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He Z, Dai J, Ho JD, Tong H, Wang X, Fang G, Liang L, Cheung C, Guo Z, Chang H, Iordachita I, Taylor RH, Poon W, Chan DT, Kwok K. Interactive Multi-Stage Robotic Positioner for Intra-Operative MRI-Guided Stereotactic Neurosurgery. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305495. [PMID: 38072667 PMCID: PMC10870025 DOI: 10.1002/advs.202305495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/30/2023] [Indexed: 02/17/2024]
Abstract
Magnetic resonance imaging (MRI) demonstrates clear advantages over other imaging modalities in neurosurgery with its ability to delineate critical neurovascular structures and cancerous tissue in high-resolution 3D anatomical roadmaps. However, its application has been limited to interventions performed based on static pre/post-operative imaging, where errors accrue from stereotactic frame setup, image registration, and brain shift. To leverage the powerful intra-operative functions of MRI, e.g., instrument tracking, monitoring of physiological changes and tissue temperature in MRI-guided bilateral stereotactic neurosurgery, a multi-stage robotic positioner is proposed. The system positions cannula/needle instruments using a lightweight (203 g) and compact (Ø97 × 81 mm) skull-mounted structure that fits within most standard imaging head coils. With optimized design in soft robotics, the system operates in two stages: i) manual coarse adjustment performed interactively by the surgeon (workspace of ±30°), ii) automatic fine adjustment with precise (<0.2° orientation error), responsive (1.4 Hz bandwidth), and high-resolution (0.058°) soft robotic positioning. Orientation locking provides sufficient transmission stiffness (4.07 N/mm) for instrument advancement. The system's clinical workflow and accuracy is validated with lab-based (<0.8 mm) and MRI-based testing on skull phantoms (<1.7 mm) and a cadaver subject (<2.2 mm). Custom-made wireless omni-directional tracking markers facilitated robot registration under MRI.
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Affiliation(s)
- Zhuoliang He
- Department of Mechanical EngineeringThe University of Hong KongHong Kong999077China
| | - Jing Dai
- Department of Mechanical EngineeringThe University of Hong KongHong Kong999077China
| | - Justin Di‐Lang Ho
- Department of Mechanical EngineeringThe University of Hong KongHong Kong999077China
| | - Hon‐Sing Tong
- Department of Mechanical EngineeringThe University of Hong KongHong Kong999077China
| | - Xiaomei Wang
- Department of Mechanical EngineeringThe University of Hong KongHong Kong999077China
- Multi‐Scale Medical Robotics CenterHong Kong999077China
| | - Ge Fang
- Department of Mechanical EngineeringThe University of Hong KongHong Kong999077China
| | - Liyuan Liang
- Department of Biomedical EngineeringThe Chinese University of Hong KongHong Kong999077China
- Multi‐Scale Medical Robotics CenterHong Kong999077China
| | - Chim‐Lee Cheung
- Department of Mechanical EngineeringThe University of Hong KongHong Kong999077China
| | - Ziyan Guo
- Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonWC1E 6BTUK
- Wellcome/EPSRC Centre for Interventional and Surgical SciencesUniversity College LondonLondonWC1E 6BTUK
| | - Hing‐Chiu Chang
- Department of Biomedical EngineeringThe Chinese University of Hong KongHong Kong999077China
- Multi‐Scale Medical Robotics CenterHong Kong999077China
| | - Iulian Iordachita
- Department of Mechanical Engineering and Laboratory for Computational Sensing and RoboticsJohns Hopkins UniversityBaltimoreMD 21218USA
| | - Russell H. Taylor
- Department of Computer Science and Laboratory for Computational Sensing and RoboticsJohns Hopkins UniversityBaltimoreMD 21218USA
| | - Wai‐Sang Poon
- Division of NeurosurgeryDepartment of SurgeryPrince of Wales HospitalThe Chinese University of Hong KongHong Kong999077China
- Neuromedicine CenterShenzhen Hospital, The University of Hong KongShenzhen518053China
| | - Danny Tat‐Ming Chan
- Division of NeurosurgeryDepartment of SurgeryPrince of Wales HospitalThe Chinese University of Hong KongHong Kong999077China
- Multi‐Scale Medical Robotics CenterHong Kong999077China
| | - Ka‐Wai Kwok
- Department of Mechanical EngineeringThe University of Hong KongHong Kong999077China
- Multi‐Scale Medical Robotics CenterHong Kong999077China
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Alipour A, Seifert AC, Delman BN, Hof PR, Fayad ZA, Balchandani P. Enhancing the brain MRI at ultra-high field systems using a meta-array structure. Med Phys 2023; 50:7606-7618. [PMID: 37874014 DOI: 10.1002/mp.16801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 04/28/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023] Open
Abstract
BACKGROUND The main advantage of ultra-high field (UHF) magnetic resonance neuroimaging is theincreased signal-to-noise ratio (SNR) compared with lower field strength imaging. However, the wavelength effect associated with UHF MRI results in radiofrequency (RF) inhomogeneity, compromising whole brain coverage for many commercial coils. Approaches to resolving this issue of transmit field inhomogeneity include the design of parallel transmit systems (PTx), RF pulse design, and applying passive RF shimming such as high dielectric materials. However, these methods have some drawbacks such as unstable material parameters of dielectric pads, high-cost, and complexity of PTx systems. Metasurfaces are artificial structures with a unique platform that can control the propagation of the electromagnetic (EM) waves, and they are very promising for engineering EM device. Implementation of meta-arrays enhancing MRI has been explored previously in several studies. PURPOSE The aim of this study was to assess the effect of new meta-array technology on enhancing the brain MRI at 7T. A meta-array based on a hybrid structure consisting of an array of broadside-coupled split-ring resonators and high-permittivity materials was designed to work at the Larmor frequency of a 7 Tesla (7T) MRI scanner. When placed behind the head and neck, this construct improves the SNR in the region of the cerebellum,brainstem and the inferior aspect of the temporal lobes. METHODS Numerical electromagnetic simulations were performed to optimize the meta-array design parameters and determine the RF circuit configuration. The resultant transmit-efficiency and signal sensitivity improvements were experimentally analyzed in phantoms followed by healthy volunteers using a 7T whole-body MRI scanner equipped with a standard one-channel transmit, 32-channel receive head coil. Efficacy was evaluated through acquisition with and without the meta-array using two basic sequences: gradient-recalled-echo (GRE) and turbo-spin-echo (TSE). RESULTS Experimental phantom analysis confirmed two-fold improvement in the transmit efficiency and 1.4-fold improvement in the signal sensitivity in the target region. In vivo GRE and TSE images with the meta-array in place showed enhanced visualization in inferior regions of the brain, especially of the cerebellum, brainstem, and cervical spinal cord. CONCLUSION Addition of the meta-array to commonly used MRI coils can enhance SNR to extend the anatomical coverage of the coil and improve overall MRI coil performance. This enhancement in SNR can be leveraged to obtain a higher resolution image over the same time slot or faster acquisition can be achieved with same resolution. Using this technique could improve the performance of existing commercial coils at 7T for whole brain and other applications.
