P194 - FEASIBILITY AND ACCURACY OF PERIPHERAL PULSE GATING IN CARDIAC MAGNETIC RESONANCE IMAGING FOR QUANTITATIVE EVALUATION OF MYOCARDIAL PARAMETRIC MAPPING

Background: Cardiac magnetic resonance imaging (CMR) using mapping is a comprehensive, non-invasive method for assessing tissue pathology in cardiac diseases . The diagnostic sensitivity, however, may be compromised by various artifacts that can degrade image quality and alter quantitative results. A common source of such artifacts is a noisy ECG signal, which leads to inconsistent triggering. Peripheral pulse gating (PG) may overcome this problem by relying on the more stable peripheral pulse only. The long delay between cardiac contraction and the arrival of the pulse wave at the finger are matters of concern. Consequently, the technique is not that widely used and neither its accuracy nor reference values for mapping have been determined based on pulse-triggered mapping. We hypothesized that in severe arrhythmia, where ECG-triggered mapping is challenging, PG can provide a feasible and reliable alternative

METHODS AND RESULTS: Forty-nine participants (62% female, mean age 57 years) were scanned on a 3T scanner. Two successive slices were acquired in the mid-third short-axis orientation using ECG- and PG MOLLI-MOCO-DL T1 (Modified Look-Locker Inversion recovery with Motion Correction with deep learning) and FSE-T2 (Double inversion recovery prepared or black- blood fast spin echo) sequences as standard method. Mid-myocardial mapping values were measured using cvi42™ (Circle Cardiovascular Imaging Inc, Calgary, Canada), employing a blinded, cross-sectional analysis. An experienced reader applied a 4-point Likert scale to evaluate image quality (IQ) in both methods 1 = non-diagnostic IQ, 2 = diagnostic IQ with many artifacts, 3 = diagnostic IQ with few artifacts, and 4 = Good IQ. A Mann-Whitney U-test was applied to compare groups.
There were no significant differences between ECG-gating and PG-gating in mapping values. The median T1 value for ECG-gating was 1191.7 ± 54.43, and from the PG, it was 1196.4 ± 52.13 (Mann-Whitney U-test: p = 0.71; Fig. 1A). The median T2 -value from the ECG gating was 45.3 ± 4.88, and from the PG, it was 45.57 ± 4.9 (Mann-Whitney U-test: p = 0.77; Fig. 1B). The image quality of the T1 and T2 mapping PG was reported as diagnostic with few artifacts in 31% (n=15) and good in 69% of participants (n=34). The IQ of the mapping ECG-gating was reported as diagnostic with few artifacts in 26.5% (n=13) and good in 73.47% of participants (n=36) (Fig 2).

Conclusion: Using peripheral pulse gating for T1 and T2 mapping is feasible and reliable. It should be used whenever ECG-gating is challenging.