Quantitative diffusion-weighted MR imaging in the differential diagnosis of parotid gland tumors: Is it a useful technique?

Abstract

Objective: Our purpose was to determine whether the apparent diffusion coefficient (ADC) measurement could be used to identify benign or malignant parotid tumors. Material and Methods: In this research 22 patients with 25 parotid gland tumors and 10 controls with 20 healthy parotid glands were studied. Diffusion-weighted magnetic resonance imaging (DW-MRI) with b factors of 0.500 and 1.000 sec/mm2 on a 1.5 T unit was used. The calculated ADCs values of the parotid gland tumors were compared with histological features of the tumors. Results: The study included 25 parotid gland tumors which consisted of 17 benign masses (10 pleomorphic adenomas, 6 Warthin tumors, 1 canalicular adenoma) and 8 malignant masses (4 lymphomas, 2 carcinoma ex pleomorphic adenomas, 1 adenoid cyctic carcinoma, 1 mucoepidermoid carcinoma). The mean ADC values of the control group, benign and malignant masses were 0.27±0.13 × 10-3 mm2/sec, 1.51±0.32 × 10-3 mm2sec, 1.05±0.26 × 10-3 mm2/sec, respectively (p<0.001). A cut-off value at 1.3×10-3 mm2/sec yielded a sensitivity of 87.50% and specifity of 58.82%, for distinguishing benign and malignant masses. Conclusion: Our results suggest that quantitative DW-MRI may be used for differentiating benign or malignant parotid gland tumors. Combination of ADC calculation with conventional MRI may have an additional value for determining malignancy. © 2010 by Türkiye Klinikleri.