Moyamoya disease (MMD) is characterized by an idiopathic progressive narrowing of intracranial ICA and its proximal branches. In consequence, an abnormal network of compensatory collateral vessels develop, originating an angiographic puff of smoke (moyamoya) sign. 
Case 1: A 29-year-old woman presents with a 3-week history of left hemihipoestesia. MRI  revealed a right MCA ischemic lesion. Conventional angiography demonstrated a severe stenosis of the distal right ICA and proximal M1 associated with hypertrophy of the ipsilateral leptomeningeal and lenticulostriate arteries. Follow-up angioCT revealed progression of right MCA stenosis and involvement of the ipsilateral proximal ACA. 
Case 2: A 35-year-old male presents with sudden onset of left hemiparesis and hemihipoestesia lasting less than 24 hours. CT and MRI did not demonstrate ischemic lesions. Both angioCT and TOF angiography revealed occlusion of proximal right M1 and a bilateral moyamoya pattern.
CSF and serum analysis were normal on both cases. Predisposing conditions associated with moyamoya were not identified. Patients were diagnosed with probable MMD (case 1) and MMD (case 2) and started on aspirin 100mg daily. 
Although the diagnosis of definite MMD requires bilateral presentation, patients with unilateral ICA involvement and no predisposing pathology may be classified as probable MMD, considering that up to 70% of such patients eventually develop contralateral disease over time. Antiplatelet therapy has been successfully used in mild cases, but surgical revascularization is the treatment of choice to prevent stroke and should be considered on both cases.  However, there is still lack of evidence on the right timing for surgical treatment.

MOYAMOYA DISEASE: WHEN IS THE BEST TIME FOR SURGERY