title: Coronary CT angiography derived fractional flow reserve: Methodology and evaluation of a point of care algorithm.
abstract: BACKGROUND
  Recently several publications described the diagnostic value of coronary CT angiography (coronary CTA) derived fractional flow reserve (CTA-FFR). For a recently introduced on-site CTA-FFR application, detailed methodology and factors potentially affecting performance have not yet been described.
  
  
  OBJECTIVE
  To provide a methodological background for an on-site CTA-FFR application and evaluate the effect of patient and acquisition characteristics.
  
  
  METHODS
  The on-site CTA-FFR application utilized a reduced-order hybrid model applying pressure drop models within stenotic regions. In 116 patients and 203 vessels the diagnostic performance of CTA-FFR was investigated using invasive FFR measurements as a reference. The effect of several potentially relevant factors on CTA-FFR was investigated.
  
  
  RESULTS
  90 vessels (44%) had a hemodynamically relevant stenosis according to invasive FFR (threshold ≤0.80). The overall vessel-based sensitivity, specificity and accuracy of CTA-FFR were 88% (CI 95%:79-94%), 65% (55-73%) and 75% (69-81%). The specificity was significantly lower in the presence of misalignment artifacts (25%, CI: 6-57%). A non-significant reduction in specificity from 74% (60-85%) to 48% (26-70%) was found for higher coronary artery calcium scores. Left ventricular mass, diabetes mellitus and large vessel size increased the discrepancy between invasive FFR and CTA-FFR values.
  
  
  CONCLUSIONS
  On-site calculation of CTA-FFR can identify hemodynamically significant CAD with an overall per-vessel accuracy of 75% in comparison to invasive FFR. The diagnostic performance of CTA-FFR is negatively affected by misalignment artifacts. CTA-FFR is potentially affected by left ventricular mass, diabetes mellitus and vessel size.
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands. Electronic address: a.coenen@erasmusmc.nl.
authors.forename: Adriaan
authors.initials: A
authors.lastname: Coenen
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Marisa M
authors.initials: MM
authors.lastname: Lubbers
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Akira
authors.initials: A
authors.lastname: Kurata
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kono
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Admir
authors.initials: A
authors.lastname: Dedic
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Raluca G
authors.initials: RG
authors.lastname: Chelu
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Marcel L
authors.initials: ML
authors.lastname: Dijkshoorn
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Robert-Jan M
authors.initials: RJ
authors.lastname: van Geuns
authors.affiliation: Siemens Healthcare, Forchheim, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Schoebinger
authors.affiliation: Corporate Technology, Siemens SRL, Brasov, Romania.
authors.forename: Lucian
authors.initials: L
authors.lastname: Itu
authors.affiliation: Medical Imaging Technologies, Siemens Medical Solutions USA, Inc., Princeton NJ, USA.
authors.forename: Puneet
authors.initials: P
authors.lastname: Sharma
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Koen
authors.initials: K
authors.lastname: Nieman
mesh_terms: D000368:Aged; D000465:Algorithms; D016477:Artifacts; D006328:Cardiac Catheterization; D000072226:Computed Tomography Angiography; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D057446:Hydrodynamics; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015999:Multivariate Analysis; D000067716:Point-of-Care Testing; D011237:Predictive Value of Tests; D011379:Prognosis; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D061205:Vascular Calcification / Q000000981:diagnostic imaging* / Q000503:physiopathology
keywords: Computational fluid dynamics; Coronary CT angiography; Diagnostic performance; Fractional flow reserve