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Toews AR, Lee PK, Nayak KS, Hargreaves BA. Comprehensive assessment of nonuniform image quality: Application to imaging near metal. Magn Reson Med 2024. [PMID: 38997797 DOI: 10.1002/mrm.30222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/06/2024] [Accepted: 06/26/2024] [Indexed: 07/14/2024]
Abstract
PURPOSE Comprehensive assessment of image quality requires accounting for spatial variations in (i) intensity artifact, (ii) geometric distortion, (iii) signal-to-noise ratio (SNR), and (iv) spatial resolution, among other factors. This work presents an ensemble of methods to meet this need, from phantom design to image analysis, and applies it to the scenario of imaging near metal. METHODS A modular phantom design employing a gyroid lattice is developed to enable the co-registered volumetric quantitation of image quality near a metallic hip implant. A method for measuring spatial resolution by means of local point spread function (PSF) estimation is presented and the relative fitness of gyroid and cubic lattices is examined. Intensity artifact, geometric distortion, and SNR maps are also computed. Results are demonstrated with 2D-FSE and MAVRIC-SL scan protocols on a 3T MRI scanner. RESULTS The spatial resolution method demonstrates a worst-case error of 0.17 pixels for measuring in-plane blurring up to 3 pixels (full width at half maximum). The gyroid outperforms a cubic lattice design for the local PSF estimation task. The phantom supports four configurations toggling the presence/absence of both metal and structure with good spatial correspondence for co-registered analysis of the four quality factors. The marginal scan time to evaluate one scan protocol amounts to five repetitions. The phantom design can be fabricated in 2 days at negligible material cost. CONCLUSION The phantom and associated analysis methods can elucidate complex image quality trade-offs involving intensity artifact, geometric distortion, SNR, and spatial resolution. The ensemble of methods is suitable for benchmarking imaging performance near metal.
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Affiliation(s)
- Alexander R Toews
- Radiology, Stanford University, Stanford, California, USA
- Electrical Engineering, Stanford University, Stanford, California, USA
| | - Philip K Lee
- Radiology, Stanford University, Stanford, California, USA
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Brian A Hargreaves
- Radiology, Stanford University, Stanford, California, USA
- Electrical Engineering, Stanford University, Stanford, California, USA
- Bioengineering, Stanford University, Stanford, California, USA
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2
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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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Keenan KE, Jordanova KV, Ogier SE, Tamada D, Bruhwiler N, Starekova J, Riek J, McCracken PJ, Hernando D. Phantoms for Quantitative Body MRI: a review and discussion of the phantom value. MAGMA (NEW YORK, N.Y.) 2024:10.1007/s10334-024-01181-8. [PMID: 38896407 DOI: 10.1007/s10334-024-01181-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/18/2024] [Accepted: 06/11/2024] [Indexed: 06/21/2024]
Abstract
In this paper, we review the value of phantoms for body MRI in the context of their uses for quantitative MRI methods research, clinical trials, and clinical imaging. Certain uses of phantoms are common throughout the body MRI community, including measuring bias, assessing reproducibility, and training. In addition to these uses, phantoms in body MRI methods research are used for novel methods development and the design of motion compensation and mitigation techniques. For clinical trials, phantoms are an essential part of quality management strategies, facilitating the conduct of ethically sound, reliable, and regulatorily compliant clinical research of both novel MRI methods and therapeutic agents. In the clinic, phantoms are used for development of protocols, mitigation of cost, quality control, and radiotherapy. We briefly review phantoms developed for quantitative body MRI, and finally, we review open questions regarding the most effective use of a phantom for body MRI.
