Which imaging modality is best to confirm soft tissue disc displacement disorders?

• A. Ultrasound is best.
• B. MRI is best.
• C. Panoramic radiograph is best.
• D. CBCT is best.

Answer: (B)

MRI is the imaging modality of choice for confirming soft tissue disc displacement disorders. It provides exceptional soft tissue contrast and lets you see the articular disc directly, showing its position relative to the condyle in both closed- and opened-mouth positions. This makes it possible to identify disc displacement with reduction or without reduction and to assess related findings like joint effusion or retrodiscal tissue changes, which are important for diagnosis and planning treatment.

Ultrasound can assess some superficial TMJ structures and may show dynamic movement, but the TMJ is deep and surrounded by bone, making consistent visualization of the disc difficult and operator-dependent, so it isn’t the best option for confirming disc displacement.

Panoramic radiographs offer a broad view of teeth and bone but provide no information about soft tissues or the disc, so they can’t confirm soft tissue disc disorders.

CBCT excels at detailing bony anatomy of the joint but has poor soft tissue contrast, so it cannot reliably visualize the articular disc or retrodiscal tissues.