Original article Accuracy of commercially available processing algorithms for planar radionuclide ventriculography using data for a dynamic left ventricular phantom Pieter De Bondt a , Olivier De Winter a , Stijn Vandenberghe b , Frederic Vandevijver a , Patrick Segers b , Art Bleukx c , Hamphrey Ham a , Pascal Verdonck b and Rudi A. Dierckx a Background Automatic and semi-automatic algorithms to calculate ejection fraction (EF) from planar radionuclide ventriculography (PRV) have been used for many years in nuclear medicine. Validation of these algorithms is scarce and often performed on outdated versions of the software. Nevertheless, clinical trials where PRV is being used as the ‘gold standard’ for EF are numerous. Because of the importance attributed to the EF calculated by these programs, the accuracy of the resulting EF was assessed with a dynamic left ventricular physical phantom. Methods A dynamic left ventricular phantom was used to simulate 21 combinations of various ejection fractions (7–66%) and end diastolic volumes (27–290 ml). For each combination, a planar radionuclide ventriculograph was acquired, converted to an interfile format and transferred into processing stations with 10 different contempora- neously available commercial algorithms. The gold stan- dard was the ‘real’ EF of the phantom, derived from the exact volume of the ventricle in end diastolic and end systolic position. Correlation and Bland–Altman analysis was performed between the real EF and the calculated EF. Results The correlation for all data was excellent (r = 0.98), the mean difference was very acceptable (0.98%). Never- theless, Bland–Altman analysis showed a significant trend in the difference between real and calculated EF, with a growing underestimation for higher ranges of EF, due to an overestimation of background in larger volumes compared to smaller ones. Conclusion The determination of EF from PRV, calculated with commercially available algorithms, correlates closely to the real EF of a dynamic left ventricular phantom. This phantom can be used in the development and validation of algorithms for PRV studies, in software audits and in quality assurance procedures. Nucl Med Commun 25:1197–1202  c 2004 Lippincott Williams & Wilkins. Nuclear Medicine Communications 2004, 25:1197–1202 Keywords: ventriculography, dynamic cardiac phantom a Division of Nuclear Medicine, Ghent University Hospital, b Hydraulics Laboratory, Ghent University and c Department of Civil Engineering, K.U. Leuven, Belgium. Sponsorship: Stijn Vandenberghe is a recipient of a specialization grant of the Flemish Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT-993171). Correspondence to Dr P. De Bondt, Nuclear Medicine Division, P7, University Hospital Ghent, De Pintelaan 185, 9000 Ghent, Belgium. Tel: +32 53 72 4477; fax: +32 53 72 4089; e-mail: pdebondt@skynet.be Received 26 April 2004 Accepted 15 July 2004 Introduction Planar radionuclide ventriculography (PRV) is well established and for many years has generally been accepted as the ‘gold standard’ for the calculation of left ventricular ejection fraction (LVEF) [1,2]. The techni- que is simple, robust and easy to perform. Nearly all manufacturers of nuclear medicine equipment provide workstations with available processing software for PRV. Most of these programs provide some references about the methods used to calculate LVEF, but information about the development and the clinical validation of the algorithm is mostly limited or absent. Therefore, the aim of this study was to investigate the general accuracy of 10 such commercially available programs for the calculation of LVEF with a dynamic ventricular phantom. Material and methods Dynamic phantom The development of the phantom used for this study has been described previously [3]. In short, a thin-walled ellipsoidal silicone ventricle was suspended in a water filled Perspex tank and contraction and relaxation were simulated by adding and withdrawing water from the tank with a piston pump. Twenty-one acquisitions were performed, covering a wide range of ventricular end diastolic volumes (27–290 ml, mean 122 ml) and stroke volumes (22–59 ml, mean 42 ml) in order to obtain a wide range of values for LVEF (7–66%, mean 35%). The atrium and ventricle were filled with a solution of [ 99m Tc]per- technetate in water, with a concentration varying between 370 and 518 MBql –1 (10 and 14 mCil –1 ), the 0143-3636  c 2004 Lippincott Williams & Wilkins Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.