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Hobson MA, Hu Y, Caldwell B, Cohen GN, Glide-Hurst C, Huang L, Jackson PD, Jang S, Langner U, Lee HJ, Levesque IR, Narayanan S, Park JC, Steffen J, Wu QJ, Zhou Y. AAPM Task Group 334: A guidance document to using radiotherapy immobilization devices and accessories in an MR environment. Med Phys 2024; 51:3822-3849. [PMID: 38648857 DOI: 10.1002/mp.17061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 11/13/2023] [Accepted: 03/28/2024] [Indexed: 04/25/2024] Open
Abstract
Use of magnetic resonance (MR) imaging in radiation therapy has increased substantially in recent years as more radiotherapy centers are having MR simulators installed, requesting more time on clinical diagnostic MR systems, or even treating with combination MR linear accelerator (MR-linac) systems. With this increased use, to ensure the most accurate integration of images into radiotherapy (RT), RT immobilization devices and accessories must be able to be used safely in the MR environment and produce minimal perturbations. The determination of the safety profile and considerations often falls to the medical physicist or other support staff members who at a minimum should be a Level 2 personnel as per the ACR. The purpose of this guidance document will be to help guide the user in making determinations on MR Safety labeling (i.e., MR Safe, Conditional, or Unsafe) including standard testing, and verification of image quality, when using RT immobilization devices and accessories in an MR environment.
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Affiliation(s)
- Maritza A Hobson
- Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Yanle Hu
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona, USA
| | - Barrett Caldwell
- School of Industrial Engineering, Purdue University, West Lafayette, Indiana, USA
- School of Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana, USA
| | - Gil'ad N Cohen
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
| | - Carri Glide-Hurst
- Department of Human Oncology, University of Wisconsin--Madison, Madison, Wisconsin, USA
- Department of Medical Physics, University of Wisconsin--Madison, Madison, Wisconsin, USA
| | - Long Huang
- Department of Radiation Oncology, University of Utah, Salt Lake City, Utah, USA
| | - Paul D Jackson
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan, USA
| | - Sunyoung Jang
- Department of Radiation Oncology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Ulrich Langner
- Department of Radiation Oncology, Rhode Island Hospital, Providence, Rhode Island, USA
| | - Hannah J Lee
- Corewell Health William Beaumont University Hospital, Royal Oak, Michigan, USA
| | - Ives R Levesque
- Gerald Bronfman Department of Oncology and Medical Physics Unit, McGill University, Montreal, QC, Canada
- Department of Medical Physics, McGill University Health Centre, Cedars Cancer Centre, Montreal, QC, Canada
| | - Sreeram Narayanan
- Department of Radiation Oncology, Virginia Mason Cancer Institute, Seattle, Washington, USA
| | - Justin C Park
- Division of Medical Physics, Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA
| | | | - Q Jackie Wu
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
| | - Yong Zhou
- Department of Radiology Services, Corewell Health, Grand Rapids, Michigan, USA
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2
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Wiesinger F, Ho ML. Zero-TE MRI: principles and applications in the head and neck. Br J Radiol 2022; 95:20220059. [PMID: 35616709 PMCID: PMC10162052 DOI: 10.1259/bjr.20220059] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Zero echo-time (ZTE) MRI is a novel imaging technique that utilizes ultrafast readouts to capture signal from short-T2 tissues. Additional sequence advantages include rapid imaging times, silent scanning, and artifact resistance. A robust application of this technology is imaging of cortical bone without the use of ionizing radiation, thus representing a viable alternative to CT for both rapid screening and "one-stop-shop" MRI. Although ZTE is increasingly used in musculoskeletal and body imaging, neuroimaging applications have historically been limited by complex anatomy and pathology. In this article, we review the imaging physics of ZTE including pulse sequence options, practical limitations, and image reconstruction. We then discuss optimization of settings for ZTE bone neuroimaging including acquisition, processing, segmentation, synthetic CT generation, and artifacts. Finally, we examine clinical utility of ZTE in the head and neck with imaging examples including malformations, trauma, tumors, and interventional procedures.
