Quantitative Radionuclide Angiocardiography
Determination of Qp : Qs in Children
A new method of determining pulmonary-to-systemic flow ratios (Qp/Qs) in patients with left-to-right shunts using radionuclide angiocardiography is described. It involves the analysis of pulmonary time-activity histograms using a gamma-variate model. It appears to be simple, relatively atraumatic, and superior to the methods using C2/C1 ratios because, in addition to accurately detecting the presence of left-to-right shunts, it permits precise quantitation. In the 35 patients studied, it was found that Qp/Qs <1.2 could be separated from Qp/Qs > 1.2 and that when the Qp/Qs is between 1.2 and <3 the shunts could be accurately quantified.
- Left-to-right shunt
- Gamma variate
- Ventricular septal defects
- Radionuclide angiocardiography
- Atrial septal defects
- Ejection fractions
- Received July 6, 1972.
- Accepted December 19, 1972.
- © 1973 American Heart Association, Inc.