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Affiliation(s)
- Kathryn E Keenan
- Physical Measurement Laboratory, National Institute of Standards and Technology, NIST, 325 Broadway, Boulder, CO, 80305, USA.
| | - Kalina V Jordanova
- Physical Measurement Laboratory, National Institute of Standards and Technology, NIST, 325 Broadway, Boulder, CO, 80305, USA
| | - Stephen E Ogier
- Physical Measurement Laboratory, National Institute of Standards and Technology, NIST, 325 Broadway, Boulder, CO, 80305, USA
- Department of Physics, University of Colorado Boulder, Boulder, CO, USA
| | | | - Natalie Bruhwiler
- Physical Measurement Laboratory, National Institute of Standards and Technology, NIST, 325 Broadway, Boulder, CO, 80305, USA
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Duarte Coello R, Valdés Hernández MDC, Zwanenburg JJM, van der Velden M, Kuijf HJ, De Luca A, Moyano JB, Ballerini L, Chappell FM, Brown R, Jan Biessels G, Wardlaw JM. Detectability and accuracy of computational measurements of in-silico and physical representations of enlarged perivascular spaces from magnetic resonance images. J Neurosci Methods 2024; 403:110039. [PMID: 38128784 DOI: 10.1016/j.jneumeth.2023.110039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/27/2023] [Accepted: 12/17/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Magnetic Resonance Imaging (MRI) visible perivascular spaces (PVS) have been associated with age, decline in cognitive abilities, interrupted sleep, and markers of small vessel disease. But the limits of validity of their quantification have not been established. NEW METHOD We use a purpose-built digital reference object to construct an in-silico phantom for addressing this need, and validate it using a physical phantom. We use cylinders of different sizes as models for PVS. We also evaluate the influence of 'PVS' orientation, and different sets of parameters of the two vesselness filters that have been used for enhancing tubular structures, namely Frangi and RORPO filters, in the measurements' accuracy. RESULTS PVS measurements in MRI are only a proxy of their true dimensions, as the boundaries of their representation are consistently overestimated. The success in the use of the Frangi filter relies on a careful tuning of several parameters. Alpha= 0.5, beta= 0.5 and c= 500 yielded the best results. RORPO does not have these requirements and allows detecting smaller cylinders in their entirety more consistently in the absence of noise and confounding artefacts. The Frangi filter seems to be best suited for voxel sizes equal or larger than 0.4 mm-isotropic and cylinders larger than 1 mm diameter and 2 mm length. 'PVS' orientation did not affect measurements in data with isotropic voxels. COMPARISON WITH EXISTENT METHODS Does not apply. CONCLUSIONS The in-silico and physical phantoms presented are useful for establishing the validity of quantification methods of tubular small structures.
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Affiliation(s)
- Roberto Duarte Coello
- Centre for Clinical Brain Sciences, Department of Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
| | - Maria Del C Valdés Hernández
- Centre for Clinical Brain Sciences, Department of Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK.
| | | | | | - Hugo J Kuijf
- Image Sciences Institute, UMC Utrecht, Utrecht, Netherlands
| | | | - José Bernal Moyano
- Centre for Clinical Brain Sciences, Department of Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK; German Centre for Neurodegenerative Diseases, Magdeburg, Germany; Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Lucia Ballerini
- Centre for Clinical Brain Sciences, Department of Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK; University for Foreigner of Perugia, Perugia, Italy
| | - Francesca M Chappell
- Centre for Clinical Brain Sciences, Department of Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
| | - Rosalind Brown
- Centre for Clinical Brain Sciences, Department of Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
| | | | - Joanna M Wardlaw
- Centre for Clinical Brain Sciences, Department of Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
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Marasini S, Quinn B, Cole M, Flores R, Kim T. System-dependent image distortion related to gantry positions of a 0.35 T MRgRT: Characterization and the corresponding correction. J Appl Clin Med Phys 2022; 24:e13826. [PMID: 36354747 PMCID: PMC9903949 DOI: 10.1002/acm2.13826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/06/2022] [Accepted: 10/04/2022] [Indexed: 11/12/2022] Open
Abstract
