Reproducibility of Circumferential Strain on Cine DENSE MRI Before and After Contrast at 3T.

Background: 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 (E_cc) before and after contrast injection for gadolinium and ferumoxytol respectively.

Methods: All imaging was conducted using 3T scanners. In 11 patients with cardiac disease, breath-hold 2D cine DENSE was acquired in a mid-ventricular short-axis slice prior to and following the injection of gadolinium (0.1mmol/kg). A separate cohort of 11 subjects (5 healthy subjects and 6 patients with ischemic heart disease) received three incremental doses of ferumoxytol: 0.125, 1.875, and 2.0mg/kg (to a cumulative dose of 4mg/kg). The same DENSE acquisition was performed before and after each incremental dose. Post-processing generated left ventricular (LV) displacement and E_ccmaps, and strain-time curves. Global and segmental E_ccin 6 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 regions of practical equivalence (ROPE) at ±5 for SNR and ±0.02 for E_cc (p<0.05 as significant).

Results: Based on the percentage within the ROPE and the corresponding p-values, global E_ccexhibited excellent practical equivalence under pre- and post-contrast conditions for gadolinium (p = 0.413) and ferumoxytol (p≥0.161). Segmental E_cc 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).

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