Non-invasive Measurement System Research Articles

Antioxidants in Asian-Korean and Caucasian Skin: The Influence of Nutrition and Stress

Background: The antioxidant status of the human skin provides protection against the destructive action of free radicals. Most antioxidants cannot be synthesized by the human organism itself, but have to be ingested with a healthy nutrition rich in fruit and vegetables. The Korean cuisine is known to be one of the healthiest worldwide. This binational study investigated the cutaneous carotenoid concentrations in German subjects, South Korean subjects and immigrant Korean subjects resident in Germany and examined whether dietary- and lifestyle-related differences are reflected in the cutaneous carotenoid concentrations. Methods: Measurements of the carotenoid concentrations of 714 healthy volunteers were performed using a non-invasive spectroscopic measurement system based on reflectance spectroscopy. Results: In the present study South Korean residents showed a significantly higher antioxidant status than both native German residents and Korean immigrants living in Germany (p < 0.001). The first generation of Korean immigrants to Germany over the age of 50 mostly preserved Korean dietary habits, showing significantly higher concentrations (p < 0.001) than the German-born second and third Korean generations under the age of 50. Conclusion: The results of the study indicate that a healthy nutrition alone does not provide a high antioxidant status unless the stress exposure can be reduced simultaneously.

Noninvasive Hemodynamic Monitoring Devices

Noninvasive Hemodynamic Monitoring Devices

Measurement of cardiac output by use of noninvasively measured transient hemodilution curves with photoacoustic technology

We present the theoretical basis and experimental verification for cardiac output measurements using noninvasively measured hemodilution curves afforded with an indicator dilution technique and the emerging photoacoustic technology. A photoacoustic system noninvasively tracks a transient hemodilution effect induced by a bolus of isotonic saline as an indicator. As a result, a photoacoustic indicator dilution curve is obtained, which allows to estimate cardiac output from the developed algorithm. The experiments with a porcine blood circulatory phantom system demonstrated the feasibility of this technology towards the development of a noninvasive cardiac output measurement system for patient monitoring.

Noninvasive continuous versus intermittent arterial pressure monitoring: evaluation of the vascular unloading technique (CNAP device) in the emergency department

BackgroundMonitoring cardiovascular function in acutely ill patients in the emergency department (ED) is of paramount importance. Arterial pressure (AP) is usually monitored using intermittent oscillometric measurements with an upper arm cuff. The vascular unloading technique (VUT) allows continuous noninvasive AP monitoring. In this study, we compare continuous AP measurements obtained by VUT with intermittent oscillometric AP measurements in ED patients. In addition, we aimed to investigate whether continuous noninvasive AP monitoring allows detection of relevant hypotensive episodes that might be missed with intermittent AP monitoring.MethodsIn a German university hospital, 130 ED patients who required AP monitoring were analyzed in this prospective method comparison study. Continuous AP monitoring was performed using VUT (CNAP technology; CNSystems Medizintechnik AG, Graz, Austria) over a 2-hour period. The oscillometric AP values were recorded simultaneously every 15 minutes for the comparison of both methods. For statistical evaluation, Bland-Altman plots accounting for repeated AP measurements per individual were used.ResultsThe mean difference (±standard deviation) between AP measurements obtained by VUT and oscillometric AP measurements was -5 mmHg (±22 mmHg) for systolic AP (SAP), -2 mmHg (±15 mmHg) for diastolic AP (DAP), and -6 mmHg (±16 mmHg) for mean AP (MAP), respectively. In the interval between two oscillometric measurements, the VUT device detected hypotensive episodes (≥4 minutes) defined as either SAP <90 mmHg or MAP <65 mmHg in 30 patients and 16 patients, respectively. In 11 (SAP <90 mmHg) and 6 (MAP <65 mmHg) of these patients, hypotension was also detected by the subsequent intermittent oscillometric AP measurement.ConclusionsVUT using the CNAP system for noninvasive continuous AP measurement shows reasonable agreement with intermittent oscillometric measurements in acutely ill ED patients. Continuous AP monitoring allows immediate recognition of clinically relevant hypotensive episodes, which are missed or only belatedly recognized with intermittent AP measurement.

Development and assessment of a microwave void-fraction measurement system

The proof of concept of a non-invasive reflection-type void measurement system using microwaves is developed. Before constructing the instrument, governing equations are used to perform numerical simulations of different electrical components (reflectometer, antenna, etc.). Design and preliminary calibrations are performed based on these simulations. The results are then used to manufacture a setup that is installed on a Plexiglas vertical tube containing known volumetric fractions of gas in water at atmospheric conditions. The amount of injected gas and water are accurately controlled and the response of the system is compared with the simulations which confirm the suitability of such a system to study two-phase water-air mixtures.

