The publication presents a comparative study of two fibre-optic sensors in the application of heart rate (HR) and respiratory rate (RR) monitoring of the human body. After consultation with clinical practitioners, two types of non-invasive measuring and analysis systems based on fibre Bragg grating (FBG) and fibre-optic interferometer (FOI) have been designed and assembled. These systems use probes (both patent pending) that have been encapsulated in the bio-compatible polydimethylsiloxane (PMDS). The main advantage of PDMS is that it is electrically non-conductive and, as well as optical fibres, has low permeability. The initial verification measurement of the system designed was performed on four subjects in a harsh magnetic resonance (MR) environment under the supervision of a senior radiology assistant. A follow-up comparative study was conducted, upon a consent of twenty volunteers, in a laboratory environment with a minimum motion load and discussed with a head doctor of the Radiodiagnostic Institute. The goal of the laboratory study was to perform measurements that would simulate as closely as possible the environment of harsh MR or the environment of long-term health care facilities, hospitals and clinics. Conventional HR and RR measurement systems based on ECG measurements and changes in the thoracic circumference were used as references. The data acquired was compared by the objective Bland⁻Altman (B⁻A) method and discussed with practitioners. The results obtained confirmed the functionality of the designed probes, both in the case of RR and HR measurements (for both types of B⁻A, more than 95% of the values lie within the ±1.96 SD range), while demonstrating higher accuracy of the interferometric probe (in case of the RR determination, 95.66% for the FOI probe and 95.53% for the FBG probe, in case of the HR determination, 96.22% for the FOI probe and 95.23% for the FBG probe).

Department of Cybernetics and Biomedical Engineering Faculty of Electrical Engineering and Computer Science VSB Technical University of Ostrava 17 Listopadu 15 70833 Ostrava Czech Republic

Department of Imaging Method Faculty of Medicine University of Ostrava Syllabova 19 703 00 Ostrava Czech Republic

Department of Telecommunications Faculty of Electrical Engineering and Computer Science VSB Technical University of Ostrava 17 Listopadu 15 70833 Ostrava Czech Republic

See more in PubMed

Roriz P., Carvalho L., Frazão O., Santos J.L., Simões A.J. From conventional sensors to fibre optic sensors for strain and force measurements in biomechanics applications: A review. J. Biomech. 2014;47:1251–1261. doi: 10.1016/j.jbiomech.2014.01.054. PubMed DOI

Fendinger N.J. Organosilicon Chemistry Set. Wiley-VCH Verlag GmbH; Weinheim, Germany: 2005. Polydimethylsiloxane (PDMS): Environmental Fate and Effects.

Nedoma J., Fajkus M., Vasinek V., Bednarek L., Frnda J., Zavadil J. Encapsulation of FBG sensor into the PDMS and its effect on spectral and power characteristics. Adv. Electr. Electron. Eng. 2016 doi: 10.15598/aeee.v14i4.1786. DOI

Nedoma J., Fajkus M., Siska P., Martinek R., Vasinek V. Non-invasive fiber optic probe encapsulated into PolyDiMethylSiloxane for measuring respiratory and heart rate of the human body. Adv. Electr. Electr. Eng. 2017;15:93–100. doi: 10.15598/aeee.v15i1.1923. DOI

Martinek R., Nedoma J., Fajkus M., Kahankova R., Konecny J., Janku P., Kepak S., Bilik P., Nazeran H. A Phonocardiographic-Based Fiber-Optic Sensor and Adaptive Filtering System for Noninvasive Continuous Fetal Heart Rate Monitoring. Sensors. 2017;17:890. doi: 10.3390/s17040890. PubMed DOI PMC

Nedoma J., Fajkus M., Vasinek V. Influence of PDMS encapsulation on the sensitivity and frequency range of fiber-optic interferometer. Proc. SPIE. 2016 doi: 10.1117/12.2243170. DOI

Zboril O., Cubik J., Kepak S., Nedoma J., Fajkus M., Zavodny P., Vasinek V. Noninvasive encapsulated fiber optic probes for interferometric measurement. Proc. SPIE Int. Soc. Opt. Eng. 2017 doi: 10.1117/12.2277923. DOI

Series G. Characteristics of a Single-Mode Optical Fibre and Cable-Recommendation ITU-T G.652. International Telecommunication Union; Geneva, Switzerland: 2016. Transmission Systems and Media, Digital Systems and Networks.

