Phantom-based correction for standardization of myocardial native T1 and extracellular volume fraction in healthy subjects at 3-Tesla cardiac magnetic resonance imaging

Objectives To investigate the effect of the phantom-based correction method for standardizing myocardial native T1 and extracellular volume fraction (ECV) in healthy subjects. Methods Seventy-one healthy asymptomatic adult (>= 20 years) volunteers of five different age groups (34 men and 37 women, 45.5 +/- 15.5 years) were prospectively enrolled in three academic hospitals. Cardiac MRI including Modified Look - Locker Inversion recovery T1 mapping sequence was performed using a 3-Tesla system with a different type of scanner for each hospital. Native T1 and ECV were measured in the short-axis T1 map and analyzed for mean values of the 16 entire segments. The myocardial T1 value of each subject was corrected based on the site-specific equation derived from the T1 Mapping and ECV Standardization phantom. The global native T1 and ECV were compared between institutions before and after phantom-based correction, and the variation in native T1 and ECV among institutions was assessed using a coefficient of variation (CoV). Results The global native T1 value significantly differed between the institutions (1198.7 +/- 32.1 ms, institution A; 1217.7 +/- 39.9 ms, institution B; 1232.7 +/- 31.1 ms, institution C; p = 0.002), but the mean ECV did not (26.6-27.5%, p = 0.355). After phantom-based correction, the global native T1 and ECV were 1289.7 +/- 32.4 ms and 25.0 +/- 2.7%, respectively, and CoV for native T1 between the three institutions decreased from 3.0 to 2.5%. The corrected native T1 value did not significantly differ between institutions (1284.5 +/- 31.5 ms, institution A; 1296.5 +/- 39.1 ms, institution B; 1291.3 +/- 29.3 ms, institution C; p = 0.440), and neither did the ECV (24.4-25.9%, p = 0.078). Conclusions The phantom-based correction method can provide standardized reference T1 values in healthy subjects.

Automated summary

The phantom-based correction method can standardize myocardial native T1 and extracellular volume fraction (ECV) in healthy subjects, providing standardized reference values.