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Affiliation(s)
- Florian Wiesinger
- Department for Neuroimaging, Institute of Psychiatry & Neuroscience, King's College London, London, UK.,Principal Scientist at GE Healthcare, Munich, Germany
| | - Mai-Lan Ho
- Nationwide Children's Hospital and The Ohio State University, Columbus, USA
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3
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Susceptibility artifacts induced by crowns of different materials with prepared teeth and titanium implants in magnetic resonance imaging. Sci Rep 2022; 12:428. [PMID: 35013440 PMCID: PMC8748466 DOI: 10.1038/s41598-021-03962-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 12/06/2021] [Indexed: 02/07/2023] Open
Abstract
This study aimed to investigate the artifacts induced by crowns composed of different materials with prepared teeth and titanium implants. Resin, metal-ceramic, ceramic and zirconia crowns were fabricated and placed onto the prepared teeth on a human cadaver head or titanium implants with prosthesis abutments on a dry human mandible. The samples were scanned on a 1.5 T MRI apparatus, and artifact areas were defined as the signal intensity and signal loss adjacent to the prosthesis and measured by a threshold tool with ImageJ2x. Data were analyzed using SPSS 22.0. Resin, ceramic, zirconia, and precious metal-ceramic crowns barely produced artifacts on the cadaver skull (p > 0.999). By contrast, pure Ti and nonprecious metal-ceramic crowns created significant artifacts (p < 0.001). The average artifacts reduction of double Au-Pt and Ag-Pd metal-ceramic crowns combined with titanium implants and abutments was 79.49 mm2 (p < 0.001) and 74.17 mm2 (p < 0.001) respectively, while artifact areas were increased in double Co-Cr and Ni–Cr metal-ceramic crowns by 150.10 mm2 (p < 0.001) and 175.50 mm2 (p < 0.001) respectively. Zirconia, ceramic and precious metal-ceramic crowns induce less MRI artifacts after tooth preparation while precious metal-ceramic crowns alleviate artifacts in combination with titanium implants.
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Abdala-Junior R, No-Cortes J, Arita ES, Ackerman JL, da Silva RLB, Kim JH, Cortes ARG. Influence of receiver bandwidth on MRI artifacts caused by orthodontic brackets composed of different alloys. Imaging Sci Dent 2022; 51:413-419. [PMID: 34988002 PMCID: PMC8695464 DOI: 10.5624/isd.20210099] [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: 04/23/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 11/18/2022] Open
Abstract
Purpose The aim of this in vitro study was to assess the role of bandwidth on the area of magnetic resonance imaging (MRI) artifacts caused by orthodontic appliances composed of different alloys, using different pulse sequences in 1.5 T and 3.0 T magnetic fields. Materials and Methods Different phantoms containing orthodontic brackets (ceramic, ceramic bracket with a stainless-steel slot, and stainless steel) were immersed in agar gel and imaged in 1.5 T and 3.0 T MRI scanners. Pairs of gradient-echo (GE), spin-echo (SE), and ultrashort echo time (UTE) pulse sequences were used differing in bandwidth only. The area of artifacts from orthodontic devices was automatically estimated from pixel value thresholds within a region of interest (ROI). Mean values for similar pulse sequences differing in bandwidth were compared at 1.5 T and 3.0 T using analysis of variance. Results The comparison of groups revealed a significant inverse association between bandwidth values and artifact areas of the stainless-steel bracket and the self-ligating ceramic bracket with a stainless-steel slot (P<0.05). The areas of artifacts from the ceramic bracket were the smallest, but were not reduced significantly in pulse sequences with higher bandwidth values (P<0.05). Significant differences were also observed between 1.5 T and 3.0 T MRI using SE and UTE, but not using GE 2-dimensional or 3-dimensional pulse sequences. Conclusion Higher receiver bandwidth might be indicated to prevent artifacts from orthodontic appliances in 1.5 T and 3.0 T MRI using SE and UTE pulse sequences.
