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Klaassen L, Haasjes C, Hol M, Cambraia Lopes P, Spruijt K, van de Steeg-Henzen C, Vu K, Bakker P, Rasch C, Verbist B, Beenakker JW. Geometrical accuracy of magnetic resonance imaging for ocular proton therapy planning. Phys Imaging Radiat Oncol 2024; 31:100598. [PMID: 38993288 PMCID: PMC11234150 DOI: 10.1016/j.phro.2024.100598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 07/13/2024] Open
Abstract
Background & purpose Magnetic resonance imaging (MRI) is increasingly used in treatment preparation of ocular proton therapy, but its spatial accuracy might be limited by geometric distortions due to susceptibility artefacts. A correct geometry of the MR images is paramount since it defines where the dose will be delivered. In this study, we assessed the geometrical accuracy of ocular MRI. Materials & methods A dedicated ocular 3 T MRI protocol, with localized shimming and increased gradients, was compared to computed tomography (CT) and X-ray images in a phantom and in 15 uveal melanoma patients. The MRI protocol contained three-dimensional T2-weighted and T1-weighted sequences with an isotropic reconstruction resolution of 0.3-0.4 mm. Tantalum clips were identified by three observers and clip-clip distances were compared between T2-weighted and T1-weighted MRI, CT and X-ray images for the phantom and between MRI and X-ray images for the patients. Results Interobserver variability was below 0.35 mm for the phantom and 0.30(T1)/0.61(T2) mm in patients. Mean absolute differences between MRI and reference were below 0.27 ± 0.16 mm and 0.32 ± 0.23 mm for the phantom and in patients, respectively. In patients, clip-clip distances were slightly larger on MRI than on X-ray images (mean difference T1: 0.11 ± 0.38 mm, T2: 0.10 ± 0.44 mm). Differences did not increase at larger distances and did not correlate to interobserver variability. Conclusions A dedicated ocular MRI protocol can produce images of the eye with a geometrical accuracy below half the MRI acquisition voxel (<0.4 mm). Therefore, these images can be used for ocular proton therapy planning, both in the current model-based workflow and in proposed three-dimensional MR-based workflows.
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Affiliation(s)
- Lisa Klaassen
- Leiden University Medical Center, Department of Ophthalmology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
| | - Corné Haasjes
- Leiden University Medical Center, Department of Ophthalmology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
| | - Martijn Hol
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | | | | | - Christal van de Steeg-Henzen
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Khanh Vu
- Leiden University Medical Center, Department of Ophthalmology, Leiden, the Netherlands
| | - Pauline Bakker
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Coen Rasch
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Berit Verbist
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Jan-Willem Beenakker
- Leiden University Medical Center, Department of Ophthalmology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
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Su H, Kwok KW, Cleary K, Iordachita I, Cavusoglu MC, Desai JP, Fischer GS. State of the Art and Future Opportunities in MRI-Guided Robot-Assisted Surgery and Interventions. PROCEEDINGS OF THE IEEE. INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS 2022; 110:968-992. [PMID: 35756185 PMCID: PMC9231642 DOI: 10.1109/jproc.2022.3169146] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Magnetic resonance imaging (MRI) can provide high-quality 3-D visualization of target anatomy, surrounding tissue, and instrumentation, but there are significant challenges in harnessing it for effectively guiding interventional procedures. Challenges include the strong static magnetic field, rapidly switching magnetic field gradients, high-power radio frequency pulses, sensitivity to electrical noise, and constrained space to operate within the bore of the scanner. MRI has a number of advantages over other medical imaging modalities, including no ionizing radiation, excellent soft-tissue contrast that allows for visualization of tumors and other features that are not readily visible by other modalities, true 3-D imaging capabilities, including the ability to image arbitrary scan plane geometry or perform volumetric imaging, and capability for multimodality sensing, including diffusion, dynamic contrast, blood flow, blood oxygenation, temperature, and tracking of biomarkers. The use of robotic assistants within the MRI bore, alongside the patient during imaging, enables intraoperative MR imaging (iMRI) to guide a surgical intervention in a closed-loop fashion that can include tracking of tissue deformation and target motion, localization of instrumentation, and monitoring of therapy delivery. With the ever-expanding clinical use of MRI, MRI-compatible robotic systems have been heralded as a new approach to assist interventional procedures to allow physicians to treat patients more accurately and effectively. Deploying robotic systems inside the bore synergizes the visual capability of MRI and the manipulation capability of robotic assistance, resulting in a closed-loop surgery architecture. This article details the challenges and history of robotic systems intended to operate in an MRI environment and outlines promising clinical applications and associated state-of-the-art MRI-compatible robotic systems and technology for making this possible.
