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Willershausen I, Kopp M, Scholz M, Ströbel A, Seidel CL, Paulsen F, Uder M, Gölz L, May MS. Feasibility of 3 Tesla MRI for the assessment of mid-palatal suture maturation: a retrospective pilot study. Odontology 2024:10.1007/s10266-024-00950-0. [PMID: 38758257 DOI: 10.1007/s10266-024-00950-0] [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: 03/08/2024] [Accepted: 05/04/2024] [Indexed: 05/18/2024]
Abstract
The maxilla occupies a key position in dentofacial orthopaedics, since its transversal development can be directly influenced by orthodontic therapy. The maturation stages of the mid-palatal suture, which are obtained from cone-beam computed tomography images (CBCT), present an addition to clinical decision-making in transversal discrepancies of the upper jaw. In an endeavour to reduce ionizing radiation in adolescents and young adults, who are particularly susceptible to long term stochastic irradiation effects, we investigated the feasibility of 3 Tesla (3T) MRI in detecting the maturation stages of the mid-palatal suture. A collective of 30 patients aged 24-93 years with routine neck MRI at 3T, underwent an additional three-dimensional isotropic T1 weighted study sequence of the midface. Image evaluation was performed on axial, multi-planar formatted reconstructions of the dataset aligned to the midline axis of the palate, and curved reconstructions aligned to the concavity of the palate. Inverted images helped to achieve an image impression similar to the well-known CBCT appearance. All datasets were reviewed by three readers and mid-palatal maturation was scored twice according to Angelieri et al. Intra- and inter-rater agreement were evaluated to measure the robustness of the images for clinical evaluation. 3T MRI deemed reliable for the assessment of mid-palatal suture maturation and hence for the appraisal of the hard palate and its adjacent sutures. The data of this pilot study display the feasibility of non-ionizing cross-sectional MRI for the determination of sutural maturation stages. These findings underline the potential of MRI for orthodontic treatment planning, further contributing to the avoidance of unnecessary radiation doses.
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Affiliation(s)
- Ines Willershausen
- Department of Orthodontics and Orofacial Orthopedics, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
| | - Markus Kopp
- Institute of Radiology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Michael Scholz
- Institute of Functional and Clinical Anatomy, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Armin Ströbel
- Center for Clinical Studies (CCS), Medical Faculty, Friedrich-Alexander University Erlangen-Nuremberg, University Hospital Erlangen, Erlangen, Germany
| | - Corinna Lesley Seidel
- Department of Orthodontics and Orofacial Orthopedics, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Friedrich Paulsen
- Institute of Functional and Clinical Anatomy, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Michael Uder
- Institute of Radiology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Lina Gölz
- Department of Orthodontics and Orofacial Orthopedics, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Matthias Stefan May
- Institute of Radiology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
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Candemil AP, Alves Dos Santos GN, Oliveira ML, Gatti F, Silva-Sousa YTC, Silva-Sousa AC, Mazzi-Chaves JF, Sousa-Neto MD. Accuracy of Magnetic Resonance Imaging in Clinical Endodontic Applications: A Systematic Review. J Endod 2024; 50:434-449. [PMID: 38290691 DOI: 10.1016/j.joen.2024.01.014] [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: 10/06/2023] [Revised: 01/16/2024] [Accepted: 01/16/2024] [Indexed: 02/01/2024]
Abstract
INTRODUCTION The development of dedicated coils and new magnetic resonance imaging (MRI) sequences has led to an increase in image resolution and a reduction in artifacts. Consequently, numerous studies have demonstrated the utility of MRI as a nonionizing alternative to cone-beam computed tomographic imaging. The aim of this systematic review was to evaluate the accuracy of MRI in clinical applications in endodontics. METHODS A literature search was conducted using PubMed, Embase, Scopus, and Web of Science. The inclusion criteria encompassed studies evaluating MRI applications in endodontics, covering tooth and root canal anatomy, root canal working length, pulp vitality and regeneration, the effect of caries on dental pulp, guided endodontics, periapical lesions, and root cracks/fractures. The selected studies examined both ex vivo and in vivo human teeth using clinical MRI units. Two researchers independently screened the studies, applied the eligibility criteria, and assessed the potential risk of bias using the revised QUADAS-2 tool (Bristol Medical School, University of Bristol, UK). RESULTS A total of 18 studies were included in this systematic review, demonstrating that the use of MRI has a high diagnostic value in endodontics. In the evaluation of tooth and root canal anatomy, pulp vitality and regeneration, the effect of caries on dental pulp, periapical lesions, and root cracks/fractures, MRI's accuracy is comparable to or even higher than reference standards such as cone-beam computed tomographic imaging, micro-computed tomographic imaging, and histology. CONCLUSIONS MRI has high potential accuracy for diagnosing various clinical endodontic tasks, except for root canal length, size of caries, and periapical lesion dimensions, which are overestimated in MRI.
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Affiliation(s)
- Amanda Pelegrin Candemil
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil; CentraleSupélec, Ecole Normale Supérieure Paris-Saclay, Centre national de la recherche scientifique, Laboratoire de Mécanique Paris-Saclay, Université Paris-Saclay, Gif-sur-Yvette, France.
| | | | - Matheus L Oliveira
- Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
| | - Filippo Gatti
- CentraleSupélec, Ecole Normale Supérieure Paris-Saclay, Centre national de la recherche scientifique, Laboratoire de Mécanique Paris-Saclay, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Alice C Silva-Sousa
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Jardel Francisco Mazzi-Chaves
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Manoel Damião Sousa-Neto
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
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El-Kateb NM, Abdallah AM, ElBackly RN. Correlation between pulp sensibility and magnetic resonance signal intensity following regenerative endodontic procedures in mature necrotic teeth- a retrospective cohort study. BMC Oral Health 2024; 24:330. [PMID: 38481211 PMCID: PMC10935898 DOI: 10.1186/s12903-024-04095-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/04/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND With increasing studies being published on regenerative endodontic procedures (REPs) as a treatment modality for mature necrotic teeth, the assessment of outcomes following regenerative endodontic procedures has become more challenging and the demand for a better understanding of the regenerated tissues following this treatment is rising. The study aimed to correlate cold, electric pulp testing (EPT), and magnetic resonance imaging (MRI) signal intensity (SI) in mature necrotic teeth treated with regenerative endodontic procedures. METHODOLOGY This retrospective cohort study included eighteen adult patients who experienced tooth necrosis in mature maxillary anterior teeth recruited from the outpatient clinic, Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt from July 2017 until December 2018 with 12 months of follow-up. regenerative endodontic procedures via blood clot were performed. The canals were instrumented by ProTaper Next (PTN) files until final sizes X3 or X5. Biodentine was used as cervical plug material. Pre and post-operative clinical follow-up was done where the patients' responses to cold and electric pulp testing were given a scoring system and were compared to the normal contralateral tooth. Pre and post-operative magnetic resonance imaging signal intensity of both the involved tooth and its contralateral at the middle and the apical thirds of the root canals were assessed after 3, 6, and 12 months. Data was analyzed using the ANOVA, Friedman and Bonferroni tests. Significance was set at a p-value < 0.05. RESULTS All 18 teeth scored a baseline score of "2" for cold and electric pulp testing. There was a significant difference between scores of the cold test at baseline and 12-month follow-up (p < 0.001). There was a significant difference between scores of the electric pulp testing of baseline and 12-month follow-up (p < 0.001). There was a moderately significant indirect (inverse) correlation between magnetic resonance imaging signal intensity and cold test in both the middle and apical thirds at 12 months. No significant correlations were detected between magnetic resonance imaging signal intensity and electric pulp testingat any of the time intervals (p > 0.05). CONCLUSION Magnetic resonance imaging is a successful non-invasive method to assess outcomes of regenerative endodontic procedures and correlating it with another reliable method of assessing pulpal responses, cold test, could validate these outcomes. CLINICAL TRIAL REGISTRATION The study was registered with ClinicalTrials.gov (ID: NCT03804450).
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Affiliation(s)
- Noha Mohamed El-Kateb
- Conservative Dentistry Department, Endodontics Division, Faculty of Dentistry, Alexandria University, Champollion Street, El Azareta., Alexandra, Egypt.
| | - Amr Mohamed Abdallah
- Conservative Dentistry Department, Endodontics Division, Faculty of Dentistry, Alexandria University, Champollion Street, El Azareta., Alexandra, Egypt
| | - Rania Noaman ElBackly
- Conservative Dentistry Department, Endodontics Division, Faculty of Dentistry, Alexandria University, Champollion Street, El Azareta., Alexandra, Egypt
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Fuglsig JMDCES, Schropp L, Hansen B, Wenzel A, Spin-Neto R. Jawbone measurements of edentulous sites related to implant planning using magnetic resonance imaging compared to cone beam computed tomography: An ex vivo study. Clin Oral Implants Res 2024; 35:179-186. [PMID: 37985190 DOI: 10.1111/clr.14211] [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: 06/19/2023] [Revised: 10/31/2023] [Accepted: 11/04/2023] [Indexed: 11/22/2023]
Abstract
AIM To compare measurements on images obtained by magnetic resonance imaging (MRI) and cone beam CT (CBCT) for height, width, and area in alveolar bone sites in human jaw specimens. MATERIAL AND METHODS Forty edentulous alveolar posterior sites in human cadaver specimens were imaged using CBCT scanners, and with zero-echo-time MRI (ZTE-MRI). Semi-automatic volume registration was performed to generate representative coronal sections of the sites related to implant planning. ZTE-MRI sections were also presented after grayscale inversion (INV MRI). Three observers measured bone height, bone width 5 mm from the alveolar crest, and bone area stretching from the width measurement to the top of the alveolar crest in the images. Interobserver agreement was assessed by intra-class correlation coefficients (ICC). The measurements were analyzed using two-way repeated measures ANOVA factoring observer and image type. RESULTS ICC was >0.95 for bone height, width, and bone area. No significant differences among observers (p = 0.14) or image type (p = 0.60) were found for bone height. For bone width, observer (p = 0.14) was not a significant factor, while ZTE-MRI produced width estimates that were significantly different and systematically smaller than CBCT-based estimates (p ≤ 0.001). Observer (p = 0.06) was not a significant factor regarding the bone area measurements, contrary to the imaging type where ZTE-MRI led to significantly smaller area estimates than CBCT (p ≤ 0.001). CONCLUSION Bone height measurements were essentially equivalent using CBCT and MRI. This was found regardless of grayscale choice for the MRI. However, ZTE-MRI resulted in smaller estimates of bone width and area.
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Affiliation(s)
| | - Lars Schropp
- Department of Dentistry and Oral Health, Oral Radiology, Aarhus University, Aarhus, Denmark
| | - Brian Hansen
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Ann Wenzel
- Department of Dentistry and Oral Health, Oral Radiology, Aarhus University, Aarhus, Denmark
| | - Rubens Spin-Neto
- Department of Dentistry and Oral Health, Oral Radiology, Aarhus University, Aarhus, Denmark
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Flick K, Smeets R, Gosau M, Meyer L, Hanning U, Kyselyova AA, Scheifele C, Höhmann B, Henningsen A. Assessment of the intrasinusidal volume before and after maxillary sinus augmentation using mri - a pilot study of eight patients. BMC Oral Health 2024; 24:142. [PMID: 38287339 PMCID: PMC10823631 DOI: 10.1186/s12903-024-03858-x] [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: 10/04/2023] [Accepted: 01/04/2024] [Indexed: 01/31/2024] Open
Abstract
PURPOSE The purpose of this study was to evaluate the suitability, accuracy, and reliability of a non-invasive 3-Tesla magnetic resonance imaging technique (3 T-MRI) for the visualization of maxillary sinus grafts in comparison to conventional, X-ray-based, established standard imaging techniques. METHODS A total of eight patients with alveolar bone atrophy who required surgical sinus floor augmentation in the course of dental implantation were included in this pilot study. Alongside pre-operative cone-beam computed tomography (CBCT), 3 T-MRI was performed before and 6 months after sinus floor augmentation. Two investigators measured the maxillary sinus volume preoperatively and after bone augmentation. RESULTS In all cases, MRI demonstrated accurately the volumes of the maxillary sinus grafts. Following surgery, the bony structures suitable for an implant placement increased at an average of 4.89 cm3, corresponding with the decrease of the intrasinusidal volumes. In general, interexaminer discrepancies were low and without statistical significance. CONCLUSION In this preliminary study, we could demonstrate the feasibility of MRI bone volume measurement as a radiation-free alternative with comparable accuracy to CT/CBCT before procedures like sinus floor augmentation. Nevertheless, costs and artifacts, also present in MRI, have to be taken into account. Larger studies will be necessary to justify the practicability of MRI bone volume evaluation.
