MR imaging of squamous cell carcinoma of the floor of the mouth. Appearance of the sublingual and submandibular glands.

<bold>Purpose: </bold>To determine the diagnostic value of MR imaging for tumors of the floor of the mouth and the effects of the tumors on the sublingual and submandibular glands.<bold>Material and Methods: </bold>Thirty-seven patients with proven squamous cell carcinoma of the floor of the mouth underwent MR imaging, including unenhanced T1-weighted, T2-weighted, dynamic, and contrast-enhanced T1-weighted images. The appearance of the tumor and the sublingual and submandibular glands was assessed qualitatively and quantitatively.<bold>Results: </bold>All tumors demonstrated replacement of the normal signal intensity in the adjacent sublingual gland. Twenty-one patients (57%) had abnormal signal intensity of the submandibular gland without tumor invasion, presumably secondary to submandibular duct obstruction by the tumor. Unenhanced T1-weighted images provided high contrast between tumor and sublingual gland. Tumors limited within the gland were well detected on unenhanced T1-weighted images. Large tumors extending beyond the gland were well delineated on dynamic images, but no better than on T2-weighted images.<bold>Conclusion: </bold>At MR imaging for tumor of the floor of the mouth, one must carefully evaluate the appearance of the sublingual and submandibular glands. Contrast-enhanced studies are unnecessary when the tumor is limited within the sublingual gland on precontrast MR images. [ABSTRACT FROM AUTHOR]