Weckesser M., Posse S., Olthoff U., Kemna L., Dager S., Müller-Gärtner H.W. Functional imaging of the visual cortex with bold-contrast MRI: Hyperventilation decreases signal response. Magn. Reson. Med. 1999;41:213–216. doi: 10.1002/(SICI)1522-2594(199901)41:1<213::AID-MRM31>3.0.CO;2-S. PubMed DOI

Giardino N.D., Friedman S.D., Dager S.R. Anxiety, Respiration and Cerebral Blood Flow: Implications for Functional Brain Imaging. Compr. Psychiatry. 2007;48:103–112. doi: 10.1016/j.comppsych.2006.11.001. PubMed DOI PMC

Webster J.G. Handbook of Research on Biomedical Engineering Education and Advanced Bioengineering Learning: Interdisciplinary Concepts. IGI Publishing; Hershey, PA, USA: 2012. Biomedical instrumentation; pp. 339–355.

Biel L., Pettersson O., Philipson L., Wide P. ECG analysis: A new approach in human identification. IEEE Trans. Instrum. Meas. 2001;50:808–812. doi: 10.1109/19.930458. DOI

Tamaki S., Yamada T., Okuyama Y., Morita T., Sanada S., Tsukamoto Y., Hori M. Cardiac iodine-123 metaiodobenzylguanidine imaging predicts sudden cardiac death independently of left ventricular ejection fraction in patients with chronic heart failure and left ventricular systolic dysfunction: Results from a comparative study with signal-averaged electrocardiogram, heart rate variability, and QT dispersion. J. Am. Coll. Cardiol. 2009;53:426–435. PubMed

Zabel M., Acar B., Klingenheben T., Franz M.R., Hohnloser S.H., Malik M. Analysis of 12-lead T-wave morphology for risk stratification after myocardial infarction. Circulation. 2000;102:1252–1257. doi: 10.1161/01.CIR.102.11.1252. PubMed DOI

Ogura R., Hiasa Y., Takahashi T., Yamaguchi K., Fujiwara K., Ohara Y., Hosokawa S. Specific findings of the standard 12-lead ECG in patients withtakotsubo’cardiomyopathy. Circ. J. 2003;67:687–690. doi: 10.1253/circj.67.687. PubMed DOI

Hen G., Imtiaz S.A., Aguilar-Pelaez E., Rodriguez-Villegas E. Algorithm for heart rate extraction in a novel wearable acoustic sensor. Healthc. Technol. Lett. 2015;2:28–33. PubMed PMC

Tóth S., Šajty M., Pekárová T., Mughees A., Štefanič P., Katz M., Spišáková K., Pella J., Pella D. Addition of omega-3 fatty acid and coenzyme Q10 to statin therapy in patients with combined dyslipidemia. J. Basic Clin. Physiol. Pharmacol. 2017;28:327–336. doi: 10.1515/jbcpp-2016-0149. PubMed DOI

Luna-Lozano P.S., García-Zetina O.A., Pérez-López J.A., Alvarado-Serrano C. Portable device for heart rate monitoring based on impedance pletysmography; Proceedings of the 2014 11th International Conference on Electrical Engineering, Computing Science and Automatic Control, CCE 2014; Campeche, Mexico. 29 September–3 October 2014.

Burke M.J., Boilson A. A digital cardiotachometer ASIC; Proceedings of the Third International Conference on Electronics, Circuits, and Systems; Rodos, Greece. 16 October 1996; pp. 1080–1083.

Pottinger H.J., Hughes C.W., Schroeder P., Barefield A., Craigmile J.C. A microcomputer-based cardiotachometer with video display. Behav. Res. Methods Instrum. 1981;13:227–234. doi: 10.3758/BF03207940. DOI

Rotariu C., Cristea C., Arotaritei D., Bozomitu R.G., Pasarica A. Continuous respiratory monitoring device for detection of sleep apnea episodes; Proceedings of the 2016 IEEE 22nd International Symposium for Design and Technology in Electronic Packaging, SIITME 2016; Svasta, Paul. 20–23 October 2016; pp. 106–109.