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Affiliation(s)
- K Flick
- Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
- Division of "Regenerative Orofacial Medicine", Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - R Smeets
- Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
- Division of "Regenerative Orofacial Medicine", Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - M Gosau
- Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - L Meyer
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - U Hanning
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - A A Kyselyova
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - C Scheifele
- Dental Radiology Unit, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - B Höhmann
- Department of Preventive and Restorative Dentistry, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - A Henningsen
- Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
- Division of "Regenerative Orofacial Medicine", Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Greiser A, Christensen J, Fuglsig JMCS, Johannsen KM, Nixdorf DR, Burzan K, Lauer L, Krueger G, Hayes C, Kettless K, Ulrici J, Spin-Neto R. Dental-dedicated MRI, a novel approach for dentomaxillofacial diagnostic imaging: technical specifications and feasibility. Dentomaxillofac Radiol 2024; 53:74-85. [PMID: 38214941 PMCID: PMC11003656 DOI: 10.1093/dmfr/twad004] [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: 08/03/2023] [Revised: 09/12/2023] [Accepted: 10/06/2023] [Indexed: 01/13/2024] Open
Abstract
MRI is a noninvasive, ionizing radiation-free imaging modality that has become an indispensable medical diagnostic method. The literature suggests MRI as a potential diagnostic modality in dentomaxillofacial radiology. However, current MRI equipment is designed for medical imaging (eg, brain and body imaging), with general-purpose use in radiology. Hence, it appears expensive for dentists to purchase and maintain, besides being complex to operate. In recent years, MRI has entered some areas of dentistry and has reached a point in which it can be provided following a tailored approach. This technical report introduces a dental-dedicated MRI (ddMRI) system, describing how MRI can be adapted to fit dentomaxillofacial radiology through the appropriate choice of field strength, dental radiofrequency surface coil, and pulse sequences. Also, this technical report illustrates the possible application and feasibility of the suggested ddMRI system in some relevant diagnostic tasks in dentistry. Based on the presented cases, it is fair to consider the suggested ddMRI system as a feasible approach to introducing MRI to dentists and dentomaxillofacial radiology specialists. Further studies are needed to clarify the diagnostic accuracy of ddMRI considering the various diagnostic tasks relevant to the practice of dentistry.
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Affiliation(s)
| | - Jennifer Christensen
- Section for Oral Radiology and Endodontics, Department of Dentistry and Oral Health, Aarhus University, Aarhus, 8000, Denmark
| | - João M C S Fuglsig
- Section for Oral Radiology and Endodontics, Department of Dentistry and Oral Health, Aarhus University, Aarhus, 8000, Denmark
| | - Katrine M Johannsen
- Section for Oral Radiology and Endodontics, Department of Dentistry and Oral Health, Aarhus University, Aarhus, 8000, Denmark
| | - Donald R Nixdorf
- Division of TMD & Orofacial Pain, School of Dentistry, University of Minnesota Twin Cities, MN, 55455, United States
- Department of Radiology, Medical School, University of Minnesota Twin Cities, MN, 55455, United States
| | - Kim Burzan
- Sirona Dental Systems GmbH, Bensheim, 64625, Germany
| | - Lars Lauer
- Siemens Healthcare GmbH, Erlangen, 91052, Germany
| | | | - Carmel Hayes
- Siemens Healthcare GmbH, Erlangen, 91052, Germany
| | | | | | - Rubens Spin-Neto
- Section for Oral Radiology and Endodontics, Department of Dentistry and Oral Health, Aarhus University, Aarhus, 8000, Denmark
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Feuerriegel GC, Kronthaler S, Weiss K, Haller B, Leonhardt Y, Neumann J, Pfeiffer D, Hesse N, Erber B, Schwaiger BJ, Makowski MR, Woertler K, Karampinos DC, Wurm M, Gersing AS. Assessment of glenoid bone loss and other osseous shoulder pathologies comparing MR-based CT-like images with conventional CT. Eur Radiol 2023; 33:8617-8626. [PMID: 37453986 PMCID: PMC10667374 DOI: 10.1007/s00330-023-09939-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 04/24/2023] [Accepted: 05/16/2023] [Indexed: 07/18/2023]
Abstract
OBJECTIVES To evaluate and compare the diagnostic performance of CT-like images based on a 3D T1-weighted spoiled gradient-echo sequence (T1 GRE), an ultra-short echo time sequence (UTE), and a 3D T1-weighted spoiled multi-echo gradient-echo sequence (FRACTURE) with conventional CT in patients with suspected osseous shoulder pathologies. MATERIALS AND METHODS Patients with suspected traumatic dislocation of the shoulder (n = 46, mean age 40 ± 14.5 years, 19 women) were prospectively recruited and received 3-T MR imaging including 3D T1 GRE, UTE, and 3D FRACTURE sequences. CT was performed in patients with acute fractures and served as standard of reference (n = 25). Agreement of morphological features between the modalities was analyzed including the glenoid bone loss, Hill-Sachs interval, glenoid track, and the anterior straight-line length. Agreement between the modalities was assessed using Bland-Altman plots, Student's t-test, and Pearson's correlation coefficient. Inter- and intrareader assessment was evaluated with weighted Cohen's κ and intraclass correlation coefficient. RESULTS All osseous pathologies were detected accurately on all three CT-like sequences (n = 25, κ = 1.00). No significant difference in the percentage of glenoid bone loss was found between CT (mean ± standard deviation, 20.3% ± 8.0) and CT-like MR images (FRACTURE 20.6% ± 7.9, T1 GRE 20.4% ± 7.6, UTE 20.3% ± 7.7, p > 0.05). When comparing the different measurements on CT-like images, measurements performed using the UTE images correlated best with CT. CONCLUSION Assessment of bony Bankart lesions and other osseous pathologies was feasible and accurate using CT-like images based on 3-T MRI compared with conventional CT. Compared to the T1 GRE and FRACTURE sequence, the UTE measurements correlated best with CT. CLINICAL RELEVANCE STATEMENT In an acute trauma setting, CT-like images based on a T1 GRE, UTE, or FRACTURE sequence might be a useful alternative to conventional CT scan sparing associated costs as well as radiation exposure. KEY POINTS • No significant differences were found for the assessment of the glenoid bone loss when comparing measurements of CT-like MR images with measurements of conventional CT images. • Compared to the T1 GRE and FRACTURE sequence, the UTE measurements correlated best with CT whereas the FRACTURE sequence appeared to be the most robust regarding motion artifacts. • The T1 GRE sequence had the highest resolution with high bone contrast and detailed delineation of even small fractures but was more susceptible to motion artifacts.
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Affiliation(s)
- Georg C Feuerriegel
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany.
| | - Sophia Kronthaler
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | | | - Bernhard Haller
- Institute of Medical Informatics, Statistics and Epidemiology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Yannik Leonhardt
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Jan Neumann
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
- Musculoskeletal Radiology Section, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Daniela Pfeiffer
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Nina Hesse
- Department of Radiology, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Bernd Erber
- Department of Radiology, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Benedikt J Schwaiger
- Department of Neuroradiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Marcus R Makowski
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Klaus Woertler
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
- Musculoskeletal Radiology Section, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Dimitrios C Karampinos
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Markus Wurm
- Department of Trauma Surgery, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Alexandra S Gersing
- Department of Radiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
- Department of Neuroradiology, University Hospital of Munich, LMU Munich, Munich, Germany
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Fuglsig JMDCES, Hansen B, Schropp L, Nixdorf DR, Wenzel A, Spin-Neto R. Alveolar bone measurements in magnetic resonance imaging compared with cone beam computed tomography: a pilot, ex-vivo study. Acta Odontol Scand 2023; 81:241-248. [PMID: 36112428 DOI: 10.1080/00016357.2022.2121321] [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] [Indexed: 11/01/2022]
Abstract
OBJECTIVES To compare alveolar bone height and width measurements from zero-echo-time MRI (ZTE-MRI) and cone beam CT (CBCT), in human specimens. MATERIAL AND METHODS Twenty posterior edentulous sites in human cadaver specimens were imaged with CBCT and ZTE-MRI. Bone height and width at 1, 3, 5, 7 and 9 mm from the top of the alveolar ridge was measured by two trained observers in cross-sections of a site where an implant was to be planned. Twenty percent of the sample was measured in duplicate to assess method error and intra-observer reproducibility (ICC). The differences between CBCT and ZTE-MRI measurements were compared (t-test). RESULTS Inter- and intra-observer reproducibility was >0.90. The method error (average between observers) for bone height was 0.45 mm and 0.39 mm, and for bone width (average) was 0.52 mm and 0.80 mm (CBCT and ZTE-MRI, respectively). The majority of the bone measurement differences were statistically insignificant, except bone width measurements at 5 mm (p ≤ .05 for both observers). Mean measurement differences were not larger than the method error. CONCLUSION ZTE-MRI is not significantly different from CBCT when comparing measurements of alveolar bone height and width.
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Affiliation(s)
| | - Brian Hansen
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Lars Schropp
- Department of Dentistry and Oral Health, Section for Oral Radiology, Aarhus University, Aarhus, Denmark
| | - Donald R Nixdorf
- Division of TMD & Orofacial Pain, School of Dentistry, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
- Department of Radiology, Medical School, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Ann Wenzel
- Department of Dentistry and Oral Health, Section for Oral Radiology, Aarhus University, Aarhus, Denmark
| | - Rubens Spin-Neto
- Department of Dentistry and Oral Health, Section for Oral Radiology, Aarhus University, Aarhus, Denmark
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9
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Feuerriegel GC, Ritschl LM, Sollmann N, Palla B, Leonhardt Y, Maier L, Gassert FT, Karampinos DC, Makowski MR, Zimmer C, Wolff KD, Probst M, Fichter AM, Burian E. Imaging of traumatic mandibular fractures in young adults using CT-like MRI: a feasibility study. Clin Oral Investig 2023; 27:1227-1233. [PMID: 36208329 PMCID: PMC9985557 DOI: 10.1007/s00784-022-04736-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 10/01/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To assess and compare the diagnostic performance of CT-like images based on a three- dimensional (3D) T1-weighted spoiled gradient-echo sequence (3D T1 GRE) with CT in patients with acute traumatic fractures of the mandible. MATERIALS AND METHODS Subjects with acute mandibular fractures diagnosed on conventional CT were prospectively recruited and received an additional 3 T MRI with a CT-like 3D T1 GRE sequence. The images were assessed by two radiologists with regard to fracture localization, degree of dislocation, and number of fragments. Bone to soft tissue contrast, diagnostic confidence, artifacts, and overall image quality were rated using a five-point Likert-scale. Agreement of measurements was assessed using an independent t-test. RESULTS Fourteen subjects and 22 fracture sites were included (26 ± 3.9 years; 4 females, 10 males). All traumatic fractures were accurately detected on CT-like MRI (n = 22, κ 1.00 (95% CI 1.00-1.00)). There was no statistically significant difference in the assessment of the fracture dislocation (axial mean difference (MD) 0.06 mm, p = 0.93, coronal MD, 0.08 mm, p = 0.89 and sagittal MD, 0.04 mm, p = 0.96). The agreement for the fracture classification as well as the inter- and intra-rater agreement was excellent (range κ 0.92-0.98 (95% CI 0.96-0.99)). CONCLUSION Assessment of mandibular fractures was feasible and accurate using CT-like MRI based on a 3D T1 GRE sequence and is comparable to conventional CT. CLINICAL RELEVANCE For the assessment of acute mandibular fractures, CT-like MRI might become a useful alternative to CT in order to reduce radiation exposure particularly in young patients.
