Role of magnetic resonance imaging in diagnosis of pediatric posterior fossa tumors

Abstract

Objective The aim was to study the role of MRI in diagnosis of pediatric posterior fossa tumors. Background Brain tumors represent the most common solid neoplasms in children and the second most common pediatric malignancy following leukemia. Patients and methods A retrospective study was conducted on 25 pediatric patients with known brain posterior fossa masses, who ranged in age from 1 to 15 years and had suspected posterior fossa tumor by computed tomography. All participants attended the MR unit of Radiology Department, Menoufia University, Menoufia Governorate, during the period from October 2016 to November 2017. Complete history taking, clinical examination, and MR data were compared with histopathology obtained from all patients. Results The mean age of the cases was 7.2 ± 3.9 years. The most common tumors were medulloblastoma (MB) and pilocytic astrocytoma. MB showed restricted diffusion with low apparent diffusion coefficient value, and pilocytic astrocytoma showed free diffusion with higher apparent diffusion coefficient value. High-grade tumors such as MB and brain stem glioma showed elevated choline and reduced N-acetyl aspartate in magnetic resonance spectroscopy curve. Low-grade tumors such as low-grade glioma showed mild rise of choline and mild reduction of creatine in magnetic resonance spectroscopy curve. Conclusion Conventional MRI provided limited information regarding tumor type and grade, falling short as a definitive diagnostic examination. Advanced brain MRI techniques provided incremental diagnostic value over conventional MRI. However, no single advanced technique was perfect, but different techniques typically complement one another.