title: Differences determined by optical coherence tomography volumetric analysis in non-culprit lesion morphology and inflammation in ST-segment elevation myocardial infarction and stable angina pectoris patients.
abstract: BACKGROUND
  While the current methodology for determining fibrous cap (FC) thickness of lipid plaques is based on manual measurements of arbitrary points, which could lead to high variability and decreased accuracy, it ignores the three-dimensional (3-D) morphology of coronary artery disease.
  
  
  OBJECTIVE
  To compare, utilizing optical coherence tomography (OCT) assessments, volumetric quantification of FC, and macrophage detection using both visual assessment and automated image processing algorithms in non-culprit lesions of STEMI and stable angina pectoris (SAP) patients.
  
  
  METHODS
  Lipid plaques were selected from 67 consecutive patients (1 artery/patient). FC was manually delineated by a computer-aided method and automatically classified into three thickness categories: FC < 65 μm (i.e., thin-cap fibroatheroma [TCFA]), 65-150 μm, and >150 μm. Minimum thickness, absolute categorical surface area, and fractional luminal area of FC were analyzed. Automated detection and quantification of macrophage was performed within the segmented FC.
  
  
  RESULTS
  A total of 5,503 cross-sections were analyzed. STEMI patients when compared with SAP patients had more absolute categorical surface area for TCFA (0.43 ± 0.45 mm(2) vs. 0.15 ± 0.25 mm(2) ; P = 0.011), thinner minimum FC thickness (31.63 ± 17.09 µm vs. 47.27 ± 26.56 µm, P = 0.012), greater fractional luminal area for TCFA (1.65 ± 1.56% vs. 0.74 ± 1.2%, P = 0.046), and greater macrophage index (0.0217 ± 0.0081% vs. 0.0153 ± 0.0045%, respectively, P < 0.01).
  
  
  CONCLUSIONS
  The novel OCT-based 3-D quantification of the FC and macrophage demonstrated thinner FC thickness and larger areas of TCFA coupled with more inflammation in non-culprit sites of STEMI compared with SAP.
authors.affiliation: Heart Institute - InCor, São Paulo University Medical School, São Paulo, Brazil.
authors.forename: Micheli Zanotti
authors.initials: MZ
authors.lastname: Galon
authors.forename: Zhao
authors.initials: Z
authors.lastname: Wang
authors.forename: Hiram G
authors.initials: HG
authors.lastname: Bezerra
authors.forename: Pedro Alves
authors.initials: PA
authors.lastname: Lemos
authors.forename: Audrey
authors.initials: A
authors.lastname: Schnell
authors.forename: David L
authors.initials: DL
authors.lastname: Wilson
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Rollins
authors.forename: Marco A
authors.initials: MA
authors.lastname: Costa
authors.forename: Guilherme F
authors.initials: GF
authors.lastname: Attizzani
mesh_terms: D000368:Aged; D000465:Algorithms; D060050:Angina, Stable / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D001331:Automation; D003331:Coronary Vessels / Q000737:chemistry / Q000473:pathology*; D005260:Female; D005355:Fibrosis; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007249:Inflammation / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D008055:Lipids / Q000032:analysis; D008264:Macrophages / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence
chemical_list: D008055:Lipids
keywords: ST-segment elevation myocardial infarction; atherosclerosis; fibrous cap; macrophage; optical coherence tomography; stable angina; thin-cap fibroatheroma