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Affiliation(s)
- Georg C Feuerriegel
- Department of Diagnostic and Interventional Radiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany.
| | - Lucas M Ritschl
- Department of Oral and Maxillofacial Surgery, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Nico Sollmann
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany.,TUM-Neuroimaging Center, Klinikum Rechts Der Isar, Technical University of Munich, Munich, Germany.,Department of Diagnostic and Interventional Radiology, University Hospital Ulm, Ulm, Germany
| | - Benjamin Palla
- Department of Oral and Maxillofacial Surgery, University of Illinois Chicago, Chicago, USA
| | - Yannik Leonhardt
- Department of Diagnostic and Interventional Radiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Lisa Maier
- Department of Oral and Maxillofacial Surgery, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Florian T Gassert
- Department of Diagnostic and Interventional Radiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Marcus R Makowski
- Department of Diagnostic and Interventional Radiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Claus Zimmer
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Klaus-Dietrich Wolff
- Department of Oral and Maxillofacial Surgery, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Monika Probst
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Andreas M Fichter
- Department of Oral and Maxillofacial Surgery, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Egon Burian
- Department of Diagnostic and Interventional Radiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany
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10
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Hilgenfeld T, Saleem MA, Schwindling FS, Ludwig U, Hövener JB, Bock M, Flügge T, Eisenbeiss AK, Nittka M, Mente J, Jende JME, Heiland S, Bendszus M, Juerchott A. High-Resolution Single Tooth MRI With an Inductively Coupled Intraoral Coil-Can MRI Compete With CBCT? Invest Radiol 2022; 57:720-727. [PMID: 35640007 DOI: 10.1097/rli.0000000000000890] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aims of this study were to quantify T1/T2-relaxation times of the dental pulp, develop a realistic tooth model, and compare image quality between cone-beam computed tomography (CBCT) and high-resolution magnetic resonance imaging (MRI) of single teeth using a wireless inductively coupled intraoral coil. METHODS T1/T2-relaxometry was performed at 3 T in 10 healthy volunteers (283 teeth) to determine relaxation times of healthy dental pulp and develop a realistic tooth model using extracted human teeth. Eight MRI sequences (DESS, CISS, TrueFISP, FLASH, SPACE, TSE, MSVAT-SPACE, and UTE) were optimized for clinically applicable high-resolution imaging of the dental pulp. In model, image quality of all sequences was assessed quantitatively (contrast-to-noise ratio) and qualitatively (visibility of anatomical structures and extent of susceptibility artifacts using a 5-point scoring scale). Cone-beam computed tomography served as the reference modality for qualitative assessment. Statistical analysis was performed using 2-way analysis of variance, Fisher exact test, and Cohen κ. RESULTS In vivo, relaxometry of dental pulps revealed T1/T2 relaxation times at 3 T of 738 ± 100/171 ± 36 milliseconds. For all sequences, an isotropic resolution of (0.21 mm) 3 was achieved, with acquisition times ranging from 6:19 to 8:02 minutes. In model, the highest contrast-to-noise ratio values were observed for UTE, followed by TSE and CISS. The best image/artifact quality, however, was found for DESS (mean ± SD: 1.3 ± 0.3/2.2 ± 0.0), FLASH (1.5 ± 0.3/2.4 ± 0.1), and CISS (1.5 ± 0.4/2.5 ± 0.1), at a level comparable to CBCT (1.2 ± 0.3/2.1 ± 0.1). CONCLUSIONS Optimized MRI protocols using an intraoral coil at 3 T can achieve an image quality comparable to reference modality CBCT within clinically applicable acquisition times. Overall, DESS revealed the best results, followed by FLASH and CISS.
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Affiliation(s)
| | | | | | - Ute Ludwig
- Department of Radiology, Medical Physics, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg
| | - Jan-Bernd Hövener
- Section Biomedical Imaging, Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel University, Kiel
| | - Michael Bock
- Department of Radiology, Medical Physics, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg
| | - Tabea Flügge
- Department of Oral and Maxillofacial Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin
| | - Anne-Katrin Eisenbeiss
- Department of Oral and Maxillofacial Surgery, University Medical Center Schleswig-Holstein, Christian-Albrechts-University, Kiel
| | | | - Johannes Mente
- Division of Endodontics and Dental Traumatology, Department of Conservative Dentistry, Heidelberg University Hospital, Heidelberg, Germany
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11
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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: 1] [Impact Index Per Article: 0.5] [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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12
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Tesfai AS, Vollmer A, Özen AC, Braig M, Semper-Hogg W, Altenburger MJ, Ludwig U, Bock M. Inductively Coupled Intraoral Flexible Coil for Increased Visibility of Dental Root Canals in Magnetic Resonance Imaging. Invest Radiol 2022; 57:163-170. [PMID: 34510099 DOI: 10.1097/rli.0000000000000826] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Accurate visualization of dental root canals is vital for the correct diagnosis and subsequent treatment. This work assesses the improvement of a dedicated new coil for dental magnetic resonance imaging (MRI) in comparison to conventional ones in terms of signal-to-noise ratio (SNR) and visibility. MATERIALS AND METHODS A newly developed intraoral flexible coil was used to display dental roots with MRI, and it provides improved sensitivity with a loop design and size adjusted to a single tooth anatomy. Ex vivo and in vivo measurements were performed on a 3 T clinical MR system, and results were compared with conventional head and surface coil images. Additional comparison was performed with a modified fast spin echo sequence and a constructive interference in steady-state sequence. RESULTS Ex vivo, an SNR gain of 6.3 could be achieved with the intraoral flexible coil setup, and higher visibility down to 200 μm was possible, whereas the external loop coil is limited to 400 μm. In vivo measurements in a volunteer resulted in an SNR gain of up to 4.5 with an improved delineation of the root canals, especially for the branch tissue splitting of the mesial root canal into mesial-buccal and mesial-lingual. CONCLUSIONS In summary, we showed the feasibility of implementing a wireless coil approach with readily available dental practice materials for sealing and placement. Highly improved MRI scans can be acquired within clinically feasible scan times, and this might provide additional medical findings to supplement available x-ray images.
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Affiliation(s)
| | - Andreas Vollmer
- Department of Oral and Craniomaxillofacial Surgery, Center for Dental Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg
| | | | | | - Wiebke Semper-Hogg
- Department of Oral and Craniomaxillofacial Surgery, Center for Dental Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg
| | - Markus Jörg Altenburger
- Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ute Ludwig
- From the Department of Radiology, Medical Physics
| | - Michael Bock
- From the Department of Radiology, Medical Physics
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13
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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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14
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Kobayashi N, Bambach S, Ho ML. Ultrashort Echo-Time MR Imaging of the Pediatric Head and Neck. Magn Reson Imaging Clin N Am 2021; 29:583-593. [PMID: 34717846 DOI: 10.1016/j.mric.2021.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Bone MR imaging techniques use extremely rapid echo times to maximize detection of short-T2 tissues with low water concentrations. The major approaches used in clinical practice are ultrashort echo-time and zero echo-time. Synthetic CT generation is feasible using atlas-based, voxel-based, and deep learning approaches. Major clinical applications in the pediatric head and neck include evaluation for craniosynostosis, sinonasal and jaw imaging, trauma, interventional planning, and postoperative follow-up. In this article, we review the technical background and practical usefulness of bone MR imaging with key imaging examples.
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Affiliation(s)
- Naoharu Kobayashi
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, 2021 6th Street SE, Minneapolis, MN 55455, USA
| | - Sven Bambach
- Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - Mai-Lan Ho
- Department of Radiology, Nationwide Children's Hospital, 700 Children's Dr - ED4, Columbus, OH 43205, USA.
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15
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Demeshkant V, Cwynar P, Slivinska K. Horse Tooth Enamel Ultrastructure: A Review of Evolutionary, Morphological, and Dentistry Approaches. Folia Biol (Praha) 2021. [DOI: 10.3409/fb_69-2.09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This review searches for and analyzes existing knowledge on horse tooth anatomy in terms of evolutionary and morphological changes, feeding habits, breeding practices, and welfare. More than 150 articles from relevant databases were analyzed, taking into account the issues of our experimental
research on the ultrastructure of Equidae tooth enamel. After our analysis, the knowledge on this subject accumulated up in the past, almost 50 years has been logically arranged into three basic directions: evolutionary-palaeontological, morpho-functional, and dentistic, which is also demonstrated
by the latest trends in the study of enamel morphology and in the practice of equine dentistry. The obtained data show that in recent years we have observed a rapid increase in publications and a thematic expansion of the scope of research. It is caused by the need to deepen knowledge in theory
and in the practice of feeding species in nature and in captivity as well as the possibility of using new technical resources to improve the excellence of such research. It is a summary of the knowledge of a certain stage of equine tooth enamel studies for this period of time, which serves
as the basis for our experimental research (the materials are prepared for publication) and at the same time, defines research perspectives for the next stage of development.
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16
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Froidevaux R, Weiger M, Rösler MB, Brunner DO, Pruessmann KP. HYFI: Hybrid filling of the dead-time gap for faster zero echo time imaging. NMR IN BIOMEDICINE 2021; 34:e4493. [PMID: 33624305 PMCID: PMC8244056 DOI: 10.1002/nbm.4493] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 05/31/2023]
Abstract
The aim of this work was to improve the SNR efficiency of zero echo time (ZTE) MRI pulse sequences for faster imaging of short-T2 components at large dead-time gaps. ZTE MRI with hybrid filling (HYFI) is a strategy for retrieving inner k-space data missed during the dead-time gaps arising from radio-frequency excitation and switching in ZTE imaging. It performs hybrid filling of the inner k-space with a small single-point-imaging core surrounded by a stack of shells acquired on radial readouts in an onion-like fashion. The exposition of this concept is followed by translation into guidelines for parameter choice and implementation details. The imaging properties and performance of HYFI are studied in simulations as well as phantom, in vitro and in vivo imaging, with an emphasis on comparison with the pointwise encoding time reduction with radial acquisition (PETRA) technique. Simulations predict higher SNR efficiency for HYFI compared with PETRA at preserved image quality, with the advantage increasing with the size of the k-space gap. These results are confirmed by imaging experiments with gap sizes of 25 to 50 Nyquist dwells, in which scan times for similar image quality could be reduced by 25% to 60%. The HYFI technique provides both high SNR efficiency and image quality, thus outperforming previously known ZTE-based pulse sequences, in particular for large k-space gaps. Promising applications include direct imaging of ultrashort-T2 components, such as the myelin bilayer or collagen, T2 mapping of ultrafast relaxing signals, and ZTE imaging with reduced chemical shift artifacts.
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Affiliation(s)
- Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Manuela B Rösler
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David O Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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17
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Peschke E, Ulloa P, Jansen O, Hoevener JB. Metallic Implants in MRI - Hazards and Imaging Artifacts. ROFO-FORTSCHR RONTG 2021; 193:1285-1293. [PMID: 33979870 DOI: 10.1055/a-1460-8566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Magnetic resonance imaging (MRI) is an examination method for noninvasive soft tissue imaging without the use of ionizing radiation. Metallic implants, however, may pose a risk for the patient and often result in imaging artifacts. Due to the increasing number of implants, reducing these artifacts has become an important goal. In this review, we describe the risks associated with implants and provide the background on how metal-induced artifacts are formed. We review the literature on methods on how to reduce artifacts and summarize our findings. METHOD The literature was searched using PubMed and the keywords "MRI metal artifact reduction", "metallic implants" and "MRI artefacts/artifacts". RESULTS AND CONCLUSION The MRI compatibility of implants has to be evaluated individually. To reduce artifacts, two general approaches were found: a) parameter optimization in standard sequences (echo time, slice thickness, bandwidth) and b) specialized sequences, such as VAT, OMAR, WARP, SEMAC and MAVRIC. These methods reduced artifacts and improved image quality, albeit at the cost of a (sometimes significantly) prolonged scan time. New developments in accelerated imaging will likely shorten the scan time of these methods significantly, such that routine use may become feasible. KEY POINTS · Metallic implants may pose a risk for patients and often cause artifacts.. · Imaging artifacts can be reduced by parameter optimization or special sequences.. · Metal artifacts are reduced with a lower TE, smaller voxel size, larger matrix, and higher bandwidth.. · SPI, STIR, VAT, SEMAC, MAVRIC, and MAVRIC-SL are specialized MR sequences that can reduce artifacts further.. CITATION FORMAT · Peschke E, Ulloa P, Jansen O et al. Metallic Implants in MRI - Hazards and Imaging Artifacts. Fortschr Röntgenstr 2021; 193: 1285 - 1293.
