title: Diagnostic performance of resting CT myocardial perfusion in patients with possible acute coronary syndrome.
abstract: OBJECTIVE
  Coronary CT angiography has high sensitivity, but modest specificity, to detect acute coronary syndrome. We studied whether adding resting CT myocardial perfusion imaging improved the detection of acute coronary syndrome.
  
  
  METHODS
  Patients with low-to-intermediate cardiac risk presenting with possible acute coronary syndrome received both the standard of care evaluation and a research thoracic 64-MDCT examination. Patients with an obstructive (> 50%) stenosis or a nonevaluable coronary segment on CT were diagnosed with possible acute coronary syndrome. CT perfusion was determined by applying gray and color Hounsfield unit maps to resting CT angiography images. Adjudicated patient diagnoses were based on the standard of care and 3-month follow-up. Patient-level diagnostic performance for acute coronary syndrome was calculated for coronary CT, CT perfusion, and combined techniques.
  
  
  RESULTS
  A total of 105 patients were enrolled. Of the nine (9%) patients with acute coronary syndrome, all had obstructive CT stenoses but only three had abnormal CT perfusion. CT perfusion was normal in all other patients. To detect acute coronary syndrome, CT angiography had 100% sensitivity, 89% specificity, and a positive predictive value of 45%. For CT perfusion, specificity and positive predictive value were each 100%, and sensitivity was 33%. Combined cardiac CT and CT perfusion had similar specificity but a higher positive predictive value (100%) than did CT angiography.
  
  
  CONCLUSIONS
  Resting CT perfusion using CT angiographic images may have high specificity and may improve CT positive predictive value for acute coronary syndrome without added radiation and contrast. However, normal resting CT perfusion cannot exclude acute coronary syndrome.
authors.affiliation: Division of Cardiology, University of Washington, Seattle, WA 98195, USA. kbranch@u.washington.edu
authors.forename: Kelley R
authors.initials: KR
authors.lastname: Branch
authors.forename: Janet
authors.initials: J
authors.lastname: Busey
authors.forename: Lee M
authors.initials: LM
authors.lastname: Mitsumori
authors.forename: Jared
authors.initials: J
authors.lastname: Strote
authors.forename: James H
authors.initials: JH
authors.lastname: Caldwell
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Busch
authors.forename: William P
authors.initials: WP
authors.lastname: Shuman
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D017023:Coronary Angiography / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000706:statistics & numerical data*; D015995:Prevalence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014861:Washington / Q000453:epidemiology