A study of the relationship between the level of anxiety declared by MRI patients in the STAI questionnaire and their respiratory rate acquired by a fibre-optic sensor system

Harnessing ChatGPT dialogues to address claustrophobia in MRI - A radiographers' education perspective

INTRODUCTION

The healthcare sector invests significantly in communication skills training, but not always with satisfactory results. Recently, generative Large Language Models, have shown promising results in medical education. This study aims to use ChatGPT to simulate radiographer-patient conversations about the critical moment of claustrophobia management during MRI, exploring how Artificial Intelligence can improve radiographers' communication skills.

METHODS

This study exploits specifically designed prompts on ChatGPT-3.5 and ChatGPT-4 to generate simulated conversations between virtual claustrophobic patients and six radiographers with varying levels of work experience focusing on their differences in model size and language generation capabilities. Success rates and responses were analysed. The methods of radiographers in convincing virtual patients to undergo MRI despite claustrophobia were also evaluated.

RESULTS

A total of 60 simulations were conducted, achieving a success rate of 96.7% (58/60). ChatGPT-3.5 exhibited errors in 40% (12/30) of the simulations, while ChatGPT-4 showed no errors. In terms of radiographers' communication during the simulations, out of 164 responses, 70.2% (115/164) were categorized as "Supportive Instructions," followed by "Music Therapy" at 18.3% (30/164). Experts mainly used "Supportive Instructions" (82.2%, 51/62) and "Breathing Techniques" (9.7%, 6/62). Intermediate participants favoured "Music Therapy" (26%, 13/50), while Beginner participants frequently utilized "Mild Sedation" (15.4%, 8/52).

CONCLUSION

The simulation of clinical scenarios via ChatGPT proves valuable in assessing and testing radiographers' communication skills, especially in managing claustrophobic patients during MRI. This pilot study highlights the potential of ChatGPT in preclinical training, recognizing different training needs at different levels of professional experience.

IMPLICATIONS FOR PRACTICE

This study is relevant in radiography practice, where AI is increasingly widespread, as it explores a new way to improve the training of radiographers.

Scan-associated anxiety (scanxiety): the enigma of emotional breathing oscillations at 0.32 Hz (19 bpm)

MRI-related anxiety in healthy participants is often characterized by a dominant breathing frequency at around 0.32 Hz (19 breaths per minute, bpm) at the beginning but in a few cases also at the end of scanning. Breathing waves at 19 bpm are also observed in patients with anxiety independently of the scanned body part. In patients with medically intractable epilepsy and intracranial electroencephalography (iEEG), spontaneous breathing through the nose varied between 0.24 and 0.37 Hz (~19 bpm). Remarkable is the similarity of the observed breathing rates at around 0.32 Hz during different types of anxiety states (e.g., epilepsy, cancer, claustrophobia) with the preferred breathing frequency of 0.32 Hz (19 bpm), which is predicted by the binary hierarchy model of Klimesch. This elevated breathing frequency most likely reflects an emotional processing state, in which energy demands are minimized due to a harmonic coupling ratio with other brain-body oscillations.

Integrative neuro-cardiovascular dynamics in response to test anxiety: A brain-heart axis study

Test anxiety (TA), a recognized form of social anxiety, is the most prominent cause of anxiety among students and, if left unmanaged, can escalate to psychiatric disorders. TA profoundly impacts both central and autonomic nervous systems, presenting as a dual manifestation of cognitive and autonomic components. While limited studies have explored the physiological underpinnings of TA, none have directly investigated the intricate interplay between the CNS and ANS in this context. In this study, we introduce a non-invasive, integrated neuro-cardiovascular approach to comprehensively characterize the physiological responses of 27 healthy subjects subjected to test anxiety induced via a simulated exam scenario. Our experimental findings highlight that an isolated analysis of electroencephalographic and heart rate variability data fails to capture the intricate information provided by a brain-heart axis assessment, which incorporates an analysis of the dynamic interaction between the brain and heart. With respect to resting state, the simulated examination induced a decrease in the neural control onto heartbeat dynamics at all frequencies, while the studying condition induced a decrease in the ascending heart-to-brain interplay at EEG oscillations up to 12Hz. This underscores the significance of adopting a multisystem perspective in understanding the complex and especially functional directional mechanisms underlying test anxiety.