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Affiliation(s)
- Akbar Alipour
- BioMedical Engineering and Imaging Institute and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
| | - Alan C Seifert
- BioMedical Engineering and Imaging Institute and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
| | - Bradley N Delman
- Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
| | - Patrick R Hof
- The Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
| | - Zahi A Fayad
- BioMedical Engineering and Imaging Institute and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
| | - Priti Balchandani
- BioMedical Engineering and Imaging Institute and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
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Bhatt S, Masterson E, Zhu T, Eizadi J, George J, Graupe N, Vareberg A, Phillips J, Bok I, Dwyer M, Ashtiani A, Hai A. Wireless in vivo Recording of Cortical Activity by an Ion-Sensitive Field Effect Transistor. SENSORS AND ACTUATORS. B, CHEMICAL 2023; 382:133549. [PMID: 36970106 PMCID: PMC10035629 DOI: 10.1016/j.snb.2023.133549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Wireless brain technologies are empowering basic neuroscience and clinical neurology by offering new platforms that minimize invasiveness and refine possibilities during electrophysiological recording and stimulation. Despite their advantages, most systems require on-board power supply and sizeable transmission circuitry, enforcing a lower bound for miniaturization. Designing new minimalistic architectures that can efficiently sense neurophysiological events will open the door to standalone microscale sensors and minimally invasive delivery of multiple sensors. Here we present a circuit for sensing ionic fluctuations in the brain by an ion-sensitive field effect transistor that detunes a single radiofrequency resonator in parallel. We establish sensitivity of the sensor by electromagnetic analysis and quantify response to ionic fluctuations in vitro. We validate this new architecture in vivo during hindpaw stimulation in rodents and verify correlation with local field potential recordings. This new approach can be implemented as an integrated circuit for wireless in situ recording of brain electrophysiology.
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Affiliation(s)
- Suyash Bhatt
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Department of Electrical & Computer Engineering, University of Wisconsin–Madison
| | - Emily Masterson
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Tianxiang Zhu
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Jenna Eizadi
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Judy George
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Nesya Graupe
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Adam Vareberg
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Jack Phillips
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Ilhan Bok
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Department of Electrical & Computer Engineering, University of Wisconsin–Madison
| | - Matthew Dwyer
- Department of Electrical & Computer Engineering, University of Wisconsin–Madison
| | - Alireza Ashtiani
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Aviad Hai
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Department of Electrical & Computer Engineering, University of Wisconsin–Madison
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, USA
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Bhatt S, Masterson E, Zhu T, Eizadi J, George J, Graupe N, Vareberg A, Phillips J, Bok I, Dwyer M, Ashtiani A, Hai A. Wireless in vivo Recording of Cortical Activity by an Ion-Sensitive Field Effect Transistor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.19.524785. [PMID: 36711824 PMCID: PMC9882301 DOI: 10.1101/2023.01.19.524785] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Wireless brain technologies are empowering basic neuroscience and clinical neurology by offering new platforms that minimize invasiveness and refine possibilities during electrophysiological recording and stimulation. Despite their advantages, most systems require on-board power supply and sizeable transmission circuitry, enforcing a lower bound for miniaturization. Designing new minimalistic architectures that can efficiently sense neurophysiological events will open the door to standalone microscale sensors and minimally invasive delivery of multiple sensors. Here we present a circuit for sensing ionic fluctuations in the brain by an ion-sensitive field effect transistor that detunes a single radiofrequency resonator in parallel. We establish sensitivity of the sensor by electromagnetic analysis and quantify response to ionic fluctuations in vitro . We validate this new architecture in vivo during hindpaw stimulation in rodents and verify correlation with local field potential recordings. This new approach can be implemented as an integrated circuit for wireless in situ recording of brain electrophysiology.
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Affiliation(s)
- Suyash Bhatt
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Department of Electrical & Computer Engineering, University of Wisconsin–Madison
| | - Emily Masterson
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Tianxiang Zhu
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Jenna Eizadi
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Judy George
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Nesya Graupe
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Adam Vareberg
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Jack Phillips
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Ilhan Bok
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Department of Electrical & Computer Engineering, University of Wisconsin–Madison
| | - Matthew Dwyer
- Department of Electrical & Computer Engineering, University of Wisconsin–Madison
| | - Alireza Ashtiani
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Aviad Hai
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Department of Electrical & Computer Engineering, University of Wisconsin–Madison
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Su H, Kwok KW, Cleary K, Iordachita I, Cavusoglu MC, Desai JP, Fischer GS. State of the Art and Future Opportunities in MRI-Guided Robot-Assisted Surgery and Interventions. PROCEEDINGS OF THE IEEE. INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS 2022; 110:968-992. [PMID: 35756185 PMCID: PMC9231642 DOI: 10.1109/jproc.2022.3169146] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Magnetic resonance imaging (MRI) can provide high-quality 3-D visualization of target anatomy, surrounding tissue, and instrumentation, but there are significant challenges in harnessing it for effectively guiding interventional procedures. Challenges include the strong static magnetic field, rapidly switching magnetic field gradients, high-power radio frequency pulses, sensitivity to electrical noise, and constrained space to operate within the bore of the scanner. MRI has a number of advantages over other medical imaging modalities, including no ionizing radiation, excellent soft-tissue contrast that allows for visualization of tumors and other features that are not readily visible by other modalities, true 3-D imaging capabilities, including the ability to image arbitrary scan plane geometry or perform volumetric imaging, and capability for multimodality sensing, including diffusion, dynamic contrast, blood flow, blood oxygenation, temperature, and tracking of biomarkers. The use of robotic assistants within the MRI bore, alongside the patient during imaging, enables intraoperative MR imaging (iMRI) to guide a surgical intervention in a closed-loop fashion that can include tracking of tissue deformation and target motion, localization of instrumentation, and monitoring of therapy delivery. With the ever-expanding clinical use of MRI, MRI-compatible robotic systems have been heralded as a new approach to assist interventional procedures to allow physicians to treat patients more accurately and effectively. Deploying robotic systems inside the bore synergizes the visual capability of MRI and the manipulation capability of robotic assistance, resulting in a closed-loop surgery architecture. This article details the challenges and history of robotic systems intended to operate in an MRI environment and outlines promising clinical applications and associated state-of-the-art MRI-compatible robotic systems and technology for making this possible.
