Usefulness of heavily T(2) weighted magnetic resonance images for the differential diagnosis of parotid tumours.

OBJECTIVES

To evaluate the usefulness of heavily T(2) weighted (T2W) magnetic resonance (MR) images for the differential diagnosis of parotid tumours.

METHODS

Conventional T2W and heavily T2W images obtained from 43 patients with parotid tumours were reviewed retrospectively. Tumours were classified pathologically into three types: pleomorphic adenoma (25 cases), Warthin's tumour (7 cases) and malignant tumour (11 cases). During interpretation of each MR image, special attention was paid to the homogeneity and signal intensity displayed by the solid portions of the tumours.

RESULTS

Heavily T2W images could distinguish pleomorphic adenoma from Warthin's tumour and malignant tumours based on the homogeneity and signal intensity of the solid portions, whereas conventional T2W images could not. On conventional T2W images, neither homogeneity nor signal intensity differed significantly among these three tumour types. On heavily T2W images, malignant and Warthin's tumours appeared more homogeneous than pleomorphic adenoma (P<0.0061); signal intensity from pleomorphic adenoma was significantly different to signal intensity from malignant tumours (P<0.05) and Warthin's tumour (P<0.005).

CONCLUSIONS

Heavily T2W MR images can be useful in distinguishing pleomorphic adenoma from Warthin's tumour and malignant tumours.