title: Multidetector computed tomography myocardial perfusion imaging during adenosine stress.
abstract: OBJECTIVE
  The purpose of this study is to validate the accuracy of multidetector computed tomography (MDCT) to measure differences in regional myocardial perfusion during adenosine stress in a canine model of left anterior descending (LAD) artery stenosis, during first-pass, contrast-enhanced helical MDCT.
  
  
  BACKGROUND
  Myocardial perfusion imaging by MDCT may have significant implications in the diagnosis and treatment of coronary artery disease.
  
  
  METHODS
  Eight dogs were prepared with a LAD stenosis, and contrast-enhanced MDCT imaging was performed 5 min into adenosine infusion (0.14 to 0.21 mg/kg/min). Images were analyzed using a semiautomated approach to define the regional signal density (SD) ratio (myocardial SD/left ventricular blood pool SD) in stenosed and remote territories, and then compared with microsphere myocardial blood flow (MBF) measurements.
  
  
  RESULTS
  Mean MBF in stenosed versus remote territories was 1.37 +/- 0.46 ml/g/min and 1.29 +/- 0.48 ml/g/min at baseline (p = NS) and 2.54 +/- 0.93 ml/g/min and 8.94 +/- 5.74 ml/g/min during adenosine infusion, respectively (p < 0.05). Myocardial SD was 92.3 +/- 39.5 HU in stenosed versus 180.4 +/- 41.9 HU in remote territories (p < 0.001). There was a significant linear association of the SD ratio with MBF in the stenosed territory (R = 0.98, p = 0.001) and between regional myocardial SD ratio and MBF <8 ml/g/min, slope = 0.035, SE = 0.007, p < 0.0001. Overall, there was a significant non-linear relationship over the range of flows studied (LR chi-square [2 degrees of freedom] = 31.8, p < 0.0001).
  
  
  CONCLUSIONS
  Adenosine-augmented MDCT myocardial perfusion imaging provides semiquantitative measurements of myocardial perfusion during first-pass MDCT imaging in a canine model of LAD stenosis.
authors.affiliation: Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: Richard T
authors.initials: RT
authors.lastname: George
authors.forename: Caterina
authors.initials: C
authors.lastname: Silva
authors.forename: Marco A S
authors.initials: MA
authors.lastname: Cordeiro
authors.forename: Anthony
authors.initials: A
authors.lastname: DiPaula
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Thompson
authors.forename: William F
authors.initials: WF
authors.lastname: McCarthy
authors.forename: Takashi
authors.initials: T
authors.lastname: Ichihara
authors.forename: Joao A C
authors.initials: JA
authors.lastname: Lima
authors.forename: Albert C
authors.initials: AC
authors.lastname: Lardo
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D003287:Contrast Media; D003326:Coronary Circulation / Q000187:drug effects*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004285:Dogs; D008863:Microspheres; D012717:Sesquiterpenes; D036542:Tomography, Spiral Computed; D014283:Triiodobenzoic Acids; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D003287:Contrast Media; D012717:Sesquiterpenes; D014283:Triiodobenzoic Acids; D014665:Vasodilator Agents; C464752:microcladallene A; C044834:iodixanol; D000241:Adenosine