Yoon J.-W., Noh Y.-S., Kwon Y.-S., Kim W.-K., Yoon H.-R. Improvement of dynamic respiration monitoring through sensor fusion of accelerometer and gyro-sensor. J. Electr. Eng. Technol. 2014;9:334–343. doi: 10.5370/JEET.2014.9.1.334. DOI

Byung-Hyun K., Jong-Gwan Y. Human health monitoring technology; Proceedings of the Micro- and Nanotechnology Sensors, Systems, and Applications IX; Anaheim, CA, USA. 9–13 April 2017.

Will C., Shi K., Lurz F., Weigel R., Koelpin A. Intelligent signal processing routine for instantaneous heart rate detection using a Six-Port microwave interferometer; Proceedings of the 2015 International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS); Nusa Dua, Bali. 9–12 November 2015; pp. 483–487.

Jourand P., De Clercq H., Puers R. Robust monitoring of vital signs integrated in textile. Sens. Actuators A Phys. 2010;161:288–296. doi: 10.1016/j.sna.2010.05.002. DOI

Hong S., Jung W., Kim T., Oh K. Compact Biocompatible Fiber Optic Temperature Microprobe Using DNA-Based Biopolymer. J. Lightw. Technol. 2018;36:974–978. doi: 10.1109/JLT.2017.2780266. DOI

Podbreznik P., Đonlagić D., Lešnik D., Cigale B., Zazula D. Nemoteče spremljanje delovanja srca z optičnim senzorjem v postelji Unobtrusive heartbeat monitoring by using a bed fiber-optic sensor. Zdravniski Vestnik. 2014;83:901–907.

Podbreznik P., Onlagić D., Lešnik D., Cigale B., Zazula D. Cost-efficient speckle interferometry with plastic optical fiber for unobtrusive monitoring of human vital signs. J. Biomed. Opt. 2013;18 doi: 10.1117/1.JBO.18.10.107001. PubMed DOI

Favero F.C., Villatoro J., Pruneri V. Microstructured optical fiber interferometric breathing sensor. J. Biomed. Opt. 2012 doi: 10.1117/1.JBO.17.3.037006. PubMed DOI

Sprager S., Donlagic D., Zazula D. Monitoring of basic human vital functions using optical interferometer; Proceedings of the IEEE 10th International Conference on Signal Processing (ICSP); Beijing, China. 24–28 October 2010; pp. 1738–1741.

Folke M., Cernerud L., Ekstrom M., Hok B. Critical review of non-invasive respiratory monitoring in medical care. Med. Biol. Eng. Comput. 2003;41:377–383. doi: 10.1007/BF02348078. PubMed DOI

Sprager S., Donlagic D., Zazula D. Estimation of heart rate, respiratory rate and motion by using optical interferometer as body sensor; Proceedings of the IASTED International Conference on Signal and Image Processing; Honolulu, HI, USA. 14–16 December 2011; pp. 280–287.

Sprager S., Holobar A., Zazula D. Feasibility Study of Heartbeat Detection from Optical Interferometric Signal by Using Convolution Kernel Compensation; Proceedings of the 6th International Conference on Bio-inspired Systems and Signal Processing; Barcelona, Spain. 11–14 February 2013.

Šprager S., Zazula D. Detection of heartbeat and respiration from optical interferometric signal by using wavelet transform. Comput. Methods Prog. Biomed. 2013;111:41–51. doi: 10.1016/j.cmpb.2013.03.003. PubMed DOI

Cikajlo I., Sprager S., Erjavec T., Zazula D. Cardiac arrhythmia alarm from optical interferometric signals during resting or sleeping for early intervention. Biocybern. Biomed. Eng. 2016;36:267–275. doi: 10.1016/j.bbe.2015.12.006. DOI

Zazula D., Sprager S. Detection of the first heart sound using fibre-optic interferometric measurements and neural networks; Proceedings of the Symposium on Neural Network Applications in Electrical Engineering; Belgrade, Serbia. 20–22 September 2012; pp. 171–176.

