title: Diagnostic Performance of Transluminal Attenuation Gradient and Noninvasive Fractional Flow Reserve Derived from 320-Detector Row CT Angiography to Diagnose Hemodynamically Significant Coronary Stenosis: An NXT Substudy.
abstract: OBJECTIVE
  To compare the diagnostic performance of 320-detector row computed tomography (CT) coronary angiography-derived computed fractional flow reserve (FFR; FFRCT), transluminal attenuation gradient (TAG; TAG320), and CT coronary angiography alone to diagnose hemodynamically significant stenosis as determined by invasive FFR.
  
  
  METHODS
  This substudy of the prospective NXT study (no. NCT01757678) was approved by each participating institution's review board, and informed consent was obtained from all participants. Fifty-one consecutive patients who underwent 320-detector row CT coronary angiographic examination and invasive coronary angiography with FFR measurement were included. Independent core laboratories determined coronary artery disease severity by using CT coronary angiography, TAG320, FFRCT, and FFR. TAG320 is defined as the linear regression coefficient between luminal attenuation and axial distance from the coronary ostium. FFRCT was computed from CT coronary angiography data by using computational fluid dynamics technology. Diagnostic performance was evaluated and compared on a per-vessel basis by the area under the receiver operating characteristic (ROC) curve (AUC).
  
  
  RESULTS
  Among 82 vessels, 24 lesions (29%) had ischemia by FFR (FFR ≤ 0.80). FFRCT exhibited a stronger correlation with invasive FFR compared with TAG320 (Spearman ρ, 0.78 vs 0.47, respectively). Overall per-vessel accuracy, sensitivity, specificity, and positive and negative predictive values for TAG320 (<15.37) were 78%, 58%, 86%, 64%, and 83%, respectively; and those of FFRCT were 83%, 92%, 79%, 65%, and 96%, respectively. ROC curve analysis showed a significantly larger AUC for FFRCT (0.93) compared with that for TAG320 (0.72; P = .003) and CT coronary angiography alone (0.68; P = .008).
  
  
  CONCLUSIONS
  FFRCT computed from 320-detector row CT coronary angiography provides better diagnostic performance for the diagnosis of hemodynamically significant coronary stenoses compared with CT coronary angiography and TAG320.
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Brian S
authors.initials: BS
authors.lastname: Ko
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Dennis T L
authors.initials: DT
authors.lastname: Wong
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Bjarne L
authors.initials: BL
authors.lastname: Nørgaard
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Darryl P
authors.initials: DP
authors.lastname: Leong
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: James D
authors.initials: JD
authors.lastname: Cameron
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Sara
authors.initials: S
authors.lastname: Gaur
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Mohamed
authors.initials: M
authors.lastname: Marwan
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Sachio
authors.initials: S
authors.lastname: Kuribayashi
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kimura
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Ian T
authors.initials: IT
authors.lastname: Meredith
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre) Monash University and Monash Heart, Monash Health, 246 Clayton Rd, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark (B.L.N., S.G.); Department of Cardiology, Erlangen University Hospital, Erlangen, Germany (M.M., S.A.); Department of Diagnostic Radiology, Keio University, Tokyo, Japan (S.K.); and Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T.K.).
authors.forename: Sujith K
authors.initials: SK
authors.lastname: Seneviratne
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D055424:Cardiac-Gated Imaging Techniques; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology*; D006801:Humans; D007472:Iohexol; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007472:Iohexol; D007479:Iopamidol