[Salivary gland masses: dynamic MR imaging and pathologic correlation].

PURPOSE

To evaluate the efficiency of dynamic contrast-enhanced magnetic resonance imaging (MRI) for the diagnosis of salivary gland masses.

MATERIALS AND METHODS

We retrospectively examined 19 salivary gland masses that were pathologically diagnosed by surgical operation or biopsy. We obtained T1- and T2-weighted images on MRI, performed dynamic studies on each mass and examined the correlation between enhancement patterns and pathological findings.

RESULTS

Four enhancement patterns were recognized on contrast-enhanced MRI: type 1 showed marked, homogeneous enhancement; type 2 slight, homogeneous enhancement; type 3 marginal enhancement; and type 4 poor enhancement of the mass. Most pleomorphic adenomas had a type 1 enhancement pattern, but two had a type 2 pattern. Pathologically, each mass enhancement pattern had different tumor cell and matrix components. Warthin's tumor generally showed the type 4 pattern. Primary malignant tumors of the salivary gland all showed the type 3 pattern, and pathological specimens showed many tumor cells along the marginal portion of the tumor. One inflammatory cyst and one Warthin's tumor also showed the type 3 pattern. Except for metastatic renal cell carcinoma, the enhancement patterns of late phase images and dynamic study images were the same.

CONCLUSIONS

Dynamic MRI added little diagnostic information about salivary gland masses, but the contrast-enhanced MR features correlated well with the pathological findings.