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Figure 2 Apparent perfusion defect due to artifact. The noncontrast image (A) shows lower levels of backscatter from the lateral wall, probably due to interposed lung. After injection of contrast agent (B), an apparent defect involves the basal half of the lateral wall (arrows). The accompanying SPECT image (C) shows normal myocardial perfusion. This pattern is the most common source of false positive findings (i.e. reduced MCE when there should be normal perfusion).