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Affiliation(s)
- Reinaldo Abdala-Junior
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.,Department of Radiology, Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Juliana No-Cortes
- Department of Dental Surgery, Faculty of Dental Surgery, University of Malta, Msida, Malta
| | - Emiko Saito Arita
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil
| | - Jerome L Ackerman
- Department of Radiology, Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | | | - Jun Ho Kim
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.,Department of Oral and Maxillofacial Radiology, School of Dentistry, Seoul National University, Seoul, Korea
| | - Arthur Rodriguez Gonzalez Cortes
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.,Department of Radiology, Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
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5
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Laurino FAR, Choi IGG, Kim JH, Gialain IO, Ferraço R, Haetinger RG, Pinhata-Baptista OH, Abdala-Junior R, Costa C, Cortes ARG. Correlation between magnetic resonance imaging and cone-beam computed tomography for maxillary sinus graft assessment. Imaging Sci Dent 2020; 50:93-98. [PMID: 32601583 PMCID: PMC7314607 DOI: 10.5624/isd.2020.50.2.93] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 01/22/2020] [Accepted: 02/13/2020] [Indexed: 11/18/2022] Open
Abstract
Purpose Little is known regarding the accuracy of clinical magnetic resonance imaging (MRI) protocols with acceptable scan times in sinus graft assessment. The aim of this study was to evaluate the correlations between MRI and cone-beam computed tomographic (CBCT) measurements of maxillary sinus grafts using 2 different clinical MRI imaging protocols. Materials and Methods A total of 15 patients who underwent unilateral sinus lift surgery with biphasic calcium phosphate were included in this study. CBCT, T1-weighted MRI, and T2-weighted MRI scans were taken 6 months after sinus lift surgery. Linear measurements of the maximum height and buccolingual width in coronal images, as well as the maximum anteroposterior depth in sagittal images, were performed by 2 trained observers using CBCT and MRI Digital Imaging and Communication in Medicine files. Microcomputed tomography (micro-CT) was also performed to confirm the presence of bone tissue in the grafted area. Correlations between MRI and CBCT measurements were assessed with the Pearson test. Results Significant correlations between CBCT and MRI were found for sinus graft height (T1-weighted, r=0.711 and P<0.05; T2-weighted, r=0.713 and P<0.05), buccolingual width (T1-weighted, r=0.892 and P<0.05; T2-weighted, r=0.956 and P<0.05), and anteroposterior depth (T1-weighted, r=0.731 and P<0.05; T2-weighted, r=0.873 and P<0.05). The presence of bone tissue in the grafted areas was confirmed via micro-CT. Conclusion Both MRI pulse sequences tested can be used for sinus graft measurements, as strong correlations with CBCT were found. However, correlations between T2-weighted MRI and CBCT were slightly higher than those between T1-weighted MRI and CBCT.
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Affiliation(s)
| | | | - Jun Ho Kim
- Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Ivan Onone Gialain
- Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil.,Stricto Sensu Research Program on Integrated Dental Sciences, Universidade de Cuiabá, Cuiabá, Brazil
| | - Renato Ferraço
- Department of Implantology, Military Hospital of São Paulo Area, São Paulo, Brazil
| | | | | | - Reinaldo Abdala-Junior
- Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil.,Department of Radiology, Centro Universitário Sudoeste Paulista, Avaré, São Paulo, Brazil
| | - Claudio Costa
- Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Arthur Rodriguez Gonzalez Cortes
- Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil.,Department of Dental Surgery, Faculty of Dental Surgery, University of Malta, Msida, Malta
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6
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Kajima Y, Takaichi A, Tsutsumi Y, Hanawa T, Wakabayashi N, Kawasaki A. Influence of magnetic susceptibility and volume on MRI artifacts produced by low magnetic susceptibility Zr-14Nb alloy and dental alloys. Dent Mater J 2019; 39:256-261. [PMID: 31723091 DOI: 10.4012/dmj.2018-426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The artifact volume generated in magnetic resonance (MR) images was quantitatively evaluated to investigate how artifact behavior correlates to the magnetic susceptibility and volume of an implanted metal device. For this, a new low-magnetic-susceptibility Zr-14Nb alloy was compared with two conventional dental alloys, Ti-6Al-7Nb alloy and Co-Cr-Mo alloy, using spherical specimens of each alloy prepared with four different diameters. Then, MR images were recorded under fast spin echo and gradient echo conditions, from which the artifact volume was measured. The artifact volume decreased with the magnetic susceptibility, volume, and mass of the specimens, and significant linear correlations were observed. The artifact volume can be estimated by the equations presented here; nevertheless, further studies are necessary to interpret the influence of some important factors (e.g., imaging conditions, shape, and orientation) to predict the artifact volume more precisely.
