title: Absolute quantitation of left ventricular wall and cavity parameters using ECG-gated PET.
abstract: BACKGROUND
  Electrocardiography (ECG)-gated scintigraphy demonstrates promising results for the simultaneous assessment of myocardial glucose metabolism and contractile function. In this study a method was evaluated for absolute quantitation of left ventricular wall and cavity parameters with the use of fluorine 18 fluorodeoxyglucose (FDG) ECG-gated positron emission tomography (PET).
  
  
  RESULTS
  A previously developed 2-dimensional mathematical model was implemented for computer-automated identification of endocardial and pericardial borders. The accuracy and precision were tested in a heart phantom and in healthy subjects. Twelve healthy men aged 64 +/- 8 years were studied by use of cine magnetic resonance imaging (MRI) and ECG-gated FDG-PET during euglycemic glucose-insulin clamp. At increasing image noise levels, the estimated cavity volume of the heart phantom was within 2 mL of the actual volume, and no significant difference was found between actual and estimated wall thicknesses. Endocardial wall motion as assessed by ECG-gated PET in the healthy subjects was systematically underestimated compared with MRI. This underestimation correlated linearly with endocardial excursion during PET end diastole as measured by MRI. Myocardial end-diastolic wall thickness was systematically overestimated by PET, whereas end-systolic thickness deviated less than 1 mm from MRI. Cavity volumes measured by PET correlated linearly with MRI, with a tendency toward an underestimation of end-diastolic cavity volumes by PET.
  
  
  CONCLUSIONS
  Absolute measures of cardiac structure and function may be obtained with a reasonable degree of accuracy by use of ECG-gated PET imaging. However, a high ECG-gating frequency appears to be required to obtain measurements comparable to what may be achieved by MRI.
authors.affiliation: Medical Department B, The Heart Center, Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Freiberg
authors.forename: Jens D
authors.initials: JD
authors.lastname: Hove
authors.forename: Klaus F
authors.initials: KF
authors.lastname: Kofoed
authors.forename: Thomas
authors.initials: T
authors.lastname: Fritz-Hansen
authors.forename: Søren
authors.initials: S
authors.lastname: Holm
authors.forename: Henrik B
authors.initials: HB
authors.lastname: Larsson
authors.forename: Henning
authors.initials: H
authors.lastname: Kelbaek
mesh_terms: D000368:Aged; D002306:Cardiac Volume; D004562:Electrocardiography; D019788:Fluorodeoxyglucose F18; D015637:Gated Blood-Pool Imaging; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000502:physiology*; D019047:Phantoms, Imaging; D014055:Tomography, Emission-Computed / Q000379:methods*; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D019788:Fluorodeoxyglucose F18