300 Longwood Avenue Boston, MA 02115 (617) 355-6000 Clinical Services (Moyamoya Disease Program): Diagnosis Magnetic resonance imaging (MRI and MRA) and occasionally computed tomography (CT) scans give the initial indications of moyamoya disease. The standard - both for diagnosing the disease and for planning surgery - is a cerebral angiogram. A dye that shows up on x-rays is fed into the carotid artery and a series of x-ray images are taken. Both the narrowed artery and the proliferation of new blood vessels (the "puff of smoke," for which the disease is named) show up in sharp relief. All angiograms carry some risks, which are slightly greater in children with moyamoya, so a highly-skilled angiographic team is essential. The information on this website should not be taken as medical advice, which can only be given to you by your personal health care professional. Copyright © Children's Hospital Boston. All rights reserved.