<p> 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;</p><p>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; %</p><p>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</p><p>(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><p>(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. </p>