title: Optimization of coronary optical coherence tomography imaging using the attenuation-compensated technique: a validation study.
abstract: OBJECTIVE
  To optimize conventional coronary optical coherence tomography (OCT) images using the attenuation-compensated technique to improve identification of plaques and the external elastic lamina (EEL) contour.
  
  
  RESULTS
  The attenuation-compensated technique was optimized via manipulating contrast exponent C, and compression exponent N, to achieve an optimal contrast and signal-to-noise ratio (SNR). This was applied to 60 human coronary lesions (38 native and 22 stented) ex vivo conventional coronary OCT images acquired from heart autopsies of 10 patients and matching histology was available as reference. Three independent reviewers assessed the conventional and attenuation-compensated OCT images blindly for plaque characteristics and EEL detection. Conventional OCT and compensated OCT assessment were compared against histology. Using an optimized algorithm, the attenuation-compensated OCT images had a 2-fold improvement in contrast between different tissues in both stented and non-stented epicardial coronaries (P < 0.05). Overall sensitivity and specificity for plaque classification increased from 84 to 89% and from 92 to 94%, respectively, with substantial agreement among the three reviewers (Fleiss' Kappa k, 0.72 and 0.71, respectively). Furthermore, operators were 2.5 times more likely to identify the EEL contour in the attenuation-compensated OCT images (k = 0.72) than in the conventional OCT images (k = 0.36).
  
  
  CONCLUSIONS
  The attenuation-compensated technique can be retrospectively applied to conventional OCT images and improves the detection of plaque characteristics and the EEL contour. This approach could complement conventional OCT imaging in the evaluation of plaque characteristics and quantify plaque burden in the clinical setting.
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609.|Department of Biomedical Engineering and Duke-NUS Medical School, National University Singapore, Singapore.
authors.forename: Jing Chun
authors.initials: JC
authors.lastname: Teo
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609.|Department of Biomedical Engineering and Duke-NUS Medical School, National University Singapore, Singapore.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Foin
authors.affiliation: CV Path Institute, Gaithersburg, MD, USA.|National Cerebral and Cardiovascular Center, Osaka, Japan.
authors.forename: Fumiyuki
authors.initials: F
authors.lastname: Otsuka
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609.|Department of Biomedical Engineering and Duke-NUS Medical School, National University Singapore, Singapore.
authors.forename: Heerajnarain
authors.initials: H
authors.lastname: Bulluck
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609.
authors.forename: Jiang Ming
authors.initials: JM
authors.lastname: Fam
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609.
authors.forename: Philip
authors.initials: P
authors.lastname: Wong
authors.affiliation: Department of Cardiology, National University Heart Center, Singapore.
authors.forename: Fatt Hoe
authors.initials: FH
authors.lastname: Low
authors.affiliation: Department of Biomedical Engineering and Duke-NUS Medical School, National University Singapore, Singapore.
authors.forename: Hwa Liang
authors.initials: HL
authors.lastname: Leo
authors.affiliation: University of French Polynesia, French Polynesia.
authors.forename: Jean-Martial
authors.initials: JM
authors.lastname: Mari
authors.affiliation: CV Path Institute, Gaithersburg, MD, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Joner
authors.affiliation: Department of Biomedical Engineering and Duke-NUS Medical School, National University Singapore, Singapore.|Singapore Eye Research Institute Singapore National Eye Centre, Singapore.
authors.forename: Michael J A
authors.initials: MJA
authors.lastname: Girard
authors.affiliation: CV Path Institute, Gaithersburg, MD, USA.
authors.forename: Renu
authors.initials: R
authors.lastname: Virmani
mesh_terms: D000368:Aged; D002423:Cause of Death; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016019:Survival Analysis; D041623:Tomography, Optical Coherence / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000379:methods