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Affiliation(s)
- Hao Su
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695 USA
| | - Ka-Wai Kwok
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong
| | - Kevin Cleary
- Children's National Health System, Washington, DC 20010 USA
| | - Iulian Iordachita
- Laboratory for Computational Sensing and Robotics (LCSR), Johns Hopkins University, Baltimore, MD 21218 USA
| | - M Cenk Cavusoglu
- Department of Electrical, Computer, and Systems Engineering, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Jaydev P Desai
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA
| | - Gregory S Fischer
- Department of Robotics Engineering, Worcester Polytechnic Institute, Worcester, MA 01609 USA
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Brujic D, Chappell KE, Ristic M. Accuracy of collagen fibre estimation under noise using directional MR imaging. Comput Med Imaging Graph 2020; 86:101796. [PMID: 33069034 PMCID: PMC7721590 DOI: 10.1016/j.compmedimag.2020.101796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/29/2020] [Accepted: 09/24/2020] [Indexed: 11/24/2022]
Abstract
In tissues containing significant amounts of organised collagen, such as tendons, ligaments, menisci and articular cartilage, MR imaging exhibits a strong signal intensity variation caused by the angle between the collagen fibres and the magnetic field. By obtaining scans at different field orientations it is possible to determine the unknown fibre orientations and to deduce the underlying tissue microstructure. Our previous work demonstrated how this method can detect ligament injuries and maturity-related changes in collagen fibre structures. Practical application in human diagnostics will demand minimisation of scanning time and likely use of open low-field scanners that can allow re-orienting of the main field. This paper analyses the performance of collage fibre estimation for various image SNR values, and in relation to key parameters including number of scanning directions and parameters of the reconstruction algorithm. The analysis involved Monte Carlo simulation studies which provided benchmark performance measures, and studies using MR images of caprine knee samples with increasing levels of synthetic added noise. Tractography plots in the form of streamlines were performed, and an Alignment Index (AI) was employed as a measure of the detected orientation distribution. The results are highly encouraging, showing high accuracy and robustness even for low image SNR values.
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Affiliation(s)
- Djordje Brujic
- Mechanical Engineering Department, Imperial College London, London, UK
| | - Karyn E Chappell
- MSK Lab, Department of Surgery and Cancer, Imperial College London, UK
| | - Mihailo Ristic
- Mechanical Engineering Department, Imperial College London, London, UK.
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Ohliger MA, Gordon JW, Carvajal L, Larson PEZ, Ou JJ, Agarwal S, Zhu Z, Vigneron DB, von Morze C. 55 Mn-based fiducial markers for rapid and automated RF coil localization for hyperpolarized 13 C MRI. Magn Reson Med 2020; 85:518-530. [PMID: 32738073 DOI: 10.1002/mrm.28424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 06/22/2020] [Indexed: 12/24/2022]
Abstract
PURPOSE To use fiducial markers containing manganese 55 to rapidly localize carbon 13 (13 C) RF coils for correcting images for B1 variation. METHODS Hollow high-density polyethylene spheres were filled with 3M sodium permanganate and affixed to a rectangular 13 C-tuned RF coil. The relative positions of the markers and coil conductors were mapped using CT. Marker positions were measured by MRI using a series of 1D projections and automated peak detection. Once the coil location was determined, coil sensitivity was estimated using a quasi-static calculation. Simulations were performed to determine the minimum number of projections required for robust localization. Phantom experiments were used to confirm the accuracy of marker localization as well as the calculated coil sensitivity. Finally, in vivo validation was performed using hyperpolarized 13 C pyruvate in a rat model. RESULTS In simulations, our algorithm was accurate in determining marker positions when at least 6 projections were used (RMSE 1.4 ± 0.9 mm). These estimates were verified in phantom experiments, where markers locations were determined with an RMS accuracy of 1.3 mm. A minimum SNR of 4 was required for automated detection to perform accurately. Computed coil sensitivity had a median error of 17% when taken over the entire measured area and 5.7% over a central region. In a rat, correction for nonuniform reception and flip angle was able to normalize the signals arising from asymmetrically positioned kidneys. CONCLUSION Manganese 55 fiducial markers are an inexpensive and reliable method for rapidly localizing 13 C RF coils and correcting 13 C images for B1 variation without user intervention.
