Value of diffusion weighted and ADC value - magnetic resonance imaging in differentiation between benign and malignant solid parotid gland masses

Abstract

Background: magnetic resonance imaging (MRI) is becoming an essential tool for assessment of parotid gland pathology. Diffusion weighted imaging (DWI) provides quantitative and qualitative information reflecting the changes in tissue cellularity and integrity of cell membranes. Objective: To evaluate the diagnostic accuracy of diffusion weighted -MRI in the differentiation between benign and malignant solid parotid gland masses using 1.5 Tesla MRI scanner and to obtain the best cutoff value of apparent diffusion coefficient (ADC) to differentiate between benign and malignant masses. Patients and methods: prospective cross-sectional analytic study was conducted in Al Imamein Al Kadhumein Medical City, at the period between January 2019 and January 2020, 50 patients were included in the study. DWI was acquired at following b-values [50, 1000 millimeter (mm) 2/second (sec)], in this study the results were obtained and depending on b-value 1000 mm2/sec. Results: The mean level of ADC value of malignant masses (0.599 ± 0.117 SD x 10-3 mm2/sec), while for benign masses (1.590 ± 0.363 SD x10-3 mm2/sec); According to Receiver operating characteristic (ROC) curve the optimal cutoff point of ADC value was (0.914x10-3 mm2/sec) with sensitivity 100%, specificity 97%. The association between MRI diagnosis and histopathological diagnosis was significant (P value< 0.001). Conclusion: Diffusion weighted- MRI and ADC values are highly sensitive and specific to differentiate between benign and malignant solid parotid gland masses and the best ADC cut off value was (0.914x10-3 mm2/sec).