artery [ICA], n=18; MCA, n=27; and anterior cerebral artery,
n=2) and 10 (18%) in the posterior circulation (basilar artery, n=3
and posterior cerebral artery, n=7; Table 2 and Figure 1).Among
the 57 lesions, 25 (44%) enhanced after contrast administration
(Figure 2), 43 (75%) were eccentric, 14 (25%) were concen-
tric, 42 (74%) were focal, and 15 (26%) were diffuse (Table 3).
Eccentric lesions were significantly associated with a focal
thickening pattern (Figure 2; Figure I in the online-only Data
Supplement) and concentric lesions with a diffuse thickening
pattern in plaques of the anterior circulation (P