Objective</i>. Since pulse wave transit time (PWTT) shortens as pulmonary artery pressure (PAP) increases it was suggested as a potential non-invasive surrogate for PAP. The state of tidal lung filling is also known to affect PWTT independently of PAP. The aim of this retrospective analysis was to test whether respiratory gating improved the correlation coefficient between PWTT and PAP.<i>Approach</i>. In each one of five anesthetized and mechanically ventilated pigs two high-fidelity pressure catheters were placed, one directly behind the pulmonary valve, and the second one in a distal branch of the pulmonary artery. PAP was raised using the thromboxane A2 analogue U46619 and animals were ventilated in a pressure controlled mode (I:E ratio 1:2, respiratory rate 12/min, tidal volume of 6 ml kg<sup>-1</sup>). All signals were recorded using the multi-channel platform PowerLab<sup>®</sup>. The arrival of the pulse wave at each catheter tip was determined using a MATLAB-based modified hyperbolic tangent algorithm and PWTT calculated as the time interval between these arrivals.<i>Main results</i>. Correlation coefficient for PWTT and mean PAP was<i>r</i>= 0.932 for thromboxane. This correlation coefficient increased considerably when heart beats either at end-inspiration (<i>r</i>= 0.978) or at end-expiration (<i>r</i>= 0.985) were selected (=respiratory gating).<i>Significance</i>. The estimation of mean PAP from PWTT improved significantly when taking the respiratory cycle into account. Respiratory gating is suggested to improve for the estimation of PAP by PWTT.</p>","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139997044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-26DOI: 10.1088/1361-6579/ad2eb6
Zhe Wang, Yongxiong Wang, Xin Wan, Yiheng Tang
Objective.Extracting discriminative spatial information from multiple electrodes is a crucial and challenging problem for electroencephalogram (EEG)-based emotion recognition. Additionally, the domain shift caused by the individual differences degrades the performance of cross-subject EEG classification.Approach.To deal with the above problems, we propose the cerebral asymmetry representation learning-based deep subdomain adaptation network (CARL-DSAN) to enhance cross-subject EEG-based emotion recognition. Specifically, the CARL module is inspired by the neuroscience findings that asymmetrical activations of the left and right brain hemispheres occur during cognitive and affective processes. In the CARL module, we introduce a novel two-step strategy for extracting discriminative features through intra-hemisphere spatial learning and asymmetry representation learning. Moreover, the transformer encoders within the CARL module can emphasize the contributive electrodes and electrode pairs. Subsequently, the DSAN module, known for its superior performance over global domain adaptation, is adopted to mitigate domain shift and further improve the cross-subject performance by aligning relevant subdomains that share the same class samples.Main Results.To validate the effectiveness of the CARL-DSAN, we conduct subject-independent experiments on the DEAP database, achieving accuracies of 68.67% and 67.11% for arousal and valence classification, respectively, and corresponding accuracies of 67.70% and 67.18% on the MAHNOB-HCI database.Significance.The results demonstrate that CARL-DSAN can achieve an outstanding cross-subject performance in both arousal and valence classification.
