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Nayak KS, Lim Y, Campbell-Washburn AE, Steeden J. Real-Time Magnetic Resonance Imaging. J Magn Reson Imaging 2022; 55:81-99. [PMID: 33295674 PMCID: PMC8435094 DOI: 10.1002/jmri.27411] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 01/03/2023] Open
Abstract
Real-time magnetic resonance imaging (RT-MRI) allows for imaging dynamic processes as they occur, without relying on any repetition or synchronization. This is made possible by modern MRI technology such as fast-switching gradients and parallel imaging. It is compatible with many (but not all) MRI sequences, including spoiled gradient echo, balanced steady-state free precession, and single-shot rapid acquisition with relaxation enhancement. RT-MRI has earned an important role in both diagnostic imaging and image guidance of invasive procedures. Its unique diagnostic value is prominent in areas of the body that undergo substantial and often irregular motion, such as the heart, gastrointestinal system, upper airway vocal tract, and joints. Its value in interventional procedure guidance is prominent for procedures that require multiple forms of soft-tissue contrast, as well as flow information. In this review, we discuss the history of RT-MRI, fundamental tradeoffs, enabling technology, established applications, and current trends. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 1.
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Affiliation(s)
- Krishna S. Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA,Address reprint requests to: K.S.N., 3740 McClintock Ave, EEB 400C, Los Angeles, CA 90089-2564, USA.
| | - Yongwan Lim
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Adrienne E. Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jennifer Steeden
- Institute of Cardiovascular Science, Centre for Cardiovascular Imaging, University College London, London, UK
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Morales Mojica CM, Velazco-Garcia JD, Pappas EP, Birbilis TA, Becker A, Leiss EL, Webb A, Seimenis I, Tsekos NV. A Holographic Augmented Reality Interface for Visualizing of MRI Data and Planning of Neurosurgical Procedures. J Digit Imaging 2021; 34:1014-1025. [PMID: 34027587 DOI: 10.1007/s10278-020-00412-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 12/06/2020] [Accepted: 12/18/2020] [Indexed: 10/21/2022] Open
Abstract
The recent introduction of wireless head-mounted displays (HMD) promises to enhance 3D image visualization by immersing the user into 3D morphology. This work introduces a prototype holographic augmented reality (HAR) interface for the 3D visualization of magnetic resonance imaging (MRI) data for the purpose of planning neurosurgical procedures. The computational platform generates a HAR scene that fuses pre-operative MRI sets, segmented anatomical structures, and a tubular tool for planning an access path to the targeted pathology. The operator can manipulate the presented images and segmented structures and perform path-planning using voice and gestures. On-the-fly, the software uses defined forbidden-regions to prevent the operator from harming vital structures. In silico studies using the platform with a HoloLens HMD assessed its functionality and the computational load and memory for different tasks. A preliminary qualitative evaluation revealed that holographic visualization of high-resolution 3D MRI data offers an intuitive and interactive perspective of the complex brain vasculature and anatomical structures. This initial work suggests that immersive experiences may be an unparalleled tool for planning neurosurgical procedures.
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Affiliation(s)
- Cristina M Morales Mojica
- MRI Lab, Department of Computer Science, University of Houston, 4800 Calhoun Road PGH 501, Houston, TX, USA
| | - Jose D Velazco-Garcia
- MRI Lab, Department of Computer Science, University of Houston, 4800 Calhoun Road PGH 501, Houston, TX, USA
| | - Eleftherios P Pappas
- Medical Physics Laboratory, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Aaron Becker
- Department of Electrical and Computer Engineering, University of Houston, Houston, TX, USA
| | - Ernst L Leiss
- MRI Lab, Department of Computer Science, University of Houston, 4800 Calhoun Road PGH 501, Houston, TX, USA
| | - Andrew Webb
- C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Ioannis Seimenis
- Medical Physics Laboratory, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Nikolaos V Tsekos
- MRI Lab, Department of Computer Science, University of Houston, 4800 Calhoun Road PGH 501, Houston, TX, USA.
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Yildirim DK, Bruce C, Uzun D, Rogers T, O'Brien K, Ramasawmy R, Campbell-Washburn A, Herzka DA, Lederman RJ, Kocaturk O. A 20-gauge active needle design with thin-film printed circuitry for interventional MRI at 0.55T. Magn Reson Med 2021; 86:1786-1801. [PMID: 33860962 DOI: 10.1002/mrm.28804] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 03/05/2021] [Accepted: 03/23/2021] [Indexed: 01/14/2023]
Abstract
PURPOSE This work aims to fabricate RF antenna components on metallic needle surfaces using biocompatible polyester tubing and conductive ink to develop an active interventional MRI needle for clinical use at 0.55 Tesla. METHODS A custom computer numeric control-based conductive ink printing method was developed. Based on electromagnetic simulation results, thin-film RF antennas were printed with conductive ink and used to fabricate a medical grade, 20-gauge (0.87 mm outer diameter), 90-mm long active interventional MRI needle. The MRI visibility performance of the active needle prototype was tested in vitro in 1 gel phantom and in vivo in 1 swine. A nearly identical active needle constructed using a 44 American Wire Gauge insulated copper wire-wound RF receiver antenna was a comparator. The RF-induced heating risk was evaluated in a gel phantom per American Society for Testing and Materials (ASTM) 2182-19. RESULTS The active needle prototype with printed RF antenna was clearly visible both in vitro and in vivo under MRI. The maximum RF-induced temperature rise of prototypes with printed RF antenna and insulated copper wire antenna after a 3.96 W/kg, 15 min. long scan were 1.64°C and 8.21°C, respectively. The increase in needle diameter was 98 µm and 264 µm for prototypes with printed RF antenna and copper wire-wound antenna, respectively. CONCLUSION The active needle prototype with conductive ink printed antenna provides distinct device visibility under MRI. Variations on the needle surface are mitigated compared to use of a 44 American Wire Gauge copper wire. RF-induced heating tests support device RF safety under MRI. The proposed method enables fabrication of small diameter active interventional MRI devices having complex geometries, something previously difficult using conventional methods.
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Affiliation(s)
- Dursun Korel Yildirim
- Institute of Biomedical Engineering, Bogazici University, Kandilli Campus, Istanbul, Turkey.,Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Christopher Bruce
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Dogangun Uzun
- Institute of Biomedical Engineering, Bogazici University, Kandilli Campus, Istanbul, Turkey.,Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Toby Rogers
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Kendall O'Brien
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Rajiv Ramasawmy
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Adrienne Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Daniel A Herzka
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert J Lederman
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Ozgur Kocaturk
- Institute of Biomedical Engineering, Bogazici University, Kandilli Campus, Istanbul, Turkey.,Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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A Platform Integrating Acquisition, Reconstruction, Visualization, and Manipulator Control Modules for MRI-Guided Interventions. J Digit Imaging 2020; 32:420-432. [PMID: 30483988 DOI: 10.1007/s10278-018-0152-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
This work presents a platform that integrates a customized MRI data acquisition scheme with reconstruction and three-dimensional (3D) visualization modules along with a module for controlling an MRI-compatible robotic device to facilitate the performance of robot-assisted, MRI-guided interventional procedures. Using dynamically-acquired MRI data, the computational framework of the platform generates and updates a 3D model representing the area of the procedure (AoP). To image structures of interest in the AoP that do not reside inside the same or parallel slices, the MRI acquisition scheme was modified to collect a multi-slice set of intraoblique to each other slices; which are termed composing slices. Moreover, this approach interleaves the collection of the composing slices so the same k-space segments of all slices are collected during similar time instances. This time matching of the k-space segments results in spatial matching of the imaged objects in the individual composing slices. The composing slices were used to generate and update the 3D model of the AoP. The MRI acquisition scheme was evaluated with computer simulations and experimental studies. Computer simulations demonstrated that k-space segmentation and time-matched interleaved acquisition of these segments provide spatial matching of the structures imaged with composing slices. Experimental studies used the platform to image the maneuvering of an MRI-compatible manipulator that carried tubing filled with MRI contrast agent. In vivo experimental studies to image the abdomen and contrast enhanced heart on free-breathing subjects without cardiac triggering demonstrated spatial matching of imaged anatomies in the composing planes. The described interventional MRI framework could assist in performing real-time MRI-guided interventions.
