title: Delayed uptake and washout of contrast in non-viable infarcted myocardium shown with dynamic computed tomography.
abstract: BACKGROUND
  Assessment of ischemic but potentially viable myocardium plays an important role in the planning of coronary revascularization. Until now SPECT, PET, and MRI have been used to identify viable myocardium. Computed tomography (CT) is increasingly used to diagnose coronary atherosclerosis.
  
  
  OBJECTIVE
  To evaluate the feasibility of CT enhancement as a viability marker by investigating myocardial contrast distribution over time in pigs with experimentally induced antero-septal myocardial infarctions.
  
  
  METHODS
  Twelve pigs were subjected to 60 min of balloon occlusion of the left anterior descending artery, followed by removal of the balloon and reperfusion. Four pigs died due to refractory ventricular fibrillation. After 6 weeks, dynamic cardiac CT was performed assessing both wall motion and contrast attenuation. Measurements of attenuation values in Hounsfield units (HU) in the infarct zone and the normal lateral wall were performed at 20 s, and 1, 3, 5, 8 and 12 min after contrast injection.
  
  
  RESULTS
  We found highly significant differences in attenuation values between the two zones at all-time points except t =1 min (ANOVA P=0.85). The normal myocardium showed higher uptake- and washout-rates of contrast than the infarct zone (84±15 vs. 58±8 at 20 s, P=0.0001 and 27±12 vs. 81±13 at 12 min, P=0.0001). Specifically, the ratio between early (20 s) and late (12 min) uptake is a valid marker of viable myocardium. In all animals this ration was above one in the normal zone and below one in the infarct zone.
  
  
  CONCLUSIONS
  Delayed infarct related uptake and washout of contrast shows promise for future clinical application of CT in a combined assessment of coronary atherosclerosis and myocardial viability.
authors.affiliation: 1 Department of Cardiothoracic & Vascular Surgery T, 2 Department of Cardiology, Cardiac Imaging Center, Aarhus University Hospital, DK-8200 Aarhus N, Denmark ; 3 Cardiac Imaging Center, Hospital Unit West, Denmark.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Udholm
authors.affiliation: 1 Department of Cardiothoracic & Vascular Surgery T, 2 Department of Cardiology, Cardiac Imaging Center, Aarhus University Hospital, DK-8200 Aarhus N, Denmark ; 3 Cardiac Imaging Center, Hospital Unit West, Denmark.
authors.forename: Sofie
authors.initials: S
authors.lastname: Laugesen
authors.affiliation: 1 Department of Cardiothoracic & Vascular Surgery T, 2 Department of Cardiology, Cardiac Imaging Center, Aarhus University Hospital, DK-8200 Aarhus N, Denmark ; 3 Cardiac Imaging Center, Hospital Unit West, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Agger
authors.affiliation: 1 Department of Cardiothoracic & Vascular Surgery T, 2 Department of Cardiology, Cardiac Imaging Center, Aarhus University Hospital, DK-8200 Aarhus N, Denmark ; 3 Cardiac Imaging Center, Hospital Unit West, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Hønge
authors.affiliation: 1 Department of Cardiothoracic & Vascular Surgery T, 2 Department of Cardiology, Cardiac Imaging Center, Aarhus University Hospital, DK-8200 Aarhus N, Denmark ; 3 Cardiac Imaging Center, Hospital Unit West, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Smerup
authors.affiliation: 1 Department of Cardiothoracic & Vascular Surgery T, 2 Department of Cardiology, Cardiac Imaging Center, Aarhus University Hospital, DK-8200 Aarhus N, Denmark ; 3 Cardiac Imaging Center, Hospital Unit West, Denmark.
authors.forename: Nichlas
authors.initials: N
authors.lastname: Udholm
authors.affiliation: 1 Department of Cardiothoracic & Vascular Surgery T, 2 Department of Cardiology, Cardiac Imaging Center, Aarhus University Hospital, DK-8200 Aarhus N, Denmark ; 3 Cardiac Imaging Center, Hospital Unit West, Denmark.
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
authors.affiliation: 1 Department of Cardiothoracic & Vascular Surgery T, 2 Department of Cardiology, Cardiac Imaging Center, Aarhus University Hospital, DK-8200 Aarhus N, Denmark ; 3 Cardiac Imaging Center, Hospital Unit West, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Bøttcher
keywords: Dynamic computed tomography (CT); attenuation values; myocardial infarct; myocardial ischemia; viability