Assessment of dynamic MRI of Warthin's tumors arising as multiple lesions in the parotid glands.

We examined three patients with multiple synchronous Warthin's tumors in the bilateral parotid and described the value of using dynamic MRI. The time course of the contrast index (CI curves) was calculated from a dynamic series. Warthin's tumors showed intermediate signal intensity on T1WI, heterogeneous high and intermediate signal intensity on T2WI and a slight enhancement on Gd-T1WI. Warthin's tumors of CI curves showed specific findings. CI curves in each lesion showed the same pattern. It was difficult to diagnose masses as Warthin's tumors using only MR images on T1, T2 and Gd-T1WI. Dynamic MRI can distinguish Warthin's tumors from other possible tumors except for oncocytoma. Therefore, the use of dynamic MRI is recommended as a diagnostic method for Warthin's tumors in multiple synchronous lesions of the parotid gland.