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Affiliation(s)
- Eva Peschke
- Department for Radiology and Neuroradiology, Molecular Imaging North Competence Center (MOIN CC), Section Biomedical Imaging, University Hospital Schleswig-Holstein - Campus Kiel, Kiel University, Germany
| | - Patricia Ulloa
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein - Campus Kiel, Germany
| | - Olav Jansen
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein - Campus Kiel, Germany
| | - Jan-Bernd Hoevener
- Department for Radiology and Neuroradiology, Molecular Imaging North Competence Center (MOIN CC), Section Biomedical Imaging, University Hospital Schleswig-Holstein - Campus Kiel, Kiel University, Germany
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18
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Age-dependent decrease in dental pulp cavity volume as a feature for age assessment: a comparative in vitro study using 9.4-T UTE-MRI and CBCT 3D imaging. Int J Legal Med 2021; 135:1599-1609. [PMID: 33903959 PMCID: PMC8206054 DOI: 10.1007/s00414-021-02603-1] [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: 03/10/2021] [Accepted: 04/14/2021] [Indexed: 11/13/2022]
Abstract
Evaluation of secondary dentin formation is generally suitable for age assessment. We investigated the potential of modern magnetic resonance imaging (MRI) technology to visualize the dental pulp in direct comparison with cone beam computed tomography (CBCT). To this end, we examined 32 extracted human teeth (teeth 11–48 [FDI]) using 9.4-T ultrashort echo time (UTE)-MRI and CBCT (methods). 3D reconstruction was performed via both manual and semi-automatic segmentation (settings) for both methods in two runs by one examiner. Nine teeth were also examined by a second examiner. We evaluated the agreement between examiners, scan methods, and settings. CBCT was able to determine the pulp volume for all teeth. This was not possible for two teeth on MRI due to MRI artifacts. The mean pulp volume estimated by CBCT was consistently higher (~ 43%) with greater variability. With lower variability in its measurements, evaluation of pulp volume using the MRI method exhibited greater sensitivity to differences between settings (p = 0.016) and between examiners (p = 0.009). The interactions of single-rooted teeth and multi-rooted teeth and method or setting were not found to be significant. For examiner agreement, the mean pulp volumes were similar with overlapping measurements (ICC > 0.995). Suitable for use in age assessment is 9.4-T UTE-MRI with good reliability and lower variation than CBCT. For MRI, manual segmentation is necessary due to a more detailed representation of the interior of the pulp cavity. Since determination of pulp volume is expected to be systematically larger using CBCT, method-specific reference values are indispensable for practical age assessment procedures. The results should be verified under in vivo conditions in the future.
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19
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Leontiev W, Bieri O, Madörin P, Dagassan-Berndt D, Kühl S, Krastl G, Krug R, Weiger R, Connert T. Suitability of Magnetic Resonance Imaging for Guided Endodontics: Proof of Principle. J Endod 2021; 47:954-960. [PMID: 33774047 DOI: 10.1016/j.joen.2021.03.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/14/2021] [Accepted: 03/16/2021] [Indexed: 02/06/2023]
Abstract
INTRODUCTION This proof-of-principle study aimed to demonstrate that magnetic resonance imaging (MRI) is sufficiently accurate for the detection of root canals using guided endodontics. METHODS One hundred extracted human teeth (anterior and premolar) were mounted onto 5 mandibular and 5 maxillary models, fitted with splints designed to accommodate a thin layer of aqueous gel for indirect imaging, and scanned by MRI. After MRI and intraoral scans were aligned using planning software, access cavities were planned virtually, and templates were manufactured with computer-aided design/computer-aided manufacturing, the access cavities were prepared. Cone-beam computed tomographic scans were performed and matched with the virtual preoperative planning data to determine the accuracy of access cavity preparation in terms of deviation between planned and prepared cavities in the mesiodistal and buccolingual dimensions and angle. Descriptive statistical analysis was performed, and the mean values were compared using the t test. RESULTS Ninety-one of 100 root canals were successfully scouted after MRI-guided access cavity preparation. The mean angle deviation was 1.82°. The mean deviation ranged from 0.21-0.31 mm at the base of the bur and from 0.28-0.44 mm at the tip of the bur. Preparation in the buccolingual dimension was significantly more precise in mandibular compared with maxillary teeth, and accuracy in the mesiodistal dimension was more precise in anterior teeth compared with premolars. CONCLUSIONS This in vitro study demonstrated the suitability of MRI for guided endodontic access cavity preparation.
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Affiliation(s)
- Wadim Leontiev
- Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine, University of Basel, Basel, Switzerland
| | - Oliver Bieri
- Department of Radiology, Division of Radiological Physics, University Hospital Basel, Basel, Switzerland
| | - Philipp Madörin
- Department of Radiology, Division of Radiological Physics, University Hospital Basel, Basel, Switzerland
| | - Dorothea Dagassan-Berndt
- Center for Dental Imaging, University Center for Dental Medicine, University of Basel, Basel, Switzerland
| | - Sebastian Kühl
- Department of Oral Surgery, University Center for Dental Medicine, University of Basel, Basel, Switzerland
| | - Gabriel Krastl
- Department of Conservative Dentistry and Periodontology, University Hospital of Würzburg, Würzburg, Germany
| | - Ralf Krug
- Department of Conservative Dentistry and Periodontology, University Hospital of Würzburg, Würzburg, Germany
| | - Roland Weiger
- Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine, University of Basel, Basel, Switzerland
| | - Thomas Connert
- Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine, University of Basel, Basel, Switzerland.
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20
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März K, Chepura T, Plewig B, Haddad D, Weber D, Schmid M, Hirschfelder U, Gölz L. Cephalometry without complex dedicated postprocessing in an oriented magnetic resonance imaging dataset: a pilot study. Eur J Orthod 2021; 43:614-621. [PMID: 33735379 DOI: 10.1093/ejo/cjaa066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Magnetic resonance imaging (MRI) enables a 3D-volume-imaging without ionizing radiation. Therefore, it was the aim of this study to present a post-processing-free method for cephalometric analysis of a MRI-dataset and to examine whether there is a significant difference between cephalometric analysis of conventional 2D cephalograms and MRI scans. METHODS One MRI scan each was performed on three cadaver heads using a 3T-MR-scanner. Cephalometric analysis was conducted directly on the 3D dataset. All reference points were projected onto a virtual sagittal plane that was perpendicular to the Frankfort horizontal plane. Double-sided points were averaged. Cephalometric angles were measured from the projected points. Results were compared with cephalometric measurements on conventional lateral cephalometric radiographs (LCRs). The cephalometric analysis was performed by five raters. RESULTS 390-angle measurements were obtained. The inter-rater reliability was high [intraclass correlation coefficients (ICCs) ≥ 0.74 for all angles]. Differences between the measurements on the cephalograms and MRI scans ranged between -0.91° (-1.88°, 0.07°) and 0.97° (-0.63°, 2.57°) on average and were equivalent with respect to a margin of [-2°, 2°] in all angles except L1-Me-Tgo (Bonferroni-Holm-corrected P < 0.05 in all angles except L1-Me-Tgo). The best match was found for the SNA angle. CONCLUSION The clinical comparability of the MRI- and LCR-based cephalometry could be stated. Using MRI in orthodontics would reduce radiation exposure and the risk of stochastic radiation damage, which is of importance especially in younger patients.
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Affiliation(s)
- Karoline März
- Department of Orthodontics and Orofacial Orthopedics, Friedrich-Alexander-University Erlangen-Nürnberg, Germany
| | - Taras Chepura
- Department of Orthodontics and Orofacial Orthopedics, Friedrich-Alexander-University Erlangen-Nürnberg, Germany
| | - Blanka Plewig
- Department of Orthodontics and Orofacial Orthopedics, Friedrich-Alexander-University Erlangen-Nürnberg, Germany
| | - Daniel Haddad
- Magnetic Resonance and X-ray Imaging Department of the Development Centre X-ray Technology EZRT, Division of Fraunhofer Institute for Integrated Circuits IIS, Würzburg, Germany
| | - Daniel Weber
- Magnetic Resonance and X-ray Imaging Department of the Development Centre X-ray Technology EZRT, Division of Fraunhofer Institute for Integrated Circuits IIS, Würzburg, Germany
| | - Matthias Schmid
- Institute for Medical Biometry, Informatics and Epidemiology (IMBIE), Faculty of Medicine, University of Bonn, Germany
| | - Ursula Hirschfelder
- Department of Orthodontics and Orofacial Orthopedics, Friedrich-Alexander-University Erlangen-Nürnberg, Germany
| | - Lina Gölz
- Department of Orthodontics and Orofacial Orthopedics, Friedrich-Alexander-University Erlangen-Nürnberg, Germany
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21
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Flügge T, Ludwig U, Amrein P, Kernen F, Vach K, Maier J, Nelson K. MRI for the display of autologous onlay bone grafts during early healing-an experimental study. Dentomaxillofac Radiol 2021; 50:20200068. [PMID: 33201739 PMCID: PMC7860956 DOI: 10.1259/dmfr.20200068] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Autologous bone grafts are the gold standard to augment deficient alveolar bone. Dimensional graft alterations during healing are not known as they are not accessible to radiography. Therefore, MRI was used to display autologous onlay bone grafts in vivo during early healing. METHODS AND MATERIALS Ten patients with alveolar bone atrophy and autologous onlay grafts were included. MRI was performed with a clinical MR system and an intraoral coil preoperatively (t0), 1 week (t1), 6 weeks (t2) and 12 weeks (t3) postoperatively, respectively. The graft volumes were assessed in MRI by manual segmentation by three examiners. Graft volumes for each time point were calculated and dimensional alteration was documented. Cortical and cancellous proportions of bone grafts were assessed. The intraobserver and interobserver variability were calculated. Statistical analysis was performed using a mixed linear regression model. RESULTS Autologous onlay bone grafts with cortical and cancellous properties were displayed in vivo in eight patients over 12 weeks. The fixation screws were visible as signal voids with a thin hyperintense fringe. The calculated volumes were between 0.12-0.74 cm3 (t1), 0.15-0.73 cm3 (t2), and 0.17-0.64 cm3 (t3). Median changes of bone graft volumes of -15% were observed. There was no significant difference between the examiners (p = 0.3). CONCLUSIONS MRI is eligible for the display and longitudinal observation of autologous onlay bone grafts. Image artifacts caused measurements deviations in some cases and minimized the precise assessment of graft volume. To the knowledge of the authors, this is the first study that used MRI for the longitudinal observation of autologous onlay bone grafts.