{"title":"Cerebral asymmetry representation learning-based deep subdomain adaptation network for electroencephalogram-based emotion recognition.","authors":"Zhe Wang, Yongxiong Wang, Xin Wan, Yiheng Tang","doi":"10.1088/1361-6579/ad2eb6","DOIUrl":"10.1088/1361-6579/ad2eb6","url":null,"abstract":"<p><p><i>Objective.</i>Extracting discriminative spatial information from multiple electrodes is a crucial and challenging problem for electroencephalogram (EEG)-based emotion recognition. Additionally, the domain shift caused by the individual differences degrades the performance of cross-subject EEG classification.<i>Approach.</i>To deal with the above problems, we propose the cerebral asymmetry representation learning-based deep subdomain adaptation network (CARL-DSAN) to enhance cross-subject EEG-based emotion recognition. Specifically, the CARL module is inspired by the neuroscience findings that asymmetrical activations of the left and right brain hemispheres occur during cognitive and affective processes. In the CARL module, we introduce a novel two-step strategy for extracting discriminative features through intra-hemisphere spatial learning and asymmetry representation learning. Moreover, the transformer encoders within the CARL module can emphasize the contributive electrodes and electrode pairs. Subsequently, the DSAN module, known for its superior performance over global domain adaptation, is adopted to mitigate domain shift and further improve the cross-subject performance by aligning relevant subdomains that share the same class samples.<i>Main Results.</i>To validate the effectiveness of the CARL-DSAN, we conduct subject-independent experiments on the DEAP database, achieving accuracies of 68.67% and 67.11% for arousal and valence classification, respectively, and corresponding accuracies of 67.70% and 67.18% on the MAHNOB-HCI database.<i>Significance.</i>The results demonstrate that CARL-DSAN can achieve an outstanding cross-subject performance in both arousal and valence classification.</p>","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139997089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-21DOI: 10.1088/1361-6579/ad2eb3
David P Byrne, Nicole Studer, Cristy Secombe, Alexander Cieslewicz, Giselle Hosgood, Anthea Raisis, Andy Adler, Martina Mosing
Objective. Data from two-plane electrical impedance tomography (EIT) can be reconstructed into various slices of functional lung images, allowing for more complete visualisation and assessment of lung physiology in health and disease. The aim of this study was to confirm the ability of 3D EIT to visualise normal lung anatomy and physiology at rest and during increased ventilation (represented by rebreathing).Approach. Two-plane EIT data, using two electrode planes 20 cm apart, were collected in 20 standing sedate horses at baseline (resting) conditions, and during rebreathing. EIT data were reconstructed into 3D EIT whereby tidal impedance variation (TIV), ventilated area, and right-left and ventral-dorsal centres of ventilation (CoVRLand CoVVD, respectively) were calculated in cranial, middle and caudal slices of lung, from data collected using the two planes of electrodes.Main results. There was a significant interaction of time and slice for TIV (p< 0.0001) with TIV increasing during rebreathing in both caudal and middle slices. The ratio of right to left ventilated area was higher in the cranial slice, in comparison to the caudal slice (p= 0.0002). There were significant effects of time and slice on CoVVDwhereby the cranial slice was more ventrally distributed than the caudal slice (p< 0.0009 for the interaction).Significance. The distribution of ventilation in the three slices corresponds with topographical anatomy of the equine lung. This study confirms that 3D EIT can accurately represent lung anatomy and changes in ventilation distribution during rebreathing in standing sedate horses.