Impact of changes in systemic vascular resistance on a novel non-invasive continuous cardiac output measurement system based on pulse wave transit time: a report of two cases

The inaccuracy of arterial waveform analysis for measuring continuos cardiac output (CCO) associated with changes in systemic vascular resistance (SVR) has been well documented. A new non-invasive continuous cardiac output monitoring system (esCCO) mainly utilizing pulse wave transit time (PWTT) in place of arterial waveform analysis has been developed. However, the trending ability of esCCO to measure cardiac output during changes in SVR remains unclear. After a previous multicenter study on esCCO measurement, we retrospectively identified two cases in which apparent changes in SVR developed in a short period during data collection. In each case, the trending ability of esCCO to measure cardiac output and time component of PWTT were analyzed. Recorded data suggest that the time component of PWTT may have a significant impact on the accuracy of estimating stroke volume during changes in SVR. However, further prospective clinical studies are required to test this hypothesis.

Measuring the solidification time of silicone rubber using optical inspection technology

A room temperature vulcanization silicone rubber was widely used as the mold making material due to its high elasticity, good heat-resistance and low surface energy. To enhance the efficiency of making the silicone rubber mold, accurately measuring the solidification time is an important issue. This study demonstrated a non-invasive measurement system to measure the solidification time of silicone rubber. The solidification time can be determined rapidly from the thickness of silicone rubber according to the predicted equation. The maximum relative error of the predicted equation is about 8.26%. The temperature rise of the silicone during the solidification process is an important phenomenon to determine the solidification behavior of silicone rubber. The solidification mechanism of silicone rubber mold is demonstrated.

Multi-sensor system with Bluetooth connectivity for non-invasive measurements of human body physical parameters

In the last few years, the availability of powerful personal computing devices, like smartphones, has opened new scenarios to the so called “Body Area Network” (BAN), i.e., sensor networks specifically designed to monitor physical conditions of the user. The traditional methods adopted to monitor physical parameters, like heart beat rate or exertion level, are not suitable for real-time measurements. However, a continuous monitoring of such kind of parameters would allow the athletes to constantly control their physical conditions, furnishing useful information to prevent overstrain and to improve their performance. In this work, a simple, portable and low-cost system for non-invasive and real-time measurement of physical parameters is proposed and experimentally characterized. It is composed of three units: the sensor apparatus, electronic interface circuit, and the data transmission unit. Two different sensors are combined in a unique structure to be placed in a clip-like fashion on the earlobe or other body part of a person. A photoplethysmographic sensor is used to optically measure the changes of blood volume in the arteries, thus to acquire information about heart beat, blood pressure, and arrhythmias. The second sensor is composed of two electrodes, hence an impedance measurement of the tissue is carried out. The impedance estimation can be used to monitor the dielectric properties of biological tissues and fluids, like blood flow. A commercial battery-operated Bluetooth earphone is used both to transmit sensor data and to provide the power supply for the sensors and the first conditioning electronics. Data transmission is operated by the standard Bluetooth Hands-Free profile; therefore, sensor data can be easily acquired, elaborated and visualized by a broad range of commercial devices. In fact, Hands-Free is the only Bluetooth data communication profile supported by any smartphone, from the low-cost ones to the high-end devices. The experimental characterization of the prototype, performed by using a specifically designed application for Android smartphone systems, has demonstrated the validity of the proposed approach.

Validation of Noninvasive MOEMS-Assisted Measurement System Based on CCD Sensor for Radial Pulse Analysis

Examination of wrist radial pulse is a noninvasive diagnostic method, which occupies a very important position in Traditional Chinese Medicine. It is based on manual palpation and therefore relies largely on the practitioner′s subjective technical skills and judgment. Consequently, it lacks reliability and consistency, which limits practical applications in clinical medicine. Thus, quantifiable characterization of the wrist pulse diagnosis method is a prerequisite for its further development and widespread use. This paper reports application of a noninvasive CCD sensor-based hybrid measurement system for radial pulse signal analysis. First, artery wall deformations caused by the blood flow are calibrated with a laser triangulation displacement sensor, following by the measurement of the deformations with projection moiré method. Different input pressures and fluids of various viscosities are used in the assembled artificial blood flow system in order to test the performance of laser triangulation technique with detection sensitivity enhancement through microfabricated retroreflective optical element placed on a synthetic vascular graft. Subsequently, the applicability of double-exposure whole-field projection moiré technique for registration of blood flow pulses is considered: a computational model and representative example are provided, followed by in vitro experiment performed on a vascular graft with artificial skin atop, which validates the suitability of the technique for characterization of skin surface deformations caused by the radial pulsation.

