Measurement of Apparent Diffusion Coefficient (ADC) Values of Ependymoma and Medulloblastoma Tumors: a Patient-based Study

Background: Some brain tumors such as ependymoma and Medulloblastoma have similar MR images which may result to undifferentiated them from each other. Objective: This study aimed to compare the apparent diffusion coefficient (ADC) of two different cerebellar pediatric tumors, including ependymoma and medulloblastoma which have shown similar clinical images in conventional magnetic resonance imaging (MRI) methods.Material and Methods: In this analytical study, thirty six pediatric patients who were suspected to have the mentioned tumors according to their CT image findings were included in this study. The patients were subjected to conventional MRI protocols followed by diffusion weighted imaging (DWI) and ADC values of the tumors were calculated automatically using MRI scanner software. Results: The mean (± SD) ADC value for ependymoma (1.2± 0.06 ×10^-3 mm^2/s) was significantly higher than medulloblastoma (0.87 ± 0.02 ×10^-3 mm^2/s) (p = 0.041). Moreover, the maximum ADC value of ependymoma was considerably different in comparison with medulloblastoma (1.4 ×10^-3 mm^2/s and 0.96×10^-3 mm^2/s, respectively; p = 0.035). Furthermore, the minimum ADC value of ependymoma was higher compared to medulloblastoma (1.0 ×10^-3 mm^2/s and 0.61×10^-3 mm^2/s, respectively), but there was not significant (p = 0.067). Conclusion: Evaluation of ADC values for ependymoma and medulloblastoma is a reliable method to differentiate these two malignancies. This is due to different ADC values reflected during the evaluation.