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Affiliation(s)
- Hao Su
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695 USA
| | - Ka-Wai Kwok
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong
| | - Kevin Cleary
- Children's National Health System, Washington, DC 20010 USA
| | - Iulian Iordachita
- Laboratory for Computational Sensing and Robotics (LCSR), Johns Hopkins University, Baltimore, MD 21218 USA
| | - M Cenk Cavusoglu
- Department of Electrical, Computer, and Systems Engineering, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Jaydev P Desai
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA
| | - Gregory S Fischer
- Department of Robotics Engineering, Worcester Polytechnic Institute, Worcester, MA 01609 USA
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Jordan CD, Thorne BRH, Wadhwa A, Losey AD, Ozhinsky E, Kondapavulur S, Fratello V, Moore T, Stillson C, Yee C, Watkins RD, Scott GC, Martin AJ, Zhang X, Wilson MW, Hetts SW. Wireless Resonant Circuits Printed Using Aerosol Jet Deposition for MRI Catheter Tracking. IEEE Trans Biomed Eng 2020; 67:876-882. [PMID: 31247538 PMCID: PMC6995687 DOI: 10.1109/tbme.2019.2922879] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Interventional magnetic resonance imaging (MRI) could allow for diagnosis and immediate treatment of ischemic stroke; however, such endovascular catheter-based procedures under MRI guidance are inherently difficult. One major challenge is tracking the tip of the catheter, as standard fabrication methods for building inductively coupled coil markers are rigid and bulky. Here, we report a new approach that uses aerosol jet deposition to three-dimensional (3-D) print an inductively coupled RF coil marker on a polymer catheter. Our approach enables lightweight conforming markers on polymer catheters and these low-profile markers allow the catheter to be more safely navigated in small caliber vessels. Prototype markers with an inductor with the geometry of a double helix are incorporated on catheters for in vitro studies, and we show that these markers exhibit good signal amplification. We report temperature measurements and, finally, demonstrate feasibility in a preliminary in vivo experiment. We provide material properties and electromagnetic simulation performance analysis. This paper presents fully aerosol jet-deposited and functional wireless resonant markers on polymer catheters for use in 3T clinical scanners.
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Yaras YS, Satir S, Ozsoy C, Ramasawmy R, Campbell-Washburn AE, Lederman RJ, Kocaturk O, Degertekin FL. Acousto-Optic Catheter Tracking Sensor for Interventional MRI Procedures. IEEE Trans Biomed Eng 2018; 66:1148-1154. [PMID: 30188810 DOI: 10.1109/tbme.2018.2868830] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The objective of this paper is to introduce an acousto-optic optical fiber sensor for tracking catheter position during interventional magnetic resonance imaging (MRI) to overcome RF induced heating of active markers. METHODS The sensor uses a miniature coil coupled to a piezoelectric transducer, which is in turn mechanically connected to an optical fiber. The piezoelectric transducer converts the RF signal to acoustic waves in the optical fiber over a region including a fiber Bragg grating (FBG). The elastic waves in the fiber modulates the FBG geometry and hence the reflected light in the optical fiber. Since the coil is much smaller than the RF wavelength and the signal is transmitted on the dielectric optical fiber, the sensor effectively reduces RF induced heating risk. Proof of concept prototypes of the sensor are implemented using commercially available piezoelectric transducers and optical fibers with FBGs. The prototypes are characterized in a 1.5 T MRI system in comparison with an active tracking marker. RESULTS Acousto-optical sensor shows linear response with flip angle and it can be used to detect signals from multiple coils for potential orientation detection. It has been successfully used to detect the position of a tacking coil in phantom in an imaging experiment. CONCLUSION Acousto-optical sensing is demonstrated for tracking catheters during interventional MRI. Real-time operation of the sensor requires sensitivity improvements like using a narrow band FBG. SIGNIFICANCE Acousto-optics provides a compact solution to sense RF signals in MRI with dielectric transmission lines.
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8
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Guo Z, Leong MCW, Su H, Kwok KW, Chan DTM, Poon WS. Techniques for Stereotactic Neurosurgery: Beyond the Frame, Toward the Intraoperative Magnetic Resonance Imaging–Guided and Robot-Assisted Approaches. World Neurosurg 2018; 116:77-87. [DOI: 10.1016/j.wneu.2018.04.155] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 11/16/2022]
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Alipour A, Gokyar S, Algin O, Atalar E, Demir HV. An inductively coupled ultra-thin, flexible, and passive RF resonator for MRI marking and guiding purposes: Clinical feasibility. Magn Reson Med 2017; 80:361-370. [PMID: 29148092 DOI: 10.1002/mrm.26996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 09/17/2017] [Accepted: 10/15/2017] [Indexed: 12/20/2022]
Abstract
PURPOSE The purpose of this study is to develop a wireless, flexible, ultra-thin, and passive radiofrequency-based MRI resonant fiducial marker, and to validate its feasibility in a phantom model and several body regions. METHODS Standard microfabrication processing was used to fabricate the resonant marker. The proposed marker consists of two metal traces in the shape of a square with an edge length of 8 mm, with upper and lower traces connected to each other by a metalized via. A 3T MRI fiducial marking procedure was tested in phantom and ex vivo, and then the marker's performance was evaluated in an MRI experiment using humans. The radiofrequency safety was also tested using temperature sensors in the proximity of the resonator. RESULTS A flexible resonator with a thickness of 115 μm and a dimension of 8 × 8 mm was obtained. The experimental results in the phantom show that at low background flip angles (6-18°), the resonant marker enables precise and rapid visibility, with high marker-to-background contrast and signal-to-noise ratio improvement of greater than 10 in the vicinity of the marker. Temperature analysis showed a specific absorption ratio gain of 1.3. Clinical studies further showed a successful biopsy procedure using the fiducial marking functionality of our device. CONCLUSIONS The ultra-thin and flexible structure of this wireless flexible radiofrequency resonant marker offers effective and safe MR visualization with high feasibility for anatomic marking and guiding at various regions of the body. Magn Reson Med 80:361-370, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Akbar Alipour
- Department of Electrical and Electronics Engineering, National Magnetic Resonance Research Center (UMRAM) National Nanotechnology Research Center and Institute of Material Science and Nanotechnology (UNAM) Department of Physics, Bilkent University, Bilkent, Ankara, Turkey
| | - Sayim Gokyar