A Bubble Layer Influences the Accuracy of a Five-Band Microwave Radiometer System for Non-Invasive Temperature Measurement of Deep Brain Temperatures

A Bubble Layer Influences the Accuracy of a Five-Band Microwave Radiometer System for Non-Invasive Temperature Measurement of Deep Brain Temperatures

Development of a flexible customised compression garment pattern design system

The paper highlighted a new method that can be used to construct a customised compression garment for athletes. The garment must be able to exert high pressure on the ankle and become lower towards the knee. The garment was generated using 3D data of an athlete’s body segment obtained by a non-invasive non-contact measurement system. Then, a 3D compression garment was generated using a novel modelling approach taking into account the properties of the fabric, how much pressure to be exerted and the curvature of body parts. The 3D garment model was then flattened into a 2D compression garment pattern design. Finally, an experiment was conducted to validate the system. The outcome of the research is a system that not only allows for the design of a customised compression garment, but also could be used to create a variety of compression garment that can exert different pressure.

人体の非侵襲的脂質等代謝測定法の開発と評価

人体の非侵襲的脂質等代謝測定法の開発と評価

The Analysis of Pulse Pressure by Vascular Strain

The objective of this paper is to use the Noninvasive Strain Measurement System to monitor the pulse pressure of the blood’s undulation in the artery as an index for the clinical diagnosis of arteriosclerosis. In the study, a strain-measuring device (350Ω) is affixed to the left side of the radial styloid process, on the surface of the skin, and is connected to the Strain FleXense. An artery-pressuring tape is set on the left humerus, and the measurement of the wavelength and frequency of the heartbeat is taken to compare with the clinical artery wave. The results show that when the subject is in a comfortable position with moderate physiological levels, the heartbeat has no connection whatsoever with blood pressure. The greatest heartbeat strain, which occurs when the veins and arteries respectively are being cleared, displays as a linear change.

The Analysis of Pulse Pressure by Vascular Strain

The objective of this paper is to use the Noninvasive Strain Measurement System to monitor the pulse pressure of the blood’s undulation in the artery as an index for the clinical diagnosis of arteriosclerosis. In the study, a strain-measuring device (350Ω) is affixed to the left side of the radial styloid process, on the surface of the skin, and is connected to the Strain FleXense. An artery-pressuring tape is set on the left humerus, and the measurement of the wavelength and frequency of the heartbeat is taken to compare with the clinical artery wave. The results show that when the subject is in a comfortable position with moderate physiological levels, the heartbeat has no connection whatsoever with blood pressure. The greatest heartbeat strain, which occurs when the veins and arteries respectively are being cleared, displays as a linear change.

In-vitro validation of a non-invasive dual fluoroscopic imaging technique for measurement of the hip kinematics

Measurement of accurate in vivo hip joint kinematics in 6-DOF is difficult. Few studies have reported non-invasive measurements of the hip kinematics. The objective of this study was to validate a non-invasive dual fluoroscopic imaging system (DFIS) for measurement of hip kinematics. Bi-lateral hip joints of a cadaveric pelvic specimen were CT scanned to create bone models of the femur and pelvis, and subsequently tested in static and dynamic conditions inside the DFIS. The poses of the hip in space were then determined by matching the bone models with the fluoroscopic images. The pose data was compared to those obtained using a radio-stereometric analysis to determine the accuracy of the DFIS. The accuracy±precision for measuring the hip kinematics were less than 0.93±1.13mm for translations and 0.59±0.82° for rotations in all conditions. The repeatability of the DFIS technique was less than ±0.77mm and ±0.64° in position and orientation for measuring hip kinematics in both static and dynamic positions. This technique could thus be a promising tool for determining 6-DOF poses of the hip during functional activities, which may help to understand biomechanical factors in hip pathologic conditions such as osteoarthritis and femoroacetabular impingement before and after surgical treatment.

A non-invasive Cochlear Microphonic measurement system

The Cochlear Microphonic is one of the electrical potentials generated by the ear in response to audible stimuli. It is very difficult to measure the CM non-invasively because it has a very small magnitude (less than 1μV). A high Common Mode Rejection Ratio (CMRR) and very large bandwidth (5Hz–20kHz) biomedical amplifier system is presented to measure the signal. The system also uses a driven right leg circuit to increase the CMRR.

