Diffusion-weighted imaging of the parotid gland: Can the apparent diffusion coefficient discriminate between normal and abnormal parotid gland tissues?

Objective: This study attempted to investigate the importance of diffusion weighted (DW)-echo planar imaging (EPI) in the characterization of normal parotid glands to facilitate the early detection of abnormal changes. Materials and Methods: This study was conducted between July 2014 and January 2016. Seventy-three patients were assessed by conventional and diffusion weighted Magnetic Resonance Imaging (MRI). Diffusion weighted MRI was performed by a single-shot spin echo (SE) echo planar imaging (EPI) sequence using b-values of 0, 500, and 1000. The Apparent Diffusion Coefficient (ADC) was automatically generated on the operating console. Results: The mean apparent diffusion coefficients (ADCs) ±SD of the superficial lobes were 0.89×10-3±0.2×10-3 and 0.9×10-3±0.17×10-3 mm2/s in the right and left sides, respectively. The mean ADCs of the deep lobes were 1.02×10-3±0.27×10-3 and 0.97×10-3±0.27×10-3 mm2/s in the right and left sides, respectively. The mean ADCs of the deep lobes were 1.02×10-3±0.27×10-3 and 0.97×10-3±0.27×10-3 mm2/s in the right and left sides, respectively. The mean±SD ADC of a normal parotid gland was 1.12×10-3±0.12×10-3 mm2/s. The mean±SD ADCs of benign and malignant tumors were 1.16×10-3±0.31×10-3 mm2/s and 0.82×10-3 mm2/s, respectively. Conclusion: The evaluation of the morphological characteristics of the parotid glands along with the Diffusion-weighted imaging (DWI) signal and ADC measurement may be valuable for detecting early pathological changes.