Management of optic pathway gliomas: Role of magnetic resonance imaging with diffusion-tensor imaging tractography in planning surgical resection

Abstract

Optic pathway gliomas (OPGs) are histological low grade but widely infiltrative tumors that arise along the optic nerves, optic chiasm, tracts, diencephalic structures, and white matter radiations to the visual cortex. When OPGs progress, management strategies may differ between pre-chiasmatic and chiasmatic lesions. Radiation therapy is often utilized as the primary treatment modality, but it is typically postponed till the age of 5–7 years because of the potential for late risks such as endocrinopathy, vasculopathy, and cognitive decline. No definitive studies establish the superiority of one specific chemotherapeutic agent over others. However, a favorable side effect profile is often opted for. Surgery is considered in patients with (1) single nerve is involved, (2) progressive and disfiguring proptosis, (3) blindness, and (4) significant mass effect or hydrocephalus. Encouragingly, diffusion-tensor imaging (DTI) has emerged as a useful tool for the assessment of white matter structures, including the visual pathways. We report an interim analysis of 14 patients with OPG, at our center, a tertiary referral center. We report that magnetic resonance imaging (MRI)-DTI studies provided additional information about visual fiber arrangement in relationship to the tumor that was not evident by conventional MRI methods.