- Department of Electrical and Electronics Engineering, National Magnetic Resonance Research Center (UMRAM) National Nanotechnology Research Center and Institute of Material Science and Nanotechnology (UNAM) Department of Physics, Bilkent University, Bilkent, Ankara, Turkey
| | - Oktay Algin
- Department of Electrical and Electronics Engineering, National Magnetic Resonance Research Center (UMRAM) National Nanotechnology Research Center and Institute of Material Science and Nanotechnology (UNAM) Department of Physics, Bilkent University, Bilkent, Ankara, Turkey.,Department of Radiology, Ankara Ataturk Training and Research Hospital, Ankara, Turkey
| | - Ergin Atalar
- Department of Electrical and Electronics Engineering, National Magnetic Resonance Research Center (UMRAM) National Nanotechnology Research Center and Institute of Material Science and Nanotechnology (UNAM) Department of Physics, Bilkent University, Bilkent, Ankara, Turkey
| | - Hilmi Volkan Demir
- Department of Electrical and Electronics Engineering, National Magnetic Resonance Research Center (UMRAM) National Nanotechnology Research Center and Institute of Material Science and Nanotechnology (UNAM) Department of Physics, Bilkent University, Bilkent, Ankara, Turkey.,LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Mathematical and Physical Sciences, Nanyang Technological University, Singapore
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10
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Saniour I, Aydé R, Perrier AL, Gaborit G, Duvillaret L, Sablong R, Beuf O. Active optical-based detuning circuit for receiver endoluminal coil. Biomed Phys Eng Express 2017. [DOI: 10.1088/2057-1976/aa5db0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Kaiser M, Detert M, Rube MA, El-Tahir A, Elle OJ, Melzer A, Schmidt B, Rose GH. Resonant marker design and fabrication techniques for device visualization during interventional magnetic resonance imaging. ACTA ACUST UNITED AC 2016; 60:89-103. [PMID: 25460277 DOI: 10.1515/bmt-2013-0097] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 10/24/2014] [Indexed: 11/15/2022]
Abstract
Magnetic resonance imaging (MRI) has great potential as an imaging modality for guiding minimally invasive interventions because of its superior soft tissue contrast and the possibility of arbitrary slice positioning while avoiding ionizing radiation and nephrotoxic iodine contrast agents. The major constraints are: limited patient access, the insufficient assortment of compatible instruments and the difficult device visualization compared to X-ray based techniques. For the latter, resonant MRI markers, fabricated by using the wire-winding technique, have been developed. This fabrication technique serves as a functional model but has no clinical use. Thus, the aim of this study is to illustrate a four-phase design process of resonant markers involving microsystems technologies. The planning phase comprises the definition of requirements and the simulation of electromagnetic performance of the MRI markers. The following technologies were considered for the realization phase: aerosol-deposition process, hot embossing technology and thin film technology. The subsequent evaluation phase involves several test methods regarding electrical and mechanical characterization as well as MRI visibility aspects. The degree of fulfillment of the predefined requirements is determined within the analysis phase. Furthermore, an exemplary evaluation of four realized MRI markers was conducted, focusing on the performance within the MRI environment.
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12
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Syms RRA, Young IR, Ahmad MM, Taylor-Robinson SD, Rea M. Magneto-inductive catheter receiver for magnetic resonance imaging. IEEE Trans Biomed Eng 2013; 60:2421-31. [PMID: 23591471 DOI: 10.1109/tbme.2013.2258020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A catheter-based RF receiver for internal magnetic resonance imaging is demonstrated. The device consists of a double-sided thin-film circuit, wrapped around a hollow catheter and sealed in place with heat-shrink tubing. Signals are detected using a resonant LC circuit at the catheter tip and transmitted along the catheter using an array of coupled LC circuits arranged as a magneto-inductive waveguide, a form of low frequency metamaterial. Coupling to a conventional RF system is accomplished using a demountable inductive transducer. Protection against external B 1 and E fields is obtained by using figure-of-eight elements with an electrical length shorter than that of an immersed dipole. The system is primarily designed for biliary imaging, can pass the biopsy channel of a side-opening duodenoscope, and is guidewire-compatible, potentially allowing clinicians to implement MR image guided procedures without changing their standard practice. Decoupling against B 1 and E fields is verified, and in vitro (1)H magnetic resonance imaging with submillimeter resolution is demonstrated at 1.5 T using phantoms.
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Affiliation(s)
- Richard R A Syms
- Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2AZ, UK.
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Celik H, Mahcicek DI, Senel OK, Wright GA, Atalar E. Tracking the position and rotational orientation of a catheter using a transmit array system. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:809-817. [PMID: 23412592 DOI: 10.1109/tmi.2013.2247047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A new method for detecting the rotational orientation and tracking the position of an inductively coupled radio frequency (ICRF) coil using a transmit array system is proposed. The method employs a conventional body birdcage coil, but the quadrature hybrid is eliminated so that the two excitation channels can be used separately. The transmit array system provides RF excitations such that the body birdcage coil creates linearly polarized and changing RF pulses instead of a conventional rotational forward-polarized excitation. The receive coils and their operations are not modified. Inductively coupled RF coils are constructed on catheters for detecting rotational orientation and for tracking purposes. Signals from the anatomy and from tissue close to the ICRF coil are different due to the new RF excitation scheme: the ICRF coil can be separated from the anatomy in real time, and after doing so, a color-coded image is reconstructed. More importantly, this novel method enables a real-time calculation of the absolute rotational orientation of an ICRF coil constructed on a catheter. Modified FLASH and TrueFISP sequences are used for the experiments. The acquired images from this technique show the feasibility of different applications, such as catheter tracking. Furthermore, applications where knowledge of the rotational orientation of the catheter is important, such as magnetic resonance-guided endoluminal-focused ultrasound, RF ablation, side-looking optical imaging, and catheters with side ports for needles, become feasible with this method.
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Affiliation(s)
- Haydar Celik
- Electrical and Electronics Engineering Department, Bilkent University, TR-06800 Ankara, Turkey.
