Fig. 4

Example of real-time ungated exercise cardiac MRI imaging during high-intensity exercise. a Short axis images are used to define the endocardial borders for the calculation of ventricular volumes. The point at which these transect the horizontal long-axis plane (b) is shown by the pink dots at the line of the red dotted line. This allows for cross-checking for the accuracy of endocardial contours and for the determination of the atrio-ventricular level on the short axis images. The endocardial ventricular borders for each short-axis slice at (c) end-diastole and (d) end-systole are summed to determine end-diastolic and end-systolic ventricular volumes respectively. This process is performed for images taken at rest and all intensities of exercise