Characteristic findings of adenoid cystic carcinoma on MR imaging and differentiation from squamous cell carcinoma

Ten patients with adenoid cystic carcinoma and 49 with squamous cell carcinoma confirmed by aiopsy were evaluated. In these patients, malignant tumors were suspected with clinical progressions and clinical symptoms. The purpose of this study was to analyze and discuss the characteristic findings on MR imaging of adenoid cystic carcinoma in the head and neck, and to examine the usefulness of MR imaging in the differentiation between adenoid cystic carcinoma and squamous cell carcinoma. The characteristics on MR imaging of adenoid cystic carcinoma are a high signal intensity on T2-weighted images, marked enhancement by Gd-DTPA, and a capsular structure. All cases of recurrent adenoid cystic carcinomas also showed upward extension. We consider that the high signal intensity on T2-weighted images, the marked contrast enhancement and the capsular structure in MR imaging can be useful in differentiating adenoid cystic carcinoma and squamous cell carcinoma.