title: Benefit of cardiac N-13 PET CFR for combined anatomical and functional diagnosis of ischemic coronary artery disease: a pilot study.
abstract: BACKGROUND
  Cardiac positron emission tomography (PET) can lead to flow impairment quantification using PET coronary flow reserve (CFRp: ratio of stress flow to rest flow) and is superior to the current standard, single-photon emission computed tomography. In this study, our first aim was to assess the benefit of CFRp in place of invasive CFR (CFRi) by comparing the correlations of each of the indices with combined pressure and flow index CDP, and combined functional (pressure-flow) and anatomical (%area stenosis, %AS) index, LFC. The second aim was to test the correlation between CFRp and CFRi.
  
  
  METHODS
  N-13 ammonia PET scans were performed and CFRp was obtained using a 1-compartment 2K-dynamic volume (DV)-constant kinetic model in Flowquant. During catheterization, simultaneous pressure and flow readings were obtained in 10 vessels (three vessels in one patient, one vessel each in 7 patients) using a dual sensor tipped Combowire, and CFRi, CDP, LFC, and FFR were computed. %AS was obtained using quantitative coronary angiography. CDP was correlated with invasive pressure index (FFR) and CFRp and with FFR and CFRi. LFC was correlated with the %AS, FFR, and CFRp/CFRi, individually and in combination. Correlation analysis was done in SAS; p < 0.05 was used for statistical significance.
  
  
  RESULTS
  The correlations between CDP vs FFR and CFRp (r = 0.62, p = 0.19) in combination, as well as CDP vs FFR and CFRi in combination (r = 0.58, p = 0.24) remained similar. The correlation between LFC vs FFR, CFRp and %AS in combination improved (r = 0.82) with a near-significant p = 0.06, in comparison to the correlation between LFC vs FFR, CFRi and %AS in combination (r = 0.75, p = 0.15). CFRp correlated strongly and significantly (r = 0.82, p = 0.003) with CFRi, and the values were within 11 %.
  
  
  CONCLUSIONS
  The novelty of the PET procedure in this study is that the noninvasive CFRp can be used instead of invasive CFRi for the functional diagnosis of CAD. Therefore, a PET scan can reduce procedure time and cost while simplifying the diagnostic protocol for assessing coronary artery disease, thus benefitting both the patients and clinicians.
authors.affiliation: Department of Mechanical and Materials Engineering, University of Cincinnati, 598 Rhodes Hall, PO Box 0072, Cincinnati, OH, 45221-0072, USA.
authors.forename: Srikara V
authors.initials: SV
authors.lastname: Peelukhana
authors.forename: Hanan
authors.initials: H
authors.lastname: Kerr
authors.forename: Kranthi K
authors.initials: KK
authors.lastname: Kolli
authors.forename: Mariano
authors.initials: M
authors.lastname: Fernandez-Ulloa
authors.forename: Myron
authors.initials: M
authors.lastname: Gerson
authors.forename: Mohamed
authors.initials: M
authors.lastname: Effat
authors.forename: Imran
authors.initials: I
authors.lastname: Arif
authors.forename: Tarek
authors.initials: T
authors.lastname: Helmy
authors.forename: Rupak
authors.initials: R
authors.lastname: Banerjee
mesh_terms: D000368:Aged; D000792:Angiography / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging / Q000379:methods; D009587:Nitrogen Isotopes / Q000737:chemistry; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods; D011312:Pressure; D015203:Reproducibility of Results; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: D009587:Nitrogen Isotopes