Byeong H.L., Young H.K., Kwan S.P., Joo B.E., Myoung J.K., Byung S.R., Hae Y.C. Interferometric Fiber Optic Sensors. Sensors. 2012;12:2467–2486. PubMed PMC

Hsieh Y.H., Chen N.K. Micro tapered Mach–Zehnder fiber interferometer for monitoring pressure fluctuation and its applications in pulse rate detection; Proceedings of the 2013 6th IEEE/International Conference on Advanced Infocomm Technology (ICAIT); Taiwan, China. 6–9 July 2013; pp. 113–115.

Chethana K., Guru Prasad A.S., Omkar S.N., Asokan S. Fiber bragg grating sensor-based device for simultaneous measurement of respiratory and cardiac activities. J. Biophotonics. 2016;10:278–285. doi: 10.1002/jbio.201500268. PubMed DOI

Nishiyama M., Sonobe M., Watanabe K. Unconstrained pulse pressure monitoring for health management using hetero-core fiber optic sensor. Biomed. Opt. Express. 2016;7:3675–3685. doi: 10.1364/BOE.7.003675. PubMed DOI PMC

Dziuda L. Fiber-optic sensors for monitoring patient physiological parameters: A review of applicable technics and relevance to use during MRI procedures. J. Biomech. 2015;20 doi: 10.1117/1.JBO.20.1.010901. PubMed DOI

Gurkan D., Starodubov D., Yuan X. Monitoring of the heartbeat sounds using an optical fiber Bragg grating sensor. IEEE Sens. 2005;2005:306–309.

Yang X., Chen Z., Elvin C.S.M., Janice L.H.Y., Ng S.H., Teo J.T., Wu R. Textile Fiber Optic Microbend Sensor Used for Heartbeat and Respiration Monitoring. IEEE Sens. J. 2015;15:757–761. doi: 10.1109/JSEN.2014.2353640. DOI

Ciocchetti M., Massaroni C., Saccomandi P., Caponero M.A., Polimadei A., Formica D., Schena E. Smart textile based on fiber bragg grating sensors for respiratory monitoring: Design and preliminary trials. Biosensors. 2015;5:602–615. doi: 10.3390/bios5030602. PubMed DOI PMC

Dziuda L., Krej M., Skibniewski F.W. Fiber Bragg grating strain sensor incorporated to monitor patient vital signs during MRI. IEEE Sens. J. 2013;13:4986–4991. doi: 10.1109/JSEN.2013.2279160. DOI

Dziuda L., Skibniewski F.W., Krej M., Baran P.M. Fiber Bragg grating-based sensor for monitoring respiration and heart activity during magnetic resonance imaging examinations. J. Biomed. Opt. 2013;18:057006. doi: 10.1117/1.JBO.18.5.057006. PubMed DOI

Chen Z., Teo J.T., Ng S.H., Yim H. Smart pillow for heart rate monitoring using a fiber optic sensor; Proceedings of the SPIE BiOS; San Francisco, CA, USA. 22–27 January 2011.

Chen Z.H., Teo J.T., Yang X.F. In-bed fibre optic breathing and movement sensor for non-intrusive monitoring; Proceedings of the SPIE BiOS; San Jose, CA, USA. 24–29 January 2009.

Dzuida L., Skibniewski F.W., Krej M., Lewandowski J. Monitoring respiration and cardiac activity using fiber Bragg grating-based sensor. IEEE Trans. Biomed. Eng. 2012;59:1934–1942. doi: 10.1109/TBME.2012.2194145. PubMed DOI

Ogawa K., Koyama S., Ishizawa H., Fujiwara S., Fujimoto K. Simultaneous Measurement of Heart Sound, Pulse Wave and Respiration with Single Fiber Bragg Grating Sensor; Proceedings of the MeMeA 2018—2018 IEEE International Symposium on Medical Measurements and Applications; Rome, Italy. 11–13 June 2018; DOI

Lau D., Chen Z., Teo J.T., Ng S.H., Rumpel H., Lian Y., Yang H., Kei P.L. Intensity-modulated microbend fiber optic sensor for respiratory monitoring and gating during MRI. IEEE Trans. Biomed. Eng. 2013;60:2655–2662. doi: 10.1109/TBME.2013.2262150. PubMed DOI

Grilett A., Kinet D., Witt J., Schukar M., Krebber K., Pirotte F., Depre A. Optical fiber sensors embedded into medical textiles for healthcare monitoring. IEEE Sens. 2008;2008:1215–1222. doi: 10.1109/JSEN.2008.926518. DOI