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Veeram Reddy SR, Arar Y, Zahr RA, Gooty V, Hernandez J, Potersnak A, Douglas P, Blair Z, Greer JS, Roujol S, Forte MNV, Greil G, Nugent AW, Hussain T. Invasive cardiovascular magnetic resonance (iCMR) for diagnostic right and left heart catheterization using an MR-conditional guidewire and passive visualization in congenital heart disease. J Cardiovasc Magn Reson 2020; 22:20. [PMID: 32213193 PMCID: PMC7098096 DOI: 10.1186/s12968-020-0605-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 02/05/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Today's standard of care, in the congenital heart disease (CHD) population, involves performing cardiac catheterization under x-ray fluoroscopy and cardiac magnetic resonance (CMR) imaging separately. The unique ability of CMR to provide real-time functional imaging in multiple views without ionizing radiation exposure has the potential to be a powerful tool for diagnostic and interventional procedures. Limiting fluoroscopic radiation exposure remains a challenge for pediatric interventional cardiologists. This pilot study's objective is to establish feasibility of right (RHC) and left heart catheterization (LHC) during invasive CMR (iCMR) procedures at our institution in the CHD population. Furthermore, we aim to improve simultaneous visualization of the catheter balloon tip, MR-conditional guidewire, and cardiac/vessel anatomy during iCMR procedures. METHODS Subjects with CHD were enrolled in a pilot study for iCMR procedures at 1.5 T with an MR-conditional guidewire. The CMR area is located adjacent to a standard catheterization laboratory. Using the interactive scanning mode for real-time control of the imaging location, a dilute gadolinium-filled balloon-tip catheter was used in combination with an MR-conditional guidewire to obtain cardiac saturations and hemodynamics. A recently developed catheter tracking technique using a real-time single-shot balanced steady-state free precession (bSSFP), flip angle (FA) 35-45°, echo time (TE) 1.3 ms, repetition time (TR) 2.7 ms, 40° partial saturation (pSAT) pre-pulse was used to visualize the gadolinium-filled balloon, MR-conditional guidewire, and cardiac structures simultaneously. MR-conditional guidewire visualization was enabled due to susceptibility artifact created by distal markers. Pre-clinical phantom testing was performed to determine the optimum imaging FA-pSAT combination. RESULTS The iCMR procedure was successfully performed to completion in 31/34 (91%) subjects between August 1st, 2017 to December 13th, 2018. Median age and weight were 7.7 years and 25.2 kg (range: 3 months - 33 years and 8 - 80 kg). Twenty-one subjects had single ventricle (SV) anatomy: one subject was referred for pre-Glenn evaluation, 11 were pre-Fontan evaluations and 9 post-Fontan evaluations for protein losing enteropathy (PLE) and/or cyanosis. Thirteen subjects had bi-ventricular (BiV) anatomy, 4 were referred for coarctation of the aorta (CoA) evaluations, 3 underwent vaso-reactivity testing with inhaled nitric oxide, 3 investigated RV volume dimensions, two underwent branch PA stenosis evaluation, and the remaining subject was status post heart transplant. No catheter related complications were encountered. Average time taken for first pass RHC, LHC/aortic pull back, and to cross the Fontan fenestration was 5.2, 3.0, and 6.5 min, respectively. Total success rate to obtain required data points to complete Fick principle calculations for all patients was 331/337 (98%). Subjects were transferred to the x-ray fluoroscopy lab if further intervention was required including Fontan fenestration device closure, balloon angioplasty of pulmonary arteries/conduits, CoA stenting, and/or coiling of aortopulmonary (AP) collaterals. Starting with subject #10, an MR-conditional guidewire was used in all subsequent subjects (15 SV and 10 BiV) with a success rate of 96% (24/25). Real-time CMR-guided RHC (25/25 subjects, 100%), retrograde and prograde LHC/aortic pull back (24/25 subjects, 96%), CoA crossing (3/4 subjects, 75%) and Fontan fenestration test occlusion (2/3 subjects, 67%) were successfully performed in the majority of subjects when an MR-conditional guidewire was utilized. CONCLUSION Feasibility for detailed diagnostic RHC, LHC, and Fontan fenestration test occlusion iCMR procedures in SV and BiV pediatric subjects with complex CHD is demonstrated with the aid of an MR-conditional guidewire. A novel real-time pSAT GRE sequence with optimized FA-pSAT angle has facilitated simultaneous visualization of the catheter balloon tip, MR-conditional guidewire, and cardiac/vessel anatomy during iCMR procedures.
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Affiliation(s)
- Surendranath R. Veeram Reddy
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
- Pediatric Cardiology, Children’s Medical Center Dallas, 1935 Medical District Dr, Dallas, TX 75235 USA
| | - Yousef Arar
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
- Pediatric Cardiology, Children’s Medical Center Dallas, 1935 Medical District Dr, Dallas, TX 75235 USA
| | - Riad Abou Zahr
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
- Pediatric Cardiology, Children’s Medical Center Dallas, 1935 Medical District Dr, Dallas, TX 75235 USA
| | - Vasu Gooty
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
- Pediatric Cardiology, Children’s Medical Center Dallas, 1935 Medical District Dr, Dallas, TX 75235 USA
| | - Jennifer Hernandez
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
- Pediatric Cardiology, Children’s Medical Center Dallas, 1935 Medical District Dr, Dallas, TX 75235 USA
| | - Amanda Potersnak
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
| | - Phillip Douglas
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
| | - Zachary Blair
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
| | - Joshua S. Greer
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
| | - Sébastien Roujol
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
| | - Mari Nieves Velasco Forte
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
| | - Gerald Greil
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
- Pediatric Cardiology, Children’s Medical Center Dallas, 1935 Medical District Dr, Dallas, TX 75235 USA
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
| | - Alan W. Nugent
- Ann & Robert H. Lurie Children’s Hospital of Chicago, 225 E Chicago Ave, Chicago, IL 60611 USA
| | - Tarique Hussain
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
- Pediatric Cardiology, Children’s Medical Center Dallas, 1935 Medical District Dr, Dallas, TX 75235 USA
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 USA
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Abstract
Diagnostic and interventional cardiac catheterization is routinely used in the diagnosis and treatment of congenital heart disease. There are well-established concerns regarding the risk of radiation exposure to patients and staff, particularly in children given the cumulative effects of repeat exposure. Magnetic resonance imaging (MRI) offers the advantage of being able to provide better soft tissue visualization, tissue characterization, and quantification of ventricular volumes and vascular flow. Initial work using MRI catheterization employed fusion of x-ray and MRI techniques, with x-ray fluoroscopy to guide catheter placement and subsequent MRI assessment for anatomical and hemodynamic assessment. Image overlay of 3D previously acquired MRI datasets with live fluoroscopic imaging has also been used to guide catheter procedures.Hybrid x-ray and MRI-guided catheterization paved the way for clinical application and validation of this technique in the assessment of pulmonary vascular resistance and pharmacological stress studies. Purely MRI-guided catheterization also proved possible with passive catheter tracking. First-in-man MRI-guided cardiac catheter interventions were possible due to the development of MRI-compatible guidewires, but halted due to guidewire limitations.More recent developments in passive and active catheter tracking have led to improved visualization of catheters for MRI-guided catheterization. Improvements in hardware and software have also increased image quality and scanning times with better interactive tools for the operator in the MRI catheter suite to navigate through the anatomy as required in real time. This has expanded to MRI-guided electrophysiology studies and radiofrequency ablation in humans. Animal studies show promise for the utility of MRI-guided interventional catheterization. Ongoing investment and development of MRI-compatible guidewires will pave the way for MRI-guided diagnostic and interventional catheterization coming into the mainstream.
