There is an error in the Abstract of “Myocardial Tracking, A New Method to Calculate Ejection Fraction with Gated SPECT: Validation with 201Tl Versus Planar Angiography,” by Itti et al. (J Nucl Med. 2001;42:845–852). The Conclusion should read: “MTK algorithm accurately calculates LVEF on early/high-count images, compared with ERNA, even in patients with severe perfusion defects, but tends to underestimate LVEF on delayed/low-contrast images, as other algorithms do.” We regret the error.