Fig. 4

Effect of image frame rate on measured LV function. Panels A-D illustrate the effect of frame rate on measured slice volume in one patient. A Measured LV volumes for 4 frame rates 11, 22, 89, and 357 fps in a single clinical subject in normal sinus rhythm (heart rate = 76 bpm) from images with an exposure time of 95.2 ms. B Dependence of measured end-diastolic (blue) and end-systolic (red) slice volumes on frame rate. C Effect of image frame rate on measured stroke volume in a slice. D Effect of frame rate on measured ejection fraction in a slice. The corresponding cine slice measurements are depicted with a solid black line in B C, and D. Real-time measurements are shown with the mean (solid colored line) and standard deviation (shaded area) obtained from several beats during the acquisition. Panels E-H illustrate the mean error between manual segmentation of cine images and semi-automated processing of real-time images from single slices in 7 different patients. The mean error (blue line) and standard deviation (shaded area) as a function of frame rate is shown for measured slice EDV (E), ESV (F), SV (G), and EF (H). The hemodynamic values show statistically significant errors (red cross) at frame rates lower than 44 fps. The black dotted line at 89 fps illustrates the close agreement in hemodynamic values