Effects of a music-based intervention on psychophysiological outcomes of patients undergoing medical imaging procedures: A systematic review and meta-analysis

INTRODUCTION

Musical intervention (MI) is a valuable strategy for addressing the psychological and emotional challenges faced by patients undergoing imaging procedures. This study explores MI's impact on psychophysiological outcomes during imaging procedures, detailing the sound repertoire and technical characteristics employed in MI.

METHODS

A systematic review (SR) and meta-analysis (MA) were conducted. Electronic database searches of PubMed, Web-of-Science, and Scopus were performed encompassing original randomised research and quasi-experimental articles published until June 2023.

RESULTS

Thirteen articles were included in this SR, scoring between 23 and 68 on the Joanna Briggs Institute (JBI) Checklist. Four articles were included to perform a MA concerning anxiety and heart rate (HR) outcomes. Most studies utilised digital playlists as the medium for MI. Headphones were commonly used, with an average volume of 50-60 dB and a musical frequency of 60-80 beats/min. While authors generally preferred selecting musical genres for the repertoire, two articles specifically chose Johann Pachelbel's "Canon in D major" as their musical theme. In terms of psychological parameters, the experimental groups exhibited lower anxiety values than the control groups, with further reductions after MI. However, MA shows that this trend is only marginally significant. Patient comfort and overall examination experience showed improvement with MI. Regarding physiological parameters, HR, especially in the final phase of the examination, was significantly lower in the experimental group compared to the control group.

CONCLUSION

Across multiple studies, MI demonstrated the ability to reduce anxiety and HR. However, no specific music repertoire emerged as the most effective.

IMPLICATIONS FOR PRACTICE

MI arises as a painless, reliable, low-cost, and side-effect-free strategy, presenting imaging departments with a practical means to enhance patient comfort and mitigate anxiety and stress during medical procedures.

Trajectories and Predictors of Raised State Anxiety Among Outpatients Who Have Undergone Medical Imaging Procedures

PURPOSE

The aim of this study was to examine the prevalence of raised state anxiety before and after medical imaging procedures, the prevalence of state anxiety trajectories, and factors associated with postprocedural raised state anxiety.

METHODS

A prospective survey was administered to outpatients undergoing elective medical imaging procedures (CT, radiography, MRI, ultrasound, angiography, or fluoroscopy) recruited from one center. Participants completed a self-report survey preprocedure (time 1) and postprocedure (time 2). State anxiety was measured using the six-item State-Trait Anxiety Inventory. The point prevalence of raised state anxiety (State-Trait Anxiety Inventory score ≥33.16) at time 1 and time 2 was calculated, as was the prevalence of four state anxiety trajectories over time: persistent low anxiety, decreasing anxiety, increasing anxiety, and persistent raised anxiety. Factors predictive of raised state anxiety at time 2 were examined using logistic regression analysis.

RESULTS

Three hundred fifteen participants completed both surveys. The prevalence of raised state anxiety at time 1 (50%) and time 2 (51%) was similar. Most patients reported persistent raised anxiety (36%) and persistent low anxiety (34%) over time. Fewer patients reported increasing anxiety (15%) and decreasing anxiety (14%). Raised state anxiety (odds ratio, 4.84; 95% confidence interval, 2.48-9.48) and lower reported health status (odds ratio, 2.48; 95% confidence interval, 1.11-5.51) at time 1 were significantly associated with greater odds of raised anxiety at time 2.

CONCLUSIONS

Raised state anxiety related to medical imaging procedures is common among outpatients. Half of patients either developed or continued to experience raised anxiety after their procedures. Outpatients may benefit from evidence-based methods of alleviating anxiety before their procedures.