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An J, Webb AG, Shah DJ, Chin K, Tsekos NV. Manipulator-driven selection of semi-active MR-visible markers. Int J Med Robot 2017; 14. [PMID: 28660676 DOI: 10.1002/rcs.1846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 04/18/2017] [Accepted: 05/06/2017] [Indexed: 11/12/2022]
Abstract
BACKGROUND A method for the identification of semi-active fiducial magnetic resonance (MR) markers is presented based on selectively optically tuning and detuning them. METHODS Four inductively coupled solenoid coils with photoresistors were connected to light sources. A microcontroller timed the optical tuning/detuning of coils and image collection. The markers were tested on an MR manipulator linking the microcontroller to the manipulator control to visibly select the marker subset according to the actuated joint. RESULTS In closed-loop control, the average and maximum were 0.76° ± 0.41° and 1.18° errors for a rotational joint, and 0.87 mm ± 0.26 mm and 1.13 mm for the prismatic joint. CONCLUSIONS This technique is suitable for MR-compatible actuated devices that use semi-active MR-compatible markers.
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Affiliation(s)
- Junmo An
- Medical Robotics Laboratory, University of Houston, Houston, TX, USA
| | - Andrew G Webb
- C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Dipan J Shah
- Methodist DeBakey Cardiology Associates, Houston Methodist, Houston, TX, USA
| | - Karen Chin
- Methodist DeBakey Cardiology Associates, Houston Methodist, Houston, TX, USA
| | - Nikolaos V Tsekos
- Medical Robotics Laboratory, University of Houston, Houston, TX, USA
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Lingala SG, Zhu Y, Lim Y, Toutios A, Ji Y, Lo WC, Seiberlich N, Narayanan S, Nayak KS. Feasibility of through-time spiral generalized autocalibrating partial parallel acquisition for low latency accelerated real-time MRI of speech. Magn Reson Med 2017; 78:2275-2282. [PMID: 28185301 DOI: 10.1002/mrm.26611] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 12/08/2016] [Accepted: 12/27/2016] [Indexed: 12/11/2022]
Abstract
PURPOSE To evaluate the feasibility of through-time spiral generalized autocalibrating partial parallel acquisition (GRAPPA) for low-latency accelerated real-time MRI of speech. METHODS Through-time spiral GRAPPA (spiral GRAPPA), a fast linear reconstruction method, is applied to spiral (k-t) data acquired from an eight-channel custom upper-airway coil. Fully sampled data were retrospectively down-sampled to evaluate spiral GRAPPA at undersampling factors R = 2 to 6. Pseudo-golden-angle spiral acquisitions were used for prospective studies. Three subjects were imaged while performing a range of speech tasks that involved rapid articulator movements, including fluent speech and beat-boxing. Spiral GRAPPA was compared with view sharing, and a parallel imaging and compressed sensing (PI-CS) method. RESULTS Spiral GRAPPA captured spatiotemporal dynamics of vocal tract articulators at undersampling factors ≤4. Spiral GRAPPA at 18 ms/frame and 2.4 mm2 /pixel outperformed view sharing in depicting rapidly moving articulators. Spiral GRAPPA and PI-CS provided equivalent temporal fidelity. Reconstruction latency per frame was 14 ms for view sharing and 116 ms for spiral GRAPPA, using a single processor. Spiral GRAPPA kept up with the MRI data rate of 18ms/frame with eight processors. PI-CS required 17 minutes to reconstruct 5 seconds of dynamic data. CONCLUSION Spiral GRAPPA enabled 4-fold accelerated real-time MRI of speech with a low reconstruction latency. This approach is applicable to wide range of speech RT-MRI experiments that benefit from real-time feedback while visualizing rapid articulator movement. Magn Reson Med 78:2275-2282, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Sajan Goud Lingala
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
| | - Yinghua Zhu
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
| | - Yongwan Lim
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
| | - Asterios Toutios
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
| | - Yunhua Ji
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Wei-Ching Lo
- Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Nicole Seiberlich
- Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Shrikanth Narayanan
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
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Real-time imaging with radial GRAPPA: Implementation on a heterogeneous architecture for low-latency reconstructions. Magn Reson Imaging 2014; 32:747-58. [PMID: 24690453 DOI: 10.1016/j.mri.2014.02.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/11/2014] [Accepted: 02/14/2014] [Indexed: 11/23/2022]
Abstract
Combination of non-Cartesian trajectories with parallel MRI permits to attain unmatched acceleration rates when compared to traditional Cartesian MRI during real-time imaging. However, computationally demanding reconstructions of such imaging techniques, such as k-space domain radial generalized auto-calibrating partially parallel acquisitions (radial GRAPPA) and image domain conjugate gradient sensitivity encoding (CG-SENSE), lead to longer reconstruction times and unacceptable latency for online real-time MRI on conventional computational hardware. Though CG-SENSE has been shown to work with low-latency using a general purpose graphics processing unit (GPU), to the best of our knowledge, no such effort has been made for radial GRAPPA. Radial GRAPPA reconstruction, which is robust even with highly undersampled acquisitions, is not iterative, requiring only significant computation during initial calibration while achieving good image quality for low-latency imaging applications. In this work, we present a very fast, low-latency, reconstruction framework based on a heterogeneous system using multi-core CPUs and GPUs. We demonstrate an implementation of radial GRAPPA that permits reconstruction times on par with or faster than acquisition of highly accelerated datasets in both cardiac and dynamic musculoskeletal imaging scenarios. Acquisition and reconstruction times are reported.
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Brunner A, Groebner J, Umathum R, Maier F, Semmler W, Bock M. An MR-compatible stereoscopic in-room 3D display for MR-guided interventions. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2013; 27:277-82. [PMID: 24322339 DOI: 10.1007/s10334-013-0423-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/10/2013] [Accepted: 11/12/2013] [Indexed: 10/25/2022]
Abstract
BACKGROUND AND METHODS A commercial three-dimensional (3D) monitor was modified for use inside the scanner room to provide stereoscopic real-time visualization during magnetic resonance (MR)-guided interventions, and tested in a catheter-tracking phantom experiment at 1.5 T. Brightness, uniformity, radio frequency (RF) emissions and MR image interferences were measured. RESULTS AND DISCUSSION Due to modifications, the center luminance of the 3D monitor was reduced by 14%, and the addition of a Faraday shield further reduced the remaining luminance by 31%. RF emissions could be effectively shielded; only a minor signal-to-noise ratio (SNR) decrease of 4.6% was observed during imaging. During the tracking experiment, the 3D orientation of the catheter and vessel structures in the phantom could be visualized stereoscopically.
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Affiliation(s)
- Alexander Brunner
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany,
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O'Donnell M, McVeigh ER, Strauss HW, Tanaka A, Bouma BE, Tearney GJ, Guttman MA, Garcia EV. Multimodality cardiovascular molecular imaging technology. J Nucl Med 2010; 51 Suppl 1:38S-50S. [PMID: 20457794 DOI: 10.2967/jnumed.109.068155] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cardiovascular molecular imaging is a new discipline that integrates scientific advances in both functional imaging and molecular probes to improve our understanding of the molecular basis of the cardiovascular system. These advances are driven by in vivo imaging of molecular processes in animals, usually small animals, and are rapidly moving toward clinical applications. Molecular imaging has the potential to revolutionize the diagnosis and treatment of cardiovascular disease. The 2 key components of all molecular imaging systems are the molecular contrast agents and the imaging system providing spatial and temporal localization of these agents within the body. They must deliver images with the appropriate sensitivity and specificity to drive clinical applications. As work in molecular contrast agents matures and highly sensitive and specific probes are developed, these systems will provide the imaging technologies required for translation into clinical tools. This is the promise of molecular medicine.
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Schirra CO, Weiss S, Krueger S, Caulfield D, Pedersen SF, Razavi R, Kozerke S, Schaeffter T. Accelerated 3D catheter visualization from triplanar MR projection images. Magn Reson Med 2010; 64:167-76. [DOI: 10.1002/mrm.22370] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Linte CA, White J, Eagleson R, Guiraudon GM, Peters TM. Virtual and Augmented Medical Imaging Environments: Enabling Technology for Minimally Invasive Cardiac Interventional Guidance. IEEE Rev Biomed Eng 2010; 3:25-47. [DOI: 10.1109/rbme.2010.2082522] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Schirra CO, Weiss S, Krueger S, Pedersen SF, Razavi R, Schaeffter T, Kozerke S. Toward true 3D visualization of active catheters using compressed sensing. Magn Reson Med 2009; 62:341-7. [PMID: 19526499 DOI: 10.1002/mrm.22001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A crucial requirement in MR-guided interventions is the visualization of catheter devices in real time. However, true 3D visualization of the full length of catheters has hitherto been impossible given scan time constraints. Compressed sensing (CS) has recently been proposed as a method to accelerate MR imaging of sparse objects. Images acquired with active interventional devices exhibit a high CNR and are inherently sparse, therefore rendering CS ideally suited for accelerating data acquisition. A framework for true visualization of active catheters in 3D is proposed employing CS to gain high undersampling factors making real-time applications feasible. Constraints are introduced taking into account prior knowledge of catheter geometry and catheter motion over time to improve and accelerate image reconstruction. The potential of the method is demonstrated using computer simulations and phantom experiments and in vivo feasibility is demonstrated in a pig experiment.