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Anderson KJT, Scott GC, Wright GA. Catheter tracking with phase information in a magnetic resonance scanner. IEEE TRANSACTIONS ON MEDICAL IMAGING 2012; 31:1173-1180. [PMID: 22186949 DOI: 10.1109/tmi.2011.2179944] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The purpose of this study is to describe a new active technique for accurately determining both the position and orientation of the tip of a catheter during magnetic resonance (MR)-guided percutaneous cardiovascular procedures. The technique utilizes phase information introduced into the MR signal from a small receive coil located on the distal tip of the catheter. Phase patterns around a small receive coil are rich in information that is directly related to position and orientation. This information can be collected over a large spherical volume with a diameter several times that of the receive coil. The high degree of redundancy yields the potential for an accurate and robust method of catheter tracking. A tracking algorithm is presented that performs catheter tip localization using phase images acquired in two orthogonal planes without any a priori knowledge of catheter position. Associated experimentation demonstrating feasibility is also presented.
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Affiliation(s)
- Kevan J T Anderson
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A1, Canada.
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Tzifa A, Schaeffter T, Razavi R. MR imaging-guided cardiovascular interventions in young children. Magn Reson Imaging Clin N Am 2012; 20:117-28. [PMID: 22118596 DOI: 10.1016/j.mric.2011.08.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
Diagnostic cardiac catheterization procedures in children have been largely replaced by magnetic resonance (MR) imaging studies. However, when invasive catheterization is required, MR imaging has a significant role to play, when combined with invasive pressure measurements. Beyond the established reduction to the radiation dose involved, solely MR image-guided or MR image-assisted catheterization procedures can accurately address clinical questions, such as estimation of pulmonary vascular resistance and cardiac output response to stress, without needing to perform laborious measurements that are prone to errors. This article describes MR image-guided or MR image-assisted cardiac catheterization procedures for diagnosis and intervention in children.
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Affiliation(s)
- Aphrodite Tzifa
- Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's & St Thomas' Hospital NHS Foundation Trust, UK.
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16
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Korn M, Umathum R, Schulz J, Semmler W, Bock M. Optically detunable, inductively coupled coil for self-gating in small animal magnetic resonance imaging. Magn Reson Med 2011; 65:882-8. [PMID: 21337415 DOI: 10.1002/mrm.22665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 08/06/2010] [Accepted: 09/09/2010] [Indexed: 11/07/2022]
Abstract
An inductively coupled coil concept is presented, which improves the compensation of physiological motion by the self-gating (SG) technique. The animal is positioned in a conventional volume coil encompassing the whole animal. A small, resonant surface coil (SG-coil) is placed on the thorax so that its sensitive region includes the heart. Via inductive coupling the SG-coil amplifies selectively the MR signal of the beating heart. With an optical detuning mechanism, this coupling can be switched off during acquisition of the MR image information, whereas it is active during SG data sampling to provide the physiological information. In vivo experiments on a mouse show an amplification of the SG signal by at least 40%.
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Affiliation(s)
- Matthias Korn
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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17
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Tzifa A, Krombach GA, Krämer N, Krüger S, Schütte A, von Walter M, Schaeffter T, Qureshi S, Krasemann T, Rosenthal E, Schwartz CA, Varma G, Buhl A, Kohlmeier A, Bücker A, Günther RW, Razavi R. Magnetic Resonance–Guided Cardiac Interventions Using Magnetic Resonance–Compatible Devices. Circ Cardiovasc Interv 2010; 3:585-92. [DOI: 10.1161/circinterventions.110.957209] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Percutaneous cardiac interventions are currently performed under x-ray guidance. Magnetic resonance imaging (MRI) has been used to guide intravascular interventions in the past, but mainly in animals. Translation of MR-guided interventions into humans has been limited by the lack of MR-compatible and safe equipment, such as MR guide wires with mechanical characteristics similar to standard guide wires. The aim of the present study was to evaluate the safety and efficacy of a newly developed MR-safe and compatible passive guide wire in aiding MR-guided cardiac interventions in a swine model and describe the 2 first-in-man solely MR-guided interventions.
Methods and Results—
In the preclinical trial, the new MR-compatible wire aided the performance of 20 interventions in 5 swine. These consisted of balloon dilation of nondiseased pulmonary and aortic valves, aortic arch, and branch pulmonary arteries. After ethics and regulatory authority approval, the 2 first-in-man MR-guided interventions were performed in a child and an adult, both with elements of valvar pulmonary stenosis. Catheter manipulations were monitored with real-time MRI sequence with interactive modification of imaging plane and slice position. Temporal resolution was 11 to 12 frames/s. Catheterization procedure times were 110 and 80 minutes, respectively. Both patients had successful relief of the valvar stenosis and no procedural complications.
Conclusions—
The described preclinical study and case reports are encouraging that with the availability of the new MR-compatible and safe guide wire, certain percutaneous cardiac interventions will become feasible to perform solely under MR guidance in the future. A clinical trial is underway in our institution.
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Affiliation(s)
- Aphrodite Tzifa
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Gabriele A. Krombach
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Nils Krämer
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Sascha Krüger
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Adrian Schütte
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Matthias von Walter
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Tobias Schaeffter
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Shakeel Qureshi
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Thomas Krasemann
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Eric Rosenthal
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Claudia A. Schwartz
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Gopal Varma
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Alexandra Buhl
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Antonia Kohlmeier
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Arno Bücker
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Rolf W. Günther
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
| | - Reza Razavi
- From King's College London BHF Centre (A.T., T.S., S.Q., G.V., R.R.), Division of Imaging Sciences, NIHR Biomedical, Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; the Pediatric Cardiology Department (A.T., S.Q., T.K., E.R., R.R.), Evelina Children's Hospital, Guy's and St Thomas' Hospital, London, United Kingdom; the Department of Diagnostic Radiology (G.A.K., N.K., C.A.S., A.K., A.B., R.W.G.), University Hospital Aachen, Aachen, Germany; Philips Research
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Krug J, Will K, Rose G. Simulation and experimental validation of resonant electric markers used for medical device tracking in magnetic resonance imaging. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2010:1878-81. [PMID: 21096422 DOI: 10.1109/iembs.2010.5627137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Magnetic resonance imaging (MRI), which was traditionally used for patient diagnosis, has gained in importance in minimally invasive interventions in the recent past. Hence, there is an increasing demand for medical devices compatible with the MR environment. One of the challenges is to visualize the medical devices, e.g. catheters, within the MR image. Several methods exist to cope with this task.
