Comprehensive evaluation of macroscopic and microscopic myocardial fibrosis by cardiac MR: intra-individual comparison of gadobutrol versus gadoterate meglumine.

PURPOSE: Late gadolinium enhancement cardiac MR (LGE-CMR) and extracellular volume fraction (ECV-CMR) are widely used to evaluate macroscopic and microscopic myocardial fibrosis. Macrocyclic contrast media are increasingly used off-label for myocardial scar assessment, given the superior safety profile of these agents. We aimed to assess the performance of two macrocyclic contrast agents, gadoterate meglumine and gadobutrol, for the evaluation of myocardial scar.

MATERIAL AND METHODS: Forty subjects (61 ± 11 years, 67.5% men) who underwent LGE-CMR using gadobutrol were prospectively recruited for a research CMR scan using same-dose gadoterate meglumine (0.2 mmol/kg) at 1.5 T. Myocardial scar quantification was performed using a short-axis phase-sensitive inversion recovery (PSIR) Turbo-FLASH and steady-state free precession (SSFP) images. Pre- and post-contrast T1-mapping was employed to assess myocardial ECV. An intraclass correlation coefficient (ICC) was used to check for reliability between the two contrast agents.

RESULTS: Using manual thresholding on PSIR Turbo-FLASH images, mean LGE scar percentage (LGE%) was 9.9 ± 9.7% and 9.4 ± 9.7% for gadobutrol and gadoterate meglumine, respectively (p > 0.05) (ICC: 0.99, 95% CI: 0.97-0.99). Using the PSIR SSFP technique and manual thresholding, LGE% averaged 7.5 ± 9.0% and 7.1 ± 8.6% for gadobutrol and gadoterate meglumine, respectively (p > 0.05) (ICC: 0.99, 95% CI: 0.98-0.99). Average ECV with gadobutrol and gadoterate meglumine were similar at 28.40 ± 4.88 and 28.46 ± 4.73 (p > 0.05) with a strong correlation (ICC: 0.98, 95% CI: 0.94-0.99).

CONCLUSION: We found LGE- and ECV-CMR values derived from gadoterate meglumine comparable to values derived from gadobutrol. Gadoterate meglumine has a comparable performance to gadobutrol in identifying LGE-derived myocardial scar both qualitatively and quantitatively.

KEY POINTS: • Late gadolinium-enhancement cardiac MR (LGE-MR) and extracellular volume (ECV) fraction are widely used to evaluate macroscopic and microscopic myocardial fibrosis. • Macrocyclic contrast media are increasingly used off-label for myocardial scar assessment, given the presumed superior safety profile of these agents. • LGE- and ECV-CMR values derived from gadoterate meglumine are comparable to values derived from gadobutrol.