Calculation of ejection fraction in gated SPECT.

TO THE EDITOR: In a recent article (1), my friend and colleague Grant Gullberg presented a method for the calculation of ejection fraction in gated myocardial perfusion SPECT studies. The crucial point is the avoidance of edge detection. In their method, the authors used the maximal activity plane as the ventricular delineator. The originality of the method resides in the latter, not in the former, since avoidance of edge detection for ventricular delimitation has been described before. Several studies (2–5) have used a method in which the delineator was the first moment of the count density distribution across the myocardial wall. I will admit that the Japanese reference could easily have been missed.