Advantages of list-mode data acquisition in gated blood-pool studies

Because of physiologic R-R interval variability and arrhythmia, frame-mode acquisition of gated images may produce erroneous left ventricular volume curves, particularly in the diastolic filling phase. Eighteen patients in sinus rhythm underwent gated imaging in which both frame-mode and list-mode acquisitions were used. The systolic portions of the volume curves were similar in both studies, and the ejection fractions correlated well (R=0.97). 'Dropout' of data in the late diastolic phase, noted in 15 patients in whom frame mode was used, was not present in list mode, in which the atrial kick was clearly delineated. In additional patients with various arrhythmias, separate volume curves were obtained with list mode for premature, post-premature, and sinus beats. In patients with atrial fibrillation, a prominent peak mid-range on the R-R histogram was selected, and a complete volume curve was obtained. It was concluded that list-mode acquisition provided improved volume curves, with particular applicability in arrhythmic patients.