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Affiliation(s)
- Johannes Krug
- Chair for Healthcare Telematics and Medical Engineering, University of Magdeburg, 39106, Germany.
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19
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Bottomley PA, Kumar A, Edelstein WA, Allen JM, Karmarkar PV. Designing passive MRI-safe implantable conducting leads with electrodes. Med Phys 2010; 37:3828-43. [PMID: 20831091 DOI: 10.1118/1.3439590] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The presence of implanted electronic devices with conducting leads and electrodes are contraindicated for magnetic resonance imaging (MRI), denying many patients its potential benefits. The prime concern is MRI's radio frequency (RF) fields, which can cause elevated local specific absorption rates (SARs) and potential heat injury. The purpose of this article is to develop and compare a range of passive implantable "MRI-safe" lead designs. METHODS Conducting leads incorporating different lengths (3-75 cm), insulation thicknesses (0-105 microm), resistances (100-3000 omega), coiled conductors (inner diameter < or = 1.2 mm), high-impedance (135-2700 omega) RF traps, and single-coiled and triple-coiled coaxial-wound "billabong" leads with reversed coil sections that oppose and reduce the induced current, are investigated both experimentally using local temperature measurements, and by numerical full-wave electromagnetic field analysis of the local SAR, in three different-sized bioanalogous model saline-gel phantoms at 1.5 T MRI and 4 W/kg exposure. RESULTS In all designs, the maximum computed 1 g average SAR and experimental temperature rise occur at the bare electrodes. Electrode heating increases with lead insulation thickness and peaks for uncoiled leads 25-50 cm long. A reasonable match between computed SAR and the point SAR estimated from thermal sensors obtained by approximating the computation volume to that of the thermal probes. Factors that maximize the impedance of leads with resistive, coiled, RF trap and billabong elements can effectively limit heating below 1-2 degrees, but folded lead configurations can be a concern. The RF trap and billabong designs can both support multiple conductors and electrodes, with billabong prototype leads also heating <1 degrees C when tested for 3 T MRI. CONCLUSIONS Lead insulation and length strongly affect implanted lead safety to RF exposure during MRI. Lead designs employing impedance and reversed winding sections offer hope for the development of passive, MRI-safe, implantable conducting leads for future human use.
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Affiliation(s)
- Paul A Bottomley
- SurgiVision, Inc., Suite B307, 1101 East 33rd Street, Baltimore, Maryland 21218, USA.
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20
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Melzer A. [Principles of MR-guided interventions, surgery, navigation, and robotics]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2010; 53:768-75. [PMID: 20700775 DOI: 10.1007/s00103-010-1101-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The application of magnetic resonance imaging (MRI) as an imaging technique in interventional and surgical techniques provides a new dimension of soft tissue-oriented precise procedures without exposure to ionizing radiation and nephrotoxic allergenic, iodine-containing contrast agents. The technical capabilities of MRI in combination with interventional devices and systems, navigation, and robotics are discussed.
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Affiliation(s)
- A Melzer
- IMSaT Institute for Medical Science and Technology, Dundee, UK.
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21
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Kettenbach J, Kacher DF, Kanan AR, Rostenberg B, Fairhurst J, Stadler A, Kienreich K, Jolesz FA. Intraoperative and interventional MRI: Recommendations for a safe environment. MINIM INVASIV THER 2009; 15:53-64. [PMID: 16754187 DOI: 10.1080/13645700600640774] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In this paper we report on current experience and review magnetic resonance safety protocols and literature in order to define practices surrounding MRI-guided interventional and surgical procedures. Direct experience, the American College of Radiology White paper on MR Safety, and various other sources are summarized. Additional recommendations for interventional and surgical MRI-guided procedures cover suite location/layout, accessibility, safety policy, personnel training, and MRI compatibility issues. Further information is freely available for sites to establish practices to minimize risk and ensure safety. Interventional and intraoperative MRI is emerging from its infancy, with twelve years since the advent of the field and well over 10,000 cases collectively performed. Thus, users of interventional and intraoperative MRI should adapt guidelines utilizing universal standards and terminology and establish a site-specific policy. With policy enforcement and proper training, the interventional and intraoperative MR imaging suite can be a safe and effective environment.
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Affiliation(s)
- Joachim Kettenbach
- Department of Radiology, Medical University Vienna, General Hospital, Vienna, Austria.
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Polygerinos P, Schaeffter T, Seneviratne L, Althoefer K. A fibre-optic catheter-tip force sensor with MRI compatibility: a feasibility study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2009:1501-1554. [PMID: 19964534 DOI: 10.1109/iembs.2009.5334163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This paper presents the development of a low-cost, Magnetic Resonance Imaging (MRI) compatible fibre-optic sensor for integration with catheters allowing the detection of contact forces between blood vessel walls and the catheter tip. Three plastic optical-fibres are aligned inside a plastic catheter in a circular pattern. A reflector is attached to a separate small part of the catheter tip, which is connected with a small deformable material to the aligned optical-fibres. In this manner a force at the catheter tip leads to a deformation of the elastic material and thus a modulation of the light yields, this is sent and received through the optical-fibres. An electronic circuit amplifies the retrieved light signal and the output voltage is used to classify the forces on the tip. The materials used are of the shelf and have a low magnetic susceptibility making this sensor fully MRI-compatible and inexpensive. Preliminary, experimental results demonstrated good force linearity in static loading and unloading conditions. The sensor was also tested in an artificial blood artery showing good dynamic response.
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Fandrey S, Weiss S, Muller J. Development of an active intravascular MR device with an optical transmission system. IEEE TRANSACTIONS ON MEDICAL IMAGING 2008; 27:1723-1727. [PMID: 19033088 DOI: 10.1109/tmi.2008.925079] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Magnetic resonance imaging (MRI) is a safe and reliable medical imaging method providing good soft tissue contrast while avoiding harmful ionizing radiation. It is highly desirable to use the MRI technology for interventional procedures. However, due to resonance effects that can result in tissue heating, long conducting cables must be avoided. Motivated by the need for more radio-frequency (RF) safety, we developed an optical transmission system for active intravascular MRI devices. An optical transmitter sends the MR signal via an optical fiber. A miniature optical modulator was designed to be integrated into a catheter tip. Furthermore, power is supplied optically to the transmitter. This system can target new medical applications, due to safe catheter tracking and safe intravascular imaging.
