Real-Time Magnetic Resonance Imaging of Temporomandibular Joint Dynamics

Abstract

Abstract:This study evaluated the use of a novel real-time MRI technique based on fast low angle shot (FLASH) MRI with radial encoding, gridding reconstruction, and sliding window for the assessment of temporomandibular joint (TMJ) dynamics in a cohort of 30 young volunteers without prior diagnosis of TMJ pathology. High-resolution images (0.75 0.75 mm 2 , 5 mm section thickness) were obtained at 3 frames per second for active jaw movements without adjunctive devices. Real-time movies were evaluated with respect to image artefacts, anatomical visibility, diagnostic confidence, and TMJ function. During the entire opening and closing of the mouth, the relative positions of the mandibular condyle and articular disc were well depicted. Mean scores were 1.01 ± 0.65 for motion artefacts (scale: 0 = no to 3 = severe artefacts) and 2.03 ± 0.71 for anatomical detectability (scale: 1 = excellent to 5 = not visible). High inter-observer agreements were found for assessments of mandibular condyle movements ( = 0.83) and articular disc displacements ( = 0.91). In latter cases, the point of disc reduction could precisely be identified. In conclusion, the proposed real-time MRI method offers robust access to TMJ dynamics with good image quality.

Improvement of a 4-Channel Spiral-Loop RF Coil Array for TMJ MR Imaging at 7T

“…9a, c) and then SNR map was compared. The TMJ image was obtained in a slightly oblique sagittal orientation perpendicular to the long axis of the condylar head (12). The SNR measurements were based on the National Electrical Manufactures Association (NEMA) method (39) and were obtained by dividing the average signal intensity inside the human image by the standard deviation (SD) of the noise in the specific region (ROI, 10 × 10 pixel) which is placed in the outside the imaging region.…”

“…Since all the obstacles to MR imaging at UHF such as 7T are closely related to the operating frequency of 300 MHz, selection of optimal coil configuration and their integration into the actual MR system appear to be the most critical factor (9). For the TMJ application, the most common coils used for TMJ imaging in high-field (HF) MRI were the single-channel circular-loop coil (10, 11) or a 4-channel receive (Rx)-only coil with externally separated transmit (Tx)-only coil (12). However, common approach to such as a single or multi-channel Rx-only surface coil in UHF appear to be limited by the absence of a local Tx capability.…”

Endovascular Magnetically Guided Robots: Navigation Modeling and Optimization

“…Spatial resolution of current medical imagers is an important limitation, especially within real-time constraints [1], [3]. However, future imagers like 7T MRI or 256 slice computed tomography devices are promising for high spatial and temporal resolution imaging.…”

“…Emerging real-time high spatial resolution medical imagers, using either computed tomography [1], optical coherence tomography or Magnetic Resonance Imaging (MRI) devices [2], [3], are promising for the development of automated medical interventions. In particular, it opens a wide field in minimally invasive diagnostic, therapy or in-vivo biosensing.…”

Measuring three‐dimensional tibiofemoral kinematics using dual‐slice real‐time magnetic resonance imaging

“…In contrast to techniques based on consecutive repetitions of motion cycles, real‐time acquisition sequences enable data acquisition of a single image slice within an individual cycle of the movement although generally with less accuracy and with lower temporospatial resolution . More recently a novel real‐time MRI using fast low‐angle shot (FLASH) gradient‐echo pulse sequences in conjunction with a radial data encoding scheme and a sliding window reconstruction algorithm was proposed and applied to study skeletal dynamics with improved image quality . In conjunction with the radial FLASH MRI, a slice‐to‐volume registration (SVR) method has been proposed for measuring 3D dynamic knee motion.…”