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Affiliation(s)
- C O Schirra
- King's College London BHF Centre, Division of Imaging Sciences, NIHR Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, London, UK.
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15
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Kocaturk O, Kim AH, Saikus CE, Guttman MA, Faranesh AZ, Ozturk C, Lederman RJ. Active two-channel 0.035'' guidewire for interventional cardiovascular MRI. J Magn Reson Imaging 2009; 30:461-5. [PMID: 19629968 DOI: 10.1002/jmri.21844] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To develop an "active" (receiver-coil) clinical-grade guidewire with enhanced visibility for magnetic resonance imaging (MRI) and favorable mechanical characteristics for interventional MRI procedures that require conspicuous intravascular instruments distinguishable from surrounding tissues. MATERIALS AND METHODS We designed a 0.035-inch guidewire combining two antenna designs on separate channels. A loop antenna visualizes the tip and a dipole antenna visualizes the whole shaft. We compared mechanical characteristics of this guidewire with x-ray alternatives and tested MRI performance at 1.5T in vitro and in vivo in swine. RESULTS Images reflected tip position within 0.97 +/- 0.42 mm and afforded whole-shaft visibility under expected conditions without sacrificing device size or handling. We report tip stiffness, torquability, and pushability comparable to commercial interventional guidewires. CONCLUSION Our clinical-grade 0.035-inch active guidewire is conspicuous under MRI and has mechanical performance comparable to x-ray interventional guidewires. This may enable a range of interventional procedures using real-time MRI.
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Affiliation(s)
- Ozgur Kocaturk
- Translational Medicine Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1061, USA.
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16
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Ratnayaka K, Faranesh AZ, Guttman MA, Kocaturk O, Saikus CE, Lederman RJ. Interventional cardiovascular magnetic resonance: still tantalizing. J Cardiovasc Magn Reson 2008; 10:62. [PMID: 19114017 PMCID: PMC2637847 DOI: 10.1186/1532-429x-10-62] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 12/29/2008] [Indexed: 12/30/2022] Open
Abstract
The often touted advantages of MR guidance remain largely unrealized for cardiovascular interventional procedures in patients. Many procedures have been simulated in animal models. We argue these opportunities for clinical interventional MR will be met in the near future. This paper reviews technical and clinical considerations and offers advice on how to implement a clinical-grade interventional cardiovascular MR (iCMR) laboratory. We caution that this reflects our personal view of the "state of the art."
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Affiliation(s)
- Kanishka Ratnayaka
- Translational Medicine Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
- Cardiology Division, Children's National Medical Center, Washington, DC, USA
| | - Anthony Z Faranesh
- Translational Medicine Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael A Guttman
- Translational Medicine Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Ozgur Kocaturk
- Translational Medicine Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Christina E Saikus
- Translational Medicine Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert J Lederman
- Translational Medicine Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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17
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Guttman MA, Raval AN, Lederman RJ, McVeigh ER. Real-time catheter-directed MRA with effective background suppression and persistent rendering. J Magn Reson Imaging 2008; 28:538-42. [PMID: 18666149 DOI: 10.1002/jmri.21409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To develop an imaging and visualization technique for real-time magnetic resonance angiography (rtMRA) fully integrated with a real-time interactive imaging environment on a clinical MR scanner. MATERIALS AND METHODS Intraarterial injections of contrast agent and imaging processing techniques were employed for rapid catheter-directed assessment of vessel patency and regional tissue perfusion. Operators can image multiple thin slices to maximize anatomic detail or use thick slice or projection imaging to maximize vessel coverage. Techniques in both pulse sequence and image processing were employed to ensure background suppression. Accumulation of maximum pixel values allows persistent display of bolus signal as it passes through the vessels and into tissues. Automatic brightness adjustment was used to ensure visibility at all stages of bolus passage. RESULTS Experimental intraarterial rtMRA of coronary, renal, and carotid arteries show that vessel trajectories and perfusion territories are well visualized in swine. Switching between standard real-time imaging and rtMRA imaging after contrast injection was easy to perform during a procedure without stopping the scanner. CONCLUSION The proposed technique facilitates visualization of intraarterial contrast injections using real-time MRI. Although designed for rapid deployment during rtMRI-guided interventional procedures, the technique may also be useful to supplement the study of vessel anatomy, flow, or perfusion.
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Affiliation(s)
- Michael A Guttman
- Laboratory of Cardiac Energetics, National Institutes of Health, National Heart, Lung and Blood Institute, Bethesda, Maryland 20892-1061, USA.
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18
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Horvath KA, Li M, Mazilu D, Guttman MA, McVeigh ER. Real-time magnetic resonance imaging guidance for cardiovascular procedures. Semin Thorac Cardiovasc Surg 2008; 19:330-5. [PMID: 18395633 DOI: 10.1053/j.semtcvs.2007.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2007] [Indexed: 12/20/2022]
Abstract
Magnetic resonance imaging (MRI) of the cardiovascular system has proven to be an invaluable diagnostic tool. Given the ability to allow for real-time imaging, MRI guidance of intraoperative procedures can provide superb visualization, which can facilitate a variety of interventions and minimize the trauma of the operations as well. In addition to the anatomic detail, MRI can provide intraoperative assessment of organ and device function. Instruments and devices can be marked to enhance visualization and tracking, all of which is an advance over standard X-ray or ultrasonic imaging.
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Affiliation(s)
- Keith A Horvath
- Cardiothoracic Surgery Research Program, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD 20892, USA.
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19
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Kozerke S, Plein S. Accelerated CMR using zonal, parallel and prior knowledge driven imaging methods. J Cardiovasc Magn Reson 2008; 10:29. [PMID: 18534005 PMCID: PMC2426690 DOI: 10.1186/1532-429x-10-29] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 06/05/2008] [Indexed: 11/17/2022] Open
Abstract
Accelerated imaging is highly relevant for many CMR applications as competing constraints with respect to spatiotemporal resolution and tolerable scan times are frequently posed. Three approaches, all involving data undersampling to increase scan efficiencies, are discussed in this review. Zonal imaging can be considered a niche but nevertheless has found application in coronary imaging and CMR flow measurements. Current work on parallel-transmit systems is expected to revive the interest in zonal imaging techniques. The second and main approach to speeding up CMR sequences has been parallel imaging. A wide range of CMR applications has benefited from parallel imaging with reduction factors of two to three routinely applied for functional assessment, perfusion, viability and coronary imaging. Large coil arrays, as are becoming increasingly available, are expected to support reduction factors greater than three to four in particular in combination with 3D imaging protocols. Despite these prospects, theoretical work has indicated fundamental limits of coil encoding at clinically available magnetic field strengths. In that respect, alternative approaches exploiting prior knowledge about the object being imaged as such or jointly with parallel imaging have attracted considerable attention. Five to eight-fold scan accelerations in cine and dynamic CMR applications have been reported and image quality has been found to be favorable relative to using parallel imaging alone.With all acceleration techniques, careful consideration of the limits and the trade-off between acceleration and occurrence of artifacts that may arise if these limits are breached is required. In parallel imaging the spatially varying noise has to be considered when measuring contrast- and signal-to-noise ratios. Also, temporal fidelity in images reconstructed with prior knowledge driven methods has to be studied carefully.