The T-Line TL-200 system for continuous non-invasive blood pressure measurement in medical intensive care unit patients

The T-Line TL-200 (Tensys Medical, San Diego, CA, USA) is a non-invasive arterial blood pressure (BP) monitoring system allowing continuous "beat-to-beat" monitoring of systolic arterial pressure (SAP), mean arterial pressure (MAP), and diastolic arterial pressure (DAP). It provides a real-time BP waveform like that obtained using an arterial catheter. The aim of this study was to compare BP measurements obtained using the T-Line TL-200 with simultaneous invasive BP measurements using a femoral arterial catheter in unselected critically ill medical patients. In 28 patients treated in a medical intensive care unit (ICU), BP values were simultaneously obtained using a femoral arterial catheter and the T-Line TL-200. All recorded data were included in the final analysis. For comparison of BP measurements, Bland-Altman analysis accounting for repeated measurements was performed (primary endpoint). A total of 76,826 pairs of BP measurements (each consisting of SAP, MAP, and DAP) were analyzed. For MAP, Bland-Altman analysis revealed a mean difference of +0.47 mmHg (95 % limits of agreement -16.53 to +17.46 mmHg). For SAP and DAP, the bias and 95 % limits of agreement were -9.01 mmHg (-37.47 to +19.45 mmHg) and +5.22 mmHg (-13.50 to +23.94 mmHg), respectively. Non-invasive, continuous, radial BP measurement with the T-Line TL-200 is basically feasible in medical ICU patients (with a low bias for MAP compared to MAP assessed using a femoral arterial catheter). High limits of agreement (particularly of SAP and DAP) preclude the use of the device as a single source of BP information in unstable critically ill patients.

Ophthalmic Artery as a sensor for non-invasive intracranial pressure measurement electronic system

Theoretical and experimental validity of ophthalmic artery (OA), as a sensor for non-invasive absolute intracranial pressure (aICP) measurement electronic system is presented in this paper. Because of OA similarity with gravimetric scales which can compare aICP with non-invasively applied external pressure Pe the value of aICP can be measured without the need of patient specific calibration. For the indication of aICP and Pe balance various blood flow parameters existing in intracranial and extracranial segments of OA are used. Pressure balance ICP=Pe occurs in the case of maximum conjunction of various blood flow parameters in intracranial and extracranial segments respectively. For the measurement of the blood flow parameters and indication of aICP, specially designed hardware and software has been created in Telematics Scientific Laboratory of Kaunas University of Technology. This innovative non-invasive aICP measurement system is described in this paper. The software of non-invasive aICP meter was developed concerning the fast location of IOA and EOA and fully automatic aICP measurement process. Prospective comparative clinical studies of 84 neurological patients were performed in order to test performance of created system and to validate ophthalmic artery performance as non-invasive aICP sensor. Ill. 3, bibl. 13 (in English; abstracts in English and Lithuanian).DOI: http://dx.doi.org/10.5755/j01.eee.122.6.1194

Net NH4 + and NO3 − flux, and expression of NH4 + and NO3 − transporters in roots of Picea glauca

Insights into the physiology of nitrogen (N) uptake help us to understand the adaption of boreal coniferous forests to their environment. We compared fluxes of nitrate and ammonium in white spruce [Picea glauca (Moench) Voss] roots, measured using a non-invasive microelectrode ion flux measurement system (MIFE), and transcript abundance of ammonium and nitrate transporter genes in roots, determined by real time PCR. Seedlings were pretreated with water, or 50 μM or 1,500 μM NH4NO3 + 200 μM CaSO4 + 25 μM KH2PO4. Measurements were made on seedling roots 0–5, 5–10, 10–20 and 20–30 mm from the root tip. As ammonium and nitrate transporter family members in spruce are still uncharacterized, primers for real time PCR were designed to cover one family with each set of primers (AMT1, AMT2, NRT1, NRT2). The expression patterns obtained by real time PCR differed significantly among transporter family, treatments and root segments. Expression of AMT1 did not show a relationship with distance from the root tip, but the expression of AMT2 was generally greater 0–5 mm from the root tip than in segments farther from the tip. Expression of NRT1 was greatest 10–30 mm from the root tip, while expression of NRT2 was greatest 5–10 mm from the tip in all treatments, except the 1,500 μM NH4NO3 treatment. MIFE measurements showed the highest N uptake and proton efflux near the root tip and declining fluxes with increased distance from the root tip in the 50 μM N treatment. Significant net ammonium efflux was observed from some root segments in the 1,500 μM N treatment. Transporter gene expression and ion fluxes were not correlated. Though the measured net fluxes of ammonium were greater than the measured net fluxes of nitrate, the nitrate transporters were, in general, more highly expressed than the ammonium transporters.

The T-Line TL-200 system for continuous noninvasive blood pressure measurement in medical ICU patients

The T-Line TL-200 (Tensys Medical Inc., San Diego, CA, USA) is a noninvasive arterial blood pressure (BP) monitoring system allowing continuous beat-to-beat monitoring of systolic arterial pressure (SAP), mean arterial pressure (MAP), and diastolic arterial pressure (DAP). It provides a real-time BP waveform like that obtained using an arterial catheter for BP monitoring. The aim of this study was to compare BP measurements obtained using the T-Line TL-200 system with simultaneous invasive BP measurements using a femoral arterial catheter in unselected critically ill medical patients.