title: Real-time MRI of the temporomandibular joint at 15 frames per second-A feasibility study.
abstract: The purpose of this study was to develop and evaluate a novel method for real-time MRI of TMJ function at high temporal resolution and with two different contrasts. Real-time MRI was based on undersampled radial fast low angle shot (FLASH) acquisitions with iterative image reconstruction by regularized nonlinear inversion. Real-time MRI movies with T1 contrast were obtained with use of a radiofrequency-spoiled FLASH sequence, while movies with T2/T1 contrast employed a gradient-refocused FLASH version. TMJ function was characterized in 40 randomly selected volunteers by sequential 20s acquisitions of both the right and left joint during voluntary opening and closing of the mouth (in a medial, central and lateral oblique sagittal section perpendicular to the long axis of the condylar head). All studies were performed on a commercial MRI system at 3T using the standard head coil, while online reconstruction was achieved with a bypass computer fully integrated into the MRI system. As a first result, real-time MRI studies of the right and left TMJ were successfully performed in all 40 subjects (80 joints) within a total examination time per subject of only 15min. Secondly, at an in-plane resolution of 0.75mm and 5mm section thickness, the achieved temporal resolution was 66.7ms per image or 15 frames per second. Thirdly, both T1-weighted and T2/T1-weighted real-time MRI movies provided information about TMJ function such as disc position, condyle mobility and disc-condyle relationship. While T1 contrast offers a better delineation of structures during rapid jaw movements, T2/T1 contrast was rated superior for characterizing the articular disc. In conclusion, the proposed real-time MRI method may become a robust and efficient tool for the clinical assessment of TMJ function.
authors.affiliation: Department of Prosthodontics, University Medical Center, Göttingen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Krohn
authors.affiliation: Department of Prosthodontics, University Medical Center, Göttingen, Germany.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Gersdorff
authors.affiliation: Department of Prosthodontics, University Medical Center, Göttingen, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Wassmann
authors.affiliation: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany.
authors.forename: Klaus-Dietmar
authors.initials: KD
authors.lastname: Merboldt
authors.affiliation: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany. Electronic address: ajoseph@mpibpc.mpg.de.
authors.forename: Arun A
authors.initials: AA
authors.lastname: Joseph
authors.affiliation: Department of Prosthodontics, University Medical Center, Göttingen, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Buergers
authors.affiliation: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Frahm
mesh_terms: D000328:Adult; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D004204:Joint Dislocations / Q000000981:diagnostic imaging; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008335:Mandibular Condyle / Q000000981:diagnostic imaging; D008875:Middle Aged; D009862:Online Systems; D016059:Range of Motion, Articular / Q000502:physiology; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging*; D019224:Temporomandibular Joint Disc / Q000000981:diagnostic imaging; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging*; D013997:Time Factors; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: Articular disk; Condyle; MR imaging/diagnosis; Real-time imaging; Temporomandibular joint