Moyamoya Syndrome in a Child with Neurofibromatosis Type 1: Magnetic Resonance Imaging as a Tool for Clinical Decision Making

Abstract

Moyamoya syndrome is a rare cerebrovasculopathy of unknown etiology which is associated with multiple risk factors. Moyamoya was first discovered in Japan and is reported to have an increased prevalence in the Japanese population. The term "Moyamoya" translates into "puff of smoke" and is named after the finding of the collateral cerebral vasculature that develops secondary to occlusion of an internal carotid artery at the entrance into the circle of Willis. This collateral vasculature characterizes the disease. Moyamoya should be included in the differential diagnosis in the pediatric population when a patient presents with stroke or stroke-like symptoms. Diagnosis can be made with catheter angiogram or magnetic resonance angiogram. Recent use of magnetic resonance perfusion imaging has been shown to be useful in clinical decision making while assessing the need for revascularization surgery. We present the case of a 15-year-old with comorbid psychiatric illness, neurofibromatosis type I with brainstem glioma, and Moyamoya syndrome. Considering our patient`s complex medical history of psychiatric illness and previously diagnosed neurofibromatosis, magnetic resonance imaging (MRI) with magnetic resonance angiogram (MRA) and magnetic resonance perfusion proved instrumental in helping rule out the progression of arteriopathy as the cause of his worsening seizures and behavior. In our patient, it was determined that the relative perfusion for each hemisphere of the patient's brain quantitatively lacked significant differences and he was therefore not a candidate for surgical revascularization. These modalities proved instrumental in surgical decision-making and clinical management of the patient.