MR of intraparotid masses.

PURPOSE To determine which MR techniques are best for identifying intraparotid masses and to assess the utility of MR for predicting specific diagnosis.

METHODS A retrospective review of 31 intraparotid masses was performed. Lesion conspicuity and signal intensity characteristics were evaluated by objectively measured regions of interest and by subjective visual review.

RESULTS The T1-weighted images produced the highest lesion conspicuity in 25 of 31 masses. All the masses were easily detected as hypointense lesions on the T1-weighted scans with good or excellent conspicuity; on the T2-weighted images nine lesions appeared isointense to the normal parotid tissue, including six malignancies. Gadolinium-enhanced images were not helpful for identifying the intraparotid masses. Warthin tumors and malignancies tended to be hypointense or low in conspicuity on T2-weighted images.

CONCLUSIONS The T1-weighted images were best for detecting parotid masses. The T2-weighted images may help in limiting a differential diagnosis, but a specific diagnosis cannot be made without biopsy.