# Reproducibility of circumferential strain on cine displacement encoding with stimulated echoes magnetic resonance imaging before and after contrast at 3T

## TL;DR

This study shows that cine DENSE MRI can reliably measure heart strain before and after contrast injection at 3T.

## Contribution

The study evaluates the reproducibility of cine DENSE MRI with two contrast agents, gadolinium and ferumoxytol.

## Key findings

- Global ECC showed excellent practical equivalence before and after contrast injection for both agents.
- Segmental ECC reproducibility was consistently high, with over 87% within the ROPE.
- Gadolinium improved SNR in early systolic phases, while ferumoxytol increased myocardium SNR during systole.

## Abstract

Magnetic resonance imaging (MRI) with displacement encoding with stimulated echoes (DENSE) is well recognized for accurate and precise quantification of myocardial displacement and strain, but its reproducibility before and after contrast injection has not been investigated. Gadolinium is the most widely used contrast agent. Ferumoxytol is increasingly used off-label in specific patient groups. We aim to assess the reproducibility of cine DENSE MRI to measure global and segmental circumferential myocardial strain (ECC) before and after contrast injection for gadolinium and ferumoxytol, respectively.

All imaging was conducted using 3T scanners. In 11 patients with cardiac disease, breath-hold two-dimensional cine DENSE was acquired in a mid-ventricular short-axis slice before and following the injection of gadolinium (0.1 mmol/kg). A separate cohort of 11 subjects (5 healthy subjects and 6 patients with ischemic heart disease) received 3 incremental doses of ferumoxytol: 0.125, 1.875, and 2.0 mg/kg (to a cumulative dose of 4.0 mg/kg). The same DENSE acquisition was performed before and after each incremental dose. Post-processing generated left ventricular (LV) displacement and ECC maps, and strain-time curves. Global and segmental ECC in six mid-level short-axis LV segments were compared. Signal-to-noise (SNR) was evaluated on the magnitude images throughout the cardiac cycle in the myocardium, liver, and back muscle, respectively. A Bayesian analysis was performed to test results with region of practical equivalence (ROPE) at ±5 for SNR and ±0.02 for ECC (p < 0.05 as significant).

Based on the percentage within the ROPE and the corresponding p-values, global ECC exhibited excellent practical equivalence under pre- and post-contrast conditions for gadolinium (p = 0.413) and ferumoxytol (p ≥ 0.161). Segmental ECC reproducibility was consistently high across all comparative analyses, with at least 87.02% falling within the ROPE. Gadolinium administration significantly improved SNR in all tissues during the early systolic phases (1–5, p ≤ 0.021). Ferumoxytol resulted in a reduction in liver SNR during diastolic phases (10–20, p ≤ 0.011) and a significant increase in myocardium SNR during systolic phases (1–5, p ≤ 0.034).

Good reproducibility of global and segmental ECC measurements using cine DENSE before and after contrast injection is achievable at 3T.

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