目的:双平面电阻抗断层扫描(EIT)的数据可重建为各种肺功能图像切片,从而更全面地观察和评估健康和疾病时的肺部生理状况。这项研究的目的是确认三维电阻抗断层成像技术在静息状态和通气量增加(以再呼吸为代表)时观察正常肺部解剖和生理结构的能力:使用相距 20 厘米的两个电极平面,收集 20 匹站立镇静的马在基线(静息)状态和再呼吸时的双平面 EIT 数据。将 EIT 数据重建为三维 EIT,根据使用两个电极平面采集的数据,计算出肺部头颅、中部和尾部切片的潮气阻抗变化(TIV)、通气面积以及左右和腹背通气中心(分别为 CoVRL 和 CoVVD):时间和切片对 TIV 有明显的交互作用(p < 0.0001),尾部和中部切片的 TIV 在再吸气时增加。头颅切片与尾部切片相比,左右通气面积之比更高(p = 0.0002)。时间和切片对 CoVVD 有显着影响,其中颅骨切片比尾部切片更偏向腹侧分布(交互作用 p < 0.0009):三个切片的通气分布与马肺的地形解剖相符。这项研究证实,3d EIT 可以准确地反映站立镇静马匹的肺部解剖结构和再呼吸时通气分布的变化。
{"title":"Validation of three-dimensional thoracic electrical impedance tomography of horses during normal and increased tidal volumes.","authors":"David P Byrne, Nicole Studer, Cristy Secombe, Alexander Cieslewicz, Giselle Hosgood, Anthea Raisis, Andy Adler, Martina Mosing","doi":"10.1088/1361-6579/ad2eb3","DOIUrl":"10.1088/1361-6579/ad2eb3","url":null,"abstract":"<p><p><i>Objective</i>. Data from two-plane electrical impedance tomography (EIT) can be reconstructed into various slices of functional lung images, allowing for more complete visualisation and assessment of lung physiology in health and disease. The aim of this study was to confirm the ability of 3D EIT to visualise normal lung anatomy and physiology at rest and during increased ventilation (represented by rebreathing).<i>Approach</i>. Two-plane EIT data, using two electrode planes 20 cm apart, were collected in 20 standing sedate horses at baseline (resting) conditions, and during rebreathing. EIT data were reconstructed into 3D EIT whereby tidal impedance variation (TIV), ventilated area, and right-left and ventral-dorsal centres of ventilation (CoV<sub>RL</sub>and CoV<sub>VD</sub>, respectively) were calculated in cranial, middle and caudal slices of lung, from data collected using the two planes of electrodes.<i>Main results</i>. There was a significant interaction of time and slice for TIV (<i>p</i>< 0.0001) with TIV increasing during rebreathing in both caudal and middle slices. The ratio of right to left ventilated area was higher in the cranial slice, in comparison to the caudal slice (<i>p</i>= 0.0002). There were significant effects of time and slice on CoV<sub>VD</sub>whereby the cranial slice was more ventrally distributed than the caudal slice (<i>p</i>< 0.0009 for the interaction).<i>Significance</i>. The distribution of ventilation in the three slices corresponds with topographical anatomy of the equine lung. This study confirms that 3D EIT can accurately represent lung anatomy and changes in ventilation distribution during rebreathing in standing sedate horses.</p>","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139997045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-21DOI: 10.1088/1361-6579/ad2f5e
Fons Schipper, Ruud J G van Sloun, Angela Grassi, Jan Brouwer, Fokke van Meulen, Sebastiaan Overeem, Pedro Fonseca
Objective. Unobtrusive long-term monitoring of cardiac parameters is important in a wide variety of clinical applications, such as the assesment of acute illness severity and unobtrusive sleep monitoring. Here we determined the accuracy and robustness of heartbeat detection by an accelerometer worn on the chest.Approach. We performed overnight recordings in 147 individuals (69 female, 78 male) referred to two sleep centers. Two methods for heartbeat detection in the acceleration signal were compared: one previously described approach, based on local periodicity, and a novel extended method incorporating maximumaposterioriestimation and a Markov decision process to approach an optimal solution.Main results. The maximumaposterioriestimation significantly improved performance, with a mean absolute error for the estimation of inter-beat intervals of only 3.5 ms, and 95% limits of agreement of -1.7 to +1.0 beats per minute for heartrate measurement. Performance held during posture changes and was only weakly affected by the presence of sleep disorders and demographic factors.Significance. The new method may enable the use of a chest-worn accelerometer in a variety of applications such as ambulatory sleep staging and in-patient monitoring.
