title: An improved method for the quantification of left-to-right cardiac shunts.
abstract: We have investigated a technique for quantifying QP/QS in left-to-right cardiac shunts. In this method, the gamma variate, which is fitted to the first-pass portion of the lung curve, is used to generate a curve, which simulates the response of a normal lung curve with systemic recirculation. The difference between this curve and the observed lung curve is then used to calculate QP/QS. This method was evaluated on a set of simulated lung time-activity curves with precisely known QP/QS values on a group of 11 patients with no clinical suspicion of cardiac shunt and on a group of 30 patients referred for cardiac shunt studies. The QP/QS in each of these studies was determined by three individuals using both the Maltz-Treves method and the new method. This method yielded QP/QS values that were more accurate on the simulated lung data and had less interobserver variation on all the studies than those obtained from the Maltz-Treves method.
authors.affiliation: Dept. of Radiology, University of Iowa Hospitals & Clinics, Iowa City 52242.
authors.forename: M T
authors.initials: MT
authors.lastname: Madsen
authors.forename: E
authors.initials: E
authors.lastname: Argenyi
authors.forename: J
authors.initials: J
authors.lastname: Preslar
authors.forename: M
authors.initials: M
authors.lastname: Grover-McKay
authors.forename: P T
authors.initials: PT
authors.lastname: Kirchner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006343:Heart Septal Defects / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D016284:Technetium Tc 99m Pentetate
chemical_list: D016284:Technetium Tc 99m Pentetate