Abstract
MR imaging of 138 patients (276 TMJs) was performed at 0.2 T with a surface coil from January 1990 to December 1990. 190 of the 276 TMJs appeared with signs and symptoms suggestive of internal derangements of the TMJ. The MR imaging protocol was as follows: (a) an axial localizer with a TR of 100 msec., TE of 20 msec., fiele of view of 26cm, 5-mm slice thickness, 256×128 matrix and two excitations (26-second imaging time); (b) 5-mm -thick sagittal slices with the jaw closed, with no interslice gap, and with TR of 500 msec., TE of 38 msec., field of view of 20cm, 256×192 matrix and five excitations (imaging time, 8 minutes) (c) 5-mm-thick coronal slices with the jaw closed, TR of 300-500 msec., TE field of view, matrix and excitations were equal to the sagittal imagings. When anterior disk displacement of the TMJ was not revealed by sagittal images, coronal imaging was added. Clinical MR imaging of the 138 patients showed sideways disk displacement in six patients (6 TMJs: 4%). These six patients had intermediate opening clicking (2 TMJs), late opening clicking (3 TMJs) and clicking at side shift (1 TMJs).