PURPOSE MR-guided radiotherapy with high accuracy treatment planning requires addressing MR imaging artifacts that originate from system imperfections. This work presents the characterization and corresponding correction of gantry-related imaging distortions including geometric distortion and isocenter shift in a 0.35 T magnetic resonance imaging (MRI)-guided radiotherapy (MRgRT) system using distortion vector fields (DVFs). METHODS Two phantoms, the magnetic resonance imaging distortion in 3D (MRID3D ) phantom and the Fluke phantom, along with a human volunteer were imaged at different gantry angles on a 0.35 T MR-Linac. The geometric distortion and isocenter shift were characterized for both phantom images. DVFs with a field of view extended beyond the physical boundary of the MRID3D phantom were extracted from images taken at 30° gantry angle increments, with vendor-provided distortion correction turned on and off (DstOff). These extended DVFs were then applied to the relevant phantom images to correct their geometric distortions and isocenter shift at the respective gantry angles. The extended DVFs produced from the MRID3D phantom were also applied to Fluke phantom and human MR images at their respective gantry angles. The resampled images were evaluated using structural similarity index measure (SSIM) comparison with the vendor corrected images from the MRgRT system. RESULTS Geometric distortion with "mean (± SD) distortion" of 3.2 ± 0.02, 2.9 ± 0.02, and 1.8 ± 0.01 mm and isocenter shift (±SD) of 0.49 ± 0.3, 0.05 ± 0.2, and 0.01 ± 0.03 mm were present in the DstOff MRID3D phantom images in right-left (RL), anterior-posterior (AP), and superior-inferior (SI) directions, respectively. After resampling the originally acquired images by applying extended DVFs, the distortion was corrected to 0.18 ± 0.02, 0.09 ± 0.01, 0.15 ± 0.01 mm, and isocenter shift was corrected to 0.14 ± 0.05, -0.02 ± 0.04, and -0.07 ± 0.05 mm in RL, AP, and SI directions, respectively. The Fluke phantom average geometric distortion with "mean (± SD) distortion" of 2.7 ± 0.1 mm was corrected to 0.2 ± 0. 1 mm and the average isocenter shift (± SD) of 0.51 ± 0.2 mm, and 0.05 ± 0.03 was corrected to -0.08 ± 0.03 mm, and -0.05 ± 0.01 in RL and AP directions, respectively. SSIM (mean ± SD) of the original images to resampled images was increased from 0.49 ± 0.02 to 0.78 ± 0.01, 0.45 ± 0.02 to 0.75 ± 0.01, and 0.86 ± 0.25 to 0.98 ± 0.08 for MRID3D phantom, Fluke phantom, and human MR images, respectively, for all the gantry angles compared to the vendor corrected images. CONCLUSION The gantry-related MR imaging distortion including geometric distortion and isocenter shift was characterized and a corresponding correction was demonstrated using extended DVFs on 0.35 T MRgRT system. The characterized gantry-related isocenter shift can be combined with geometric distortion correction to provide a technique for the correction of the full system-dependent distortion in an MRgRT system.
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Affiliation(s)
- Shanti Marasini
- Department of Radiation OncologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Benjamin Quinn
- Department of the Modus MedicalModus Medical Devices Inc.LondonOntarioCanada
| | - Mike Cole
- Department of the Modus MedicalModus Medical Devices Inc.LondonOntarioCanada
| | - Rocco Flores
- Department of the Modus MedicalModus Medical Devices Inc.LondonOntarioCanada
| | - Taeho Kim
- Department of Radiation OncologyWashington University School of MedicineSt. LouisMissouriUSA
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6
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Tuna EE, Poirot NL, Franson D, Bayona JB, Huang S, Seiberlich N, Griswold MA, Cavusoglu MC. MRI Distortion Correction and Robot-to-MRI Scanner Registration for an MRI-Guided Robotic System. IEEE ACCESS : PRACTICAL INNOVATIONS, OPEN SOLUTIONS 2022; 10:99205-99220. [PMID: 37041984 PMCID: PMC10085576 DOI: 10.1109/access.2022.3207156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Magnetic resonance imaging (MRI) guided robotic procedures require safe robotic instrument navigation and precise target localization. This depends on reliable tracking of the instrument from MR images, which requires accurate registration of the robot to the scanner. A novel differential image based robot-to-MRI scanner registration approach is proposed that utilizes a set of active fiducial coils, where background subtraction method is employed for coil detection. In order to use the presented preoperative registration approach jointly with the real-time high speed MRI image acquisition and reconstruction methods in real-time interventional procedures, the effects of the geometric MRI distortion in robot to scanner registration is analyzed using a custom distortion mapping algorithm. The proposed approach is validated by a set of target coils placed within the workspace, employing multi-planar capabilities of the scanner. Registration and validation errors are respectively 2.05 mm and 2.63 mm after the distortion correction showing an improvement of respectively 1.08 mm and 0.14 mm compared to the results without distortion correction.
