Delineation of eccentricity measurement. (a), Eccentricity Index = (A - B)/A. A (Maximum wall thickness) and B (Minimum wall thickness) can be measured by CASCADE automatically. The eccentric lesion is defined as EI ≥ 0.5, concentric lesion as EI < 0.5; (b) and (c), Examples of femoral arterial plaques with eccentricity index of 0.31 and 0.83, respectively. A big calcification can be seen in the eccentric plaque (dark area). (blue: outer wall boundary; red: lumen).