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Affiliation(s)
- Yuka Kajima
- Department of Materials Processing, Graduate School of Engineering, Tohoku University
| | - Atsushi Takaichi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Yusuke Tsutsumi
- Department of Metallic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University
| | - Takao Hanawa
- Department of Metallic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Akira Kawasaki
- Department of Materials Processing, Graduate School of Engineering, Tohoku University
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7
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Kuusisto N, Huumonen S, Kotiaho A, Haapea M, Rekola J, Vallittu P. Intensity of artefacts in cone beam CT examinations caused by titanium and glass fibre-reinforced composite implants. Dentomaxillofac Radiol 2019; 48:20170471. [PMID: 30084258 PMCID: PMC6476382 DOI: 10.1259/dmfr.20170471] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 07/16/2018] [Accepted: 08/01/2018] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVES: The aim was to compare titanium and glass fibre-reinforced composite (FRC) orbital floor implants using cone beam CT (CBCT). FRC implants are nonmetallic and these implants have not been analysed in CBCT images before. The purpose of this study is to compare the artefact formation of the titanium and the FRC orbital floor implants in CBCT images. METHODS: One commercially pure titanium and one S-glass FRC with bioactive glass particles implant were imaged with CBCT using the same imaging values (80 kV, 1 mA, FOV 60 × 60 mm). CBCT images were analysed in axial slices from three areas to determine the magnitude of the artefacts in the vicinity of the implants. Quantified results based on the gray values of images were analysed using analysis-of-variance. RESULTS: Compared to the reference the gray values of the titanium implant are more negative in every region of interest in all slices (p < 0.05) whereas the gray values of the FRC implant differ statistically significantly in less than half of the examined areas. CONCLUSIONS: The titanium implant caused artefacts in all of the analysed CBCT slices. Compared to the reference the gray values of the FRC implant changed only slightly and this feature enables to use wider imaging options postoperatively.
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Affiliation(s)
| | | | | | | | - Jami Rekola
- Department of Otorhinolaryngology, Turku University Hospital, Turku, Finland
| | - Pekka Vallittu
- Department of Biomaterials Science and Turku Clinical Biomaterials Centre – TCBC, Institute of Dentistry and BioCity, University of Turku and City of Turku, Welfare Division, Turku, Finland
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8
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Chockattu SJ, Suryakant DB, Thakur S. Unwanted effects due to interactions between dental materials and magnetic resonance imaging: a review of the literature. Restor Dent Endod 2018; 43:e39. [PMID: 30483463 PMCID: PMC6237727 DOI: 10.5395/rde.2018.43.e39] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/25/2018] [Indexed: 12/20/2022] Open
Abstract
Magnetic resonance imaging (MRI) is an advanced diagnostic tool used in both medicine and dentistry. Since it functions based on a strong uniform static magnetic field and radiofrequency pulses, it is advantageous over imaging techniques that rely on ionizing radiation. Unfortunately, the magnetic field and radiofrequency pulses generated within the magnetic resonance imager interact unfavorably with dental materials that have magnetic properties. This leads to unwanted effects such as artifact formation, heat generation, and mechanical displacement. These are a potential source of damage to the oral tissue surrounding the affected dental materials. This review aims to compile, based on the current available evidence, recommendations for dentists and radiologists regarding the safety and appropriate management of dental materials during MRI in patients with orthodontic appliances, maxillofacial prostheses, dental implants, direct and indirect restorative materials, and endodontic materials.
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Affiliation(s)
- Sherin Jose Chockattu
- Department of Conservative Dentistry & Endodontics, Bapuji Dental College & Hospital, Davangere, KA, India
| | - Deepak Byathnal Suryakant
- Department of Conservative Dentistry & Endodontics, Dental College, Regional Institute of Medical Sciences, Imphal, MN, India
| | - Sophia Thakur
- Department of Conservative Dentistry & Endodontics, Bapuji Dental College & Hospital, Davangere, KA, India
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9
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Rendenbach C, Schoellchen M, Bueschel J, Gauer T, Sedlacik J, Kutzner D, Vallittu PK, Heiland M, Smeets R, Fiehler J, Siemonsen S. Evaluation and reduction of magnetic resonance imaging artefacts induced by distinct plates for osseous fixation: an in vitro study @ 3 T. Dentomaxillofac Radiol 2018; 47:20170361. [PMID: 29718688 DOI: 10.1259/dmfr.20170361] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVES: To analyze MRI artefacts induced at 3 T by bioresorbable, titanium (TI) and glass fibre reinforced composite (GFRC) plates for osseous reconstruction. METHODS: Fixation plates including bioresorbable polymers (Inion CPS, Inion Oy, Tampere, Finland; Rapidsorb, DePuy Synthes, Umkirch, Germany; Resorb X, Gebrueder KLS Martin GmbH, Tuttlingen, Germany), GFRC (Skulle Implants Oy, Turku, Finland) and TI plates of varying thickness and design (DePuy Synthes, Umkirch, Germany) were embedded in agarose gel and a 3 T MRI was performed using a standard protocol for head and neck imaging including T1W and T2W sequences. Additionally, different artefact reduction techniques (slice encoding for metal artefact reduction & ultrashort echo time) were used and their impact on the extent of artefacts evaluated for each material. RESULTS: All TI plates induced significantly more artefacts than resorbable plates in T1W and T2W sequences. GFRCs induced the least artefacts in both sequences. The total extent of artefacts increased with plate thickness and height. Plate thickness had no influence on the percentage of overestimation in all three dimensions. TI-induced artefacts were significantly reduced by both artefact reduction techniques. CONCLUSIONS: Polylactide, GFRC and magnesium plates produce less susceptibility artefacts in MRI compared to TI, while the dimensions of TI plates directly influence artefact extension. Slice encoding for metal artefact reduction and ultrashort echo time significantly reduce metal artefacts at the expense of scan time or image resolution.
