This study describes a pilot clinical validation of a new low-cost system for the continuous monitoring of the human body's cardiorespiratory activities within the magnetic resonance examination area. This study primarily focuses on monitoring cardiac activity and the related cardiac triggering. The patented system tested by the authors is based on seismocardiography (SCG). The study was conducted on 18 subjects on a Siemens Prisma 3T MR scanner. Standard anatomical and diffusion sequences were used to test cardiac activity monitoring. A wide range of commonly used diagnostic sequences were used to test imaging of the heart by means of cardiac triggering. System functionality was verified against a commercially available electrocardiography (ECG) system. Monitoring of cardiac activity (detection of the R-R interval in ECG and the AO-AO interval in SCG) was objectively evaluated by determining the overall probability of correct detection (ACC), sensitivity (SE), positive predictive value (PPV), and harmonic mean between SE and PPV, i.e. F1. Imaging quality control using Cardiac Triggering was performed by subjective evaluation of images by the physicians. The study conducted clearly confirmed the functionality of the system in terms of continuous cardiac activity monitoring. In all 18 subjects, a mean PPV > 99 % was achieved; F1 > 99 %; SE > 99 %; ACC > 98 %; 1.96σ < 3.5 bpm. Also, Cardiac Triggering functionality was confirmed by the physicians on the basis of analyzing cardiac images using the T1/T2 balanced echo sequences and the T1 flash sequence measured natively. INDEX TERMS Seismocardiography-based cardiac triggering, seismocardiography (SCG), siemens prisma 3T, monitor patient vital signs during MRI, cardiac magnetic resonance imaging (CMRI).
New possibilities of vibration monitoring can be found in completely different physical approaches, where all measuring technology is currently based on sensors in the electrical domain. This paper presents two different promising alternative approaches to vibration measurement, specifically in the field of fiber-optics and pneumatic sensors. The proposed solution uses a Michelson fiber-optic interferometer designed without polarization fading and with operationally passive demodulation technique using three mutually phase-shifted optical outputs. Experimentally developed sensor systems for the registration of anthropogenic seismic phenomena were complemented by standard instrumentation for measuring seismicity used as a standard. The measurement was performed under simplified conditions using a calibrated stroke as a source of dynamic loading. In addition to alternative systems, the paper also presents the results of recalculation of the measured values in a time domain and basic relationships for the conversion to basic units derived from the SI (International System of Units) system and used internationally in the field of seismic engineering. The results presented demonstrate that even systems operating on a different physical principle have great potential to replace the existing seismic devices. The correlation coefficients for both sensory devices were high (above 0.9) and the average deviations from the measured values of the amplitude of the oscillation velocity did not exceed the value of 0.02, neither with the fiber-optic or pneumatic sensor.
This pilot pre-clinical study demonstrates the applicability of a new type of pneumatic cardiac triggering (PCT) for cardiac imaging. The pilot research compares the novel FPGA-based pad monitoring system for cardiac triggering using ballistocardiography (BCG) with conventional systems based on electrocardiography (ECG) and photoplethysmography (PPG). The implemented system enables cardiac triggering without the need to fix the sensors to the patient's body. This unique approach has the potential to reduce the preparation time for examination and the examination itself and to increase patient's comfort. The pilot pre-clinical study was conducted on 10 subjects at the Siemens Prisma 3T MRI Scanner within the
As the infrastructure grows, space on the surface in the urban area is diminishing, and the view of the builders is increasingly moving underground. Implementation of underground structures, however, presents a number of problems during construction. One of the primary side effects of tunnel excavation is vibration. These vibrations need to be monitored for potential damage to structures on the surface, and this monitoring is an integral part of any such structure. This paper brings an original pilot comparative study of standard seismic instrumentation with experimentally developed fiber-optic interferometric and acoustic systems for the purpose of monitoring vibration caused by the blasting operation. The results presented show that systems operating on physical principles (other than those previously used) have the potential to be an alternative that will replace the existing costly seismic equipment. The paper presents waveform images and frequency spectra from experimental measurements of the dynamic response of the rock environment, due to blasting operation performed shallowly during the tunnel excavation of a sewer collector. In the time and frequency domain, there is, by comparison, significant agreement both in the character of the waveform images (recording length, blasting operation timing) and in the spectra (bandwidth, dominant maxima).
This article introduces fiber Bragg grating (FBG) system for monitoring selected traffic flow parameters in urban areas. The system is able to monitor traffic density or speed of cars driving in single lane. The proposed system consists of five Bragg gratings encapsulated in Polydimethylsiloxane polymer and is characterized by easy and inexpensive installation in the milled upper layer of the road covered with an asphalt mixture. The results of first operational tests presented in this study include 3978 passing vehicles of various specifications. The system's vehicle detection success rate is 99.62%. And further, a mean absolute error 1.35 kph and a relative error 2.62% when measuring vehicle speed.
This pilot comparative study evaluates the usability of the alternative approaches to magnetic resonance (MR) cardiac triggering based on ballistocardiography (BCG): fiber-optic sensor (O-BCG) and pneumatic sensor (P-BCG). The comparison includes both the objective and subjective assessment of the proposed sensors in comparison with a gold standard of ECG-based triggering. The objective evaluation included several image quality assessment (IQA) parameters, whereas the subjective analysis was performed by 10 experts rating the diagnostic quality (scale 1 -3, 1 corresponding to the best image quality and 3 the worst one). Moreover, for each examination, we provided the examination time and comfort rating (scale 1 -3). The study was performed on 10 healthy subjects. All data were acquired on a 3 T SIEMENS MAG-NETOM Prisma. In image quality analysis, all approaches reached comparable results, with ECG slightly outperforming the BCGbased methods, especially according to the objective metrics. The subjective evaluation proved the best quality of ECG (average score of 1.68) and higher performance of P-BCG (1.97) than O-BCG (2.03). In terms of the comfort rating and total examination time, the ECG method achieved the worst results, i.e. the highest score and the longest examination time: 2.6 and 10:49s, respectively. The BCG-based alternatives achieved comparable results (P-BCG 1.5 and 8:06s; OBCG 1.9, 9:08s). This study confirmed that the proposed BCG-based alternative approaches to MR cardiac triggering offer comparable quality of resulting images with the benefits of reduced examination time and increased patient comfort.
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