title: Limitations of OCT in identifying and quantifying lipid components: an in vivo comparison study with IVUS-NIRS.
abstract: OBJECTIVE
  We aimed to assess the agreement between IVUS-NIRS and OCT to assess lipid plaques in patients with acute coronary syndromes or stable angina. In addition, the impact of both macrophages and calcifications was investigated.
  
  
  RESULTS
  Forty-three patients undergoing both IVUS-NIRS and OCT assessment of the culprit and/or non-culprit coronary lesions were enrolled. Cross-sections from lipid plaques, calcified plaques and normal-appearing vessel tracts were identified and matched with the two imaging techniques. Lipid arc was measured by both IVUS-NIRS and OCT. Macrophage presence and calcifications were also investigated with OCT. OCT detected a lipid plaque in 90 cross-sections (48.9%), with a sensitivity of 85.5% and a specificity of 69.7% as compared with IVUS-NIRS. The percentage of OCT false positive was 20.1% and of false negative was 4.9% for lipid plaque detection. The Pearson correlation coefficient for lipid arc was 0.675, p=0.0001. Macrophages were detected in 73% of OCT false positive cross-sections. Conversely, calcifications were present in 66.7% of OCT false negative cross-sections. The variability of lipid arc was independently associated with macrophages (beta=0.295, p=0.013).
  
  
  CONCLUSIONS
  Agreement between IVUS-NIRS and OCT for lipid plaque detection is suboptimal. The presence of macrophages and superficial calcifications on OCT negatively affects lipid detection.
authors.affiliation: Centro per la Lotta contro l'Infarto - CLI Foundation, Rome, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Di Vito
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Imola
authors.forename: Laura
authors.initials: L
authors.lastname: Gatto
authors.forename: Enrico
authors.initials: E
authors.lastname: Romagnoli
authors.forename: Ugo
authors.initials: U
authors.lastname: Limbruno
authors.forename: Valeria
authors.initials: V
authors.lastname: Marco
authors.forename: Andrea
authors.initials: A
authors.lastname: Picchi
authors.forename: Antonio
authors.initials: A
authors.lastname: Micari
authors.forename: Mario
authors.initials: M
authors.lastname: Albertucci
authors.forename: Francesco
authors.initials: F
authors.lastname: Prati
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D060050:Angina, Stable / Q000000981:diagnostic imaging*; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008055:Lipids / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging*; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D018084:Ultrasonography, Interventional / Q000379:methods
chemical_list: D008055:Lipids