Interferometric measurement of complex-field changes in transient detection imaging.

We report an experimental method that combines nonlinear-crystal-based transient detection imaging (TDI) with interferometric complex-field retrieval. The system allows measuring both phase and amplitude of a dynamic scene while suppressing stationary background. Theoretical and experimental results prove the linear relation existing between input and output phases, as well as the benefits of phase analysis for both detection and measurement with high resolutions of λ/30, even under noisy conditions. Additionally, we present experimental evidence of the remarkable ability of the technique to detect phase sign changes in the scene -what we call differential-phase TDI- showing great detection sensitivity and no calibration requirements.

A Contact-Free Optical Device for the Detection of Pulmonary Congestion-A Pilot Study.

BACKGROUND: The cost of heart failure hospitalizations in the US alone is over USD 10 billion per year. Over 4 million Americans are hospitalized every year due to heart failure (HF), with a median length of stay of 4 days and an in-hospital mortality rate that exceeds 5%. Hospitalizations of patients with HF can be prevented by early detection of lung congestion. Our study assessed a new contact-free optical medical device used for the early detection of lung congestion. METHODS: The Gili system is an FDA-cleared device used for measuring chest motion vibration data. Lung congestion in the study was assessed clinically and verified via two cardiologists. An algorithm was developed using machine learning techniques, and cross-validation of the findings was performed to estimate the accuracy of the algorithm. RESULTS: A total of 227 patients were recruited (101 cases vs. 126 controls). The sensitivity and specificity for the device in our study were 0.91 (95% CI: 0.86-0.93) and 0.91 (95% CI: 0.87-0.94), respectively. In all instances, the observed estimates of PPVs and NPVs were at least 0.82 and 0.90, respectively. The accuracy of the algorithm was not affected by different covariates (including respiratory or valvular conditions). CONCLUSIONS: This study demonstrates the efficacy of a contact-free optical device for detecting lung congestion. Further validation of the study results across a larger and precise scale is warranted.

A novel contact-free atrial fibrillation monitor: a pilot study.

Aims: Atrial fibrillation (AF) is a major cause of morbidity and mortality. Current guidelines support performing electrocardiogram (ECG) screenings to spot AF in high-risk patients. The purpose of this study was to validate a new algorithm aimed to identify AF in patients measured with a recent FDA-cleared contact-free optical device. Methods and results: Study participants were measured simultaneously using two devices: a contact-free optical system that measures chest motion vibrations (investigational device, 'Gili') and a standard reference bed-side ECG monitor (Mindray®). Each reference ECG was evaluated by two board certified cardiologists that defined each trace as: regular rhythm, AF, other irregular rhythm or indecipherable/missing. A total of 3582, 30-s intervals, pertaining to 444 patients (41.9% with a history of AF) were made available for analysis. Distribution of patients with active AF, other irregular rhythm, and regular rhythm was 16.9%, 29.5%, and 53.6% respectively. Following application of cross-validated machine learning approach, the observed sensitivity and specificity were 0.92 [95% confidence interval (CI): 0.91-0.93] and 0.96 (95% CI: 0.95-0.96), respectively. Conclusion: This study demonstrates for the first time the efficacy of a contact-free optical device for detecting AF.

Validation of a novel contact-free heart and respiratory rate monitor.

There is a growing need for remote monitoring of patients due to a lack of resources and infection control. Current systems use sensors that require constant physical contact with the user, which may result in discomfort or lack of adherence. In the present study, we evaluated the accuracy of a new contact-free system to monitor heart and respiratory rate. Study participants were measured simultaneously using two devices: a contact-free optical system that measures nano-vibrations and movements (investigational device, "Gili Pro BioSensor") and a standard reference bed-side monitor, inclusive of an electrocardiogram and capnograph modules (Mindray®). Co-primary endpoints included HR and RR accuracy in subjects without active arrhythmias for HR, and for all study populations for RR (i.e., for subjects with and without active arrhythmias). Confirmatory secondary endpoints included HR scored continuously for all study populations, inclusive of subjects with arrhythmias. The present study included 115 patients who completed study procedures. Mean age was 66 ± 14.6 (range 29-93) with 60% males, 31% obese patients (i.e., BMI > 30 kg/m2, range 17-44) and 56% measured in a chair. For the dichotomised accuracy analysis, both co-primary endpoint for HR and RR resulted in 100% accuracy (95% CI: HR 98.8-100%; RR 98.9-100%), whereas for the confirmatory secondary analysis, 99.1% of the HR measurements across subjects with and without active arrhythmias were deemed accurate (95% CI: 97.4-99.8%). The current study demonstrated over 99% accuracy in detecting heart and respiratory rate using a novel contact-free optical system.