Diagnostic Accuracy of Diffusion Weighted Imaging in Evaluation of High and Low Grade Pediatric Brain Tumors

Abstract
Background: Diagnosis and classification of brain tumors at pediatric age group is a challenging issue. MRI with different sequences including conventional MRI, post contrast study and diffusion weighted imaging (DWI) and well as ADC value measurement are considered accurate imaging modality to properly diagnose, classify brain lesions according to their site, extent and biological behaviour.
Aim of Study: To evaluate the diagnostic accuracy of DWI in differentiation of high and low grade pediatric brain tumors.
Patients and Method: Pre-operative MRI examination including; conventional MRI, post contrast study and DWI were done for 30 pediatric patients with suspected brain tumors by CT examination. Lesions evaluation regarding their size, site, signal intensity, pattern of enhancement, appearance at DWI and ADC values were done for all cases.
Results: The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of diffusion weighted imaging were 89%, 100%, 100%, 86% and 93% respectively. All high grade tumors showed restricted diffusion. Post contrast MRI examination revealed no significant differ-ence between low and high grade tumors.
Conclusion: Addition of DWI and ADC values measure-ment to the routine MRI examination of the brain improved the diagnostic accuracy of prediction of pediatric brain tumor histopathological grade.