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Resonance-Based Microwave Technique for Body Implant Sensing. SENSORS 2019; 19:s19224828. [PMID: 31698742 PMCID: PMC6891467 DOI: 10.3390/s19224828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/31/2019] [Accepted: 11/04/2019] [Indexed: 11/17/2022]
Abstract
There is an increasing need for safe and simple techniques for sensing devices and prostheses implanted inside the human body. Microwave wireless inspection may be an appropriate technique for it. The implanted device may have specific characteristics that allow to distinguish it from its environment. A new sensing technique based on the principle of differential resonance is proposed and its basic parameters are discussed. This technique allows to use the implant as a signal scattering device and to detect changes produced in the implant based on the corresponding change in its scattering signature. The technique is first tested with a canonic human phantom and then applied to a real in vivo clinical experiment to detect coronary stents implanted in swine animals.
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Gálvez-Montón C, Arauz-Garofalo G, Rodriguez-Leor O, Soler-Botija C, Amorós García de Valdecasas S, Gerez-Britos FD, Bayes-Genis A, O'Callaghan JM, Macià F, Tejada J. Ex vivo assessment and in vivo validation of non-invasive stent monitoring techniques based on microwave spectrometry. Sci Rep 2018; 8:14808. [PMID: 30287932 PMCID: PMC6172211 DOI: 10.1038/s41598-018-33254-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 09/25/2018] [Indexed: 12/01/2022] Open
Abstract
Some conditions are well known to be directly associated with stent failure, including in-stent re-occlusion and stent fracture. Currently, identification of these high-risk conditions requires invasive and complex procedures. This study aims to assess microwave spectrometry (MWS) for monitoring stents non-invasively. Preliminary ex vivo data are presented to move to in vivo validation. Fifteen mice were assigned to receive subcutaneous stent implantations (n = 10) or sham operations (n = 5). MWS measurements were carried out at 0, 2, 4, 7, 14, 22, and 29 days of follow-up. Additionally, 5 stented animals were summited to micro-CT analyses at the same time points. At 29 days, 3 animals were included into a stent fracture subgroup and underwent a last MWS and micro-CT analysis. MWS was able to identify stent position and in-stent stenosis over time, also discerning significant differences from baseline measures (P < 0.001). Moreover, MWS identified fractured vs. non-fractured stents in vivo. Taken together, MWS emerges as a non-invasive, non-ionizing alternative for stent monitoring. MWS analysis clearly distinguished between in-stent stenosis and stent fracture phenomena.
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Affiliation(s)
- Carolina Gálvez-Montón
- ICREC Research Program, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Barcelona, Spain. .,CIBER Cardiovascular, Instituto de Salud Carlos III, Madrid, Spain.
| | - Gianluca Arauz-Garofalo
- Grup de Magnetisme, Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
| | - Oriol Rodriguez-Leor
- CIBER Cardiovascular, Instituto de Salud Carlos III, Madrid, Spain.,Servei de Cardiologia, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.,Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Carolina Soler-Botija
- ICREC Research Program, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Barcelona, Spain.,CIBER Cardiovascular, Instituto de Salud Carlos III, Madrid, Spain
| | | | - Flavio David Gerez-Britos
- Grup de Magnetisme, Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
| | - Antoni Bayes-Genis
- ICREC Research Program, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Barcelona, Spain.,CIBER Cardiovascular, Instituto de Salud Carlos III, Madrid, Spain.,Servei de Cardiologia, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.,Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | - Ferran Macià
- Grup de Magnetisme, Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
| | - Javier Tejada
- Grup de Magnetisme, Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
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Lopez-Dominguez V, Garcia MA, Marin P, Hernando A. Measurement of the magnetic permeability of amorphous magnetic microwires by using their antenna resonance. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:124704. [PMID: 29289228 DOI: 10.1063/1.4996640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present here a new free space method to measure the magnetic permeability of a single amorphous magnetic microwire (AMM) at microwave frequencies. The technique consists in inducing a high frequency electric current along the AMM axis by illumination with an electromagnetic wave at antenna resonance conditions. Fitting the induced electric current to the Hallen-Pocklington equation allows computing the relative magnetic permeability of the microwire as a function of the wave frequency. The method results particularly useful for the study of the giant magnetoimpedance effect of AMM by measuring the magnetic permeability upon the application of DC magnetic fields.
