Radiology, Vol 150, 813-818, Copyright © 1984 by Radiological Society of North America
Count-based left ventricular volume determination utilizing a left posterior oblique view for attenuation correction
MA Rabinovitch, V Kalff, K Koral, W Chan, JE Juni, B Lerman, R Lampman, J Walton, D Grassley and R Vogel
This study aimed to determine the inherent error of the left ventricular
volume measurement from the gated equilibrium blood pool scintigram
utilizing the count-based technique. The study population consisted of 26
patients who had undergone biplane contrast ventriculography. The patients
were imaged with a parallel-hole collimator in the left anterior oblique
position showing the septum to best advantage. A reference blood sample was
counted and radionuclide volumes calculated without correction for
attenuation. Attenuation corrected volumes were derived with the factor
1/e-mud, where d = distance from skin marker to center of the left
ventricle in the orthogonal left posterior oblique view and mu = linear
attenuation coefficient. A series of mu values from 0.08 to 0.15 cm-1 was
evaluated. There was a trend toward improvement in the r value and lowering
of the SEE with attenuation correction. The tightest 95% confidence limits
achieved for an end-diastolic 150-ml ventricle were +/- 44 ml, and for an
end-systolic 75-ml ventricle +/- 32 ml. In view of the magnitude of
inherent error, the count-based volume measurement may be more suitable for
group analyses and in cases in which an individual patient serves as his
own control.
