MRI is currently the gold standard for imaging TMJ internal derangements, providing information on the disc morphology and position through high soft-tissue resolution.
T1 (longitudinal relaxation time): It is a measure of the time taken for spinning protons to realign with the external magnetic field.
T2 (transverse relaxation time): It is a measure of the time taken for spinning protons to lose phase coherence among the nuclei spinning perpendicular to the main field.
The best way to tell the two apart is to look at the grey-white matter. T1 sequences will have grey matter being darker than white matter. T2 weighted sequences, whether fluid-attenuated or not, will have white matter being darker than grey matter.
STIR is Short-TI Inversion Recovery and is typically used to null the signal from fat. This one is mostly used for better visualization of malignancies.
For TMJ:
|
T1 |
T2 |
| Bone marrow will be bright. | Synovial fluid and blood will be bright (if there is joint effusion will be brighter). |
| Collagen (disc, muscle) will be dark. | Collagen (disc, muscle) will be dark. |