title: Direct Comparison of Virtual-Histology Intravascular Ultrasound and Optical Coherence Tomography Imaging for Identification of Thin-Cap Fibroatheroma.
abstract: BACKGROUND
  Although rupture of thin-cap fibroatheroma (TCFA) underlies most myocardial infarctions, reliable TCFA identification remains challenging. Virtual-histology intravascular ultrasound (VH-IVUS) and optical coherence tomography (OCT) can assess tissue composition and classify plaques. However, direct comparisons between VH-IVUS and OCT are lacking and it remains unknown whether combining these modalities improves TCFA identification.
  
  
  RESULTS
  Two hundred fifty-eight regions-of-interest were obtained from autopsied human hearts, with plaque composition and classification assessed by histology and compared with coregistered ex vivo VH-IVUS and OCT. Sixty-seven regions-of-interest were classified as fibroatheroma on histology, with 22 meeting criteria for TCFA. On VH-IVUS, plaque (10.91±4.82 versus 8.42±4.57 mm(2); P=0.01) and necrotic core areas (1.59±0.99 versus 1.03±0.85 mm(2); P=0.02) were increased in TCFA versus other fibroatheroma. On OCT, although minimal fibrous cap thickness was similar (71.8±44.1 μm versus 72.6±32.4; P=0.30), the number of continuous frames with fibrous cap thickness ≤85 μm was higher in TCFA (6.5 [1.75-11.0] versus 2.0 [0.0-7.0]; P=0.03). Maximum lipid arc on OCT was an excellent discriminator of fibroatheroma (area under the curve, 0.92; 95% confidence interval, 0.87-0.97) and TCFA (area under the curve, 0.86; 95% confidence interval, 0.81-0.92), with lipid arc ≥80° the optimal cut-off value. Using existing criteria, the sensitivity, specificity, and diagnostic accuracy for TCFA identification was 63.6%, 78.1%, and 76.5% for VH-IVUS and 72.7%, 79.8%, and 79.0% for OCT. Combining VH-defined fibroatheroma and fibrous cap thickness ≤85 μm over 3 continuous frames improved TCFA identification, with diagnostic accuracy of 89.0%.
  
  
  CONCLUSIONS
  Both VH-IVUS and OCT can reliably identify TCFA, although OCT accuracy may be improved using lipid arc ≥80° and fibrous cap thickness ≤85 μm over 3 continuous frames. Combined VH-IVUS/OCT imaging markedly improved TCFA identification.
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Brown
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Obaid
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Charis
authors.initials: C
authors.lastname: Costopoulos
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Parker
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Calvert
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Zhongzhao
authors.initials: Z
authors.lastname: Teng
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Hoole
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Nick E J
authors.initials: NE
authors.lastname: West
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Goddard
authors.affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom. mrb@mole.bio.cam.ac.uk.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Bennett
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000175:diagnosis*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000175:diagnosis*; D011237:Predictive Value of Tests; D041623:Tomography, Optical Coherence / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000379:methods*
keywords: atherosclerosis; autopsy; coronary artery disease; lipids; myocardial infarction