The Psychological, Physiological, and Behavioral Responses of Patients to Magnetic Resonance Imaging (MRI): A Systematic Review and Meta-Analysis

BACKGROUND

MRI is generally well-tolerated although it may induce physiological stress responses and anxiety in patients.

PURPOSE

Investigate the psychological, physiological, and behavioral responses of patients to MRI, their evolution over time, and influencing factors.

STUDY TYPE

Systematic review with meta-analysis.

POPULATION

181,371 adult patients from 44 studies undergoing clinical MRI.

ASSESSMENT

Pubmed, PsycInfo, Web of Science, and Scopus were systematically searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Quality appraisal was conducted with the Joanna Briggs Institute critical appraisal tools. Meta-analysis was conducted via Meta-Essentials workbooks when five studies were available for an outcome. Psychological and behavioral outcomes could be analyzed. Psychological outcomes were anxiety (State-Trait-Anxiety Inventory, STAI-S; 37) and willingness to undergo MRI again. Behavioral outcomes included unexpected behaviors: No shows, sedation, failed scans, and motion artifacts. Year of publication, sex, age, and positioning were examined as moderators.

STATISTICAL TESTS

Meta-analysis, Hedge's g. A P value <0.05 was considered to indicate statistical significance.

RESULTS

Of 12,755 initial studies, 104 studies were included in methodological review and 44 (181,371 patients) in meta-analysis. Anxiety did not significantly reduce from pre- to post-MRI (Hedge's g = -0.20, P = 0.051). Pooled values of STAI-S (37) were 44.93 (pre-MRI) and 40.36 (post-MRI). Of all patients, 3.9% reported unwillingness to undergo MRI again. Pooled prevalence of unexpected patient behavior was 11.4%; rates for singular behaviors were: Failed scans, 2.1%; no-shows, 11.5%; sedation, 3.3%; motion artifacts, 12.2%. Year of publication was not a significant moderator (all P > 0.169); that is, the patients' response was not improved in recent vs. older studies. Meta-analysis of physiological responses was not feasible since preconditions were not met for any outcome.

DATA CONCLUSION

Advancements of MRI technology alone may not be sufficient to eliminate anxiety in patients undergoing MRI and related unexpected behaviors.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 5.

Quantitative sensory testing in a magnetic resonance environment: considerations for thermal sensitivity and patient safety

Introduction

Quantitative sensory testing (QST) is often used to understand the perceptual basis of acute and chronic conditions, including pain. As the need grows for developing a mechanistic understanding of neurological pathways underlying perception in the basic and clinical sciences, there is a greater need to adapt techniques such as QST to the magnetic resonance (MR) environment. No studies have yet evaluated the impact of the MR environment on the perception of thermal stimuli. This study aimed to evaluate the differences in temperature sensitivity outside an MR environment and during an MRI scanning session. We hypothesized that there would be a difference in how participants reported their pain sensitivity between the two environments.

Methods

Healthy participants underwent thermal QST outside the MR scanning environment, where they were asked to rate the temperature of a noxious stimulus at which they perceived their pain to be 7/10, using a Likert scale ranging from 0 to 10. Participants repeated this procedure inside a 3.0 T MRI approximately 30 min later. We repeated our investigation in a clinical cohort of participants with a chronic pain condition.

Results

There were statistically significant changes of 1.1°C in thermal sensitivity between environments. This increase in pain threshold was found in healthy participants and replicated in the clinical cohort.

Discussion

Findings can be applied toward improving MR safety, the resolution of brain pathways underlying pain mechanisms, and to more broadly comment on the impact of the MR environment on investigations that integrate perception-influenced processes.

Individual and Contextual Variables as Predictors of MRI-Related Perceived Anxiety

BACKGROUND

Magnetic resonance imaging (MRI) generates patient anxiety (PA) and, therefore, it is important to understand individual and contextual variables that may cause it. In study one, we explored those anxiety predictors. In study two, we examined the effect of the experience of MRI on PA comparing anxiety pre- to post-MRI.

