title: The Incremental Prognostic Value of Cardiac Computed Tomography in Comparison with Single-Photon Emission Computed Tomography in Patients with Suspected Coronary Artery Disease.
abstract: BACKGROUND
  Coronary computed tomographic angiography (CCTA) facilitates comprehensive evaluation of coronary artery disease (CAD), including plaque characterization, and can provide additive diagnostic value to single-photon emission computed tomography (SPECT). However, data regarding the incremental prognostic value of CCTA to SPECT remain sparse. We evaluated the independent and incremental prognostic value of CCTA, as compared with clinical risk factors and SPECT.
  
  
  METHODS
  A total of 1,077 patients with suspected CAD who underwent both SPECT and cardiac CT between 2004 and 2012 were enrolled retrospectively. Presence of reversible or fixed perfusion defect (PD) and summed stress score were evaluated on SPECT. Presence, extent of coronary atherosclerosis and diameter stenosis (DS) were evaluated on CCTA. Plaque composition was categorized as non-calcified, mixed, or calcified according to the volume of calcified component (>130 Hounsfield Units). Patients were followed up for the occurrence of adverse cardiac events including cardiac death, non-fatal myocardial infarction, unstable angina, and late revascularization (>90 days after imaging studies).
  
  
  RESULTS
  During follow-up (median 23 months), adverse cardiac events were observed in 71 patients (6.6%). When adjusted for clinical risk factors and SPECT findings, the presence of any coronary plaque, any plaque in ≥3 segments, coronary artery calcium score (CACS) ≥400, a plaque ≥50% DS, presence of non-calcified plaque (NCP) or mixed plaque (MP), and NCP/MP in ≥2 segments were independent predictors of adverse cardiac events; however, the presence of calcified plaque (CP) was not. Conventional CCTA findings, including CACS ≥400 and a plaque ≥50% DS, demonstrated incremental prognostic value over clinical risk factors and SPECT (χ² 54.19 to 101.03; p <0.001). Addition of NCP/MP in ≥2 segments resulted in further significantly improved prediction (χ² 101.03 to 113.29; p <0.001).
  
  
  CONCLUSIONS
  Comprehensive CCTA evaluation of coronary atherosclerosis provides independent and incremental prognostic value in relation to SPECT evaluation of myocardial ischemia. Specifically, segmentally-analyzed plaque composition with CCTA provides further risk stratification in addition to CACS and DS.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Heesun
authors.initials: H
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Department of Cardiology, Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Yeonyee E
authors.initials: YE
authors.lastname: Yoon
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jun-Bean
authors.initials: JB
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Division of Cardiology, Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Hack-Lyoung
authors.initials: HL
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Hyo Eun
authors.initials: HE
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Seung-Pyo
authors.initials: SP
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Hyung-Kwan
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Su-Yeon
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Department of Cardiology, Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Goo-Yeong
authors.initials: GY
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Division of Cardiology, Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Joo-Hee
authors.initials: JH
authors.lastname: Zo
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Dae-Won
authors.initials: DW
authors.lastname: Sohn
mesh_terms: D000368:Aged; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000175:diagnosis*; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed