MRI of salivary gland tumors

MRI findings of 13 patients with proven salivary gland tumors, including 7 cases of parotid gland tumors, 2 cases of submandibular gland tumors, and 4 cases of minor salivary gland tumors, were reviewed. All examinations were carried out on a 1.5-T MRI system (General Electric, SIGNA Performance plus and SIMAZU, SMT-150X) with spin echo sequence. T1 and T2 weighted images and Gd-DTPA enhanced T1 weighted images were obtained. The results were as follows: All tumors demonstrated low to intermediate signal intensity on T1 weighted images and intermediate to high signal intensity on T2 weighted images. The differences between malignant and benign tumors were not detected by means of the signal intensity of the tumors. Tumor margins were clear except for 2 cases, including inflamed pleomorphic adenoma of the submandibular gland and adenoid cystic carcinoma of the parotid gland. Except for the case of adenolymphoma, internal structures of the tumor are inhomogenous, especially on T2 weighted images. Although the intraparotid facial nerve is not detected directly, whether the tumor is located on superficial or deep lobe could be detected by drawing a line between the lateral surface of the posterior belly of the digastric muscle and the lateral posterior border of the mandible except for one case and using the retromandibular vein except for two cases. (author)