{"title":"Maximum a posteriori detection of heartbeats from a chest-worn accelerometer.","authors":"Fons Schipper, Ruud J G van Sloun, Angela Grassi, Jan Brouwer, Fokke van Meulen, Sebastiaan Overeem, Pedro Fonseca","doi":"10.1088/1361-6579/ad2f5e","DOIUrl":"10.1088/1361-6579/ad2f5e","url":null,"abstract":"<p><p><i>Objective</i>. Unobtrusive long-term monitoring of cardiac parameters is important in a wide variety of clinical applications, such as the assesment of acute illness severity and unobtrusive sleep monitoring. Here we determined the accuracy and robustness of heartbeat detection by an accelerometer worn on the chest.<i>Approach</i>. We performed overnight recordings in 147 individuals (69 female, 78 male) referred to two sleep centers. Two methods for heartbeat detection in the acceleration signal were compared: one previously described approach, based on local periodicity, and a novel extended method incorporating maximum<i>a</i><i>posteriori</i>estimation and a Markov decision process to approach an optimal solution.<i>Main results</i>. The maximum<i>a</i><i>posteriori</i>estimation significantly improved performance, with a mean absolute error for the estimation of inter-beat intervals of only 3.5 ms, and 95% limits of agreement of -1.7 to +1.0 beats per minute for heartrate measurement. Performance held during posture changes and was only weakly affected by the presence of sleep disorders and demographic factors.<i>Significance</i>. The new method may enable the use of a chest-worn accelerometer in a variety of applications such as ambulatory sleep staging and in-patient monitoring.</p>","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140022410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background and Objective. Sleep-disordered breathing (SDB) poses health risks linked to hypertension, cardiovascular disease, and diabetes. However, the time-consuming and costly standard diagnostic method, polysomnography (PSG), limits its wide adoption and leads to underdiagnosis. To tackle this, cost-effective algorithms using single-lead signals (like respiratory, blood oxygen, and electrocardiogram) have emerged. Despite respiratory signals being preferred for SDB assessment, a lack of comprehensive reviews addressing their algorithmic scope and performance persists. This paper systematically reviews 2012-2022 literature, covering signal sources, processing, feature extraction, classification, and application, aiming to bridge this gap and provide future research references.Methods. This systematic review followed the registered PROSPERO protocol (CRD42022385130), initially screening 342 papers, with 32 studies meeting data extraction criteria.Results. Respiratory signal sources include nasal airflow (NAF), oronasal airflow (OAF), and respiratory movement-related signals such as thoracic respiratory effort (TRE) and abdominal respiratory effort (ARE). Classification techniques include threshold rule-based methods (8), machine learning models (13), and deep learning models (11). The NAF-based algorithm achieved the highest average accuracy at 94.11%, surpassing 78.19% for other signals. Hypopnea detection sensitivity with single-source respiratory signals remained modest, peaking at 73.34%. The TRE and ARE signals proved to be reliable in identifying different types of SDB because distinct respiratory disorders exhibited different patterns of chest and abdominal motion.Conclusions. Multiple detection algorithms have been widely applied for SDB detection, and their accuracy is closely related to factors such as signal source, signal processing, feature selection, and model selection.
{"title":"Algorithmic detection of sleep-disordered breathing using respiratory signals: a systematic review.","authors":"Liqing Yang, Zhimei Ding, Jiangjie Zhou, Siyuan Zhang, Qi Wang, Kaige Zheng, Xing Wang, Lin Chen","doi":"10.1088/1361-6579/ad2c13","DOIUrl":"10.1088/1361-6579/ad2c13","url":null,"abstract":"<p><p><i>Background and Objective</i>. Sleep-disordered breathing (SDB) poses health risks linked to hypertension, cardiovascular disease, and diabetes. However, the time-consuming and costly standard diagnostic method, polysomnography (PSG), limits its wide adoption and leads to underdiagnosis. To tackle this, cost-effective algorithms using single-lead signals (like respiratory, blood oxygen, and electrocardiogram) have emerged. Despite respiratory signals being preferred for SDB assessment, a lack of comprehensive reviews addressing their algorithmic scope and performance persists. This paper systematically reviews 2012-2022 literature, covering signal sources, processing, feature extraction, classification, and application, aiming to bridge this gap and provide future research references.<i>Methods</i>. This systematic review followed the registered PROSPERO protocol (CRD42022385130), initially screening 342 papers, with 32 studies meeting data extraction criteria.