 For each Look-Locker image series, the endocardial and epicardial borders of the LV were traced and divided into six standard segments. Signal intensity versus time curves for each segment and the blood pool were used to determine segmental T1 by nonlinear, least-squares fitting to an analytic expression for the magnitude signal measured during the inversion recovery. T1 was calculated from the T1 and the amplitude parameters to correct for the effects of radiofrequency pulses applied during the inversion recovery. 