(A) Maximal aortic diameter at ulcer site diameter (from ulcer across to opposite aortic wall). (B) Depth of intramural blood pool. (C) Length of intimal defect at ulcer site. (D) Width of intramural blood pool. Adapted from Gifford et al,11 Copyright 2016, with permission from Elsevier, Inc., and from Cho et al,9 Copyright 2004 with permission from the Society for Vascular Surgery.