METHODS

PA was measured with an anxiety and stress scale in an interview format. Data collection occurred at a public hospital with MRI outpatients aged 18 or older. In study one (n = 204), participants answered the questionnaire immediately after experiencing the MRI and the data were analyzed through structural equation modeling. In study two (n = 242), participants answered the questionnaire before and after the examination and the data were analyzed through Bayesian statistics.

RESULTS

Being female, having a higher education level (EL), and not receiving information about the examination predicts higher PA after MRI. Patients with prior information have a decrease in PA from pre- to post-MRI. Those who do not have no change in PA. In low-educated patients, PA also decreases and no changes occur in highly educated patients.

CONCLUSION

This study provides health professionals with valuable indicators about patients who are more likely to perceive and express anxiety during MRI.

'Scanxiety': Content analysis of pre-MRI patient experience on Instagram

INTRODUCTION

Distress and anxiety are commonly reported during the Magnetic Resonance Imaging (MRI) experience with prior studies suggesting the pre-MRI period is a time of heightened distress. There is a paucity of literature exploring preprocedural distress and anxiety, in particular qualitative research analysing patient experience. Instagram is rapidly becoming an important social media platform though which to conduct health research. A gradually increasing number of studies have examined social media to gain insight into patient experience within medical radiation science (MRS). This study is considered as the first to explore patient experience of MRI using Instagram as a data source.

METHODS

This study investigated the patient experience during the pre-MRI period by performing a content analysis on open-source Instagram posts. Ethical approval for the study was sought and approved by the Charles Sturt University, Human Research Ethics Committee.

RESULTS

Six themes emerged from the extracted data; Journey to the MRI, Waiting, Anticipating the MRI procedure, Preparing for the MRI procedure, Negative interaction, and Fear of the results.

CONCLUSION

The findings of this study provide novel self-reported and unsolicited insight into the diverse, multifactorial, and often concomitant nature of preprocedural MRI anxiety and distress.

IMPLICATIONS FOR PRACTICE

This study adds to a growing body of literature advocating for a compassionate, holistic, and person-centered approach when caring for patients in MRI that also considers their emotional and psychological wellbeing.

Effects of a 360° virtual counselling environment on patient anxiety and CCTA process time: A randomised controlled trial

INTRODUCTION

This study investigated whether a 360° virtual counselling environment (360°VCE) was more effective at decreasing patients' anxiety than routine standard of care counselling for patients undergoing coronary computed tomography angiography (CCTA), and if there was any difference in the process times for both of these groups.

METHODS

A total of 86 patients underwent CCTA in this randomised controlled trial. Patients were randomly assigned to intervention and control groups. The 360°VCE was developed using spherical panoramic images and non-immersive 360° technology. The primary outcome, anxiety, was measured using the State-Trait Anxiety Inventory (STAI). The secondary outcome, CCTA process time, was measured from the time of arrival in the department until end of examination.

RESULTS

Pre-scan anxiety was lower among patients in the 360°VCE group immediately before CCTA in comparison to patients in the control group (p = 0.015). Women demonstrated higher levels of anxiety than men in both groups. No between-group differences were discerned in CCTA process time.

CONCLUSION

Access to 360°VCE can reduce patients' pre-CCTA anxiety levels.

IMPLICATIONS FOR PRACTICE

The presented results can be used to improve patient counselling and care, reduce anxiety among patients undergoing CCTA, and optimise the CCTA examination procedure.

Brain motion networks predict head motion during rest- and task-fMRI

Introduction

The capacity to stay still during scanning, which is necessary to avoid motion confounds while imaging, varies markedly between people.

