mrimaster

Temporomandibular Joint (TMJ) MRI

Introduction

Magnetic resonance imaging (MRI) is the most valuable and extensively utilized imaging technique for assessing the temporomandibular joint (TMJ). In comparison to computed tomography (CT) and arthrography, MRI offers superior tissue contrast, enabling clear visualization of soft tissues and other articular structures within the TMJ. Notably, MRI allows for direct visualization of the articular disc without the need for any contrast medium, giving it an edge over arthrography. The proper selection of coils and meticulous imaging techniques significantly contribute to successful TMJ imaging.

TMJ Anatomy

The temporomandibular joint (TMJ) is a crucial and complex anatomical structure that plays a central role in jaw movement and function. It is a bilateral joint located on either side of the head, connecting the lower jaw (mandible) to the temporal bone of the skull. The TMJ is responsible for facilitating essential functions like chewing, speaking, and swallowing.

Anatomically, the TMJ is comprised of several key components that work together harmoniously. The articular surfaces of the joint consist of the rounded condyle of the mandible and the concave mandibular fossa on the temporal bone. Separating these surfaces is a fibrocartilaginous articular disc, which acts as a cushion and helps to distribute forces during jaw movements.

Ligaments surrounding the TMJ provide stability and limit excessive movements. The lateral ligament, also known as the temporomandibular ligament, is the primary stabilizer and prevents the mandible from moving too far backward. The stylomandibular ligament and the sphenomandibular ligament also contribute to joint stability.

Muscles surrounding the TMJ are vital for its proper functioning. The muscles of mastication, including the temporalis, masseter, medial pterygoid, and lateral pterygoid muscles, are responsible for jaw movements during chewing. Disorders of the TMJ can lead to various symptoms such as pain, clicking, or difficulty in jaw movement.

Please check our new video tutorial for protocols and planning

Indications for TMJ MRI Scan

Contraindications

Patient preparation for TMJ MRI scan

Positioning for TMJ MRI Scan

mri brain planning and positioning

Recommended TMJ MRI Protocols, Parameters, and Planning

TMJ MRI Localizer

To plan the sequences, it is essential to acquire a three-plane localizer. These localizers typically have a duration of less than 25 seconds and are T1-weighted with low resolution.

TMJ MRI localiser image

T2 tse axial

Plan the axial slices on the sagittal plane and angle the planning block parallel to the hard palate. The slices must be sufficient to cover the mandible from the corpus callosum up to the line of the angle of the jaw. Check the positioning block in the other two planes, ensuring an appropriate angle is given in the coronal plane (perpendicular to the brain stem)

Parameters

temporomandibular joint(TMJ) MRI axial T2 planning image

TR

3000-4000

TE

100-120

SLICE

4MM

FLIP

130-150

PHASE

R>L

MATRIX

320X320

FOV

210-230

GAP

10%

NEX(AVRAGE)

2

TMJ scan planning localizers

Plan the sagittal localizers on the axial plane: for the right sagittal localizer, angle the planning block perpendicular to the right condyle of the mandible, and for the left side localizer, angle the planning block perpendicular to the left condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the coronal plane (parallel to the line along the temporal bone and ramus of the mandible).

Plan the coronal localizer on the axial plane: angle the planning block parallel to the line along the left and right mandibular condyles. Check the positioning block in the sagittal plane (parallel to the mandibular ramus).

Localisers should have a small field of view (FOV) with a maximum of 280mm FOV.

PD coronal 2mm SFOV RT TMJ

Plan the right side coronal slices on the axial plane, and angle the planning block parallel to the right condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the sagittal plane (parallel to the line along the ramus and right mandibular condyle). Ensure that the slices are sufficient to cover the right temporomandibular joint (RT TMJ) from the articular eminence up to the line of the internal auditory meatus.

MRI TMJ Planning of coronal right side scans

Parameters

TR

2500-3500

TE

15-30

FLIP

150

NEX

2

SLICE

2MM

MATRIX

256×256

FOV

100

PHASE

R>L

OVERSAMPLE

80%

FAT SAT

NO

PD coronal 2mm SFOV LT TMJ

Plan the left side coronal slices on the axial plane; angle the planning block parallel to the left condyle of the mandible. Check the planning block in the other two planes. Ensure an appropriate angle is given in the sagittal plane, parallel to the line along the ramus and left mandibular condyle. The slices must be sufficient to cover the left temporomandibular joint (TMJ) from the articular eminence up to the line of the internal auditory meatus.

Parameters

TR

2500-3500

TE

15-30

FLIP

150

NEX

2

SLICE

2MM

MATRIX

256×256

FOV

100

PHASE

R>L

OVERSAMPLE

80%

FAT SAT

NO

PD sagittal 2mm SFOV RT TMJ Close mouth

Plan the right side sagittal slices on the axial plane; angle the planning block perpendicular to the right condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the coronal plane (parallel to the line along the right temporal bone and ramus of the mandible). The slices should adequately cover the right temporomandibular joint (TMJ) from one side to the other.

