Author + information
- Received January 20, 1984
- Revision received July 25, 1984
- Accepted November 6, 1984
- Published online April 1, 1985.
- Pere Guiteras, MD1,2,
- Maria Green, RTNM1,
- Margaret DeSouza, MA1,
- David Gilday, MD1 and
- Peter Olley, MB, FACC*,1
- ↵*Address for reprints: Peter Olley, MD, Cardiovascular Research, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8.
A “phantom“ was used to validate 1) estimates of different depths of a constant radioactivity source, and 2) the calculation of different volumes using a constant depth and different attenuation coefficients. Using data from this in vitro study, scintigraphic estimates of right ventricular volume and ejection fraction were compared with those obtained by cineangiography in 36 children with either a normal right ventricle or various right ventricular diseases.
The static program accurately estimates the distance from the radiation source to the collimator surface (r = 0.99). Radionuclide count methods best predict “phantom” volumes using attenuation coefficients between 0.11−1and 0.13−1cm. A coefficient of 0.10−1underestimates, whereas 0.15−1cm grossly overestimates actual volumes.
In vivo data were therefore analyzed using an attenuation coefficient of 0.11−1with right ventricular counts corrected using either right ventricular or left ventricular background. Closest agreement between scintigraphic and cineangiography volumes was obtained using right ventricular background, although end-diastolic volumes larger than 100 ml were substantially underestimated. On the basis of this study, the use of two different attenuation coefficients is suggested: the smaller 0.11−1cm to calculate end-systolic and end-diastolic volumes and the larger 0.15−1cm for volumes greater than 100 ml.
- Received January 20, 1984.
- Revision received July 25, 1984.
- Accepted November 6, 1984.
- American College of Cardiology Foundation