Supplemental Table Patient Information and ATT Distribution

Supplemental Table Patient information and ATT distribution Patient A ge S e Suzuki classification % Pixels R L ATT (clinical x 1.5-2s 2s-2.5s >2.5s category) 1 (A) 18 M 3 4 87 11 2 2 (A) 48 M 3 6 89 11 0 3 (A) 13 F 2 2 91 9 0 4 (A) 43 M 1 3 87 10 3 5 (A) 44 F 2 3 91 8 1 6 (A) 40 M 2 2 89 11 0 7 (A) 48 M 3 3 90 10 0 8 (A) 11 M 4 2 92 8 0 9 (A) 25 F 2 5 92 8 0 10 (B) 24 M 3 2 98 2 0 11 (B) 32 F 5 6 80 17 3 12 (B) 32 M 2 3 89 10 1 13 (B) 50 F 3 3 96 4 0 14 (B) 48 M 3 3 93 7 0 15 (B) 31 M 4 3 93 6 1 16 (B) 48 F 3 5 85 13 2 17 (B) 60 M 5 4 73 23 4 Note.Clinical category A: moderate; B:severe. M = male; F = femal;

Suzuki classification was graded according to DSA. Stage 1 (bilateral terminal ICA stenosis) to stage 6 (complete obliteration of the ICA circulation with supply of brain derived entirely from the external carotid artery). ATT = arterial transit time; %

Pixels, number of pixels in the corresponding segmented regions according to ATT value as a percentage of the total number of pixels. Supplemental Fig. 1. Theoretical signal-weighted delay (WD) as a monotonically increasing function of arterial transit delay (ATT). This could be numerically inverted to calculate ATT from WD. Supplemental Fig. 2. Simulated dynamic pCASL signals (labeling duration = 1.5s) as a function of arterial transit time (ATT) using Eq[2]. It can be clearly seen that dynamic pCASL signals peak at the ATT. When PLD is shorter than ATT, there is still ASL signal increase

(not no signal) as the bolus of labeled blood accumulates in the imaging voxel. Supplemental Fig 3. Voxel-wise scatterplots and pearson correlation coefficients

(p<0.001) between the magnitudes of ASL and CTP maps of a representative moyamoya patient (patient #9). Each marker represents a single voxel (5mm3). Supplemental Fig.4. Normalized ASL CBF images (same coverage with CTP) in gray matter (A) and white matter (B) overlayed to normalized T1 map. C: Template of vascular territory masks used in the present study overlayed to normalized T1 map.