Coronary CT angiography derived fractional flow reserve: Methodology and evaluation of a point of care algorithm

J Cardiovasc Comput Tomogr. 2016 Mar-Apr;10(2):105-13. doi: 10.1016/j.jcct.2015.12.006. Epub 2015 Dec 18.


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.

Keywords: Computational fluid dynamics; Coronary CT angiography; Diagnostic performance; Fractional flow reserve.

Publication types

  • Comparative Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Algorithms*
  • Artifacts
  • Cardiac Catheterization
  • Computed Tomography Angiography*
  • Coronary Angiography / methods*
  • Coronary Artery Disease / diagnostic imaging*
  • Coronary Artery Disease / physiopathology
  • Coronary Stenosis / diagnostic imaging*
  • Coronary Stenosis / physiopathology
  • Coronary Vessels / diagnostic imaging*
  • Coronary Vessels / physiopathology
  • Female
  • Fractional Flow Reserve, Myocardial*
  • Humans
  • Hydrodynamics
  • Male
  • Middle Aged
  • Multidetector Computed Tomography*
  • Multivariate Analysis
  • Point-of-Care Testing*
  • Predictive Value of Tests
  • Prognosis
  • Radiographic Image Interpretation, Computer-Assisted
  • Reproducibility of Results
  • Retrospective Studies
  • Severity of Illness Index
  • Vascular Calcification / diagnostic imaging*
  • Vascular Calcification / physiopathology