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Affiliation(s)
- Sebastian Kozerke
- Institute for Biomedical Engineering, University of Zurich and Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Sven Plein
- Academic Unit of Cardiovascular Medicine, University of Leeds, Leeds, UK
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20
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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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21
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Guttman MA, Ozturk C, Raval AN, Raman VK, Dick AJ, DeSilva R, Karmarkar P, Lederman RJ, McVeigh ER. Interventional cardiovascular procedures guided by real-time MR imaging: an interactive interface using multiple slices, adaptive projection modes and live 3D renderings. J Magn Reson Imaging 2008; 26:1429-35. [PMID: 17968897 DOI: 10.1002/jmri.21199] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To develop and test a novel interactive real-time MRI environment that facilitates image-guided cardiovascular interventions. MATERIALS AND METHODS Color highlighting of device-mounted receiver coils, accelerated imaging of multiple slices, adaptive projection modes, live three-dimensional (3D) renderings and other interactive features were utilized to enhance navigation of devices and targeting of tissue. RESULTS Images are shown from several catheter-based interventional procedures performed in swine that benefit from this custom interventional MRI interface. These include endograft repair of aortic aneurysm, balloon septostomy of the cardiac interatrial septum, angioplasty and stenting, and endomyocardial cell injection, all using active catheters containing MRI receiver coils. CONCLUSION Interactive features not available on standard clinical scanners enhance real-time MRI for guiding cardiovascular interventional procedures.
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Affiliation(s)
- Michael A Guttman
- Laboratory of Cardiac Energetics, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1061, USA.
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22
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Celik H, Ulutürk A, Tali T, Atalar E. A catheter tracking method using reverse polarization for MR-guided interventions. Magn Reson Med 2008; 58:1224-31. [PMID: 18046701 DOI: 10.1002/mrm.21419] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To conduct interventional procedures in MRI, reliable visualization of interventional devices such as catheters is necessary. For this purpose, the use of inductively-coupled radio frequency (ICRF) coils has been proposed. Without a wired connection, the signal around the ICRF coil is amplified, enabling catheters to be visualized. The wireless connection allows easy handling of catheters, in some pulse sequences, however, it might be difficult to differentiate the catheters from anatomical background information. In this work, a novel ICRF coil visualization method, which allows separation of the catheter and the anatomical information by using the reverse and forward polarization modes of a coil, is proposed. This method allows images of the anatomy and the catheter to be combined into a color-coded image. First, an ICRF coil with decoupling diodes was constructed; we call this a receive-coupled RF (RCRF) coil. The RF safety profile of the RCRF coil is shown to be better than the ICRF coil. Second, to demonstrate the feasibility of this method, a receive-only birdcage coil without a hybrid coupler was constructed and then connected to a scanner as a two-channel phased-array coil. MR signals acquired from two channels were added after phase adjustments to create the reverse and forward polarization mode images. The reverse polarization mode image contained signal only from the RCRF coil, but the forward polarization mode displayed both anatomical information and the RCRF coil. The performance of this novel tracking method was tested in phantom and animal experiments. Color-coded images demonstrate the feasibility of the method to track catheters using RCRF coils.
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Affiliation(s)
- Haydar Celik
- Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
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23
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Raman VK, Lederman RJ. Interventional cardiovascular magnetic resonance imaging. Trends Cardiovasc Med 2007; 17:196-202. [PMID: 17662914 PMCID: PMC2291392 DOI: 10.1016/j.tcm.2007.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 05/01/2007] [Accepted: 05/03/2007] [Indexed: 11/26/2022]
Abstract
Magnetic resonance imaging provides structural and functional cardiovascular information with excellent soft tissue contrast. Real-time magnetic resonance imaging can guide transcatheter cardiovascular interventions in large animal models and may prove superior to x-ray and adjunct modalities for peripheral vascular, structural heart, and cardiac electrophysiology applications. We describe technical considerations, preclinical work, and early clinical studies in this emerging field.
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Affiliation(s)
- Venkatesh K Raman
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1538, USA
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24
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Sathyanarayana S, Aksit P, Arepally A, Karmarkar PV, Solaiyappan M, Atalar E. Tracking planar orientations of active MRI needles. J Magn Reson Imaging 2007; 26:386-91. [PMID: 17610285 DOI: 10.1002/jmri.20960] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To determine and track the planar orientation of active interventional devices without using localizing RF microcoils. MATERIALS AND METHODS An image-based tracking method that determines a device's orientation using projection images was developed. An automated and a manual detection scheme were implemented. The method was demonstrated in an in vivo mesocaval puncture procedure in swine, which required accurate orientation of an active transvascular needle catheter. RESULTS The plane of the catheter was determined using two projection images. The scan plane was adjusted automatically to follow the catheter plane, and its orientation with respect to a previously acquired target plane was displayed. The algorithm facilitated navigation for a fast and accurate puncture. CONCLUSION Using image-based techniques, with no mechanical design changes, the orientation of an active intravascular probe could be tracked.
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Affiliation(s)
- Shashank Sathyanarayana
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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25
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Raman VK, Lederman RJ. Advances in interventional cardiovascular MRI. CURRENT CARDIOVASCULAR RISK REPORTS 2007. [DOI: 10.1007/s12170-007-0050-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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26
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Kirchberg KJ, Wimmer A, Lorenz CH. Modeling the human aorta for MR-driven real-time virtual endoscopy. MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION : MICCAI ... INTERNATIONAL CONFERENCE ON MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION 2007; 9:470-7. [PMID: 17354924 DOI: 10.1007/11866565_58] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
As interventional magnetic resonance imaging (iMRI) is getting closer to clinical practice, new means of visualization and navigation are required. We present an approach to create a virtual endoscopic view inside the human aorta in real-time. In our approach, defined cross-sectional slices are acquired and segmented in a highly optimized fashion. A geometric shape model is fit to the segmentation points and continuously updated during the intervention. The physician can then view and navigate inside the structure to plan the intervention and get immediate feedback about the procedure. As a component of this system, this work focuses on the segmentation of the cross-sectional images and the fitting of the shape model. We present a real-time 2D segmentation implementation for this application domain and a model fitting scheme for a generalized cylinder (GC) model. For the latter we employ a new scheme for choosing the local reference frame.
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27
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Zhang S, Rafie S, Chen Y, Hillenbrand CM, Wacker FK, Duerk JL, Lewin JS. In vivo cardiovascular catheterization under real-time MRI guidance. J Magn Reson Imaging 2006; 24:914-7. [PMID: 16941633 DOI: 10.1002/jmri.20694] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To test the hypothesis that cardiac and coronary catheterization can be successfully performed under real-time MR guidance using a conventional x-ray angiographic catheter. MATERIALS AND METHODS Cardiac and coronary catheterization was conducted on eight farm pigs using a real-time True FISP sequence. A pigtail catheter was used for both left- and right-heart catheterizations performed on all eight animals, while an Amplatz or Judkins catheter was used for the right coronary catheterization that was attempted on five animals. The intravascular devices were visualized by means of their native susceptibility artifacts. For right coronary artery catheterizations, 25% diluted gadolinium (Gd) contrast material was injected to confirm engagement of the right coronary artery. RESULTS Cardiac catheterization of both the right- and left-heart chambers was successfully performed in all eight pigs. In addition, right coronary catheterization was successfully completed in four of the five pigs in which it was attempted. The procedure time for cardiac catheterization was one minute, while the time range required for coronary catheterization was 32-91 minutes. CONCLUSION This work demonstrates that MRI-guided cardiac catheterization using conventional X-ray angiographic catheters is feasible; however, coronary catheterization with this passive-tracking technique is limited.
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Affiliation(s)
- Shaoxiong Zhang
- Department of Radiology, University Hospitals of Cleveland, Cleveland, Ohio, USA.
