Table 1:

MRA score in Moyamoya patient*

ICA	Normal	0
	Stenosis at supraclinoid portion	1
	Loss of continuous signal intensity at supraclinoid portion	2
	Invisible	3
MCA	Normal	0
	Stenosis at M1	1
	Loss of continuous signal intensity at M1	2
	Invisible	3
ACA	Distal to A2 is normal	0
	Stenosis of ACA distal to A2	1
	Invisible	2
PCA	Distal to P2 is normal	0
	Stenosis of PCA distal to P2	1
	Invisible	2

Note:—MRA indicates MR angiography; ICA, internal carotid artery; MCA, middle cerebral artery; ACA, anterior cerebral artery; PCA, posterior cerebral artery.
* MRA score 0–1, MRA grade I; MRA score 2–4, MRA grade II; MRA score 5–7, MRA grade III; MRA score 8–10, MRA grade IV.