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Affiliation(s)
- E Erdem Tuna
- Department of Electrical, Computer, and Systems Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Nate Lombard Poirot
- Department of Electrical, Computer, and Systems Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | | | - Juana Barrera Bayona
- School of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Sherry Huang
- General Electric Healthcare, Royal Oak, MI 48067, USA
| | - Nicole Seiberlich
- Department of Radiology, University of Michigan, Ann-Anbor, MI 48109, USA
| | - Mark A Griswold
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - M Cenk Cavusoglu
- Department of Electrical, Computer, and Systems Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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7
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Taylor JM, Chang M, Vaughan J, Horn PS, Zhang B, Leach JL, Vadivelu S, Abruzzo T. Cerebral Arterial Growth in Childhood. Pediatr Neurol 2022; 134:59-66. [PMID: 35839526 DOI: 10.1016/j.pediatrneurol.2022.06.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 05/22/2022] [Accepted: 06/19/2022] [Indexed: 10/17/2022]
Abstract
BACKGROUND Improved understanding of cerebral arterial growth in children may lead to advances in the diagnosis and treatment of pediatric cerebrovascular disease. We correlated cross-sectional diameters of major cerebral arterial structures with age, sex, head circumference, weight, and height in children without cerebrovascular disease. METHODS Children with normal brain magnetic resonance imaging (MRI) were retrospectively identified and stratified into 23 age cohorts from birth to age 18 years. Absence of vascular disease was verified by medical record review. Demographic and biometric data were obtained from medical records. Intracranial arterial diameter (IAD) was measured on T2-weighted fast spin echo brain MRI of vertebral, basilar, internal carotid artery, and circle of Willis arterial segments. RESULTS A total of 307 subjects are included in the analysis, including 5833 vessel segments (mean age 8.4 years, 53% female). Indications for imaging were headache (73%), seizure (26%) and concussion (1%). IAD rapidly increased during the first year of life (mean growth velocity 0.064 to 0.213 mm/month) and then plateaued or slightly decreased between age one and 18 years (mean growth velocity -0.002 to 0.003 mm/month). Multivariable analysis shows strongest correlation with head circumference as a predictor of IAD. Weaker correlations are associated with weight and age. Height and sex are not well correlated with IAD. CONCLUSIONS Intracranial arteries grow rapidly during the first year of life and then sharply plateau or slightly decrease in luminal diameter between infancy and early adulthood. IAD is more closely correlated with head circumference than age.
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Affiliation(s)
- J Michael Taylor
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; University of Cincinnati, College of Medicine, Cincinnati, Ohio.