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Affiliation(s)
- Michael A Ohliger
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Jeremy W Gordon
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Lucas Carvajal
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Jao J Ou
- Department of Radiology, Wake Forest School of Medicine, Winston Salem, North Carolina, USA
| | - Shubhangi Agarwal
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Zihan Zhu
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Cornelius von Morze
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri, USA
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Chappell KE, Brujic D, Van Der Straeten C, Meeson R, Gedroyc W, McRobbie D, Ristic M. Detection of maturity and ligament injury using magic angle directional imaging. Magn Reson Med 2019; 82:1041-1054. [PMID: 31081201 DOI: 10.1002/mrm.27794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/10/2019] [Accepted: 04/10/2019] [Indexed: 01/14/2023]
Abstract
PURPOSE To investigate whether magnetic field-related anisotropies of collagen may be correlated with postmortem findings in animal models. METHODS Optimized scan planning and new MRI data-processing methods were proposed and analyzed using Monte Carlo simulations. Six caprine and 10 canine knees were scanned at various orientations to the main magnetic field. Image intensities in segmented voxels were used to compute the orientation vectors of the collagen fibers. Vector field and tractography plots were computed. The Alignment Index was defined as a measure of orientation distribution. The knees were subsequently assessed by a specialist orthopedic veterinarian, who gave a pathological diagnosis after having dissected and photographed the joints. RESULTS Using 50% less scans than reported previously can lead to robust calculation of fiber orientations in the presence of noise, with much higher accuracy. The 6 caprine knees were found to range from very immature (< 3 months) to very mature (> 3 years). Mature specimens exhibited significantly more aligned collagen fibers in their patella tendons compared with the immature ones. In 2 of the 10 canine knees scanned, partial cranial caudal ligament tears were identified from MRI and subsequently confirmed with encouragingly high consistency of tractography, Alignment Index, and dissection results. CONCLUSION This method can be used to detect injury such as partial ligament tears, and to visualize maturity-related changes in the collagen structure of tendons. It can provide the basis for new, noninvasive diagnostic tools in combination with new scanner configurations that allow less-restricted field orientations.
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Affiliation(s)
- Karyn E Chappell
- Department of Surgery and Cancer, MSK Lab, Imperial College London, London, United Kingdom
| | - Djordje Brujic
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | | | - Richard Meeson
- Department of Clinical Sciences and Services, Royal Veterinary College, Hertfordshire, United Kingdom
| | - Wladyslaw Gedroyc
- MRI Unit, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Donald McRobbie
- Department of Surgery and Cancer, MSK Lab, Imperial College London, London, United Kingdom
| | - Mihailo Ristic
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
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Guo Z, Dong Z, Lee KH, Cheung CL, Fu HC, Ho JD, He H, Poon WS, Chan DTM, Kwok KW. Compact Design of a Hydraulic Driving Robot for Intraoperative MRI-Guided Bilateral Stereotactic Neurosurgery. IEEE Robot Autom Lett 2018. [DOI: 10.1109/lra.2018.2814637] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hajesmaeelzadeh F, Shanehsazzadeh S, Grüttner C, Daha FJ, Oghabian MA. Effect of coating thickness of iron oxide nanoparticles on their relaxivity in the MRI. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2016; 19:166-71. [PMID: 27081461 PMCID: PMC4818364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Iron oxide nanoparticles have found prevalent applications in various fields including drug delivery, cell separation and as contrast agents. Super paramagnetic iron oxide (SPIO) nanoparticles allow researchers and clinicians to enhance the tissue contrast of an area of interest by increasing the relaxation rate of water. In this study, we evaluate the dependency of hydrodynamic size of iron oxide nanoparticles coated with Polyethylene glycol (PEG) on their relativities with 3 Tesla clinical MRI. MATERIALS AND METHODS We used three groups of nanoparticles with nominal sizes 20, 50 and 100 nm with a core size of 8.86 nm, 8.69 nm and 10.4 nm that they were covered with PEG 300 and 600 Da. A clinical magnetic resonance scanner determines the T1 and T2 relaxation times for various concentrations of PEG-coated nanoparticles. RESULTS The size measurement by photon correlation spectroscopy showed the hydrodynamic sizes of MNPs with nominal 20, 50 and 100 nm with 70, 82 and 116 nm for particles with PEG 600 coating and 74, 93 and 100 nm for particles with PEG 300 coating, respectively. We foud that the relaxivity decreased with increasing overall particle size (via coating thickness). Magnetic resonance imaging showed that by increasing the size of the nanoparticles, r2/r1 increases linearly. CONCLUSION According to the data obtained from this study it can be concluded that increments in coating thickness have more influence on relaxivities compared to the changes in core size of magnetic nanoparticles.
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Affiliation(s)
- Farzaneh Hajesmaeelzadeh
- Biomolecular Imaging Analysis Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran,Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Science, Tehran, Iran
| | - Saeed Shanehsazzadeh
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
| | - Cordula Grüttner
- Micromod Partikeltechnologie GmbH, Friedrich-Barnewitz-Str. 4, D-18119 Rostock, Germany
| | - Fariba Johari Daha
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
| | - Mohammad Ali Oghabian
- Biomolecular Imaging Analysis Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran,Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Science, Tehran, Iran,Corresponding author: Mohammad Ali Oghabian. Biomolecular Imaging Analysis Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran, Department of Medical Physics and Biomedical Engineering, Faculty of Medicine Tehran University of Medical Science, Tehran, Iran. Tel : +98-21-66907518; Fax: +98-21-664386310;
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