Background & Methods: The local reduction of Nogo-B might contribute the plaque formation and/or instability. However, the effect of Nogo-B in the progression of fibroatheroma(FA) is not well known. We assessed the expression of Nogo-B and compared early to late fibroatheromas using virtual histology intravascular ultrasound (VH-IVUS) analysis in 43 autopsied coronary arteries of non-sudden cardiac death and 4 cases of sudden cardiac death. IVUS imaging was performed 30mm from the ostium of each coronary artery. Early FA was defined as necrotic core (NC) area <0.1mm2 and <10% in the presence of a plaque burden >40% and late FA was defined NC area 0.1-1.0mm2 and >10% of NC area in the presence of a plaque burden >40%. Results: Pt age was 43짹11yrs and 67% were males. Grey scale IVUS showed plaque burden was similar(52.1짹8.3% vs 51.0짹7.5%, p=0.527), however lumen area was smaller in early FA (4.03짹1.22mm2 vs 4.69짹1.33mm2, p=0.028). VH-IVUS analysis of small, early FAs showed a smaller NC (4.46짹2.30% vs 16.61짹5.25%, p<0.001) and more calcium in late FA(2.77짹2.90% vs 8.22짹6.17%, p<0.001). Similarly, histopathology showed early FA showed a smaller NC, less calcium, and less infiltration of CD68+ macrophage. The Nogo-B was negatively correlated with the progression of FA; remarkably increased in early FA, however decrease in advanced late FA (Figure). Conclusion: The changes of Nogo-B may predict plaque formation vulnerability. More studies are necessary to assess the potential role of Nogo-B.