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Affiliation(s)
- Tabea Flügge
- Department of Oral and Maxillofacial Surgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Oral and Maxillofacial Surgery, Translational Implantology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ute Ludwig
- Department of Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Philipp Amrein
- Department of Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Florian Kernen
- Department of Oral and Maxillofacial Surgery, Translational Implantology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Kirstin Vach
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center - University of Freiburg, Freiburg, Germany
| | - Johannes Maier
- Department of Oral and Maxillofacial Surgery, Translational Implantology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Katja Nelson
- Department of Oral and Maxillofacial Surgery, Translational Implantology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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22
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Timme M, Borkert J, Nagelmann N, Schmeling A. Evaluation of secondary dentin formation for forensic age assessment by means of semi-automatic segmented ultrahigh field 9.4 T UTE MRI datasets. Int J Legal Med 2020; 134:2283-2288. [PMID: 32940844 PMCID: PMC7578159 DOI: 10.1007/s00414-020-02425-7] [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: 08/10/2020] [Accepted: 09/10/2020] [Indexed: 12/17/2022]
Abstract
Dental methods are an important element of forensic age assessment of living persons. After the development of all the teeth, including third molars, is completed, degenerative characteristics can be used to assess age. The radiologically detectable reduction of the dental pulp cavity has been described as such a feature. We investigated the suitability of ultrahigh field 9.4 T ultrashort time echo (UTE) magnetic resonance imaging (MRI) for the evaluation of pulp cavity volume in relation to the total tooth volume in 4 extracted human teeth. The volume calculations were performed after semi-automatic segmentation by software AMIRA using the different intensities of the structures in the MRI dataset. The automatically selected intensity range was adjusted manually to the structures. The visual distinction of pulp and tooth structure was possible in all cases with in-plane resolution < 70 μm. Ratios of tooth/pulp volume were calculated, which could be suitable for age estimation procedures. Intensity shifts within the pulp were not always correctly assigned by the software in the course of segmentation. 9.4 T UTE-MRI technology is a forward-looking, radiation-free procedure that allows the volume of the dental pulp to be determined at high spatial resolution and is thus potentially a valuable instrument for the age assessment of living persons.
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Affiliation(s)
- Maximilian Timme
- Institute of Legal Medicine, University Hospital Münster, Röntgenstraße 23, 48149, Münster, Germany.
| | - Jens Borkert
- Institute of Legal Medicine, University Hospital Münster, Röntgenstraße 23, 48149, Münster, Germany
| | - Nina Nagelmann
- Department of Clinical Radiology, Translational Research Imaging Center (TRIC), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Andreas Schmeling
- Institute of Legal Medicine, University Hospital Münster, Röntgenstraße 23, 48149, Münster, Germany
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23
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Nishimura DA, Choi IGG, Arita ES, Cortes ARG. Estimating bone mineral density using MRI in medicine and dentistry: a literature review. Oral Radiol 2020; 37:366-375. [PMID: 32930913 DOI: 10.1007/s11282-020-00484-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/02/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Studies performed in the medical area have shown that an indirect diagnosis of bone mineral density (BMD) is feasible by assessing the amount of bone marrow fat with non-ionizing magnetic resonance imaging (MRI). In dentistry, radiographic methods are still the most used for alveolar bone diagnosis. The present literature review aimed at addressing the role of MRI in assessing BMD in medicine and dentistry. METHODS MEDLINE and EMBASE databases were searched for articles published up to 2019. RESULTS A total of 428 potentially eligible papers were screened. Of these, 397 were excluded after title, abstract and keyword assessment, yielding 31 papers that potentially met the inclusion criteria. Eleven studies were then excluded because their full texts did not discuss the role of MRI in the indirect diagnosis of BMD. As a result, a total of 20 studies were finally identified as eligible for inclusion in this literature review. Most studies found satisfactory accuracy of MRI for indirectly assessing BMD by quantifying bone mineral fat (BMF). However, only one of these studies was on dentistry. CONCLUSION Within the limitations of this study, the present findings suggest that MRI is accurate to indirectly estimate bone density by assessing BMF, and could be clinically relevant during dental treatment planning.
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Affiliation(s)
- Danielle Ayumi Nishimura
- Department of Stomatology, School of Dentistry, University of São Paulo (USP), Av. Prof. Lineu Prestes, 2227, São Paulo, 05508-000, Brazil.
| | - Isabela Goulart Gil Choi
- Department of Stomatology, School of Dentistry, University of São Paulo (USP), Av. Prof. Lineu Prestes, 2227, São Paulo, 05508-000, Brazil
| | - Emiko Saita Arita
- Department of Stomatology, School of Dentistry, University of São Paulo (USP), Av. Prof. Lineu Prestes, 2227, São Paulo, 05508-000, Brazil
| | - Arthur Rodriguez Gonzalez Cortes
- Department of Stomatology, School of Dentistry, University of São Paulo (USP), Av. Prof. Lineu Prestes, 2227, São Paulo, 05508-000, Brazil
- Department of Dental Surgery, Faculty of Dental Surgery, University of Malta, Msida, Malta
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24
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Flügge T, Ludwig U, Winter G, Amrein P, Kernen F, Nelson K. Fully guided implant surgery using Magnetic Resonance Imaging – An in vitro study on accuracy in human mandibles. Clin Oral Implants Res 2020; 31:737-746. [DOI: 10.1111/clr.13622] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 04/30/2020] [Accepted: 05/11/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Tabea Flügge
- Department of Oral and Maxillofacial Surgery Translational Implantology Medical Center–University of FreiburgFaculty of Medicine–University of Freiburg Freiburg Germany
- Department of Oral and Maxillofacial Surgery Charité–Universitätsmedizin BerlinCorporate Member of Freie Universität BerlinHumboldt‐Universität zu BerlinBerlin Institute sof Health Berlin Germany
| | - Ute Ludwig
- Department of Radiology, Medical Physics Medical Center–University of FreiburgFaculty of Medicine–University of Freiburg Freiburg Germany
| | - Gita Winter
- Department of Oral and Maxillofacial Surgery Translational Implantology Medical Center–University of FreiburgFaculty of Medicine–University of Freiburg Freiburg Germany
| | - Philipp Amrein
- Department of Radiology, Medical Physics Medical Center–University of FreiburgFaculty of Medicine–University of Freiburg Freiburg Germany
| | - Florian Kernen
- Department of Oral and Maxillofacial Surgery Translational Implantology Medical Center–University of FreiburgFaculty of Medicine–University of Freiburg Freiburg Germany
| | - Katja Nelson
- Department of Oral and Maxillofacial Surgery Translational Implantology Medical Center–University of FreiburgFaculty of Medicine–University of Freiburg Freiburg Germany
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25
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Lu A, Gorny KR, Ho ML. Zero TE MRI for Craniofacial Bone Imaging. AJNR Am J Neuroradiol 2020; 40:1562-1566. [PMID: 31467238 DOI: 10.3174/ajnr.a6175] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 07/08/2019] [Indexed: 11/07/2022]
Abstract
Zero TE MR imaging is a novel technique that achieves a near-zero time interval between radiofrequency excitation and data acquisition, enabling visualization of short-T2 materials such as cortical bone. Zero TE offers a promising radiation-free alternative to CT with rapid, high-resolution, silent, and artifact-resistant imaging, as well as the potential for "pseudoCT" reconstructions. In this report, we will discuss our preliminary experience with zero TE, including technical principles and a clinical case series demonstrating emerging applications in neuroradiology.
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Affiliation(s)
- A Lu
- Department of Medical Physics (A.L., K.R.G.), Mayo Clinic, Rochester, Minnesota
| | - K R Gorny
- Department of Medical Physics (A.L., K.R.G.), Mayo Clinic, Rochester, Minnesota
| | - M-L Ho
- From the Department of Radiology, Nationwide Children's Hospital (M.-L.H.), The Ohio State University College of Medicine, Columbus, Ohio
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26
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Mastrogiacomo S, Dou W, Jansen JA, Walboomers XF. Magnetic Resonance Imaging of Hard Tissues and Hard Tissue Engineered Bio-substitutes. Mol Imaging Biol 2020; 21:1003-1019. [PMID: 30989438 DOI: 10.1007/s11307-019-01345-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Magnetic resonance imaging (MRI) is a non-invasive diagnostic imaging tool based on the detection of protons into the tissues. This imaging technique is remarkable because of high spatial resolution, strong soft tissue contrast and specificity, and good depth penetration. However, MR imaging of hard tissues, such as bone and teeth, remains challenging due to low proton content in such tissues as well as to very short transverse relaxation times (T2). To overcome these issues, new MRI techniques, such as sweep imaging with Fourier transformation (SWIFT), ultrashort echo time (UTE) imaging, and zero echo time (ZTE) imaging, have been developed for hard tissues imaging with promising results reported. Within this article, MRI techniques developed for the detection of hard tissues, such as bone and dental tissues, have been reviewed. The main goal was thus to give a comprehensive overview on the corresponding (pre-) clinical applications and on the potential future directions with such techniques applied. In addition, a section dedicated to MR imaging of novel biomaterials developed for hard tissue applications was given as well.
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Affiliation(s)
- Simone Mastrogiacomo
- Department of Biomaterials, Radboud University Medical Center, Philips van Leijdenlaan 25, 6525 EX, Nijmegen, The Netherlands.
- Laboratory of Functional and Molecular Imaging, NINDS, National Institutes of Health, Building 10, 5S261, Bethesda, MD, 20892, USA.
| | - Weiqiang Dou
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
- GE Healthcare, MR Research, Beijing, People's Republic of China
| | - John A Jansen
- Department of Biomaterials, Radboud University Medical Center, Philips van Leijdenlaan 25, 6525 EX, Nijmegen, The Netherlands
| | - X Frank Walboomers
- Department of Biomaterials, Radboud University Medical Center, Philips van Leijdenlaan 25, 6525 EX, Nijmegen, The Netherlands
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27
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Stumpf K, Kaye E, Paul J, Wundrak S, Pauly JM, Rasche V. Two‐dimensional UTE overview imaging for dental application. Magn Reson Med 2020; 84:2616-2624. [DOI: 10.1002/mrm.28312] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/10/2020] [Accepted: 04/16/2020] [Indexed: 12/22/2022]
Affiliation(s)
- Kilian Stumpf
- Department of Internal Medicine II Ulm University Medical Center Ulm Germany
| | - Elena Kaye
- Department of Medical Physics Memorial Sloan Kettering Cancer Center New York New York USA
| | - Jan Paul
- Department of Internal Medicine II Ulm University Medical Center Ulm Germany
- Dental Imaging Dentsply Sirona Bensheim Germany
| | - Stefan Wundrak
- Department of Internal Medicine II Ulm University Medical Center Ulm Germany
- Dental Imaging Dentsply Sirona Bensheim Germany
| | - John M. Pauly
- Department of Electrical Engineering Stanford University Stanford California USA
| | - Volker Rasche
- Department of Internal Medicine II Ulm University Medical Center Ulm Germany
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28
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El-Kateb NM, El-Backly RN, Amin WM, Abdalla AM. Quantitative Assessment of Intracanal Regenerated Tissues after Regenerative Endodontic Procedures in Mature Teeth Using Magnetic Resonance Imaging: A Randomized Controlled Clinical Trial. J Endod 2020; 46:563-574. [DOI: 10.1016/j.joen.2020.01.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/23/2020] [Accepted: 01/31/2020] [Indexed: 12/15/2022]
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29
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Jang H, Carl M, Ma Y, Searleman AC, Jerban S, Chang EY, Corey-Bloom J, Du J. Inversion recovery zero echo time (IR-ZTE) imaging for direct myelin detection in human brain: a feasibility study. Quant Imaging Med Surg 2020; 10:895-906. [PMID: 32489915 DOI: 10.21037/qims.2020.04.13] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background Myelin alteration is closely associated with neurological diseases such as multiple sclerosis (MS). Unfortunately, due to myelin's extremely short T2* (~0.3 ms or shorter at 3T), it cannot be directly imaged with conventional MR imaging techniques. Recently, ultrashort echo time (UTE) imaging-based methods have been proposed for direct imaging of myelin. In this study, we explore the feasibility and efficacy of inversion recovery prepared zero echo time (IR-ZTE) imaging for direct volumetric imaging of myelin in white matter of the brain in vivo. Methods In the proposed method, an adiabatic IR preparation pulse is used to suppress long T2 white matter signal, followed by dual echo ZTE imaging where the remaining long T2 components, including gray matter, are suppressed by dual echo subtraction. In the implementation of ZTE, the sampling strategy introduced in Water- and Fat-Suppressed Proton Projection MRI (WASPI) was incorporated to acquire the k-space data missing due to the radiofrequency (RF) transmit/receiver switching time. The IR-ZTE sequence was implemented on a 3T clinical MR system and evaluated using a myelin phantom composed of six different myelin concentrations (0% to 20%), a cadaveric human brain, four healthy volunteers, and seven MS patients. Results In the myelin phantom experiment, the ZTE signal intensity showed high linearity to the myelin concentrations (R2=0.98). In the ex vivo and in vivo experiments, the IR-ZTE sequence provided high contrast volumetric imaging of myelin in human brains. The IR-ZTE sequence was able to detect demyelinated foci lesions in all MS patients. Conclusions Adiabatic IR prepared dual echo ZTE imaging allows for direct, volumetric imaging of myelin in white matter of the brain in vivo.
