Absolute quantitation of left ventricular wall and cavity parameters using ECG-gated PET.
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.
Freiberg
Jacob
J
Medical Department B, The Heart Center, Rigshospitalet, University of Copenhagen, Denmark.
Hove
Jens D
JD
Kofoed
Klaus F
KF
Fritz-Hansen
Thomas
T
Holm
Søren
S
Larsson
Henrik B
HB
Kelbaek
Henning
H
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*
D019788:Fluorodeoxyglucose F18