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28
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Elgort DR, Hillenbrand CM, Zhang S, Wong EY, Rafie S, Lewin JS, Duerk JL. Image-guided and -monitored renal artery stenting using only MRI. J Magn Reson Imaging 2006; 23:619-27. [PMID: 16555228 DOI: 10.1002/jmri.20554] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To demonstrate the ability of a unique interventional MR system to be used safely and effectively as the only imaging modality for all phases of MR-guided stent-supported angioplasty. MATERIALS AND METHODS An experimental disease model of renal stenosis was created in six pigs. An interventional MR system, which employed previously reported tools for real-time catheter tracking with automated scan-plane positioning, adaptive image parameters, and radial true-FISP imaging with steady-state precession (True-FISP) imaging coupled with a high-speed reconstruction technique, was then used to guide all phases of the intervention, including: guidewire and catheter insertion, stent deployment, and confirmation of therapeutic success. Pre- and postprocedural X-ray imaging was used as a gold standard to validate the experimental results. RESULTS All of the stent-supported angioplasty interventions were a technical success and were performed without complications. The average postoperative residual stenosis was 14.9%. The image guidance enabled the stents to be deployed with an accuracy of 0.98 +/- 0.69 mm. Additionally, using this interventional MRI system to guide renal artery stenting significantly reduces the procedure time, as compared to using X-ray fluoroscopy. CONCLUSION This study has clearly demonstrated the first successful treatment of renal artery stenting in an experimental animal model solely under MRI guidance and monitoring.
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Affiliation(s)
- Daniel R Elgort
- Department of Radiology, University Hospitals of Cleveland, Cleveland, Ohio 044106, USA
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29
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Abstract
Because of its superior soft tissue imaging, MRI has become a valuable diagnostic tool in cardiovascular disease. These strengths make MRI attractive to guide therapeutic catheter-based procedures, both conventional and novel. We review how to configure an interventional MRI suite, how MRI catheter devices differ from conventional radiographic catheters, and finally developments in preclinical and investigational clinical applications.
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Affiliation(s)
- Venkatesh K Raman
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1538, USA
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30
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Raval AN, Karmarkar PV, Guttman MA, Ozturk C, DeSilva R, Aviles RJ, Wright VJ, Schenke WH, Atalar E, McVeigh ER, Lederman RJ. Real-time MRI guided atrial septal puncture and balloon septostomy in swine. Catheter Cardiovasc Interv 2006; 67:637-43. [PMID: 16532499 PMCID: PMC1463249 DOI: 10.1002/ccd.20579] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cardiac perforation during atrial septal puncture (ASP) might be avoided by improved image guidance. X-ray fluoroscopy (XRF), which guides ASP, visualizes tissue poorly and does not convey depth information. Ultrasound is limited by device shadows and constrained imaging windows. Alternatively, real-time MRI (rtMRI) provides excellent tissue contrast in any orientation and may enable ASP and balloon atrial septostomy (BAS) in swine. Custom MRI catheters incorporated "active" (receiver antenna) and "passive" (iron or gadolinium) elements. Wholly rtMRI-guided transfemoral ASP and BAS were performed in 10 swine in a 1.5T interventional suite. Hemodynamic results were measured with catheters and velocity encoded MRI. Successful ASP was performed in all 10 animals. Necropsy confirmed septostomy confined within the fossa ovalis in all. BAS was successful in 9/10 animals. Antenna failure in a re-used needle led to inadvertent vena cava tear prior to BAS in 1 animal. ASP in the same animal was easily performed using a new needle. rtMRI illustrated clear device-tissue-lumen relationships in multiple orientations, and facilitated simple ASP and BAS. The mean procedure time was 19 +/- 10 minutes. Septostomy achieved a mean left to right shunt ratio of 1.3:1 in these healthy animals. Interactive rtMRI permits rapid transcatheter ASP and BAS in swine. Further technical development may enable novel applications.
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Affiliation(s)
- Amish N. Raval
- From the Cardiovascular Branch (ANR, PVK, CO, RDS, RJA, VJW, WHS, RJL) and the
| | - Parag V. Karmarkar
- From the Cardiovascular Branch (ANR, PVK, CO, RDS, RJA, VJW, WHS, RJL) and the
- Department of Radiology, The Johns Hopkins University, Baltimore, MD, USA
| | - Michael A. Guttman
- Laboratory of Cardiac Energetics (MAG, ERM), Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA; and
| | - Cengizhan Ozturk
- From the Cardiovascular Branch (ANR, PVK, CO, RDS, RJA, VJW, WHS, RJL) and the
| | - Ranil DeSilva
- From the Cardiovascular Branch (ANR, PVK, CO, RDS, RJA, VJW, WHS, RJL) and the
| | - Ronnier J. Aviles
- From the Cardiovascular Branch (ANR, PVK, CO, RDS, RJA, VJW, WHS, RJL) and the
| | - Victor J. Wright
- From the Cardiovascular Branch (ANR, PVK, CO, RDS, RJA, VJW, WHS, RJL) and the
| | - William H. Schenke
- From the Cardiovascular Branch (ANR, PVK, CO, RDS, RJA, VJW, WHS, RJL) and the
| | - Ergin Atalar
- Department of Radiology, The Johns Hopkins University, Baltimore, MD, USA
| | - Elliot R. McVeigh
- Laboratory of Cardiac Energetics (MAG, ERM), Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA; and
| | - Robert J. Lederman
- From the Cardiovascular Branch (ANR, PVK, CO, RDS, RJA, VJW, WHS, RJL) and the
- Address for Correspondence: Robert J. Lederman, MD, 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. Telephone: 1-301-402-6769.
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31
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Abstract
Dynamic changes in cardiac structure and function are usually examined by real-time imaging techniques such as angiography or echocardiography. MRI has many advantages compared with these established cardiac imaging modalities. However, system hardware and software limitations have limited cardiac MRI to gated acquisitions that are lengthy and often result in failed acquisitions and examinations. Recently, MRI has evolved into a technique capable of imaging dynamic processes in real time. Improvements in hardware, pulse sequences, and image reconstruction algorithms have enabled real-time cardiac MRI with high spatial resolution, high temporal resolution, and various types of image contrast without requiring cardiac gating or breath-holding. This article provides an overview of current capability and highlights key technical and clinical advances. The future prospects of real-time cardiac MRI will depend on 1) the development of techniques that further improve signal to noise ratio, contrast, spatial resolution, and temporal resolution, without introducing artifacts; 2) the development of software infrastructure that facilitates rapid interactive examination; and 3) the development and validation of several new clinical assessments.
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Affiliation(s)
- Krishna S Nayak
- Electrical Engineering-Systems, 3740 McClintock Avenue, EEB 406, University of Southern California, Los Angeles, CA 90089-2564, USA.
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32
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Graham JJ, Lederman RJ, Dick AJ. Magnetic resonance imaging and its role in myocardial regenerative therapy. Regen Med 2006; 1:347-55. [PMID: 17465788 DOI: 10.2217/17460751.1.3.347] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
There has been extensive interest recently in cardiac stem cell therapy. Current research has been hampered by differences in cell type, methods of delivery and efficacy evaluation. In this article we review the use of magnetic resonance imaging in this growing area and argue that it is well suited to all areas of myocardial regeneration: from patient identification, through cell delivery and tracking of appropriately labeled cells, to evaluation of therapeutic effect. Potential future advances are discussed including magnetic resonance imaging-guided intervention suites and the use of higher field strength magnets for cell tracking.
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Affiliation(s)
- John J Graham
- Division of Cardiology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
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33
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Affiliation(s)
- Alexander J Dick
- Cardiovascular Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1538, USA
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Affiliation(s)
- Robert J Lederman
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1538, USA.
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Raval AN, Karmarkar PV, Guttman MA, Ozturk C, Sampath S, DeSilva R, Aviles RJ, Xu M, Wright VJ, Schenke WH, Kocaturk O, Dick AJ, Raman VK, Atalar E, McVeigh ER, Lederman RJ. Real-time magnetic resonance imaging-guided endovascular recanalization of chronic total arterial occlusion in a swine model. Circulation 2006; 113:1101-7. [PMID: 16490819 PMCID: PMC1428785 DOI: 10.1161/circulationaha.105.586727] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Endovascular recanalization (guidewire traversal) of peripheral artery chronic total occlusion (CTO) can be challenging. X-ray angiography resolves CTO poorly. Virtually "blind" device advancement during x-ray-guided interventions can lead to procedure failure, perforation, and hemorrhage. Alternatively, MRI may delineate the artery within the occluded segment to enhance procedural safety and success. We hypothesized that real-time MRI (rtMRI)-guided CTO recanalization can be accomplished in an animal model. METHODS AND RESULTS Carotid artery CTO was created by balloon injury in 19 lipid-overfed swine. After 6 to 8 weeks, 2 underwent direct necropsy analysis for histology, 3 underwent primary x-ray-guided CTO recanalization attempts, and the remaining 14 underwent rtMRI-guided recanalization attempts in a 1.5-T interventional MRI system. Real-time MRI intervention used custom CTO catheters and guidewires that incorporated MRI receiver antennae to enhance device visibility. The mean length of the occluded segments was 13.3+/-1.6 cm. The rtMRI-guided CTO recanalization was successful in 11 of 14 swine and in only 1 of 3 swine with the use of x-ray alone. After unsuccessful rtMRI (n=3), x-ray-guided attempts were also unsuccessful. CONCLUSIONS Recanalization of long CTO is entirely feasible with the use of rtMRI guidance. Low-profile clinical-grade devices will be required to translate this experience to humans.
