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.

Computational fluid dynamics, Coronary CT angiography, Diagnostic performance, Fractional flow reserve
dx.doi.org/10.1016/j.jcct.2015.12.006, hdl.handle.net/1765/90236
Journal of Cardiovascular Computed Tomography
Department of Radiology

Coenen, A, Lubbers, M.M, Kurata, A, Kono, A, Dedic, A, Chelu, R.G, … Nieman, K. (2016). Coronary CT angiography derived fractional flow reserve. Journal of Cardiovascular Computed Tomography, 10(2), 105–113. doi:10.1016/j.jcct.2015.12.006