Fig. 11. MRI scans demonstrating optic pathway glioma in a 14-month-old child with neurofibromatosis type 1, who presented with irritability and bilateral visual loss. The patient was treated with two courses of carboplatin and vincristine, resulting in marked visual recovery and a reduction in tumor size. Compare pretreatment MRI scan (A) with post-treatment MRI performed 5 months later (B). (Courtesy of Russell W. Walker, MD)