MRI TMJ Planning of sagittal right side scans

Parameters

TR

2500-3500

TE

15-30

FLIP

150

NEX

2

SLICE

2MM

MATRIX

256×256

FOV

100

PHASE

R>L

OVERSAMPLE

80%

FAT SAT

NO

PD sagittal 2mm SFOV LT TMJ Close mouth

Plan the left side sagittal slices on the axial plane; angle the planning block perpendicular to the left condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the coronal plane (parallel to the line along the left temporal bone and ramus of the mandible). The slices should adequately cover the left temporomandibular joint (TMJ) from one side to the other.

Parameters

TR

2500-3500

TE

15-30

FLIP

150

NEX

2

SLICE

2MM

MATRIX

256×256

FOV

100

PHASE

R>L

OVERSAMPLE

80%

FAT SAT

NO

STIR sagittal 2mm SFOV RT TMJ Close mouth

Plan the right side sagittal slices on the axial plane; angle the planning block perpendicular to the right condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the coronal plane (parallel to the line along the right temporal bone and ramus of the mandible). The slices should adequately cover the right temporomandibular joint (TMJ) from one side to the other.

MRI TMJ Planning of sagittal right side scans

Parameters

TR

3000-4000

TE

90-100

FLIP

130

NEX

3

SLICE

2MM

MATRIX

256×224

FOV

100

PHASE

A>P

OVERSAMPLE

100%

TI

150

STIR sagittal 2mm SFOV LT TMJ Close mouth

Plan the left side sagittal slices on the axial plane; angle the planning block perpendicular to the left condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the coronal plane (parallel to the line along the left temporal bone and ramus of the mandible). The slices should adequately cover the left temporomandibular joint (TMJ) from one side to the other.

Parameters

TR

3000-4000

TE

90-100

FLIP

130

NEX

3

SLICE

2MM

MATRIX

256×224

FOV

100

PHASE

A>P

OVERSAMPLE

100%

T1

150

In order to perform the open mouth scans, a bite block must be placed in the patient’s mouth. The bite block should be big enough to keep the mouth wide open. If your department does not have a bite block, you can use a large 50 ml syringe instead.

PD sagittal 2mm SFOV RT TMJ open mouth

Plan the right side open mouth sagittal slices on the axial plane; angle the planning block perpendicular to the right condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the coronal plane (parallel to the line along the right temporal bone and ramus of the mandible). The slices should adequately cover the right temporomandibular joint (TMJ) from one side to the other.

MRI TMJ Planning of sagittal right side open mouth scans

Parameters

TR

2500-3500

TE

15-30

FLIP

150

NEX

2

SLICE

2MM

MATRIX

256×256

FOV

100

PHASE

R>L

OVERSAMPLE

80%

FAT SAT

NO

PD sagittal 2mm SFOV LT TMJ open mouth

Plan the left side open mouth sagittal slices on the axial plane; angle the planning block perpendicular to the left condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the coronal plane (parallel to the line along the left temporal bone and ramus of the mandible). The slices should adequately cover the left temporomandibular joint (TMJ) from one side to the other.

MRI TMJ Planning of sagittal left side open mouth scans

Parameters

TR

2500-3500

TE

15-30

FLIP

150

NEX

2

SLICE

2MM

MATRIX

256×256

FOV

100

PHASE

R>L

OVERSAMPLE

80%

FAT SAT

NO

Optional Scans

TRUFISP\FLASH CINE DYNAMIC sagittal 3mm RT

A small FOV True Fast Imaging with Steady Precession (TRUFISP) cine scan can provide dynamic real-time movement information of the TMJ (Temporomandibular Joint). This imaging technique is commonly used as a supplementary scan to gather additional information about TMJ anomalies during motion, such as dislocation. To conduct a dynamic scan, a single-slice TRUFISP sequence is used, lasting approximately 1 minute. During this time, the patient is instructed to slowly open and close their mouth to observe the joint in motion. Since this sequence is employed to gather supplementary information, a fast 1-minute dynamic scan is generally sufficient.

Some other radiologists prefer using single-slice high-resolution PD or T1 imaging in the same position but with different mouth opening positions, utilizing various bite blocks. The images are then combined to create dynamic sequences. However, this technique requires a minimum of 10 minutes for each side. In our department, we prefer the first method to save time.

Plan the right side dynamic sagittal slice on the axial plane; angle the planning block perpendicular to the right condyle of the mandible. Check the planning block in the other two planes. An appropriate angle must be given in the coronal plane (parallel to the line along the right temporal bone and ramus of the mandible). 

MRI TMJ Planning of sagittal right side dynamic scan

Parameters

TR

4-5

TE

2-3

FLIP

60

NEX

1

SLICE

3 MM

MATRIX

256×256

FOV

150-200

PHASE

A>P

OVERSAMPLE

50%

IPAT

OFF