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Affiliation(s)
- Carsten Rendenbach
- 1 Department of Oral and Maxillofacial Surgery, Charité - Universitaetsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health , Berlin , Germany.,2 Berlin Institute of Health (BIH) , Berlin , Germany
| | - Max Schoellchen
- 3 Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Julie Bueschel
- 3 Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Tobias Gauer
- 4 Department of Radiotherapy and Radiation Oncology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Jan Sedlacik
- 5 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Daniel Kutzner
- 5 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Pekka K Vallittu
- 6 Department of Biomaterials Science, Institute of Dentistry, University of Turku, and City of Turku, Welfare Division , Turku , Finland
| | - Max Heiland
- 1 Department of Oral and Maxillofacial Surgery, Charité - Universitaetsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health , Berlin , Germany
| | - Ralf Smeets
- 3 Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Jens Fiehler
- 5 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Susanne Siemonsen
- 5 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
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10
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Cortes ARG, Cohen O, Zhao M, Aoki EM, Ribeiro RA, Abu Nada L, Costa C, Arita ES, Tamimi F, Ackerman JL. Assessment of alveolar bone marrow fat content using 15 T MRI. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 125:244-249. [PMID: 29292160 DOI: 10.1016/j.oooo.2017.11.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 11/03/2017] [Accepted: 11/11/2017] [Indexed: 12/25/2022]
Abstract
OBJECTIVES Bone marrow fat is inversely correlated with bone mineral density. The aim of this study is to present a method to quantify alveolar bone marrow fat content using a 15 T magnetic resonance imaging (MRI) scanner. STUDY DESIGN A 15 T MRI scanner with a 13-mm inner diameter loop-gap radiofrequency coil was used to scan seven 3-mm diameter alveolar bone biopsy specimens. A 3-D gradient-echo relaxation time (T1)-weighted pulse sequence was chosen to obtain images. All images were obtained with a voxel size (58 µm3) sufficient to resolve trabecular spaces. Automated volume of the bone marrow fat content and derived bone volume fraction (BV/TV) were calculated. Results were compared with actual BV/TV obtained from micro-computed tomography (CT) scans. RESULTS Mean fat tissue volume was 20.1 ± 11%. There was a significantly strong inverse correlation between fat tissue volume and BV/TV (r = -0.68; P = .045). Furthermore, there was a strong agreement between BV/TV derived from MRI and obtained with micro-CT (interclass correlation coefficient = 0.92; P = .001). CONCLUSIONS Bone marrow fat of small alveolar bone biopsy specimens can be quantified with sufficient spatial resolution using an ultra-high-field MRI scanner and a T1-weighted pulse sequence.
