Moyamoya disease (MMD) is a cerebrovascular disorder involving stenosis of brain vessels. Brain perfusion SPECT in MMD demonstrates impaired perfusion in ischemic areas. We present a 6-year-old boy with MMD. The patient had numbness on the right arm and simultaneous electroencephalography changes while studying arms up on the table. To differentiate seizure and ischemic symptoms, brain perfusion SPECT studies were obtained when the patient was asymptomatic (SPECT-A) and during the symptoms-EEG changes (SPECT-B). SPECT-A showed perfusion defect on the right frontal cortex, hypoperfusion on the right parieto-occipital region and slightly increased perfusion on the left parietal cortex. SPECT-B displayed significant hyperperfusion on the left parietal cortex; hypoperfusion on the right parietal, right temporal, right parieto-occipital and left frontal cortex. Additionally, brain perfusion SPECT of the child's younger brother diagnosed with MMD showed decreased regional cerebral perfusion. Physiopathological mechanisms of our patient's SPECT findings and indications of brain perfusion SPECT in MMD were also discussed. (C) 2011 Elsevier Espana, S.L. and SEMNIM. All rights reserved.