Methods

Here we investigated the effect of head motion on functional connectivity using connectome-based predictive modeling (CPM) and publicly available brain functional magnetic resonance imaging (fMRI) data from 414 individuals with low frame-to-frame motion (Δd < 0.18 mm). Leave-one-out was used for internal cross-validation of head motion prediction in 207 participants, and twofold cross-validation was used in an independent sample (n = 207).

Results and Discussion

Parametric testing, as well as CPM-based permutations for null hypothesis testing, revealed strong linear associations between observed and predicted values of head motion. Motion prediction accuracy was higher for task- than for rest-fMRI, and for absolute head motion (d) than for Δd. Denoising attenuated the predictability of head motion, but stricter framewise displacement threshold (FD = 0.2 mm) for motion censoring did not alter the accuracy of the predictions obtained with lenient censoring (FD = 0.5 mm). For rest-fMRI, prediction accuracy was lower for individuals with low motion (mean Δd < 0.02 mm; n = 200) than for those with moderate motion (Δd < 0.04 mm; n = 414). The cerebellum and default-mode network (DMN) regions that forecasted individual differences in d and Δd during six different tasks- and two rest-fMRI sessions were consistently prone to the deleterious effect of head motion. However, these findings generalized to a novel group of 1,422 individuals but not to simulated datasets without neurobiological contributions, suggesting that cerebellar and DMN connectivity could partially reflect functional signals pertaining to inhibitory motor control during fMRI.

Preparing patients according to their individual coping style improves patient experience of magnetic resonance imaging

MRI-related anxiety is present in 30% of patients and may evoke motion artifacts/failed scans, which impair clinical efficiency. It is unclear how patient anxiety can be countered most effectively. Habitual preferences for coping with stressful situations by focusing or distracting one’s attention thereof (coping style) may play a key role in this context. This study aimed to compare the effectiveness of two patient-preparation videos with informational vs. relaxational content and to determine whether the fit between content and coping style affects effectivity. The sample consisted of 142 patients (M = 48.31 ± 15.81 years). Key outcomes were anxiety, and cortisol as a physiological stress marker. When not considering coping style, neither intervention improved the patients’ reaction; only patient preparation that matched the patients’ coping style was associated with an earlier reduction of anxiety. This suggests that considering individual preferences for patient preparation may be more effective than a one-size-fits-all approach.

A Wearable Breath Sensor Based on Fiber-Tip Microcantilever

Respiration rate is an essential vital sign that requires monitoring under various conditions, including in strong electromagnetic environments such as in magnetic resonance imaging systems. To provide an electromagnetically-immune breath-sensing system, we propose an all-fiber-optic wearable breath sensor based on a fiber-tip microcantilever. The microcantilever was fabricated on a fiber-tip by two-photon polymerization microfabrication based on femtosecond laser, so that a micro Fabry-Pérot (FP) interferometer was formed between the microcantilever and the end-face of the fiber. The cavity length of the micro FP interferometer was reduced as a result of the bending of the microcantilever induced by breath airflow. The signal of breath rate was rebuilt by detecting power variations of the FP interferometer reflected light and applying dynamic thresholds. The breath sensor achieved a high sensitivity of 0.8 nm/(m/s) by detecting the reflection spectrum upon applied flow velocities from 0.53 to 5.31 m/s. This sensor was also shown to have excellent thermal stability as its cross-sensitivity of airflow with respect to the temperature response was only 0.095 (m/s)/°C. When mounted inside a wearable surgical mask, the sensor demonstrated the capability to detect various breath patterns, including normal, fast, random, and deep breaths. We anticipate the proposed wearable breath sensor could be a useful and reliable tool for respiration rate monitoring.

Deep learning-based method for the continuous detection of heart rate in signals from a multi-fiber Bragg grating sensor compatible with magnetic resonance imaging

A method for the continuous detection of heart rate (HR) in signals acquired from patients using a sensor mat comprising a nine-element array of fiber Bragg gratings during routine magnetic resonance imaging (MRI) procedures is proposed. The method is based on a deep learning neural network model, which learned from signals acquired from 153 MRI patients. In addition, signals from 343 MRI patients were used for result verification. The proposed method provides automatic continuous extraction of HR with the root mean square error of 2.67 bpm, and the limits of agreement were -4.98-5.45 bpm relative to the reference HR.