| | - Michael Chang
- Division of Ophthalmology, West Virginia University, School of Medicine, Morgantown, West Virginia
| | - Jessica Vaughan
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Paul S Horn
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; University of Cincinnati, College of Medicine, Cincinnati, Ohio; Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Bin Zhang
- University of Cincinnati, College of Medicine, Cincinnati, Ohio; Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - James L Leach
- University of Cincinnati, College of Medicine, Cincinnati, Ohio; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Sudhakar Vadivelu
- University of Cincinnati, College of Medicine, Cincinnati, Ohio; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Todd Abruzzo
- Department of Radiology, Phoenix Children's Medical Group, Phoenix, Arizona; Mayo Clinic College of Medicine, Phoenix, Arizona; University of Arizona, College of Medicine, Phoenix, Arizona
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Doughty M, Ghugre NR, Wright GA. Augmenting Performance: A Systematic Review of Optical See-Through Head-Mounted Displays in Surgery. J Imaging 2022; 8:jimaging8070203. [PMID: 35877647 PMCID: PMC9318659 DOI: 10.3390/jimaging8070203] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 02/01/2023] Open
Abstract
We conducted a systematic review of recent literature to understand the current challenges in the use of optical see-through head-mounted displays (OST-HMDs) for augmented reality (AR) assisted surgery. Using Google Scholar, 57 relevant articles from 1 January 2021 through 18 March 2022 were identified. Selected articles were then categorized based on a taxonomy that described the required components of an effective AR-based navigation system: data, processing, overlay, view, and validation. Our findings indicated a focus on orthopedic (n=20) and maxillofacial surgeries (n=8). For preoperative input data, computed tomography (CT) (n=34), and surface rendered models (n=39) were most commonly used to represent image information. Virtual content was commonly directly superimposed with the target site (n=47); this was achieved by surface tracking of fiducials (n=30), external tracking (n=16), or manual placement (n=11). Microsoft HoloLens devices (n=24 in 2021, n=7 in 2022) were the most frequently used OST-HMDs; gestures and/or voice (n=32) served as the preferred interaction paradigm. Though promising system accuracy in the order of 2–5 mm has been demonstrated in phantom models, several human factors and technical challenges—perception, ease of use, context, interaction, and occlusion—remain to be addressed prior to widespread adoption of OST-HMD led surgical navigation.
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Affiliation(s)
- Mitchell Doughty
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A1, Canada; (N.R.G.); (G.A.W.)
- Schulich Heart Program, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Correspondence:
| | - Nilesh R. Ghugre
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A1, Canada; (N.R.G.); (G.A.W.)
- Schulich Heart Program, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
| | - Graham A. Wright
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A1, Canada; (N.R.G.); (G.A.W.)
- Schulich Heart Program, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
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Nousiainen K, Mäkelä T, Peltonen JI. Characterizing geometric distortions of 3D sequences in clinical head MRI. MAGNETIC RESONANCE MATERIALS IN PHYSICS, BIOLOGY AND MEDICINE 2022; 35:983-995. [PMID: 35657535 PMCID: PMC9596562 DOI: 10.1007/s10334-022-01020-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/20/2022] [Accepted: 05/12/2022] [Indexed: 11/25/2022]
Abstract
Objective Phantoms are often used to estimate the geometric accuracy in magnetic resonance imaging (MRI). However, the distortions may differ between anatomical and phantom images. This study aimed to investigate the applicability of a phantom-based and a test-subject-based method in evaluating geometric distortion present in clinical head-imaging sequences. Materials and methods We imaged a 3D-printed phantom and test subjects with two MRI scanners using two clinical head-imaging 3D sequences with varying patient-table positions and receiver bandwidths. The geometric distortions were evaluated through nonrigid registrations: the displaced acquisitions were compared against the ideal isocenter positioning, and the varied bandwidth volumes against the volume with the highest bandwidth. The phantom acquisitions were also registered to a computed tomography scan. Results Geometric distortion magnitudes increased with larger table displacements and were in good agreement between the phantom and test-subject acquisitions. The effect of increased distortions with decreasing receiver bandwidth was more prominent for test-subject acquisitions. Conclusion Presented results emphasize the sensitivity of the geometric accuracy to positioning and imaging parameters. Phantom limitations may become an issue with some sequence types, encouraging the use of anatomical images for evaluating the geometric accuracy.
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Affiliation(s)
- Katri Nousiainen
- HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
- Department of Physics, University of Helsinki, Helsinki, Finland.