Mokhtar M.R., Sun T., Grattan K.T.V. Bragg Grating Packages with Nonuniform Dimensions for Strain and Temperature Sensing. IEEE Sens. J. 2012;12:139–144. doi: 10.1109/JSEN.2011.2134845. DOI

Tosi D., Olivero M., Perrone G. Low-cost fiber bragg grating vibroacoustic sensor for voice and heartbeat detection. Appl. Opt. 2008;47:5123–5129. doi: 10.1364/AO.47.005123. PubMed DOI

Wo J., Wang H., Sun Q., Shum P.P., Liu D. Noninvasive respiration movement sensor based on distributed Bragg reflector fiber laser with beat frequency interrogation. J. Biomed. Opt. 2014;19 doi: 10.1117/1.JBO.19.1.017003. PubMed DOI

Dziuda L., Skibniewski F.W. A new approach to ballistocardiographic measurements using fibre Bragg grating-based sensors. Biocybern. Biomed. Eng. 2014;34:101–106. doi: 10.1016/j.bbe.2014.02.001. DOI

Spillman W.B., Mayer M., Bennett J., Gong J., Meissner K.E., Davis B., Xu X. A ’smart’ bed for non-intrusive monitoring of patient physiological factors. J. Meas. Sci. Technol. 2004;15:1614–1620. doi: 10.1088/0957-0233/15/8/032. DOI

Witt J., Narbonneau F., Schukar M., Krebber K., De Jonckheere J., Jeanne M., Thiel T. Medical textiles with embedded fiber optic sensors for monitoring of respiratory movement. IEEE Sens. J. 2012;12:246–254. doi: 10.1109/JSEN.2011.2158416. DOI

Fajkus M., Nedoma J., Martinek R., Vasinek V., Nazeran H., Siska P. A Non-invasive Multichannel Hybrid Fiber-optic Sensor System for Vital Sign Monitoring. Sensors. 2017;17:111. doi: 10.3390/s17010111. PubMed DOI PMC

Chen Z., Lau D., Teo J.T., Ng S.H., Yang X., Kei P.L. Simultaneous measurement of breathing rate and heart rate using a microbend multimode fiber optic sensor. J. Biomed. Opt. 2014;19 doi: 10.1117/1.JBO.19.5.057001. PubMed DOI

Deepu C.J., Chen Z., Teo J.T., Ng S.H., Yang X., Lian Y. A smart cushion for real-time heart rate monitoring; Proceedings of the 2012 IEEE Biomedical Circuits and Systems Conference (BioCAS); Taiwan, China. 28–30 November 2012; pp. 53–56.

Lydtin H., Schnelle K., Lohmöller G., Zöllner N. Synchronous recordings of Bcg, ECG, carotid pulse wave, and PCG in acute pharmacological trials. Bibl. Cardiol. 1969;26:36–41. PubMed

Martín-Yebra A., Landreani F., Casellato C., Pavan E., Frigo C., Migeotte P.-F., Caiani E.G. Studying heart rate variability from ballistocardiography acquired by force platform: Comparison with conventional ECG; Proceedings of the 42nd Conference of Computing in Cardiology; Nice, France. 6–9 September 2015; pp. 929–932.

Al-Qazzaz N.K., Abdulazez I.F., Ridha S.A. Simulation Recording of an ECG, PCG, and PPG for Feature Extractions. Al-Khwarizmi Eng. J. 2014;10:81–91.

Varshneya D., Maida J.L. Fiber-Optic Monitor Using Interferometry for Detecting Vital Signs of a Patient. No. 6498652. U.S. Patent. 2002 Dec 24;

Varshneya D., Maida J.L., Jeffers L.A. Fiber-Optic Interferometric Vital Sign Monitor for Use in Magnetic Resonance Imaging, Confined Care Facilities and in-Hospital. No. 6816266. U.S. Patent. 2004 Nov 9;

Zyczkowski M., Uzieblo-Zyczkowska B. Human psychophysiology activity monitoring methods using fiber optic sensors; Proceedings of the International Society for Optical Engineering; San Diego, CA, USA. 2 August 2010.