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Affiliation(s)
- Stephan Fandrey
- Hamburg University of Technology, Institute of MicroSystems Technology, 21073 Hamburg, Germany.
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25
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Kraitchman DL, Gilson WD, Lorenz CH. Stem cell therapy: MRI guidance and monitoring. J Magn Reson Imaging 2008; 27:299-310. [PMID: 18219684 DOI: 10.1002/jmri.21263] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
With the recent advances in magnetic resonance (MR) labeling of cellular therapeutics, it is natural that interventional MRI techniques for targeting would be developed. This review provides an overview of the current methods of stem cell labeling and the challenges that are created with respect to interventional MRI administration. In particular, stem cell therapies will require specialized, MR-compatible devices as well as integration of graphical user interfaces with pulse sequences designed for interactive, real-time delivery in many organs. Specific applications that are being developed will be reviewed as well as strategies for future translation to the clinical realm.
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Affiliation(s)
- Dara L Kraitchman
- Johns Hopkins University, School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD 21287, USA.
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26
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Kos S, Huegli R, Bongartz GM, Jacob AL, Bilecen D. MR-guided endovascular interventions: a comprehensive review on techniques and applications. Eur Radiol 2007; 18:645-57. [PMID: 18071710 DOI: 10.1007/s00330-007-0818-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2007] [Revised: 10/01/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022]
Abstract
The magnetic resonance (MR) guidance of endovascular interventions is probably one of the greatest challenges of clinical MR research. MR angiography is not only an imaging tool for the vasculature but can also simultaneously depict high tissue contrast, including the differentiation of the vascular wall and perivascular tissues, as well as vascular function. Several hurdles had to be overcome to allow MR guidance for endovascular interventions. MR hardware and sequence design had to be developed to achieve acceptable patient access and to allow real-time or near real-time imaging. The development of interventional devices, both applicable and safe for MR imaging (MRI), was also mandatory. The subject of this review is to summarize the latest developments in real-time MRI hardware, MRI, visualization tools, interventional devices, endovascular tracking techniques, actual applications and safety issues.
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Affiliation(s)
- Sebastian Kos
- Institute of Radiology, Division of Interventional Radiology, University Hospital Basel, Petersgraben 4, 4031, Basel, Switzerland.
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27
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Jacquier A, Higgins CB, Saeed M. MR imaging in assessing cardiovascular interventions and myocardial injury. CONTRAST MEDIA & MOLECULAR IMAGING 2007; 2:1-15. [PMID: 17326039 DOI: 10.1002/cmmi.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Performing an MR-guided endovascular intervention requires (1) real-time tracking and guidance of catheters/guide wires to the target, (2) high-resolution images of the target and its surroundings in order to define the extent of the target, (3) performing a therapeutic procedure (delivery of stent or injection of gene or cells) and (4) evaluating the outcome of the therapeutic procedure. The combination of X-ray and MR imaging (XMR) in a single suite was designed for new interventional procedures. MR contrast media can be used to delineate myocardial infarcts and microvascular obstruction, thereby defining the target for local delivery of therapeutic agents under MR-guidance. Iron particles, or gadolinium- or dysprosium-chelates are mixed with the soluble injectates or stem cells in order to track intramyocardial delivery and distribution. Preliminary results show that genes encoded for vascular endothelial and fibroblast growth factor and cells are effective in promoting angiogenesis, arteriogenesis, perfusion and LV function. Angiogenic growth factors, genes and cells administered under MR-guided minimally invasive catheter-based procedures will open up new avenues in treating end-stage ischemic heart disease. The optimum dose of the therapeutic agents, delivery devices and real-time imaging techniques to guide the delivery are currently the subject of ongoing research. The aim of this review is to (1) provide an updated review of experiences using MR imaging to guide transcatheter therapy, (2) address the potential of cardiovascular magnetic resonance (MR) imaging and MR contrast media in assessing myocardial injury at a molecular level and labeling cells and (3) illustrate the applicability of the non-invasive MR imaging in the field of angiogenic therapies through recent clinical and experimental publications.
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Affiliation(s)
- Alexis Jacquier
- Department of Radiology, University of California San Francisco, CA 94134-0628, USA
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Krafft A, Müller S, Umathum R, Semmler W, Bock M. B1 field-insensitive transformers for RF-safe transmission lines. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2006; 19:257-66. [PMID: 17115123 DOI: 10.1007/s10334-006-0055-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 10/11/2006] [Accepted: 10/12/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Integration of transformers into transmission lines suppresses radiofrequency (RF)-induced heating. New figure-of-eight-shaped transformer coils are compared to conventional loop transformer coils to assess their signal transmission properties and safety profile. MATERIALS AND METHODS The transmission properties of figure-of-eight-shaped transformers were measured and compared to transformers with loop coils. Experiments to quantify the effect of decoupling from the B1 field of the MR system were conducted. Temperature measurements were performed to demonstrate the effective reduction of RF-induced heating. The transformers were investigated during active tracking experiments. RESULTS Coupling to the B1 field was reduced by 18 dB over conventional loop-shaped transformer coils. MR images showed a significantly reduced artifact for the figure-of-eight- shaped coils generated by local flip-angle amplification. Comparable transmission properties were seen for both transformer types. Temperature measurements showed a maximal temperature increase of 30 K/3.5 K for an unsegmented/segmented cable. With a segmented transmission line a robotic assistance system could be successfully localized using active tracking. CONCLUSION The figure-of-eight-shaped transformer design reduces both RF field coupling with the MR system and artifact sizes. Anatomical structure close to the figure-of-eight-shaped transformer may be less obscured as with loop-shaped transformers if these transformers are integrated into e.g. intravascular catheters.
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Affiliation(s)
- Axel Krafft
- Deutsches Krebsforschungszentrum (dkfz), Abt. Medizinische Physik in der Radiologie (E020), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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Abstract
Longer electrically conducting parts are needed for various instruments such as pacemakers, defibrillators, deep brain stimulators and interventional instruments. Magnetic resonance imaging in the presence of these instruments can be potentially harmful, due to resonance effects and heating of conducting wires. A review of the literature revealed that neither manufacturers of pacemakers and defibrillators nor the FDA consider these medical instruments to be MR-safe, despite the fact that there are some reports about MR scanning of pacemaker patients without critical incidents. MR-guided angiographic interventions require not only high quality real-time imaging, but also MR compatible and MR-safe instruments. Consequently, metallic guidewires as used for angiographic interventions were examined during in vitro experiments in the MR environment. Heating of guidewires to>70 degrees was reported during in vitro experiments. Our own in vivo experiments using commercially available metallic guidewires observed heating to up to 35 degrees at the guidewire tip, despite the cooling effect of blood flowing around the guidewire. Moreover, we saw the development of sparks at the end of the guidewire if it was bent inside of the MR scanner and touched to the animal. But it was not possible to reliably repeat these heating results. We conclude that longer metallic parts have to be avoided inside the MR scanner to guarantee patient safety. In order to exploit more sophisticated technologies such as active tip tracking, solutions without the need for conducting wires have to be further developed before interventional MR can safely move into the clinical setting.
