title: Hybrid imaging using quantitative H215O PET and CT-based coronary angiography for the detection of coronary artery disease.
abstract: Hybrid imaging using PET in conjunction with CT-based coronary angiography (PET/CTCA) enables near-simultaneous quantification of myocardial blood flow (MBF) and anatomical evaluation of coronary arteries. CTCA is an excellent imaging modality to rule out obstructive coronary artery disease (CAD), but functional assessment is warranted in the presence of a CTCA-observed stenosis because the specificity of CTCA is relatively low. Quantitative H(2)(15)O PET/CTCA may yield complementary information and enhance diagnostic accuracy. The purpose of this study was to evaluate the diagnostic accuracy of quantitative H(2)(15)O PET/CTCA in a clinical cohort of patients with suspected CAD who underwent both cardiac H(2)(15)O PET/CTCA and invasive coronary angiography (ICA). In addition, this study aimed to evaluate and compare the accuracy of hyperemic MBF versus coronary flow reserve (CFR).
  
  
  METHODS
  Patients (n = 120; mean age ± SD, 61 ± 10 y; 77 men and 43 women) with a predominantly intermediate pretest likelihood for CAD underwent both quantitative H(2)(15)O PET/CTCA and ICA. A ≥50% stenosis at ICA or a fractional flow reserve ≤ 0.80 was considered significant.
  
  
  RESULTS
  Obstructive CAD was diagnosed in 49 of 120 patients (41%). The diagnostic accuracy of hyperemic MBF was significantly higher than CFR (80% vs. 68%, respectively, P = 0.02), with optimal cutoff values of 1.86 mL/min/g and 2.30, respectively. On a per-patient basis, the sensitivity, specificity, negative predictive value, and positive predictive value of CTCA were 100%, 34%, 100%, and 51%, respectively, as compared with 76%, 83%, 83%, and 76%, respectively, for quantitative hyperemic MBF PET. Quantitative H(2)(15)O PET/CTCA reduced the number of false-positive CTCA studies from 47 to 6, although 12 of 49 true-positive CTCAs were incorrectly reclassified as false-negative hybrid scans on the basis of (presumably) sufficient hyperemic MBF. Compared with CTCA (61%) or H(2)(15)O PET (80%) alone (both P < 0.05), the hybrid approach significantly improved diagnostic accuracy (85%).
  
  
  CONCLUSIONS
  The diagnostic accuracy of quantitative H(2)(15)O PET/CTCA is superior to either H(2)(15)O PET or CTCA alone for the detection of clinically significant CAD. Hyperemic MBF was more accurate than CFR, implying that a single measurement of MBF in diagnostic protocols may suffice.
authors.affiliation: Department of Cardiology, VU University Medical Center, Amsterdam, The Netherlands. i.danad@vumc.nl
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Danad
authors.forename: Pieter G
authors.initials: PG
authors.lastname: Raijmakers
authors.forename: Yolande E
authors.initials: YE
authors.lastname: Appelman
authors.forename: Hendrik J
authors.initials: HJ
authors.lastname: Harms
authors.forename: Stefan
authors.initials: S
authors.lastname: de Haan
authors.forename: Mijntje L P
authors.initials: ML
authors.lastname: van den Oever
authors.forename: Martijn W
authors.initials: MW
authors.lastname: Heymans
authors.forename: Igor I
authors.initials: II
authors.lastname: Tulevski
authors.forename: Cornelis
authors.initials: C
authors.lastname: van Kuijk
authors.forename: Otto S
authors.initials: OS
authors.lastname: Hoekstra
authors.forename: Adriaan A
authors.initials: AA
authors.lastname: Lammertsma
authors.forename: Mark
authors.initials: M
authors.lastname: Lubberink
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
authors.forename: Paul
authors.initials: P
authors.lastname: Knaapen
mesh_terms: D015331:Cohort Studies; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography; D012039:Regional Blood Flow; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014867:Water
chemical_list: D010104:Oxygen Radioisotopes; D014867:Water