Introduction of Cardiac Magnetic Resonance Imaging in Kosovo: First Fifty Consecutive Patients Registry Report

BACKGROUND: Cardiac magnetic resonance (CMR) as advanced diagnostic tool for the heart has been introduced in our institution since September 2019. AIM: We report on the first fifty consecutive patients using this imaging modality. METHODS AND MATERIALS: Strict protocol for CMR procedure, imaging quality assessment, contraindications, and informed consent were established. Patients selected for CMR were enrolled in a prospective registry. Visualizing the heart chambers, heart muscle and heart valves, resulted in acquiring complex imaging of the heart structure and function. When applicable, patients received gadolinium contrast agent for Late Gadolinium Enhancement (LGE). Adenosine was used for stress induced myocardial perfusion study. In this study, we report on the initial CMR procedures in the first 15 months. RESULTS: The age of the patients ranges from 17 to 82 and the number of male and female patients was well balanced. No absolute contraindications were met in any patient. Relative contraindications were noted but did not prevent from performing the scan. Different cardiac pathologies were encountered in the examined patients. Most common was the ischemic heart disease – 19 (38%). We had 15 (30%) out of 46 (92%) CMR procedures with LGE showing fibrotic scaring. Quality image assessment was scaled from poor to excellent. Most of the assessments were graded very good and good (46% and 48%), no poor, and very poor noted. CONCLUSION: CMR has been successfully introduced in Kosovo as excellent imaging tool for diagnosing and characterizing a nearly exhaustive spectrum of heart diseases.

Development of the short version of the spielberger state-trait anxiety inventory

The Spielberger State-Trait Anxiety Inventory (STAI) has been widely used to measure the state and trait components of anxiety. We sought to develop a short, yet reliable and valid form of these scales for use in circumstances where the full-form is not feasible. We abbreviated the scales using item response theory analyses to retain the items that could discriminate the best among participants. One sample (N = 922) completed the state scale, a second sample (N = 2227) completed the trait scale, while a third sample (N = 250) completed the short forms. Our participants completed the Hungarian version of STAI alongside other measures to observe external validity. We calculated cut-off scores for the state (>9.5,) and trait (>13.5) scales. A total of 19.5% and 20.1% of the respondents reached the cut-off scores. The five-item short forms of STAI had sound psychometric properties that are comparable to those obtained on the full-form. The external validity of the scales is also demonstrated. We report detailed descriptive statistics that could be used in further studies as standards. The short scales are reliable measures that could be used in clinical screening and behavioural research; especially where practical considerations preclude the use of a longer questionnaire.

Prevalence and Financial Impact of Claustrophobia, Anxiety, Patient Motion, and Other Patient Events in Magnetic Resonance Imaging

Claustrophobia, other anxiety reactions, excessive motion, and other unanticipated patient events in magnetic resonance imaging (MRI) not only delay or preclude diagnostic-quality imaging but can also negatively affect the patient experience. In addition, by impeding MRI workflow, they may affect the finances of an imaging practice. This review article offers an overview of the various types of patient-related unanticipated events that occur in MRI, along with estimates of their frequency of occurrence as documented in the available literature. In addition, the financial implications of these events are discussed from a microeconomic perspective, primarily from the point of view of a radiology practice or hospital, although associated limitations and other economic viewpoints are also included. Efforts to minimize these unanticipated patient events can potentially improve not only patient satisfaction and comfort but also an imaging practice's operational efficiency and diagnostic capabilities.