<i>Results</i>. Respiratory signal sources include nasal airflow (NAF), oronasal airflow (OAF), and respiratory movement-related signals such as thoracic respiratory effort (TRE) and abdominal respiratory effort (ARE). Classification techniques include threshold rule-based methods (8), machine learning models (13), and deep learning models (11). The NAF-based algorithm achieved the highest average accuracy at 94.11%, surpassing 78.19% for other signals. Hypopnea detection sensitivity with single-source respiratory signals remained modest, peaking at 73.34%. The TRE and ARE signals proved to be reliable in identifying different types of SDB because distinct respiratory disorders exhibited different patterns of chest and abdominal motion.<i>Conclusions</i>. Multiple detection algorithms have been widely applied for SDB detection, and their accuracy is closely related to factors such as signal source, signal processing, feature selection, and model selection.</p>","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139932391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-20DOI: 10.1088/1361-6579/ad2eb4
Esmée C de Boer, Catarina Dinis Fernandes, Danihel van Neerven, Christoph Pennings, Rohan Joshi, Sabina Manzari, Sergei Shulepov, Luuk van Knippenberg, John van Rooij, R Arthur Bouwman, Massimo Mischi
Objective. Carotid ultrasound (US) has been studied as a non-invasive alternative for hemodynamic monitoring. A long-axis (LA) view is traditionally employed but is difficult to maintain and operator experience may impact the diameter estimates, making it unsuitable for monitoring. Preliminary results show that a new, i.e. rotated and tilted (RT) view is more robust to motion and less operator-dependent. This study aimed to quantitatively assess common carotid diameter estimates obtained in a clinical setting from an RT view and compare those to corresponding estimates obtained using other views.Approach. Carotid US measurements were performed in 30 adult cardiac-surgery patients (26 males, 4 females) with short-axis (SA), LA, and RT probe orientations, the first being used as a reference for measuring the true vessel diameter. Per 30 s acquisition, the median and spread in diameter values were computed, the latter representing a measure of robustness, and were statistically compared between views.Main results. The median (IQR) over all the patients of the median diameter per 30 s acquisition was 7.15 (1.15) mm for the SA view, 7.03 (1.51) mm for the LA view, and 6.99 (1.72) mm for the RT view. The median spread in diameter values was 0.18 mm for the SA view, 0.16 mm for the LA view, and 0.18 mm for the RT view. There were no statistically significant differences between views in the median diameter values (p= 0.088) or spread (p= 0.122).Significance. The RT view results in comparable and equally robust median carotid diameter values compared to the reference. These findings open the path for future studies investigating the use of the RT view in new applications, such as in wearable ultrasound devices.
{"title":"Quantitative assessment of carotid ultrasound diameter measurements in the operating room: a comparable analysis of long-axis versus rotated and tilted orientation.","authors":"Esmée C de Boer, Catarina Dinis Fernandes, Danihel van Neerven, Christoph Pennings, Rohan Joshi, Sabina Manzari, Sergei Shulepov, Luuk van Knippenberg, John van Rooij, R Arthur Bouwman, Massimo Mischi","doi":"10.1088/1361-6579/ad2eb4","DOIUrl":"10.1088/1361-6579/ad2eb4","url":null,"abstract":"<p><p><i>Objective</i>. Carotid ultrasound (US) has been studied as a non-invasive alternative for hemodynamic monitoring. A long-axis (LA) view is traditionally employed but is difficult to maintain and operator experience may impact the diameter estimates, making it unsuitable for monitoring. Preliminary results show that a new, i.e. rotated and tilted (RT) view is more robust to motion and less operator-dependent. This study aimed to quantitatively assess common carotid diameter estimates obtained in a clinical setting from an RT view and compare those to corresponding estimates obtained using other views.<i>Approach</i>. Carotid US measurements were performed in 30 adult cardiac-surgery patients (26 males, 4 females) with short-axis (SA), LA, and RT probe orientations, the first being used as a reference for measuring the true vessel diameter. Per 30 s acquisition, the median and spread in diameter values were computed, the latter representing a measure of robustness, and were statistically compared between views.<i>Main results</i>. The median (IQR) over all the patients of the median diameter per 30 s acquisition was 7.15 (1.15) mm for the SA view, 7.03 (1.51) mm for the LA view, and 6.99 (1.72) mm for the RT view. The median spread in diameter values was 0.18 mm for the SA view, 0.16 mm for the LA view, and 0.18 mm for the RT view. There were no statistically significant differences between views in the median diameter values (<i>p</i>= 0.088) or spread (<i>p</i>= 0.122).<i>Significance</i>. The RT view results in comparable and equally robust median carotid diameter values compared to the reference. These findings open the path for future studies investigating the use of the RT view in new applications, such as in wearable ultrasound devices.</p>","PeriodicalId":20047,"journal":{"name":"Physiological measurement","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139997090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}