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Affiliation(s)
- Amish N Raval
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1538, USA
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Abstract
Magnetic resonance imaging (MRI), which provides superior soft-tissue imaging and no known harmful effects, has the potential as an alternative modality to guide various medical interventions. This review will focus on MR-guided endovascular interventions and present its current state and future outlook. In the first technical part, enabling technologies such as developments in fast imaging, catheter devices, and visualization techniques are examined. This is followed by a clinical survey that includes proof-of-concept procedures in animals and initial experience in human subjects. In preclinical experiments, MRI has already proven to be valuable. For example, MRI has been used to guide and track targeted cell delivery into or around myocardial infarctions, to guide atrial septal puncture, and to guide the connection of portal and systemic venous circulations. Several investigational MR-guided procedures have already been reported in patients, such as MR-guided cardiac catheterization, invasive imaging of peripheral artery atheromata, selective intraarterial MR angiography, and preliminary angioplasty and stent placement. In addition, MR-assisted transjugular intrahepatic portosystemic shunt procedures in patients have been shown in a novel hybrid double-doughnut x-ray/MRI system. Numerous additional investigational human MR-guided endovascular procedures are now underway in several medical centers around the world. There are also significant hurdles: availability of clinical-grade devices, device-related safety issues, challenges to patient monitoring, and acoustic noise during imaging. The potential of endovascular interventional MRI is great because as a single modality, it combines 3-dimensional anatomic imaging, device localization, hemodynamics, tissue composition, and function.
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Affiliation(s)
- Cengizhan Ozturk
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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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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McVeigh ER, Guttman MA, Kellman P, Raval AN, Lederman RJ. Real-time, Interactive MRI for cardiovascular interventions. Acad Radiol 2005; 12:1121-7. [PMID: 16112512 PMCID: PMC2169205 DOI: 10.1016/j.acra.2005.05.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 05/29/2005] [Accepted: 02/15/2005] [Indexed: 11/25/2022]
Affiliation(s)
- Elliot R McVeigh
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room B1D416, Bethesda, MD 20892-106, USA.
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Raval AN, Telep JD, Guttman MA, Ozturk C, Jones M, Thompson RB, Wright VJ, Schenke WH, DeSilva R, Aviles RJ, Raman VK, Slack MC, Lederman RJ. Real-time magnetic resonance imaging-guided stenting of aortic coarctation with commercially available catheter devices in Swine. Circulation 2005; 112:699-706. [PMID: 16043639 PMCID: PMC1513629 DOI: 10.1161/circulationaha.105.542647] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Real-time MR imaging (rtMRI) is now technically capable of guiding catheter-based cardiovascular interventions. Compared with x-ray, rtMRI offers superior tissue imaging in any orientation without ionizing radiation. Translation to clinical trials has awaited the availability of clinical-grade catheter devices that are both MRI visible and safe. We report a preclinical safety and feasibility study of rtMRI-guided stenting in a porcine model of aortic coarctation using only commercially available catheter devices. METHOD AND RESULTS Coarctation stenting was performed wholly under rtMRI guidance in 13 swine. rtMRI permitted procedure planning, device tracking, and accurate stent deployment. "Active" guidewires, incorporating MRI antennas, improved device visualization compared with unmodified "passive" nitinol guidewires and shortened procedure time (26+/-11 versus 106+/-42 minutes; P=0.008). Follow-up catheterization and necropsy showed accurate stent deployment, durable gradient reduction, and appropriate neointimal formation. MRI immediately identified aortic rupture when oversized devices were tested. CONCLUSIONS This experience demonstrates preclinical safety and feasibility of rtMRI-guided aortic coarctation stenting using commercially available catheter devices. Patients may benefit from rtMRI in the future because of combined device and tissue imaging, freedom from ionizing radiation, and the ability to identify serious complications promptly.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Robert J. Lederman
- Correspondence to Robert J. Lederman, MD, Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bldg 10, Room 2c713, MSC 1538, Bethesda, MD 20892–1538. E-mail
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Raman VK, Karmarkar PV, Guttman MA, Dick AJ, Peters DC, Ozturk C, Pessanha BSS, Thompson RB, Raval AN, DeSilva R, Aviles RJ, Atalar E, McVeigh ER, Lederman RJ. Real-time magnetic resonance-guided endovascular repair of experimental abdominal aortic aneurysm in swine. J Am Coll Cardiol 2005; 45:2069-77. [PMID: 15963411 PMCID: PMC1317097 DOI: 10.1016/j.jacc.2005.03.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2004] [Revised: 02/20/2005] [Accepted: 03/01/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES This study tested the hypotheses that endografts can be visualized and navigated in vivo solely under real-time magnetic resonance imaging (rtMRI) guidance to repair experimental abdominal aortic aneurysms (AAA) in swine, and that MRI can provide immediate assessment of endograft apposition and aneurysm exclusion. BACKGROUND Endovascular repair for AAA is limited by endoleak caused by inflow or outflow malapposition. The ability of rtMRI to image soft tissue and flow may improve on X-ray guidance of this procedure. METHODS Infrarenal AAA was created in swine by balloon overstretch. We used one passive commercial endograft, imaged based on metal-induced MRI artifacts, and several types of homemade active endografts, incorporating MRI receiver coils (antennae). Custom interactive rtMRI features included color coding the catheter-antenna signals individually, simultaneous multislice imaging, and real-time three-dimensional rendering. RESULTS Eleven repairs were performed solely using rtMRI, simultaneously depicting the device and soft-tissue pathology during endograft deployment. Active devices proved most useful. Intraprocedural MRI provided anatomic confirmation of stent strut apposition and functional corroboration of aneurysm exclusion and restoration of laminar flow in successful cases. In two cases, there was clear evidence of contrast accumulation in the aneurysm sac, denoting endoleak. CONCLUSIONS Endovascular AAA repair is feasible under rtMRI guidance. Active endografts facilitate device visualization and complement the soft tissue contrast afforded by MRI for precise positioning and deployment. Magnetic resonance imaging also permits immediate post-procedural anatomic and functional evaluation of successful aneurysm exclusion.