| | - Teemu Mäkelä
- HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Juha I Peltonen
- HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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10
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Doughty M, Ghugre NR. Head-Mounted Display-Based Augmented Reality for Image-Guided Media Delivery to the Heart: A Preliminary Investigation of Perceptual Accuracy. J Imaging 2022; 8:jimaging8020033. [PMID: 35200735 PMCID: PMC8878166 DOI: 10.3390/jimaging8020033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/25/2022] [Accepted: 01/28/2022] [Indexed: 01/14/2023] Open
Abstract
By aligning virtual augmentations with real objects, optical see-through head-mounted display (OST-HMD)-based augmented reality (AR) can enhance user-task performance. Our goal was to compare the perceptual accuracy of several visualization paradigms involving an adjacent monitor, or the Microsoft HoloLens 2 OST-HMD, in a targeted task, as well as to assess the feasibility of displaying imaging-derived virtual models aligned with the injured porcine heart. With 10 participants, we performed a user study to quantify and compare the accuracy, speed, and subjective workload of each paradigm in the completion of a point-and-trace task that simulated surgical targeting. To demonstrate the clinical potential of our system, we assessed its use for the visualization of magnetic resonance imaging (MRI)-based anatomical models, aligned with the surgically exposed heart in a motion-arrested open-chest porcine model. Using the HoloLens 2 with alignment of the ground truth target and our display calibration method, users were able to achieve submillimeter accuracy (0.98 mm) and required 1.42 min for calibration in the point-and-trace task. In the porcine study, we observed good spatial agreement between the MRI-models and target surgical site. The use of an OST-HMD led to improved perceptual accuracy and task-completion times in a simulated targeting task.
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Affiliation(s)
- Mitchell Doughty
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A1, Canada;
- Schulich Heart Program, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Correspondence:
| | - Nilesh R. Ghugre
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A1, Canada;
- Schulich Heart Program, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
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11
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Ramachandran P, Noble C, Langton C, Perrett B, Cox J, Chapman M, McGill G. A 3D printed phantom to assess MRI geometric distortion. Biomed Phys Eng Express 2021; 7. [PMID: 33657539 DOI: 10.1088/2057-1976/abeb7e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 03/03/2021] [Indexed: 11/12/2022]
Abstract
Magnetic Resonance has become a standard imaging modality for target volume delineation and treatment planning in radiation oncology. Geometric distortions, however, have the potential to detrimentally affect both tumour definition and the dose delivered to the target volume. We report the design, fabrication and imaging of a 3D printed unibody MR distortion phantom along with quantitative image analysis. METHODS The internal cavity of the phantom is an orthogonal three-dimensional planar lattice, composed of 3mm diameter rods spaced equidistantly at a 20mm centre-centre offset repeating along the X, Y and Z axes. The phantom featured an overall length of 308.5 mm, a width of 246 mm and a height of 264 mm with lines on the external surface for phantom positioning matched to external lasers. The MR phantom was 3D printed in Nylon-12 using an advancement on traditional selective laser sintering (SLS) (HP Jet Fusion 3D - 4200 machine). The phantom was scanned on a Toshiba Aquilion CT scanner to check the integrity of the 3D print and to correct for any resultant issues. The phantom was then filled with NiSO4 solution and scanned on a 3T PET-MR Siemens scanner for selected T1 and T2 sequences, from which distortion vectors were generated and analysed using in-house software written in Python. RESULTS All deviations were less than 1 mm, with an average displacement of 0.228 mm. The majority of the deviations are smaller than the 0.692 mm pixel size for this dataset. CONCLUSION A cost-effective, 3D printed MRI-phantom was successfully printed and tested for assessing geometric distortion on MRI scanners. The custom phantom with markings for phantom alignment may be considered for radiotherapy departments looking to add MR scanners for simulation and image guidance.
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Affiliation(s)
- Prabhakar Ramachandran
- Radiation Oncology, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Woolloongabba, Queensland, 4102, AUSTRALIA
| | - Chris Noble
- Department of Radiation Oncology, Princess Alexandra Hospital, 199 Ipswich Rd, Woolloongabba, 4102, AUSTRALIA
| | - Christian Langton
- Clinical Sciences, Queensland University of Technology, 3D One, Brisbane, 4107, AUSTRALIA
| | - Ben Perrett
- Department of Radiation Oncology, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, 4102, AUSTRALIA
| | - Joshua Cox
- One Australia Pty Ltd, 3D one, Salisbury, 4107, AUSTRALIA
| | - Mike Chapman
- One Australia Pty Ltd, 3D one, Salisbury, 4107, AUSTRALIA
| | - George McGill
- Queensland University of Technology, 199 Ipswich Road, Brisbane, 4102, AUSTRALIA
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