Feature seen on cerebral angiography – both of the following:
(1) stenosis or occlusion at one or more of the following:
(1a) at the terminal portion of the internal carotid artery
(1b) at the proximal portion of the anterior cerebral artery
(1c) at the proximal portion of the middle cerebral artery
(2) abnormal vascular networks in the vicinity of the occlusive or stenotic lesions
Feature seen on MRI angiography – both of the following:
(1) stenosis or occlusion :at the terminal portion of the internal carotid artery AND at the proximal portion of the anterior cerebral artery AND at the proximal portion of the middle cerebral artery
(2) abnormal vascular network in the basal ganglia
where:
• An abnormal vascular network in the basal ganglia can be diagnosed on MRI if > 2 apparent flow voids are seen in one side of the basal ganglia.
• Conventional angiography is not needed if the findings are clearly seen on MRI angiography.
Conditions to be excluded:
(1) arteriosclerosis
(2) autoimmune disease
(3) meningitis
(4) brain tumor
(5) Down syndrome
(6) von Recklinghausen’s disease
(7) head trauma
(8) irradiation to the head
(9) any other condition
If any of the conditions to be excluded are present then the diagnosis is uncertain.
Definite diagnosis criteria 1:
(1) bilateral findings on angiography or MRI angiography
Definite diagnosis criteria 2:
(1) pediatric patient
(2) unilateral findings on angiography or MRI angiography
(3) opposite side shows stenosis at the terminal portion of the internal carotid artery
