Does a brain Magnetic Resonance Imaging (MRI) view images of the jaw?

Brain MRI Does Not Typically View Images of the Jaw

A standard brain MRI does not typically include or adequately visualize the jaw structures, as it is primarily designed to image the brain and not the maxillofacial structures. 1

Why Brain MRI Is Not Appropriate for Jaw Imaging

Brain MRI protocols are specifically designed to focus on intracranial structures with the following limitations when it comes to jaw visualization:

• According to the ACR Appropriateness Criteria, "there is no relevant literature to support the use of MRI of the brain in the initial imaging evaluation of suspected mandibular injury" 1
• Brain MRI protocols typically do not extend inferiorly enough to fully capture the jaw structures
• The field of view and slice parameters are optimized for brain tissue, not facial bones or temporomandibular joints
• Standard brain MRI sequences are not optimized for bone or joint visualization in the maxillofacial region

Appropriate Imaging for Jaw Structures

If jaw imaging is clinically indicated, the following modalities are more appropriate:

1. CT Maxillofacial:

   • Nearly 100% sensitive for mandibular fractures with improved interobserver agreement 1
   • Provides high-resolution images with thin-section acquisitions
   • Superior to radiography for mandibular evaluation
   • Allows multiplanar and 3D reconstructions

2. Dedicated TMJ MRI:

   • Specifically designed protocols for temporomandibular joint evaluation
   • Allows detailed evaluation of TMJ anatomy due to inherent tissue contrast 2
   • Can assess joint biomechanics through closed and open jaw positions
   • Requires specific positioning and sequences not included in brain MRI

3. Panoramic Radiograph (OPG):

   • 86-92% sensitivity for detecting simple mandibular fractures 1
   • Better sensitivity than standard 4-view mandibular imaging series

Special Considerations

While standard brain MRI does not adequately visualize the jaw, there are some exceptions:

• Incidental TMJ findings may sometimes be partially visible on brain MRI, though these are often incomplete and not diagnostic 3
• In a study of patients undergoing brain MRI, some TMJ information was visible, but did not clearly correlate with clinical symptoms 3
• Specialized MRI protocols that focus on the posterior fossa and skull base may partially visualize the upper portions of the TMJ, but these are not standard brain MRI protocols 1

Clinical Implications

When jaw or TMJ evaluation is needed:

• Request the appropriate dedicated imaging study rather than relying on brain MRI
• For suspected mandibular pathology, CT maxillofacial is typically the first-line imaging modality 1
• For TMJ soft tissue evaluation, a dedicated TMJ MRI protocol should be ordered
• Brain MRI should be reserved for evaluating intracranial structures, not maxillofacial anatomy

In conclusion, if clinical assessment of the jaw is required, specific maxillofacial imaging studies should be ordered rather than relying on brain MRI, which is not designed to adequately visualize these structures.