MRI OF THE TMJ DISC WITH INTRAVENOUS ADMINISTRATION OF GADOPENTETATE DIMEGLUMINE

Purpose: The purpose of this study was to ascertain whether MR imaging with intravenous administration of gadopenetate dimeglumine (Gd-DTPA) is useful in the demonstration of the temporomandibular joint (TMJ) d isc. Method: Sagittal T1-weighted MR images of 50 TMJs (25 patients) w ere obtained using a 0.5-T system both before and after intravenous in jection of Gd-DTPA. The authors depicted the TMJ in which intravenous injection of Gd-DTPA improved visualization of the disc. Results: Intr avenous injection of Gd-DTPA increased intensity in the retrodiscal sp ace, the pterygoid venous plexus, as well as joint effusion by diffuse d Gd-DTPA. The technique improved visualization of 10 (50%) of 20 norm al discs and 20 (67%) of 30 anterior disc displacements in closed-mout h position, and also 23 (74%) of 31 normal discs and 12 (63%) of 19 an terior disc displacements in open-mouth position. There were 12 TMJs ( 24% of the 50 TMJs) in which equivocal findings became highly diagnost ic. The incidence in marked contrast effect was higher in TMJs with se vere internal derangement than in those with normal or mild internal d erangement (p < 0.005). Conclusion: Using a 0.5-T MR imager, T1-weight ed imaging with intravenous injection of Gd-DTPA showed more anatomic details than imaging without the contrast agent.