Value of dynamic contrast enhanced MRI in differential diagnostics of Warthin tumors and parotid malignancies.

To define an algorithm for differential diagnostics of parotid malignancies and Warthin tumors (WTs) based on dynamic contrast enhanced MRI (DCE-MRI). 55 patients with parotid tumors treated surgically were analyzed. Of which, 19 had parotid malignancy and 36 had WTs confirmed with postoperative histopathological examination. Accuracy of DCE-MRI parameters (Tpeak and WR) was compared with the histopathological diagnosis. ROC analysis was performed to determine sensitivity and specificity of DCE-MRI with various Tpeak and WR cut-off values. WT showed significantly lower median Tpeak and higher median WR than malignant lesions. The cut-off values for Tpeak and WR providing maximum sensitivity (84.2%) and specificity (86.1%) for malignant tumors were Tpeak > 60 s and WR ≤ 30%. Different diagnostic algorithm, i.e., lower cut-off value for Tpeak (Tpeak = 60 s), increases sensitivity of DCE-MRI in differentiating parotid malignancies from WTs. However, WR > 30% seems to be a key diagnostic criterion for benign lesions. Precise and reliable preoperative diagnostics of parotid tumors aids in careful surgical planning, thereby assisting in achieving sufficient surgical resection margins and facial nerve preservation.