Table 1.

ATTs to Various Vessel Segments

Note.—Unless otherwise indicated, data are mean ATTs ± standard deviations. Mean ATT was defined as the labeling duration at which ROI signal was greater than one-half of its value with 2.5 seconds of labeling. Standard deviation was calculated across subjects in each cohort. ATT included time to acquisition of the center of k-space. Significant differences in ATT were found between various segments (left and right branches were assessed separately) with the one-sided paired t test. In cohort 1, P < .01 for all MCA and ACA branches compared to the COW, unless otherwise indicated. ACA = anterior cerebral artery, ECA = external carotid artery, MCA = middle cerebral artery. Subscripts a, b, and c indicate relative distance along the artery from the COW, with a being the closest.

^*Data are mean ATTs.

^†P = .03.

^‡P < .04 in comparison with MCA_a.

^§From ACA_a to ACA_b, P = .07 for left and P = .005 for right.

^‖P = .19.

^#P = .04.

^**P < .014 between the COW and MCA/ACA branches.

^††P = .07 between vertebral and basilar arteries.

^‡‡P = .014 between vertebral and basilar arteries.