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Affiliation(s)
- Arno Buecker
- Clinic of Diagnostic Radiology, University Hospital Aachen, Aachen, Germany.
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Mekle R, Hofmann E, Scheffler K, Bilecen D. A polymer-based MR-compatible guidewire: a study to explore new prospects for interventional peripheral magnetic resonance angiography (ipMRA). J Magn Reson Imaging 2006; 23:145-55. [PMID: 16374877 DOI: 10.1002/jmri.20486] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To introduce a newly developed polymer-based and magnetic resonance (MR)-compatible guidewire and to explore its capabilities with respect to interventional peripheral magnetic resonance angiography (ipMRA) in a flow phantom. MATERIALS AND METHODS The guidewire is based on a polyetheretherketone (PEEK) polymer core, and small iron particles are embedded in its coating. A passive device tracking technique was designed utilizing a susceptibility artifact induced by the wire in images acquired with a balanced steady-state free precession (b-SSFP) sequence using small flip angles. The position of the guidewire tip was determined from image intensity maxima and overlayed onto a roadmap in near real-time. Guidewire tracking and balloon angioplasty of an artificial stenosis were attempted in two configurations of a flow phantom. RESULTS Successful passive guidewire tracking was performed for all phantom configurations. Robustness and accuracy of the tracking technique were sufficient for phantom studies. A balloon catheter was placed into the stenosis using the guidewire under complete MR guidance, and subsequent balloon angioplasty yielded improved flow conditions. CONCLUSION The new guidewire is well-suited for clinical application due to an absence of the risk of core fracture and its atraumatic flexible tip. It opens novel prospects for the realization of ipMRA in humans that need to be explored in further studies.
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Affiliation(s)
- Ralf Mekle
- MR-Physics, University of Basel/University Hospital, Basel, Switzerland.
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Krueger JJ, Ewert P, Yilmaz S, Gelernter D, Peters B, Pietzner K, Bornstedt A, Schnackenburg B, Abdul-Khaliq H, Fleck E, Nagel E, Berger F, Kuehne T. Magnetic resonance imaging-guided balloon angioplasty of coarctation of the aorta: a pilot study. Circulation 2006; 113:1093-100. [PMID: 16490822 DOI: 10.1161/circulationaha.105.578112] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND MRI guidance of percutaneous transluminal balloon angioplasty (PTA) of aortic coarctation (CoA) would be desirable for continuous visualization of anatomy and to eliminate x-ray exposure. The aim of this study was (1) to determine the suitability of MRI-controlled PTA using the iron oxide-based contrast medium Resovist (ferucarbotran) for catheter visualization and (2) to subsequently apply this technique in a pilot study with patients with CoA. METHODS AND RESULTS The MRI contrast-to-noise ratio and artifact behavior of Resovist-treated balloon catheters was optimized in in vitro and animal experiments (pigs). In 5 patients, anatomy of the CoA was evaluated before and after intervention with high-resolution respiratory-navigated 3D MRI and multiphase cine MRI. Position monitoring of Resovist-treated catheters was realized with interactive real-time MRI. Aortic pressures were continuously recorded. Conventional catheterization was performed before and after MRI to confirm interventional success. During MRI, catheters filled with 25 micromol of iron particles per milliliter of Resovist produced good signal contrast between catheters and their background anatomy but no image distortion due to susceptibility artifacts. All MRI procedures were performed successfully in the patient study. There was excellent agreement between the diameters of CoA and pressure gradients as measured during MRI and conventional catheterization. In 4 patients, PTA resulted in substantial widening of the CoA and a decrease in pressure gradients. In 1 patient, PTA was ineffective. CONCLUSIONS The MRI method described represents a potential alternative to conventional x-ray fluoroscopy for catheter-based treatment of patients with CoA.
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Affiliation(s)
- Julia J Krueger
- Department of Congenital Heart Disease and Pediatric Cardiology, Deutsches Herzzentrum Berlin, Berlin, Germany
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Elgort DR, Duerk JL. A review of technical advances in interventional magnetic resonance imaging. Acad Radiol 2005; 12:1089-99. [PMID: 16099690 DOI: 10.1016/j.acra.2005.06.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Revised: 06/01/2005] [Accepted: 06/01/2005] [Indexed: 10/25/2022]
Abstract
Initial research in the development of interventional magnetic resonance (MR) imaging in the late 1980s and early to mid-1990s focused on pulse sequences, devices, and clinical applications. This focus was largely a result of the limited number of areas in which the academic research community leading the development could provide innovation on the MR systems of the time. However, during the past decade, computational power, higher bandwidth graphical displays, faster computer networks, improved pulse sequence architectures, and improved technical specifications have accelerated the pace of development on modern MR systems. Today, it is the combination of multiple system factors that are enabling the future of interventional MR. These developments, their impact on the field, and newly emerging applications are described.
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Affiliation(s)
- Daniel R Elgort
- Department of Radiology-MRI, Case Western Reserve University and University Hospitals of Cleveland, 11100 Euclid Avenue, Cleveland, OH 44106, USA
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Abstract
Although x-ray fluoroscopy (XRF) has guided diagnostic and therapeutic transcatheter procedures for decades, certain limitations still exist. XRF still visualizes tissue poorly and relies on projection of shadows that do not convey depth information. Adjunctive echocardiography overcomes some of these limitations but still suffers suboptimal or unreliable imaging windows. Furthermore, ionizing radiation exposure in children imparts a cancer risk. An interventional platform using real-time magnetic resonance imaging (MRI) may offer superior image guidance without radiation. Although there are many remaining challenges, but real-time MRI has the potential to revolutionize transcatheter therapeutics.
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Affiliation(s)
- A N Raval
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Building 10, Room 2c713, MSC 1538, Bethesda, MD 20892-1538, USA
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