TMJ meniscus and bilaminar zone: MR imaging of the substructure--diagnostic landmarks and pitfalls of interpretation

Area of Science:

• Radiology
• Anatomy
• Biomedical Imaging

Background:

• Accurate identification of the temporomandibular joint (TMJ) meniscus posterior band and bilaminar zone junction is crucial for diagnosing anterior displacements on magnetic resonance (MR) imaging.
• Variations in meniscus tissue characteristics can complicate interpretation of MR images, making anatomical correlation challenging.

Purpose of the Study:

• To identify reliable MR imaging landmarks for the junction of the posterior band and bilaminar zone of the TMJ meniscus.
• To improve the accuracy of diagnosing anterior TMJ meniscus displacements using MR imaging.

Main Methods:

• Sagittal MR imaging of six cadaveric TMJ specimens at 1.5 T with varied pulse sequences and coils.
• Correlation of in vitro MR images with corresponding histologic sections to identify anatomical structures and tissue characteristics.
• Comparison of in vitro findings with in vivo MR images from 100 TMJ joints.

Main Results:

• A vertical, linear, low-signal-intensity band was identified as a key landmark for the posterior band-bilaminar zone junction.
• Understanding the signal intensity of the posterior band's center and surfaces, along with the bilaminar zone's insertion, enhances visualization.
• This landmark aids in avoiding false-positive diagnoses of anterior TMJ meniscus displacement.

Conclusions:

• The identified low-signal band serves as a critical MR imaging landmark for the TMJ meniscus posterior band and bilaminar zone junction.
• Improved recognition of this landmark enhances diagnostic confidence and accuracy in detecting anterior TMJ meniscus displacements.
• This finding contributes to more reliable interpretation of MR images for TMJ disorders.