Spontaneously infarcted parotid tumours: MRI findings.

Objectives: To report MRI findings of spontaneous infarction in parotid tumours. Methods: 14 patients (13 male, 1 female; mean age 73 years) with spontaneously infarcted parotid tumours were reviewed retrospectively. MR images were assessed for the location, the presence of synchronous parotid masses, margin characteristics, signal intensity on T-1 and T-2 weighted images, and internal architecture according to the distribution of T-2 signal hyperintensity. Results: 12 tumours were located in the parotid tail and 2 in the superficial lobe. Synchronous parotid masses were seen in four tumours, three of which were located in the ipsilateral parotid tail and one in the contralateral parotid tail. Seven tumours had well-defined margins and seven had ill-defined margins. The signal intensities on T-1 weighted images were a mixture of high and intermediate in all cases; in 11 tumours, hyperintense areas were dominant. On T-2 weighted images, all tumours also showed a mixture of high and intermediate signal intensities. Internal architectures on T-2 weighted images were mosaic hyperintensity in three tumours, central hyperintensity in five, and multiseparated hyperintensity in six. Conclusions: Spontaneously infarcted parotid tumours were mostly located in the parotid tail and showed mixed signal intensities with predominant hyperintensity on T-1 weighted images. Half of the tumours had ill-defined margins, and the internal architectures varied.