[Effect of Pulse Wave Synchronization on T1 Value in Cardiac T1 Mapping: Is Pulse Wave Synchronization a Substitute for Electrocardiogram Gating?]

ABSTRACT

PURPOSE: We investigated whether peripheral pulse synchronization (PPUS) can be an alternate method for electrocardiographic synchronization (ECGS) in measuring myocardial T1 values in cardiac magnetic resonance imaging (CMRI). METHODS: T1 map imaging was performed on 49 patients undergoing CMRI using the 5s (3s) 3s modified Look-Locker inversion recovery (MOLLI) method for both ECGS and PPUS. The short-axis images of basal, mid, and apical segments were obtained. The T1 map images were analyzed using an image processing system, and T1 values were obtained for each cardiac segment. To assess the degree of agreement between T1 values obtained from ECGS and PPUS, the Bland-Altman analysis and the estimating intraclass correlation coefficient (ICC) were performed for the average T1 value of the entire myocardium and T1 values of each cardiac segment. Also, to evaluate whether PPUS imaging is possible in the diastole phase, we measured the length of systole in the electrocardiogram and the length of transmission (R-R') from R in the electrocardiogram to R (R') in the pulse waveform. RESULTS: From the comparison of T1 values, a good agreement of ICC was confirmed between the ECGS and PPUS (whole myocardium 0.97, apical 0.93, mid 0.98, and basal 0.97). The results of the Bland-Altman analysis also indicated good agreement. Moreover, it was shown that the heart was imaged in the diastole phase even with the default scan parameters of PPUS. CONCLUSION: Our results indicated that PPUS can be an alternate method for ECGS.