Intelligent Technical Textiles Based on Fiber Bragg Gratings for Strain Monitoring

In this paper, the concept design of intelligent technical textile blocks implemented with optical fibers that include fiber Bragg gratings for strain and temperature sensing is briefly introduced. In addition to the main design of the system, a design of measurement blocks with integrated fiber Bragg grating elements for strain measurement is also presented. In the basic measurement, the created textile block was tested for deformation sensitivity when a load was applied. Moreover, a unique robust and low profile connector was designed, created and verified. The fibers are terminated with GRIN lenses, allowing easy manipulation and completion of the connector in the field, with an average insertion loss of 5.5 dB.

Multifunctional Textile Platform for Fiber Optic Wearable Temperature-Monitoring Application

Wearable sensing technologies have been developed rapidly in the last decades for physiological and biomechanical signal monitoring. Much attention has been paid to functions of wearable applications, but comfort parameters have been overlooked. This research presents a developed fabric temperature sensor by adopting fiber Bragg grating (FBG) sensors and processing via a textile platform. This FBG-based quasi-distributed sensing system demonstrated a sensitivity of 10.61 ± 0.08 pm/°C with high stability in various temperature environments. No obvious wavelength shift occurred under the curvatures varying from 0 to 50.48 m⁻¹ and in different integration methods with textiles. The temperature distribution monitored by the developed textile sensor in a complex environment with multiple heat sources was deduced using MATLAB to present a real-time dynamic temperature distribution in the wearing environment. This novel fabric temperature sensor shows high sensitivity, stability, and usability with comfort textile properties that are of great potential in wearable applications.

Modification of the mechanical cardiac performance during end-expiratory voluntary apnea recorded with ballistocardiography and seismocardiography

OBJECTIVE

To assess if micro-accelerometers and gyroscopes may provide useful information for the detection of breathing disturbances in further studies.

APPROACH

Forty-three healthy volunteers performed a 10 s end-expiratory breath-hold, while ballistocardiograph (BCG) and seismocardiograph (SCG) determined changes in kinetic energy and its integral over time (iK, J · s). BCG measures overall body accelerations in response to blood mass ejection into the main vasculature at each cardiac cycle, while SCG records local chest wall vibrations generated beat-by-beat by myocardial activity. This minimally intrusive technology assesses linear accelerations and angular velocities in 12 degrees of freedom to calculate iK during the whole cardiac cycle. iK produced during systole and diastole were also computed.

MAIN RESULTS

The iK during normal breathing was 87.1 [63.3; 132.8] µJ · s for the SCG and 4.5 [3.3; 6.2] µJ · s for the BCG. Both increased to 107.1 [69.0; 162.0] µJ · s and 6.1 [4.4; 9.0] µJ · s, respectively, during breath-holding (p   =  0.003 and p   <  0.0001, respectively). The iK of the SCG further increased during spontaneous respiration following apnea (from 107.1 [69.0; 162.0] µJ · s to 160.0 [96.3; 207.3] µJ · s, p   <  0.0001). The ratio between the iK of diastole and systole increased from 0.35 [0.24; 0.45] during apnea to 0.49 [0.31; 0.80] (p   <  0.0001) during the restoration of respiration.

SIGNIFICANCE

A brief voluntary apnea generates large and distinct increases in SCG and BCG waveforms. iK monitoring during sleep may prove useful for the detection of respiratory disturbances. ClinicalTrials.gov number: NCT03760159.

An Active Self-Driven Piezoelectric Sensor Enabling Real-Time Respiration Monitoring

In this work, we report an active respiration monitoring sensor based on a piezoelectric-transducer-gated thin-film transistor (PTGTFT) aiming to measure respiration-induced dynamic force in real time with high sensitivity and robustness. It differs from passive piezoelectric sensors in that the piezoelectric transducer signal is rectified and amplified by the PTGTFT. Thus, a detailed and easy-to-analyze respiration rhythm waveform can be collected with a sufficient time resolution. The respiration rate, three phases of respiration cycle, as well as phase patterns can be further extracted for prognosis and caution of potential apnea and other respiratory abnormalities, making the PTGTFT a great promise for application in long-term real-time respiration monitoring.