Feasibility of finger-pulse triggering as a substitute for electrocardiogram triggering in cardiac magnetic resonance T1 mapping: a prospective comparative study.

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.