Determining whether a parotid tumor is in the superficial or deep lobe using magnetic resonance imaging

Purpose: This study examined the usefulness of magnetic resonance imaging (MRI) in assessing whether parotid tumors were located in the superficial or deep lobe. Patients and Methods: Eight patients with parotid gland tumors underwent MRI using a spin echo pulse sequence. T1- and T2-weighted images were obtained. To assess tumor localization in the parotid gland, two anatomic landmarks were used: 1) a line connecting the lateral surface of posterior belly of digastric muscle and lateral surface of the cortical bone of ascending ramus (facial nerve [FN] line) and 2) the relationship to the retromandibular vein (RV). Results of all MRI examinations were compared with the surgical findings. Results: Seven of eight cases were correctly diagnosed using the FN line criterion. Five of eight cases were correctly diagnosed using the RV criterion. Conclusion: MRT is an excellent modality to show tumor localization in the parotid gland.