Abstract
BACKGROUND: Electrocardiogram (ECG) triggering in cardiac magnetic resonance (MR) faces limitations with high-field systems (≥3.0T) due to magnetohydrodynamic (MHD) artifacts. This study aimed to evaluate the feasibility of using finger-pulse triggering for cardiac MR T1 mapping by comparing image quality and native T1 quantification with conventional ECG triggering. METHODS: Patients who underwent cardiac MR examination between March and April 2024 were prospectively and consecutively enrolled in the study. All the patients underwent identical pre-contrast T1 mapping with both ECG- and pulse-triggering acquisitions using a modified Look-Locker inversion-recovery (MOLLI) 5(3)3 sequence, covering short-axis views at basal, mid, and apical slices of the left ventricle. Three radiologists independently evaluated image quality using the Likert scale (range, 1-5). Two radiologists manually delineated myocardial regions of interest (ROIs) on native T1 maps to quantify segmental native T1 values. Paired t-tests or Wilcoxon signed-rank tests were used to compare the characteristics derived from the two triggering images. Bland-Altman plots, Kendall's W test, and intraclass correlation coefficients (ICCs) were used for the agreement analysis. RESULTS: A total of 15 participants were included in the study (mean age: 41±19 years; 60% male). ECG and finger-pulse triggering demonstrated equivalent diagnostic image quality (median scores: 4.0 vs. 4.0, P=0.655), with excellent interobserver agreement (ECG: Kendall's W =0.861, P<0.001; pulse: Kendall's W =0.838, P=0.001). There were no statistically significant differences in the native T1 values between the two methods (all P>0.05). Bland-Altman plots revealed that the differences between the two triggering methods for native T1 values mostly fell within the 95% confidence interval. Both triggering modalities demonstrated good to excellent interobserver and intraobserver agreement (ICC range, 0.768-0.936). CONCLUSIONS: Finger-pulse triggering demonstrates comparable accuracy and reliability to ECG triggering in cardiac MR T1 mapping, offering a viable clinical alternative for patients with ECG distortion or triggering failure.