The vessel and wall areas at the maximal lumen narrowing (MLN) site will be measured. The plaque volume will be calculated as the product of the plaque area and the thickness of the slices containing the plaque. The plaque/wall ratio was defined as the plaque area divided by wall area ×100%. The remodeling index was calculated as the ratio of the vessel area at the MLN site to that at the reference site. The reference site was selected based on the Warfarin-Aspirin Symptomatic Intracranial Disease trial method.