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Affiliation(s)
- Hyungseok Jang
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | | | - Yajun Ma
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Adam C Searleman
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Saeed Jerban
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Eric Y Chang
- Department of Radiology, University of California San Diego, San Diego, CA, USA.,Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Jody Corey-Bloom
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, CA, USA
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30
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Froidevaux R, Weiger M, Rösler MB, Brunner DO, Dietrich BE, Reber J, Pruessmann KP. High-resolution short-T 2 MRI using a high-performance gradient. Magn Reson Med 2020; 84:1933-1946. [PMID: 32176828 DOI: 10.1002/mrm.28254] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/20/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022]
Abstract
PURPOSE To achieve high resolution in imaging of short-T2 materials and tissues by using a high-performance human-sized gradient insert with strength up to 200 mT/m and 100% duty cycle. METHODS Dedicated short-T2 methodology and hardware are used, such as the pointwise encoding time reduction with radial acquisition (PETRA) technique with modulated excitation pulses, optimized radio-frequency hardware, and a high-performance gradient insert. A theoretical analysis of actual spatial resolution and SNR is provided to support the choice of scan parameters and interpretation of the results. Imaging is performed in resolution phantoms, animal specimen, and human volunteers at both conventional and maximum available gradient strengths and compared using image subtraction. RESULTS Calculations suggest that increasing gradient strength beyond conventional values considerably improves both actual resolution and SNR efficiency in short-T2 imaging. Resolution improvements are confirmed in all investigated samples, in particular 2 mm slots were resolved in a hard-plastic plate with T2 ≈ 10 μs and in vivo musculoskeletal images were acquired at isotropic 200 μm resolution. Expected improvements in signal yield are realized in fine structures benefitting from high resolution but to less extent in regions of low contrast where decay-related blurring leads to signal overlap between neighboring locations. CONCLUSION Strong gradients with high duty cycle enable short-T2 imaging at unprecedentedly high resolution, holding the potential for improving MRI of, eg, bone, tendon, lung, or teeth. Moreover, it allows direct access of tissues with T2 of tens of microseconds such as myelin or collagen.
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Affiliation(s)
- Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Manuela B Rösler
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David O Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Benjamin E Dietrich
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Jonas Reber
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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31
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Flügge T, Ludwig U, Hövener JB, Kohal R, Wismeijer D, Nelson K. Virtual implant planning and fully guided implant surgery using magnetic resonance imaging-Proof of principle. Clin Oral Implants Res 2020; 31:575-583. [PMID: 32105363 DOI: 10.1111/clr.13592] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 01/29/2020] [Accepted: 02/17/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To present a workflow of virtual implant planning and guided implant surgery with magnetic resonance imaging (MRI) and virtual dental models without the use of ionizing radiation. METHODS Five patients scheduled for implant placement underwent an MR examination at three Tesla using individualized 2D and 3D turbo spin-echo (TSE) sequences and dedicated head coils. The MRI data and virtual dental models derived from either optical model scans or intraoral scans were imported to a virtual implant planning software (coDiagnostiX, Dental Wings, Montreal, Canada). Virtual prosthetic planning and implant planning were performed regarding the hard and soft tissue anatomy. A drill guide was designed on the virtual dental model using computer-aided design (CAD) and manufactured in-house, using a 3D printer (Eden 260V, Stratasys, Eden Prairie, MN, USA). RESULTS The MRI displayed all relevant anatomical structures for dental implant planning such as cortical and cancellous bone, floor of the nasal and maxillary sinus, inferior alveolar nerve and neighboring teeth. The manual alignment of virtual dental models with the MRI was possible using anatomical landmarks. Dental implant planning, CAD/CAM of a drill guide and fully guided implant placement were successfully performed. CONCLUSIONS Guided implant surgery is feasible with MRI without ionizing radiation. Further studies will have to be conducted to study the accuracy of the presented protocol and compare it to the current workflow of guided surgery using CBCT.
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Affiliation(s)
- Tabea Flügge
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Department of Oral and Maxillofacial Surgery, Berlin, Germany.,Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Translational Implantology, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Ute Ludwig
- Medical Physics, Department of Radiology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Jan-Bernd Hövener
- Medical Physics, Department of Radiology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany.,Section for Biomedical Imaging and MOIN CC, Clinic for Radiology, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Ralf Kohal
- Department of Prosthetic Dentistry, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Daniel Wismeijer
- Department of Oral Implantology, Academisch Centrum Tandheelkunde Amsterdam (ACTA), Amsterdam, Netherlands
| | - Katja Nelson
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Translational Implantology, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
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32
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Evaluation of magnetic resonance imaging for diagnostic purposes in operative dentistry—a systematic review. Clin Oral Investig 2019; 24:547-557. [DOI: 10.1007/s00784-019-03103-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/26/2019] [Indexed: 10/25/2022]
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33
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Weiger M, Pruessmann KP. Short-T 2 MRI: Principles and recent advances. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:237-270. [PMID: 31779882 DOI: 10.1016/j.pnmrs.2019.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/14/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Among current modalities of biomedical and diagnostic imaging, MRI stands out by virtue of its versatile contrast obtained without ionizing radiation. However, in various cases, e.g., water protons in tissues such as bone, tendon, and lung, MRI performance is limited by the rapid decay of resonance signals associated with short transverse relaxation times T2 or T2*. Efforts to address this shortcoming have led to a variety of specialized short-T2 techniques. Recent progress in this field expands the choice of methods and prompts fresh considerations with regard to instrumentation, data acquisition, and signal processing. In this review, the current status of short-T2 MRI is surveyed. In an attempt to structure the growing range of techniques, the presentation highlights overarching concepts and basic methodological options. The most frequently used approaches are described in detail, including acquisition strategies, image reconstruction, hardware requirements, means of introducing contrast, sources of artifacts, limitations, and applications.
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Affiliation(s)
- Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland.
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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34
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Timme M, Masthoff M, Nagelmann N, Masthoff M, Faber C, Bürklein S. Imaging of root canal treatment using ultra high field 9.4T UTE-MRI - a preliminary study. Dentomaxillofac Radiol 2019; 49:20190183. [PMID: 31530016 DOI: 10.1259/dmfr.20190183] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVES To investigate the potential of 9.4T ultrashort echo time (UTE) technology visualizing tooth anatomy and root canal treatment in vitro. In particular, it was evaluated whether the currently achievable resolution is suited presenting all anatomical structures and whether the root canal filling materials are distinguishable in UTE-MRI. METHODS Four extracted human teeth were examined using 9.4T UTE-MRI prior endodontic treatment (native teeth), after preparation and after obturation procedure. Root canal obturation was performed using warm vertical compaction (Schilder technique) with an epoxy-resin-based sealer. A single gutta-percha cone measured by MRI served as intensity-reference. MRI results were validated with corresponding histologic sections of the teeth. In addition, all teeth were examined at the different stages with CBCT and conventional X-ray. RESULTS 9.4T UTE-MRI enabled a precise visualization of root canal anatomy of all teeth at a resolution of 66 µm. After obturation, dentin, sealer and gutta-percha cones showed distinct MRI signal changes that allowed clear differentiation of the obturation materials from surrounding tooth structure. The filling materials, isthmal root canal connections and even dentin-cracks that were identified in the MR-images could be verified in histological sections. CONCLUSIONS 9.4T UTE-MRI is suitable for visualization of root canal anatomy, the evaluation of root canal preparation and obturation with a high spatial resolution and may provide a versatile tool for dental material research in endodontics.
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Affiliation(s)
- Maximilian Timme
- Department of Oral and Maxillofacial Surgery, University Hospital Münster, Muenster, Germany
| | - Max Masthoff
- Department of Clinical Radiology, University Hospital Muenster, Germany
| | - Nina Nagelmann
- Department of Clinical Radiology, University Hospital Muenster, Germany
| | | | - Cornelius Faber
- Department of Clinical Radiology, University Hospital Muenster, Germany
| | - Sebastian Bürklein
- Central Interdisciplinary Ambulance in the School of Dentistry, University Hospital Muenster, Germany
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35
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Cankar K, Vidmar J, Nemeth L, Serša I. T2 Mapping as a Tool for Assessment of Dental Pulp Response to Caries Progression: An in vivo MRI Study. Caries Res 2019; 54:24-35. [PMID: 31509847 DOI: 10.1159/000501901] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 07/03/2019] [Indexed: 11/19/2022] Open
Abstract
Among radiological methods, magnetic resonance imaging (MRI) excels in its ability to image soft tissue at great contrast and without the need of harmful radiation. This study tested whether in vivo MRI based on standard MRI sequences run on a standard clinical MRI system can be used to quantify dental pulp response to caries progression using the T2 mapping method. In the study, 74 teeth were scanned on a 3-T MRI system, and caries was assessed according to the International Caries Detection and Assessment System (ICDAS). The T2 maps were processed to obtain T2 profiles along selected root canals (from crown to apex), and the profiles were sorted according to both tooth type (single-rooted vs. molar) and ICDAS score. In all the examined dental pulps, it was found that T2 values decrease with an increase in the ICDAS score. In the coronal part of dental pulps, average T2 values of 166, 153, and 115 ms were found in ICDAS groups 0, 1-3, and 4-6, respectively. In single-rooted teeth, T2 values were found approximately constant as a function of dental pulp depth, while in multi-rooted teeth, they were found increasing in the coronal part and decreasing towards the root apex. The study confirmed that T2 mapping of dental pulp can be used to reliably quantify its response to caries progression and that it has a potential to become a complementary diagnostic tool to standard radiographic methods in the assessment of dental pulp response to caries.