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Affiliation(s)
- V Lopez-Dominguez
- Instituto de Magnetismo Aplicado, Universidad Complutense de Madrid-CSIC-Adif, A6 km 22.5-Apdo Correos 155, Las Rozas, Madrid 28230, Spain
| | - M A Garcia
- Instituto de Magnetismo Aplicado, Universidad Complutense de Madrid-CSIC-Adif, A6 km 22.5-Apdo Correos 155, Las Rozas, Madrid 28230, Spain
| | - P Marin
- Instituto de Ceramica y Vidrio, CSIC, C/ Kelsen n° 5, Campus de Cantoblanco, 28049 Madrid, Spain
| | - A Hernando
- Instituto de Ceramica y Vidrio, CSIC, C/ Kelsen n° 5, Campus de Cantoblanco, 28049 Madrid, Spain
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Arauz-Garofalo G, López-Domínguez V, Hernàndez JM, Rodríguez-Leor O, Bayés-Genís A, O'Callaghan JM, García-Santiago A, Tejada J. Microwave spectrometry for the evaluation of the structural integrity of metallic stents. Med Phys 2014; 41:041902. [PMID: 24694133 DOI: 10.1118/1.4866881] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To assess the feasibility of a method based on microwave spectrometry to detect structural distortions of metallic stents in open air conditions and envisage the prospects of this approach toward possible medical applicability for the evaluation of implanted stents. METHODS Microwave absorbance spectra between 2.0 and 18.0 GHz were acquired in open air for the characterization of a set of commercial stents using a specifically design setup. Rotating each sample over 360°, 2D absorbance diagrams were generated as a function of frequency and rotation angle. To check our approach for detecting changes in stent length (fracture) and diameter (recoil), two specific tests were performed in open air. Finally, with a few adjustments, this same system provides 2D absorbance diagrams of stents immersed in a water-based phantom, this time over a bandwidth ranging from 0.2 to 1.8 GHz. RESULTS The authors show that metallic stents exhibit characteristic resonant frequencies in their microwave absorbance spectra in open air which depend on their length and, as a result, may reflect the occurrence of structural distortions. These resonances can be understood considering that such devices behave like dipole antennas in terms of microwave scattering. From fracture tests, the authors infer that microwave spectrometry provides signs of presence of Type I to Type IV stent fractures and allows in particular a quantitative evaluation of Type III and Type IV fractures. Recoil tests show that microwave spectrometry seems able to provide some quantitative assessment of diametrical shrinkage, but only if it involves longitudinal shortening. Finally, the authors observe that the resonant frequencies of stents placed inside the phantom shift down with respect to the corresponding open air frequencies, as it should be expected considering the increase of dielectric permittivity from air to water. CONCLUSIONS The evaluation of stent resonant frequencies provided by microwave spectrometry allows detection and some quantitative assessment of stent fracture and recoil in open air conditions. Resonances of stents immersed in water can be also detected and their characteristic frequencies are in good agreement with theoretical estimates. Although these are promising results, further verification in a more relevant phantom is required in order to foresee the real potential of this approach.
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Affiliation(s)
- Gianluca Arauz-Garofalo
- Grup de Magnetisme, Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, planta 4, edifici nou, ES-08028 Barcelona, Spain
| | - Víctor López-Domínguez
- Grup de Magnetisme, Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, planta 4, edifici nou, ES-08028 Barcelona, Spain
| | - Joan Manel Hernàndez
- Grup de Magnetisme, Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, planta 4, edifici nou, ES-08028 Barcelona, Spain and Institut de Nanociència i Nanotecnologia IN2UB, Universitat de Barcelona, Martí i Franquès 1, planta 3, edifici nou, ES-08028 Barcelona, Spain
| | - Oriol Rodríguez-Leor
- Servei de Cardiologia, Hospital Universitari Germans Trias i Pujol, Carretera del Canyet s/n, ES-08916 Badalona, Spain
| | - Antoni Bayés-Genís
- Servei de Cardiologia, Hospital Universitari Germans Trias i Pujol, Carretera del Canyet s/n, ES-08916 Badalona, Spain
| | - Juan M O'Callaghan
- Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, Jordi Girona 1, ES-08034 Barcelona, Spain
| | - Antoni García-Santiago
- Grup de Magnetisme, Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, planta 4, edifici nou, ES-08028 Barcelona, Spain and Institut de Nanociència i Nanotecnologia IN2UB, Universitat de Barcelona, Martí i Franquès 1, planta 3, edifici nou, ES-08028 Barcelona, Spain
| | - Javier Tejada
- Grup de Magnetisme, Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, planta 4, edifici nou, ES-08028 Barcelona, Spain and Institut de Nanociència i Nanotecnologia IN2UB, Universitat de Barcelona, Martí i Franquès 1, planta 3, edifici nou, ES-08028 Barcelona, Spain
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