title: Fractional flow reserve calculation from 3-dimensional quantitative coronary angiography and TIMI frame count: a fast computer model to quantify the functional significance of moderately obstructed coronary arteries.
abstract: OBJECTIVE
  This study sought to present a novel computer model for fast computation of myocardial fractional flow reserve (FFR) and to evaluate it in patients with intermediate coronary stenoses.
  
  
  BACKGROUND
  FFR is an indispensable tool to identify individual coronary stenoses causing ischemia. Calculation of FFR from x-ray angiographic data may increase the utility of FFR assessment.
  
  
  METHODS
  Consecutive patients with intermediate coronary stenoses undergoing pressure wire-based FFR measurements were analyzed by a core laboratory. Three-dimensional quantitative coronary angiography (QCA) was performed and the mean volumetric flow rate at hyperemia was calculated using TIMI (Thrombolysis In Myocardial Infarction) frame count combined with 3-dimensional QCA. Computational fluid dynamics was applied subsequently with a novel strategy for the computation of FFR. Diagnostic performance of the computed FFR (FFRQCA) was assessed using wire-based FFR as reference standard.
  
  
  RESULTS
  Computation of FFRQCA was performed on 77 vessels in 68 patients. Average diameter stenosis was 46.6 ± 7.3%. FFRQCA correlated well with FFR (r = 0.81, p < 0.001), with a mean difference of 0.00 ± 0.06 (p = 0.541). Applying the FFR cutoff value of ≤0.8 to FFRQCA resulted in 18 true positives, 50 true negatives, 4 false positives, and 5 false negatives. The area under the receiver-operating characteristic curve was 0.93 for FFRQCA, 0.73 for minimum lumen area, and 0.65 for percent diameter stenosis.
  
  
  CONCLUSIONS
  Computation of FFRQCA is a novel method that allows the assessment of the functional significance of intermediate stenosis. It may emerge as a safe, efficient, and cost-reducing tool for evaluation of coronary stenosis severity during diagnostic angiography.
authors: Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands. Electronic address: S.T.Tu@lumc.nl.
authors: Shengxian
authors: S
authors: Tu
authors: Cardiovascular Center Aalst, Onze-Lieve-Vrouwziekenhuis (OLV) Hospital, Aalst, Belgium.
authors: Emanuele
authors: E
authors: Barbato
authors: Invasive Cardiology Laboratory, Jósa András Teaching Hospital, Nyíregyháza, Hungary.
authors: Zsolt
authors: Z
authors: Köszegi
authors: Department of Cardiology, Guangdong General Hospital, Guangzhou, China.
authors: Junqing
authors: J
authors: Yang
authors: Department of Cardiology, TEDA International Cardiovascular Hospital, Tianjin, China.
authors: Zhonghua
authors: Z
authors: Sun
authors: Department of Cardiology, Aarhus University Hospital, Skejby, Denmark.
authors: Niels R
authors: NR
authors: Holm
authors: Invasive Cardiology Laboratory, Jósa András Teaching Hospital, Nyíregyháza, Hungary.
authors: Balázs
authors: B
authors: Tar
authors: Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands.
authors: Yingguang
authors: Y
authors: Li
authors: Cardiovascular Center Aalst, Onze-Lieve-Vrouwziekenhuis (OLV) Hospital, Aalst, Belgium.
authors: Dan
authors: D
authors: Rusinaru
authors: Cardiovascular Center Aalst, Onze-Lieve-Vrouwziekenhuis (OLV) Hospital, Aalst, Belgium.
authors: William
authors: W
authors: Wijns
authors: Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands.
authors: Johan H C
authors: JH
authors: Reiber
mesh_terms: D000368:Aged; D019540:Area Under Curve; D006328:Cardiac Catheterization; D002681:China; D003198:Computer Simulation; D017023:Coronary Angiography / Q000379:methods* / Q000592:standards; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D006814:Hungary; D006940:Hyperemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D021621:Imaging, Three-Dimensional / Q000592:standards; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D055414:Myocardial Perfusion Imaging / Q000379:methods* / Q000592:standards; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000592:standards; D012015:Reference Standards; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards
keywords: cardiovascular physiology; computational fluid dynamics; fractional flow reserve; quantitative coronary angiography