Nedoma J., Fajkus M., Kepak S., Cubik J., Kahankova R., Janku P., Vasinek V., Nazeran H., Martinek R. Noninvasive fetal heart rate monitoring: Validation of phonocardiography-based fiber-optic sensing and adaptive filtering using the nlms algorithm. Adv. Electr. Electron. Eng. 2017;15:544–552. doi: 10.15598/aeee.v15i3.2195. DOI

Zazula D., Đonlagic D., Sprager S. Application of fiber-optic interferometry to detection of human vital signs. J. Laser Health Acad. 2012;2012:27–32.

Chen Q., Claus R.O., Spillman W.B., Arregui F.J., Matias I.R., Cooper K.L. Optical fiber sensors for breathing diagnostics; Proceedings of the Optical Fiber Sensors Conference Technical Digest; Portland, OR, USA. 6–11 May 2002.

Kang Y., Ruan H., Wang Y., Arregui F.J., Matias I.R., Claus R.O. Nanostructured optical fiber sensors for breathing airflow monitoring. Meas. Sci. Technol. 2006;17:1207–1210. doi: 10.1088/0957-0233/17/5/S44. DOI

Kang Y., Ruan H., Mecham J., Wang Y., Arregui F.J., Matias I.R., Claus R.O. Nanostructured optical fiber sensors for breathing airflow monitoring. Proc. SPIE Int. Soc. Opt. Eng. 2005:407–410. doi: 10.1117/12.623653. DOI

Durand L.G., Pibarot P. Digital signal processing of the phonocardiogram: Review of the most recent advancements. Crit. Rev. Biomed. Eng. 1995;23:3–4. doi: 10.1615/CritRevBiomedEng.v23.i3-4.10. PubMed DOI

Webster J.G. Medical Devices and Instrumentation. Wiley-Interscience; Hoboken, NJ, USA: 1988.

Phanphaisarn W., Roeksabutr A., Wardkein P., Koseeyaporn J., Yupapin P.P. Heart detection and diagnosis based on Ecg and EPcg relationships. Med. Dev. 2011;4 doi: 10.2147/MDER.S23324. PubMed DOI PMC

Southern E.M. Electrocardiography and phonocardiography of the foetal heart. Int. J. Obstet. Gynaecol. 1954;61:231–237. doi: 10.1111/j.1471-0528.1954.tb07472.x. PubMed DOI

Kersay A.D., Davis M.A., Patrick H.J., LeBlanc M., Koo K.P., Askins C.G., Putnam M.A., Friebele E.J. Tunable Erbium-Doped Fiber Lasers Using Various Inline Fiber Filters. Engineering. 2010;2:1442–1463.

Pinheiro E., Postolache O., Girão P. Theory and developments in an unobtrusive cardiovascular system representation: Ballistocardiography. Open Biomed. Eng. J. 2010;4:201–216. doi: 10.2174/1874120701004010201. PubMed DOI PMC

Gordon J.W. Certain Molar Movements of the Human Body produced by the Circulation of the Blood. J. Anat. Physiol. 1877;11:533–536. PubMed PMC

Kepak S., Cubik J., Siska P., Zboril O., Martinek R. A Device for Monitoring Vital Functions of a Pregnant Woman’s Foetus. [(accessed on 30 October 2018)]; Available online: https://isdv.upv.cz/webapp/webapp.pts.det?xprim=10232644&lan=cs&s_majs=&s_puvo=kep%C3%A1k%20stanislav&s_naze=&s_anot=

Chen D.-S., Xiao L., Cui J., Liu T.-T., Sun D.-X. Analysis of 3 × 3 coupler demodulation method for optical fiber interferometer and polarization fading. J. Optoelectron. Laser. 2007;18:523–525.

Mao X., Huang J.-B., Gu H.-C. Demodulation Technology of Distributed Feedback Fiber Laser Sensor Based on 3 × 3 Coupler. Chin. J. Lumin. 2017;38:395–401.

Sprager S., Zazula D. Heartbeat and respiration detection from optical interferometric signals by using a multimethod approach. IEEE Trans. Biomed. Eng. 2012;59:2922–2929. doi: 10.1109/TBME.2012.2213302. PubMed DOI

UFI PnuemoTrace II Piezo-Electric Respiration Transducer. [(accessed on 26 October 2018)]; Available online: https://www.artisantg.com/Scientific/730671/UFI_PneumoTrace_II_1132_Piezo_Electric_Respiration_Transducer.

