Myocardial cells obtain 60-90% of their energy from free fatty acids under aerobic conditions. 123I-BMIPP can demonstrate fatty acid metabolism in the myocardium and is used to evaluate cardiac diseases. Forty-three patients underwent BMIPP imaging in the early (15 min) and delayed (4 hr) phase, and the washout rate was calculated. We evaluate the washout rate by two methods, the polar map method and the planar image method. The two methods showed close correlation (r=0.473).