It might be helpful at this point to see an example of a MUGA report for an exam that had been reported as within normal limits.  This is old ADAC software that has been around for decades for planar multigated acquisitions, and is still in use today in many institutions. 

The report of this MUGA scan shows us global and regional ejection fractions, the frames chosen to represent the ED and ES portions of the cardiac cycle, the size, shape and location of the background region of interest, and the volume curves.  The heart rate, the duration of the R-R interval in milliseconds, the number of cycles counted, and the left ventricular ejection fraction of 60% is in the report.

The upper left viewport displays the percent regional ejection fraction, percent of radial shortening, and regional ejection fractions and radial shortenings corresponding to points on the region of interest. The regional ejection fraction and radial shortening values are calculated for each region of interest by the Gated Analysis Application.  Each region is divided into eight pie-shaped ROIs by eight line segments that originate from the geometric center of each ROI.  These segments are generated at 45 degree intervals.  The change in the length of the radial line segments determines the radial shortening, and the change in counts of each pie-shaped region determine the regional ejection fractions.  

Beneath this viewport, patient information, ejection fraction, heart rate, R-R interval in milliseconds, number of cardiac cycles the data has collected, and the end-diastolic and end-systolic frame numbers.

Moving to the right upper quadrant, the ED and ES viewports display the end diastole and end systole images with corresponding ROIs and the background ROI drawn by the user, respectively.  The amplitude and phase images provide information on ventricular motion.  Fourier phase analysis reduces four-dimensional data into a pair of two-dimensional images.  The images created depict contractility (amplitude) and contraction sequence (phase).

Wall motion abnormalities are portrayed on phase images as low-amplitude areas. Regions of paradoxical motion due to aneurysms, for example, are 180 degrees “out of phase” normally. Abnormal conduction patterns like those seen in bundle-branch-block cause affected areas to be slightly out of phase with adjacent portions of the ventricle owing to premature or delayed contraction. In the paradox image the end-diastolic frame is subtracted from the end-systolic frame. In normal ventricular function, this leaves a void. In ventricles showing areas of paradoxical ventricular wall motion, the systolic bulge is readily detected as an area of unsubtracted activity.

volume curve detail

The volume curves shown on the right bottom viewport can tell the interpreting physician at a glance whether the ventricle is filling and emptying efficiently.  The red line is a time-activity curve where the vertical axis represents the percentage of blood remaining in the ventricle, while the horizontal axis shows the time in milliseconds.  The red line shows the interpreting physician that the ejection fraction and wall motion are normal, and the left ventricle refills with blood in the post-systolic portion of the histogram within normal limits.  The green is the volume derivative time-activity curve.

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