Value of apparent diffusion coefficient and magnetic resonance spectroscopy in the identification of various pathological subtypes of parotid gland tumors

Abstract Background and purpose Pre-operative imaging has a major role in surgical planning of parotid gland tumors. Aim To assess the role of the combined techniques of ADC generated from DWI and MR spectroscopy in identification of various pathological subtypes of parotid gland tumors. Patients and methods Prospective study was conducted on 25 patients with primary parotid tumors (11 males, 14 females, age ranged 22–79 years with mean of 53.4 ± 13.6 years). DWI and MRS were performed for all patients and the results were correlated with histopathological findings. Results The 18 (72%) benign and 7 (28%) malignant tumors consisted of 11 pleomorphic adenomas, 7 Warthin tumors, and 7 malignant tumors. The mean ADC value for pleomorphic adenomas was 1.89 ± 0.18 × 10 −3  mm 2 /s, for Warthin tumors was 0.92 ± 0.22 × 10 −3  mm 2 /s, and for the malignant tumors was 1.03 ± 0.13 × 10 −3  mm 2 /s, significant difference was seen between benign and malignant tumors ( P =  0.037). The mean values of Cho/Cr ratios were 3.37 ± 0.78, 5.9 ± 1.75 and 1.72 ± 0.41, for pleomorphic adenomas, Warthin tumors, and malignant tumors, respectively. Difference was significant between benign and malignant tumors ( P  = 0.001). Conclusion DWI and MRS are useful noninvasive diagnostic modalities in identification of various pathological subtypes of parotid tumors.