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Affiliation(s)
- Ksenija Cankar
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia,
| | - Jernej Vidmar
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Institute of Radiology, University Medical Center Ljubljana, Ljubljana, Slovenia.,Jožef Stefan Institute, Ljubljana, Slovenia
| | - Lidija Nemeth
- Department of Dental Diseases and Normal Dental Morphology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Igor Serša
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Jožef Stefan Institute, Ljubljana, Slovenia
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Manso‐Díaz G, Taeymans O, García‐López JM, Weller R. Application and indications of magnetic resonance imaging and computed tomography of the equine head. EQUINE VET EDUC 2019. [DOI: 10.1111/eve.13075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- G. Manso‐Díaz
- Hospital Clínico Veterinario Complutense Universidad Complutense de Madrid Madrid Spain
- The Royal Veterinary College Hatfield Hertfordshire UK
| | | | - J. M. García‐López
- Department of Clinical Sciences Cummings School of Veterinary Medicine Tufts University North Grafton Massachusetts USA
| | - R. Weller
- The Royal Veterinary College Hatfield Hertfordshire UK
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Magnetic resonance imaging of third molars in forensic age estimation: comparison of the Ghent and Graz protocols focusing on apical closure. Int J Legal Med 2018; 133:583-592. [DOI: 10.1007/s00414-018-1905-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/18/2018] [Indexed: 10/28/2022]
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Di Nardo D, Gambarini G, Capuani S, Testarelli L. Nuclear Magnetic Resonance Imaging in Endodontics: A Review. J Endod 2018; 44:536-542. [DOI: 10.1016/j.joen.2018.01.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 12/30/2017] [Accepted: 01/01/2018] [Indexed: 01/31/2023]
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Dou W, Mastrogiacomo S, Veltien A, Alghamdi HS, Walboomers XF, Heerschap A. Visualization of calcium phosphate cement in teeth by zero echo time 1 H MRI at high field. NMR IN BIOMEDICINE 2018; 31:e3859. [PMID: 29160917 DOI: 10.1002/nbm.3859] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/25/2017] [Accepted: 10/13/2017] [Indexed: 06/07/2023]
Abstract
1 H magnetic resonance imaging (MRI) by a zero echo time (ZTE) sequence is an excellent method to image teeth. Calcium phosphate cement (CPC) materials are applied in the restoration of tooth lesions, but it has not yet been investigated whether they can be detected by computed tomography (CT) or MRI. The aim of this study was to optimize high-field ZTE imaging to enable the visualization of a new CPC formulation implanted in teeth and to apply this in the assessment of its decomposition in vivo. CPC was implanted in three human and three goat teeth ex vivo and in three goat teeth in vivo. An ultrashort echo time (UTE) sequence with multiple flip angles and echo times was applied at 11.7 T to measure T1 and T2 * values of CPC, enamel and dentin. Teeth with CPC were imaged with an optimized ZTE sequence. Goat teeth implanted with CPC in vivo were imaged after 7 weeks ex vivo. T2 * relaxation of implanted CPC, dentin and enamel was better fitted by a model assuming a Gaussian rather than a Lorentzian distribution. For CPC and human enamel and dentin, the average T2 * values were 273 ± 19, 562 ± 221 and 476 ± 147 μs, respectively, the average T2 values were 1234 ± 27, 963 ± 151 and 577 ± 41 μs, respectively, and the average T1 values were 1065 ± 45, 972 ± 40 and 903 ± 7 ms, respectively. In ZTE images, CPC had a higher signal-to-noise-ratio than dentin and enamel because of the higher water content. Seven weeks after in vivo implantation, the CPC-filled lesions showed less homogeneous structures, a lower T1 value and T2 * separated into two components. MRI by ZTE provides excellent contrast for CPC in teeth and allows its decomposition to be followed.
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Affiliation(s)
- Weiqiang Dou
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Simone Mastrogiacomo
- Department of Biomaterials, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Andor Veltien
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Hamdan S Alghamdi
- Department of Biomaterials, Radboud University Medical Center, Nijmegen, the Netherlands
- College of Dentistry Research Center, King Saud University, Riyadh, Saudi Arabia
| | - X Frank Walboomers
- Department of Biomaterials, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
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Wanner L, Ludwig U, Hövener JB, Nelson K, Flügge T. Magnetic resonance imaging-a diagnostic tool for postoperative evaluation of dental implants: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol 2018; 125:e103-e107. [PMID: 29501353 DOI: 10.1016/j.oooo.2018.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 01/03/2018] [Accepted: 01/08/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Compared with cone beam computed tomography (CBCT), magnetic resonance imaging (MRI) might be superior for the diagnosis of nerve lesions associated with implant placement. STUDY DESIGN A patient presented with unilateral pain associated with dysesthesia in the region of the right lower lip and chin after implant placement. Conventional orthopantomography could not identify an association between the position of the inferior alveolar nerve and the implant. For 3-dimensional display of the implant in relation to the surrounding anatomy, CBCT was compared with MRI. RESULTS MRI enabled the precise depiction of the implant position and its spatial relation to the inferior alveolar nerve, whereas the nerve position and its exact course within the mandible could not be directly displayed in CBCT. CONCLUSION MRI may be a valuable, radiation-free diagnostic tool for the visualization of intraoral hard and soft tissues, offering an objective assessment of nerve injuries by a direct visualization of the inferior alveolar neurovascular bundle.
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Affiliation(s)
- Laura Wanner
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Ute Ludwig
- Department of Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Jan-Bernd Hövener
- Department of Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Katja Nelson
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tabea Flügge
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties. Acta Biomater 2017; 62:340-351. [PMID: 28842333 DOI: 10.1016/j.actbio.2017.08.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/12/2017] [Accepted: 08/12/2017] [Indexed: 11/21/2022]
Abstract
Different materials have been used for vital dental pulp treatment. Preferably a pulp capping agent should show appropriate biological performance, excellent handling properties, and a good imaging contrast. These features can be delivered into a single material through the combination of therapeutic and diagnostic agents (i.e. theranostic). Calcium phosphate based composites (CPCs) are potentially ideal candidate for pulp treatment, although poor imaging contrast and poor dentino-inductive properties are limiting their clinical use. In this study, a theranostic dental pulp capping agent was developed. First, imaging properties of the CPC were improved by using a core-shell structured dual contrast agent (csDCA) consisting of superparamagnetic iron oxide (SPIO) and colloidal gold, as MRI and CT contrast agent respectively. Second, biological properties were implemented by using a dentinogenic factor (i.e. bone morphogenetic protein 2, BMP-2). The obtained CPC/csDCA/BMP-2 composite was tested in vivo, as direct pulp capping agent, in a male Habsi goat incisor model. Our outcomes showed no relevant alteration of the handling and mechanical properties (e.g. setting time, injectability, and compressive strength) by the incorporation of csDCA particles. In vivo results proved MRI contrast enhancement up to 7weeks. Incisors treated with BMP-2 showed improved tertiary dentin deposition as well as faster cement degradation as measured by µCT assessment. In conclusion, the presented theranostic agent matches the imaging and regenerative requirements for pulp capping applications. STATEMENT OF SIGNIFICANCE In this study, we combined diagnostic and therapeutic agents in order to developed a theranostic pulp capping agent with enhanced MRI and CT contrast and improved dentin regeneration ability. In our study we cover all the steps from material preparation, mechanical and in vitro characterization, to in vivo study in a goat dental model. To the best of our knowledge, this is the first time that a theranostic pulp capping material have been developed and tested in an in vivo animal model. Our promising results in term of imaging contrast enhancement and of induction of new dentin formation, open a new scenario in the development of innovative dental materials.
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Traser L, Birkholz P, Flügge TV, Kamberger R, Burdumy M, Richter B, Korvink JG, Echternach M. Relevance of the Implementation of Teeth in Three-Dimensional Vocal Tract Models. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2017; 60:2379-2393. [PMID: 28898358 DOI: 10.1044/2017_jslhr-s-16-0395] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 02/23/2017] [Indexed: 06/07/2023]
Abstract
PURPOSE Recently, efforts have been made to investigate the vocal tract using magnetic resonance imaging (MRI). Due to technical limitations, teeth were omitted in many previous studies on vocal tract acoustics. However, the knowledge of how teeth influence vocal tract acoustics might be important in order to estimate the necessity of implementing teeth in vocal tract models. The aim of this study was therefore to estimate the effect of teeth on vocal tract acoustics. METHOD The acoustic properties of 18 solid (3-dimensional printed) vocal tract models without teeth were compared to the same 18 models including teeth in terms of resonance frequencies (fRn). The fRn were obtained from the transfer functions of these models excited by white noise at the glottis level. The models were derived from MRI data of 2 trained singers performing 3 different vowel conditions (/i/, /a/, and /u/) in speech and low-pitched and high-pitched singing. RESULTS Depending on the oral configuration, models exhibiting side cavities or side branches were characterized by major changes in the transfer function when teeth were implemented via the introduction of pole-zero pairs. CONCLUSIONS To avoid errors in modeling, teeth should be included in 3-dimensional vocal tract models for acoustic evaluation. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.5386771.
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Affiliation(s)
- Louisa Traser
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Department of Otolaryngology, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
| | - Peter Birkholz
- Institute of Acoustics and Speech Communication, Technische Universität, Dresden, Germany
| | - Tabea Viktoria Flügge
- Faculty of Medicine, University of Freiburg, Germany
- Department of Craniomaxillofacial Surgery, Freiburg University Medical Center, Germany
| | - Robert Kamberger
- Laboratory of Simulation, Department of Microsystems Engineering-IMTEK, University of Freiburg, Germany
| | - Michael Burdumy
- Faculty of Medicine, University of Freiburg, Germany
- Department of Medical Physics, Radiology, Freiburg University Medical Center, Germany
| | - Bernhard Richter
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
| | - Jan Gerrit Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Matthias Echternach
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
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Froidevaux R, Weiger M, Brunner DO, Dietrich BE, Wilm BJ, Pruessmann KP. Filling the dead-time gap in zero echo time MRI: Principles compared. Magn Reson Med 2017; 79:2036-2045. [PMID: 28856717 DOI: 10.1002/mrm.26875] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 11/07/2022]
Abstract
PURPOSE MRI of tissues with short coherence lifetimes T2 or T2* can be performed efficiently using zero echo time (ZTE) techniques such as algebraic ZTE, pointwise encoding time reduction with radial acquisition (PETRA), and water- and fat-suppressed proton projection MRI (WASPI). They share the principal challenge of recovering data in central k-space missed due to an initial radiofrequency dead time. The purpose of this study was to compare the three techniques directly, with a particular focus on their behavior in the presence of ultra-short-lived spins. METHODS The most direct comparison was enabled by aligning acquisition and reconstruction strategies of the three techniques. Image quality and short- T2* performance were investigated using point spread functions, 3D simulations, and imaging of phantom and bone samples with short (<1 ms) and ultra-short (<100 μs) T2*. RESULTS Algebraic ZTE offers favorable properties but is limited to k-space gaps up to approximately three Nyquist dwells. At larger gaps, PETRA enables robust imaging with little compromise in image quality, whereas WASPI may be prone to artifacts from ultra-short T2* species. CONCLUSION For small k-space gaps (<4 dwells) and T2* much larger than the dead time, all techniques enable artifact-free short- T2* MRI. However, if these requirements are not fulfilled careful consideration is needed and PETRA will generally achieve better image quality. Magn Reson Med 79:2036-2045, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David O Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Benjamin E Dietrich
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Bertram J Wilm
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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Heil A, Lazo Gonzalez E, Hilgenfeld T, Kickingereder P, Bendszus M, Heiland S, Ozga AK, Sommer A, Lux CJ, Zingler S. Lateral cephalometric analysis for treatment planning in orthodontics based on MRI compared with radiographs: A feasibility study in children and adolescents. PLoS One 2017; 12:e0174524. [PMID: 28334054 PMCID: PMC5363936 DOI: 10.1371/journal.pone.0174524] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/10/2017] [Indexed: 11/18/2022] Open
Abstract
Objective The objective of this prospective study was to evaluate whether magnetic resonance imaging (MRI) is equivalent to lateral cephalometric radiographs (LCR, “gold standard”) in cephalometric analysis. Methods The applied MRI technique was optimized for short scanning time, high resolution, high contrast and geometric accuracy. Prior to orthodontic treatment, 20 patients (mean age ± SD, 13.95 years ± 5.34) received MRI and LCR. MRI datasets were postprocessed into lateral cephalograms. Cephalometric analysis was performed twice by two independent observers for both modalities with an interval of 4 weeks. Eight bilateral and 10 midsagittal landmarks were identified, and 24 widely used measurements (14 angles, 10 distances) were calculated. Statistical analysis was performed by using intraclass correlation coefficient (ICC), Bland-Altman analysis and two one-sided tests (TOST) within the predefined equivalence margin of ± 2°/mm. Results Geometric accuracy of the MRI technique was confirmed by phantom measurements. Mean intraobserver ICC were 0.977/0.975 for MRI and 0.975/0.961 for LCR. Average interobserver ICC were 0.980 for MRI and 0.929 for LCR. Bland-Altman analysis showed high levels of agreement between the two modalities, bias range (mean ± SD) was -0.66 to 0.61 mm (0.06 ± 0.44) for distances and -1.33 to 1.14° (0.06 ± 0.71) for angles. Except for the interincisal angle (p = 0.17) all measurements were statistically equivalent (p < 0.05). Conclusions This study demonstrates feasibility of orthodontic treatment planning without radiation exposure based on MRI. High-resolution isotropic MRI datasets can be transformed into lateral cephalograms allowing reliable measurements as applied in orthodontic routine with high concordance to the corresponding measurements on LCR.
