Neuroimaging of Posterior Fossa Ependymoma in Children

Abstract

Neuroimaging studies are crucial for the identification and characterization of posterior fossa ependymomas as well as in the presurgical planning and evaluation of treatment results including the outcome of surgery, chemotherapy, and irradiation. Magnetic resonance imaging (MRI) and computerized tomography (CT) are the imaging methods in current use to evaluate these, as well as other, brain tumors. These methods detect tumors as lesions whose density and signal intensity are different from those of normal brain, with a variable degree of mass effect causing distortion of normal structures. MRI is superior to CT in the characterization of brain tumors and in the follow-up after treatment, thanks to its greater soft tissue contrast and multiplanar imaging capability without the burden of ionizing radiations, an especially relevant issue in infants and children who are more susceptible than adults to radiation-induced complications, including malignancy. Furthermore, advanced MRI modalities such as diffusion, perfusion, and spectroscopy provide additional information regarding functional features of brain tumors, including cellularity, hemodynamics, and metabolism, which may add significant information regarding their biological behavior and prognosis. MRI is also crucial for surveillance after surgery and chemoradiotherapy.