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Affiliation(s)
| | - Parag V. Karmarkar
- From the Cardiovascular Branch and the
- Laboratory of Cardiac Energetics, Division of Intramural Research, National Heart, Lung, and Blood Institute, Bethesda, Maryland; and the
| | - Michael A. Guttman
- Laboratory of Cardiac Energetics, Division of Intramural Research, National Heart, Lung, and Blood Institute, Bethesda, Maryland; and the
| | | | - Dana C. Peters
- Laboratory of Cardiac Energetics, Division of Intramural Research, National Heart, Lung, and Blood Institute, Bethesda, Maryland; and the
| | | | | | - Richard B. Thompson
- Laboratory of Cardiac Energetics, Division of Intramural Research, National Heart, Lung, and Blood Institute, Bethesda, Maryland; and the
| | | | | | | | - Ergin Atalar
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland. Supported by NIH Z01-HL005062-01CVB (to Dr. Lederman). Drs. Raman and Karmarkar contributed equally to this work
| | - Elliot R. McVeigh
- Laboratory of Cardiac Energetics, Division of Intramural Research, National Heart, Lung, and Blood Institute, Bethesda, Maryland; and the
| | - Robert J. Lederman
- From the Cardiovascular Branch and the
- Reprint requests and correspondence: Dr. Robert J. Lederman, Cardiovascular Branch, Clinical Research Program, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2c713, Bethesda, Maryland 20892-1538. E-mail:
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Dick AJ, Raman VK, Raval AN, Guttman MA, Thompson RB, Ozturk C, Peters DC, Stine AM, Wright VJ, Schenke WH, Lederman RJ. Invasive human magnetic resonance imaging: feasibility during revascularization in a combined XMR suite. Catheter Cardiovasc Interv 2005; 64:265-74. [PMID: 15736247 PMCID: PMC1317610 DOI: 10.1002/ccd.20302] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We tested the feasibility and safety of invasive magnetic resonance imaging (MRI) during peripheral angioplasty. Real-time MRI can image soft tissue and may potentially guide therapeutic procedures without ionizing radiation or nephrotoxic contrast. MRI-guided diagnostic catheterization has been described recently, but safe and conspicuous catheter devices are not widely available. An active guidewire, which serves as an MRI receiver antenna, might be useful to guide catheterization or even to image atheroma. We describe a combined interventional suite offering both X-ray fluoroscopy and real-time MRI. We used a 0.030'' active guidewire receiver coil for invasive MRI after X-ray lesion traversal in patients undergoing percutaneous iliofemoral artery revascularization. Intravascular MRI was compared with noninvasive MRI, X-ray angiography, and intravascular ultrasound (IVUS). Seven eligible patients consented to participate, but three were excluded because of lengthy revascularization procedures. Four remaining patients safely underwent combined X-ray fluoroscopy and real-time magnetic resonance imaging (XMR) transport, continuous monitoring, and all imaging modalities. There was no device dislodgment, contamination or evidence of heating. The intravascular MRI coil was well visualized except at the tip, but did not provide superior mural imaging compared with IVUS. Therefore, because an adequate safety and workflow experience was obtained, enrollment was terminated after only four subjects. Invasive MRI is feasible and apparently safe during peripheral angioplasty. Patients can safely be transported and monitored in an XMR interventional suite. An active quarter-wavelength guidewire coil does not provide superior imaging compared with IVUS, but provides satisfactory guidewire visualization. These tools may prove useful for advanced therapeutic procedures in the future.
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Affiliation(s)
- Alexander J. Dick
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Venkatesh K. Raman
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Amish N. Raval
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | | | - Richard B. Thompson
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Cengizhan Ozturk
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Dana C. Peters
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Annette M. Stine
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Victor J. Wright
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - William H. Schenke
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Robert J. Lederman
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland
- *Correspondence to: Dr. Robert J. Lederman, 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. E-mail:
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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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Peters DC, Guttman MA, Dick AJ, Raman VK, Lederman RJ, McVeigh ER. Reduced field of view and undersampled PR combined for interventional imaging of a fully dynamic field of view. Magn Reson Med 2004; 51:761-7. [PMID: 15065249 PMCID: PMC2034278 DOI: 10.1002/mrm.20037] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Active catheter imaging was investigated using real-time undersampled projection reconstruction (PR) combined with the temporal filtering technique of reduced field of view (rFOV). Real-time rFOV processing was interactively enabled during highly undersampled catheter imaging, resulting in improved artifact suppression with better temporal resolution than that obtained by view-sharing. Imaging with 64 to 32 projections provided a resolution of 2 x 2 x 8 mm, and four to eight true frames per second. Image artifacts were reduced when rFOV processing was applied to the undersampled images. A comparison with Cartesian rFOV showed that PR image quality is less susceptible to aliasing that results from rFOV imaging with a wholly dynamic outer FOV. Simulations and MRI experiments demonstrated that PR rFOV provides significant artifact suppression, even for a fully dynamic FOV. The near doubling of temporal resolution that is possible with PR rFOV permits accurate monitoring of highly dynamic events, such as catheter movements, and arrhythmias, such as ventricular ectopy.
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Affiliation(s)
- Dana C Peters
- Laboratory of Cardiac Energetics, NHLBI, National Institutes of Health, DHHS, Bethesda, Maryland, USA.
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Dick AJ, Guttman MA, Raman VK, Peters DC, Pessanha BS, Hill JM, Smith S, Scott G, McVeigh ER, Lederman RJ. Magnetic resonance fluoroscopy allows targeted delivery of mesenchymal stem cells to infarct borders in Swine. Circulation 2003; 108:2899-904. [PMID: 14656911 PMCID: PMC1325104 DOI: 10.1161/01.cir.0000095790.28368.f9] [Citation(s) in RCA: 184] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND The local environment of delivered mesenchymal stem cells (MSCs) may affect their ultimate phenotype. MR fluoroscopy has the potential to guide intramyocardial MSC injection to desirable targets, such as the border between infarcted and normal tissue. We tested the ability to (1) identify infarcts, (2) navigate injection catheters to preselected targets, (3) inject safely even into fresh infarcts, and (4) confirm injection success immediately. METHODS AND RESULTS A 1.5-T MRI scanner was customized for interventional use, with rapid imaging, independent color highlighting of catheter channels, multiple-slice 3D rendering, catheter-only viewing mode, and infarct-enhanced imaging. MRI receiver coils were incorporated into guiding catheters and injection needles. These devices were tested for heating and used for targeted MSC delivery. In infarcted pigs, myocardium was targeted by MR fluoroscopy. Infarct-enhanced imaging included both saturation preparation MRI after intravenous gadolinium and wall motion. Porcine MSCs were MRI-labeled with iron-fluorescent particles. Catheter navigation and multiple cell injections were performed entirely with MR fluoroscopy at 8 frames/s with 1.7x3.3x8-mm voxels. Infarct-enhanced MR fluoroscopy permitted excellent delineation of infarct borders. All injections were safely and successfully delivered to their preselected targets, including infarct borders. Iron-fluorescent particle-labeled MSCs were readily visible on delivery in vivo and post mortem. CONCLUSIONS Precise targeted delivery of potentially regenerative cellular treatments to recent myocardial infarction borders is feasible with an MR catheter delivery system. MR fluoroscopy permits visualization of catheter navigation, myocardial function, infarct borders, and labeled cells after injection.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Robert J. Lederman
- Correspondence to Robert J. Lederman, MD, Cardiovascular Branch, Clinical Research Program, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2c713, Bethesda, MD 20892-1538. E-mail
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Guttman MA, Kellman P, Dick AJ, Lederman RJ, McVeigh ER. Real-time accelerated interactive MRI with adaptive TSENSE and UNFOLD. Magn Reson Med 2003; 50:315-21. [PMID: 12876708 PMCID: PMC2034320 DOI: 10.1002/mrm.10504] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Reduced field-of-view (FOV) acceleration using time-adaptive sensitivity encoding (TSENSE) or unaliasing by Fourier encoding the overlaps using the temporal dimension (UNFOLD) can improve the depiction of motion in real-time MRI. However, increased computational resources are required to maintain a high frame rate and low latency in image reconstruction and display. A high-performance software system has been implemented to perform TSENSE and UNFOLD reconstructions for real-time MRI with interactive, on-line display. Images were displayed in the scanner room to investigate image-guided procedures. Examples are shown for normal volunteers and cardiac interventional experiments in animals using a steady-state free precession (SSFP) sequence. In order to maintain adequate image quality for interventional procedures, the imaging rate was limited to seven frames per second after an acceleration factor of 2 with a voxel size of 1.8 x 3.5 x 8 mm. Initial experiences suggest that TSENSE and UNFOLD can each improve the compromise between spatial and temporal resolution in real-time imaging, and can function well in interactive imaging. UNFOLD places no additional constraints on receiver coils, and is therefore more flexible than SENSE methods; however, the temporal image filtering can blur motion and reduce the effective acceleration. Methods are proposed to overcome the challenges presented by the use of TSENSE in interactive imaging. TSENSE may be temporarily disabled after changing the imaging plane to avoid transient artifacts as the sensitivity coefficients adapt. For imaging with a combination of surface and interventional coils, a hybrid reconstruction approach is proposed whereby UNFOLD is used for the interventional coils, and TSENSE with or without UNFOLD is used for the surface coils.
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Affiliation(s)
- Michael A Guttman
- Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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