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Affiliation(s)
- Alexander Heil
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
- * E-mail:
| | | | - Tim Hilgenfeld
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Sabine Heiland
- Division of Experimental Radiology, Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Ann-Kathrin Ozga
- Institute for Medical Biometry and Informatics, Heidelberg University Hospital, Heidelberg, Germany
| | - Andreas Sommer
- Department of Orthodontics and Dentofacial Orthopaedics, Heidelberg University Hospital, Germany
| | - Christopher J. Lux
- Department of Orthodontics and Dentofacial Orthopaedics, Heidelberg University Hospital, Germany
| | - Sebastian Zingler
- Department of Orthodontics and Dentofacial Orthopaedics, Heidelberg University Hospital, Germany
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De Tobel J, Hillewig E, Bogaert S, Deblaere K, Verstraete K. Magnetic resonance imaging of third molars: developing a protocol suitable for forensic age estimation. Ann Hum Biol 2016; 44:130-139. [DOI: 10.1080/03014460.2016.1202321] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Jannick De Tobel
- Department of Radiology and Nuclear Medicine, Ghent University, Gent, Belgium
| | - Elke Hillewig
- Department of Radiology and Nuclear Medicine, Ghent University, Gent, Belgium
| | - Stephanie Bogaert
- Ghent Institute for Functional and Metabolic Imaging (GIFMI), Gent, Belgium
| | - Karel Deblaere
- Department of Radiology and Nuclear Medicine, Ghent University, Gent, Belgium
| | - Koenraad Verstraete
- Department of Radiology and Nuclear Medicine, Ghent University, Gent, Belgium
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Rovedo P, Knecht S, Bäumlisberger T, Cremer AL, Duckett SB, Mewis RE, Green GGR, Burns M, Rayner PJ, Leibfritz D, Korvink JG, Hennig J, Pütz G, von Elverfeldt D, Hövener JB. Molecular MRI in the Earth’s Magnetic Field Using Continuous Hyperpolarization of a Biomolecule in Water. J Phys Chem B 2016; 120:5670-7. [DOI: 10.1021/acs.jpcb.6b02830] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Philipp Rovedo
- Department
of Radiology, Medical Physics, Medical Center – University
of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher
Strasse 60 a, 79106 Freiburg, Germany
| | - Stephan Knecht
- Department
of Radiology, Medical Physics, Medical Center – University
of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher
Strasse 60 a, 79106 Freiburg, Germany
| | - Tim Bäumlisberger
- Department
of Radiology, Medical Physics, Medical Center – University
of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher
Strasse 60 a, 79106 Freiburg, Germany
| | - Anna Lena Cremer
- Department
of Radiology, Medical Physics, Medical Center – University
of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher
Strasse 60 a, 79106 Freiburg, Germany
| | - Simon B. Duckett
- Centre
for Hyperpolarization in Magnetic Resonance, University of York, York, YO10 5DD, U.K
| | - Ryan E. Mewis
- School
of Science and the Environment, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, U.K
| | - Gary G. R. Green
- Centre
for Hyperpolarization in Magnetic Resonance, University of York, York, YO10 5DD, U.K
| | - Michael Burns
- Centre
for Hyperpolarization in Magnetic Resonance, University of York, York, YO10 5DD, U.K
| | - Peter J. Rayner
- Centre
for Hyperpolarization in Magnetic Resonance, University of York, York, YO10 5DD, U.K
| | - Dieter Leibfritz
- Department
of Radiology, Medical Physics, Medical Center – University
of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher
Strasse 60 a, 79106 Freiburg, Germany
| | - Jan G. Korvink
- Institute
of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Jürgen Hennig
- Department
of Radiology, Medical Physics, Medical Center – University
of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher
Strasse 60 a, 79106 Freiburg, Germany
| | - Gerhard Pütz
- Institute
for Clinical Chemistry, University Medical Center, Breisacher Strasse
60 a, 79106 Freiburg, Germany
| | - Dominik von Elverfeldt
- Department
of Radiology, Medical Physics, Medical Center – University
of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher
Strasse 60 a, 79106 Freiburg, Germany
| | - Jan-Bernd Hövener
- Department
of Radiology, Medical Physics, Medical Center – University
of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher
Strasse 60 a, 79106 Freiburg, Germany
- German Consortium for Cancer Research (DKTK) Partner Site Freiburg, 69120 Heidelberg, Germany
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Detterbeck A, Hofmeister M, Hofmann E, Haddad D, Weber D, Hölzing A, Zabler S, Schmid M, Hiller KH, Jakob P, Engel J, Hiller J, Hirschfelder U. MRI vs. CT for orthodontic applications: comparison of two MRI protocols and three CT (multislice, cone-beam, industrial) technologies. J Orofac Orthop 2016; 77:251-61. [DOI: 10.1007/s00056-016-0028-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/13/2015] [Indexed: 10/21/2022]
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Ludwig U, Eisenbeiss AK, Scheifele C, Nelson K, Bock M, Hennig J, von Elverfeldt D, Herdt O, Flügge T, Hövener JB. Dental MRI using wireless intraoral coils. Sci Rep 2016; 6:23301. [PMID: 27021387 PMCID: PMC4810435 DOI: 10.1038/srep23301] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 03/03/2016] [Indexed: 11/09/2022] Open
Abstract
Currently, the gold standard for dental imaging is projection radiography or cone-beam computed tomography (CBCT). These methods are fast and cost-efficient, but exhibit poor soft tissue contrast and expose the patient to ionizing radiation (X-rays). The need for an alternative imaging modality e.g. for soft tissue management has stimulated a rising interest in dental magnetic resonance imaging (MRI) which provides superior soft tissue contrast. Compared to X-ray imaging, however, so far the spatial resolution of MRI is lower and the scan time is longer. In this contribution, we describe wireless, inductively-coupled intraoral coils whose local sensitivity enables high resolution MRI of dental soft tissue. In comparison to CBCT, a similar image quality with complementary contrast was obtained ex vivo. In-vivo, a voxel size of the order of 250 ∙ 250 ∙ 500 μm(3) was achieved in 4 min only. Compared to dental MRI acquired with clinical equipment, the quality of the images was superior in the sensitive volume of the coils and is expected to improve the planning of interventions and monitoring thereafter. This method may enable a more accurate dental diagnosis and avoid unnecessary interventions, improving patient welfare and bringing MRI a step closer to becoming a radiation-free alternative for dental imaging.
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Affiliation(s)
- Ute Ludwig
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany
| | - Anne-Katrin Eisenbeiss
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany
- Division of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Freiburg, Germany
| | - Christian Scheifele
- Division of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Freiburg, Germany
| | - Katja Nelson
- Division of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Freiburg, Germany
| | - Michael Bock
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany
| | - Jürgen Hennig
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany
| | - Dominik von Elverfeldt
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany
| | - Olga Herdt
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany
| | - Tabea Flügge
- Division of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Freiburg, Germany
| | - Jan-Bernd Hövener
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany
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Flügge T, Hövener JB, Ludwig U, Eisenbeiss AK, Spittau B, Hennig J, Schmelzeisen R, Nelson K. Magnetic resonance imaging of intraoral hard and soft tissues using an intraoral coil and FLASH sequences. Eur Radiol 2016; 26:4616-4623. [PMID: 26910905 PMCID: PMC5101280 DOI: 10.1007/s00330-016-4254-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 12/21/2022]
Abstract
Objectives To ascertain the feasibility of MRI as a non-ionizing protocol for routine dentomaxillofacial diagnostic imaging. Wireless coils were used for MRI of intraoral hard and soft tissues. Methods FLASH MRI was applied in vivo with a mandible voxel size of 250 × 250 × 500 μm3, FOV of 64 × 64 × 28 mm3 and acquisition time of 3:57 min and with a maxilla voxel size of 350 μm3 and FOV of 34 cm3 in 6:40 min. Ex vivo imaging was performed in 4:38 min, with a resolution of 200 μm3 and FOV of 36.5 cm3. Cone beam (CB) CT of the mandible and subjects were acquired. MRI was compared to CBCT and histological sections. Deviations were calculated with intraclass correlation coefficient (ICC) and coefficient of variation (cv). Results A high congruence between CBCT, MRI and specimens was demonstrated. Hard and soft tissues including dental pulp, periodontium, gingiva, cancellous bone and mandibular canal contents were adequately displayed with MRI. Conclusions Imaging of select intraoral tissues was achieved using custom MRI protocols with an easily applicable intraoral coil in a clinically acceptable acquisition time. Comparison with CBCT and histological sections helped demonstrate dimensional accuracy of the MR images. The course of the mandibular canal was accurately displayed with CBCT and MRI. Key points • MRI is a clinically available diagnostic tool in dentistry • Intraoral hard and soft tissues can be imaged with a high resolution with MRI • The dimensional accuracy of MRI is comparable to cone beam CT Electronic supplementary material The online version of this article (doi:10.1007/s00330-016-4254-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tabea Flügge
- Department of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany.
| | - Jan-Bernd Hövener
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Breisacher Str. 60, 79106, Freiburg, Germany
| | - Ute Ludwig
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Breisacher Str. 60, 79106, Freiburg, Germany
| | - Anne-Kathrin Eisenbeiss
- Department of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
| | - Björn Spittau
- Institute of Anatomy and Cell Biology, Albert Ludwig University of Freiburg, Albertstr. 17, 79104, Freiburg, Germany
| | - Jürgen Hennig
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Breisacher Str. 60, 79106, Freiburg, Germany
| | - Rainer Schmelzeisen
- Department of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
| | - Katja Nelson
- Department of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
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Gradl J, Höreth M, Pfefferle T, Prager M, Hilgenfeld T, Gareis D, Bäumer P, Heiland S, Bendszus M, Hähnel S. Application of a Dedicated Surface Coil in Dental MRI Provides Superior Image Quality in Comparison with a Standard Coil. Clin Neuroradiol 2016; 27:371-378. [PMID: 26869445 DOI: 10.1007/s00062-016-0500-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/15/2016] [Indexed: 01/30/2023]
Abstract
PURPOSE Purpose of our research was the evaluation of a dedicated dental surface coil in comparison with a standard head and neck coil for the improvement of dental magnetic resonance imaging (MRI). MATERIALS AND METHODS Axial T1-weighted spin echo MRI was performed by using a newly developed dental coil for MRI and a standard head and neck coil on five volunteers. In addition, MRI was implemented with dental coil on five patients. Using the Wilcoxon test, we compared the volunteers' signal-to-noise ratio (SNR) of a variety of anatomical structures (e.g., hard tooth tissue, pulp tissue, bone, muscle tissue). Also subjective evaluation of image quality was performed on both volunteers and patients. RESULTS Compared with the head and neck coil, the mean SNR was 3.5-fold higher on an average with the dental coil (range: from 2.7 [masseter muscle] to 4.6 [pulp tissue]). That difference was statistically significant for all evaluated structures. The higher SNR also resulted in a superior image quality as determined by subjective evaluation. CONCLUSION Dental MRI benefits profoundly from using a dedicated dental coil.
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Affiliation(s)
- J Gradl
- Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany.
| | - M Höreth
- Heidelberg University School of Medicine, Heidelberg, Germany
| | - T Pfefferle
- Department of Oral, Dental and Maxillofacial Diseases, University of Heidelberg Medical Center, Heidelberg, Germany
| | - M Prager
- Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - T Hilgenfeld
- Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - D Gareis
- NORAS MRI Products GmbH, Leibnizstrasse 4, 97204, Höchberg, Germany
| | - P Bäumer
- Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - S Heiland
- Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - M Bendszus
- Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - S Hähnel
- Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
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