Fig. 2.

Coronary CTA Napkin-Ring sign and corresponding plaque map. (A) ‘Napkin-Ring’ sign with low attenuation plaque surrounding by higher attenuation non-calcified plaque. (B) Plaque Map with plaque quantification necrotic core (35.3%-dark green) surrounded by fibrous plaque (51.5%-light green)(orange = lumen, calcified plaque = pink (13.2%) Necrotic core/fibrous plaque ratio = 0.69. (C) Co-registered VH-IVUS fibroatheroma (red = necrotic core, green = fibrous plaque and white = calcified plaque). Insets show cross-sectional images at arrows.