Products. [(accessed on 26 October 2018)]; Available online: https://www.physio-control.com/ProductDetails.aspx.

Taffoni F., Formica D., Saccomandi P., Di Pino G., Schena E. Optical fiber-based MR-compatible sensors for medical applications: An overview. Sensors. 2013;13:14105–14120. doi: 10.3390/s131014105. PubMed DOI PMC

Grillet A., Kinet D., Witt J., Schukar M., Krebber K., Pirotte F., Depré A. Optical fibre sensors embedded into medical textiles for monitoring of respiratory movements in MRI environment; Proceedings of the SPIE—The International Society for Optical Engineering; Napoli, Italy. 4 July 2007.

Moerman K.M., Sprengers A.M.J., Nederveen A.J., Simms C.K. A novel MRI compatible soft tissue indentor and fibre Bragg grating force sensor. Med. Eng. Phys. 2013;35:486–499. doi: 10.1016/j.medengphy.2012.06.014. PubMed DOI

Tan U.-X., Yang B., Gullapalli R., Desai J.P. Triaxial MRI-compatible fiber-optic force sensor. IEEE Trans. Robot. 2011;27:65–74. doi: 10.1109/TRO.2010.2090061. PubMed DOI PMC

Yoo W.J., Jang K.W., Seo J.K., Heo J.Y., Moon J.S., Park J.Y., Lee B. Development of respiration sensors using plastic optical fiber for respiratory monitoring inside MRI system. J. Opt. Soc. Korea. 2010;14:235–239. doi: 10.3807/JOSK.2010.14.3.235. DOI

Kam W., Mohammed W.S., Leen G., O’Sullivan K., O’Keeffe M., O’Keeffe S., Lewis E. All plastic optical fiber-based respiration monitoring sensor; Proceedings of the IEEE Sensors; New Delhi, India. 29–31 December 2017; pp. 1–3.

Filograno M.L., Pisco M., Catalano A., Forte E., Aiello M., Cavaliere C., Soricelli A., Davino D., Visone C., Cutolo A., et al. Triaxial Fiber Optic Magnetic Field Sensor for Magnetic Resonance Imaging. J. Lightw. Technol. 2017;35:3924–3933. doi: 10.1109/JLT.2017.2722545. DOI

Nedoma J., Fajkus M., Novak M., Strbikova N., Vasinek V., Nazeran H., Vanus J., Perecar F., Martinek R. Validation of a novel fiber-optic sensor system for monitoring cardiorespiratory activities during mri examinations. Adv. Electr. Electron. Eng. 2017;15:536–543. doi: 10.15598/aeee.v15i3.2194. DOI

Su H., Shang W., Li G., Patel N., Fischer G.S. An MRI-Guided Telesurgery System Using a Fabry–Perot Interferometry Force Sensor and a Pneumatic Haptic Device. Ann. Biomed. Eng. 2017;45:1917–1928. doi: 10.1007/s10439-017-1839-z. PubMed DOI PMC

Bland J.M., Altman D.G. Measuring agreement in method comparison studies. Stat. Methods Med. Res. 1999;8:135–160. doi: 10.1177/096228029900800204. PubMed DOI

Signa HDxt 1.5T. [(accessed on 26 October 2018)]; Available online: http://www3.gehealthcare.in/en/products/categories/magnetic-resonance-imaging/signa-hdxt-1-5t.

Counter S.A., Olofsson A., Grahn H.F., Borg E. MRI acoustic noise: Sound pressure and frequency analysis. J. Mag. Reson. Imag. 1997;7:606–611. doi: 10.1002/jmri.1880070327. PubMed DOI

Quandt B.M., Scherer L.J., Boesel L.F., Wolf M., Bona G.-L., Rossi R.M. Body-Monitoring and Health Supervision by Means of Optical Fiber-Based Sensing Systems in Medical Textiles. Adv. Healthc. Mater. 2015;4:330–355. doi: 10.1002/adhm.201400463. PubMed DOI

Multichannel ballistocardiography: A comparative analysis of heartbeat detection across different body locations

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