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Affiliation(s)
- Arthur Rodriguez Gonzalez Cortes
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA; Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, Brazil.
| | - Ouri Cohen
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Ming Zhao
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA; Department of Physics, University of Massachusetts Lowell, Lowell, Massachusetts, USA
| | - Eduardo Massaharu Aoki
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Rodrigo Alves Ribeiro
- Department of Oral Implantology, School of Dentistry, Metropolitan University of Santos, Santos, Brazil
| | - Lina Abu Nada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Claudio Costa
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Emiko Saito Arita
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Faleh Tamimi
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Jerome L Ackerman
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
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11
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Jungmann PM, Agten CA, Pfirrmann CW, Sutter R. Advances in MRI around metal. J Magn Reson Imaging 2017; 46:972-991. [PMID: 28342291 DOI: 10.1002/jmri.25708] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 03/03/2017] [Indexed: 01/02/2023] Open
Abstract
The prevalence of orthopedic metal implants is continuously rising in the aging society. Particularly the number of joint replacements is increasing. Although satisfying long-term results are encountered, patients may suffer from complaints or complications during follow-up, and often undergo magnetic resonance imaging (MRI). Yet metal implants cause severe artifacts on MRI, resulting in signal-loss, signal-pileup, geometric distortion, and failure of fat suppression. In order to allow for adequate treatment decisions, metal artifact reduction sequences (MARS) are essential for proper radiological evaluation of postoperative findings in these patients. During recent years, developments of musculoskeletal imaging have addressed this particular technical challenge of postoperative MRI around metal. Besides implant material composition, configuration and location, selection of appropriate MRI hardware, sequences, and parameters influence artifact genesis and reduction. Application of dedicated metal artifact reduction techniques including high bandwidth optimization, view angle tilting (VAT), and the multispectral imaging techniques multiacquisition variable-resonance image combination (MAVRIC) and slice-encoding for metal artifact correction (SEMAC) may significantly reduce metal-induced artifacts, although at the expense of signal-to-noise ratio and/or acquisition time. Adding advanced image acquisition techniques such as parallel imaging, partial Fourier transformation, and advanced reconstruction techniques such as compressed sensing further improves MARS imaging in a clinically feasible scan time. This review focuses on current clinically applicable MARS techniques. Understanding of the main principles and techniques including their limitations allows a considerate application of these techniques in clinical practice. Essential orthopedic metal implants and postoperative MR findings around metal are presented and highlighted with clinical examples. LEVEL OF EVIDENCE 4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:972-991.
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Affiliation(s)
- Pia M Jungmann
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland.,Faculty of Medicine, University of Zurich, Zurich, Switzerland.,Department of Radiology, Technical University of Munich, Munich, Germany
| | - Christoph A Agten
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland.,Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Christian W Pfirrmann
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland.,Department of Radiology, Technical University of Munich, Munich, Germany
| | - Reto Sutter
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland.,Department of Radiology, Technical University of Munich, Munich, Germany
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12
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Terra GTC, Oliveira JXD, Hernandez A, Lourenço SV, Arita ES, Cortes ARG. Diffusion-weighted MRI for differentiation between sialadenitis and pleomorphic adenoma. Dentomaxillofac Radiol 2016; 46:20160257. [PMID: 27845594 DOI: 10.1259/dmfr.20160257] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVES The aim of this study was to compare apparent diffusion coefficient (ADC) values from diffusion-weighted MRI (DWI) among normal salivary glands, cases with sialadenitis and cases with pleomorphic adenoma of major salivary glands. METHODS 22 patients (totalling 44 major salivary glands) diagnosed with either unilateral sialadenitis (on either parotid or submandibular gland) or parotid gland pleomorphic adenoma were selected. Contralateral non-affected glands (normal) were also analyzed. DW images were achieved using a spin-echo pulse sequence with a 1.5-T MRI device. Mean ADC values were compared among the three groups analyzed (contralateral normal glands, sialadenitis and pleomorphic adenoma). RESULTS The mean ADC values were significantly higher in cases of parotid sialadenitis (p = 0.001), but not in cases of submandibular sialadenitis (p = 0.466), as compared with the contralateral non-affected glands. Cases of pleomorphic adenoma presented the highest ADC values of the study. In addition, one-way ANOVA test revealed a significant difference among the three groups of parotid glands analyzed. CONCLUSIONS Within the limitations of this study, the present results suggest that DWI allows for differentiation between parotid sialadenitis and pleomorphic adenoma.
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Affiliation(s)
- Guilherme T C Terra
- 1 Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Jefferson X D Oliveira
- 1 Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Adalsa Hernandez
- 2 Department of Oral Radiology, Clinica Felix Boada, Caracas, Venezuela
| | - Silvia V Lourenço
- 1 Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Emiko S Arita
- 1 Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Arthur R G Cortes
- 1 Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, Brazil
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