Cardiac MOLLI T₁ mapping at 3.0 T: comparison of patient-adaptive dual-source RF and conventional RF transmission

To prospectively compare image quality and myocardial T₁ relaxation times of modified Look-Locker inversion recovery (MOLLI) imaging at 3.0 T (T) acquired with patient-adaptive dual-source (DS) and conventional single-source (SS) radiofrequency (RF) transmission. Pre- and post-contrast MOLLI T₁ mapping using SS and DS was acquired in 27 patients. Patient wise and segment wise analysis of T₁ times was performed. The correlation of DS MOLLI measurements with a reference spin echo sequence was analysed in phantom experiments. DS MOLLI imaging reduced T₁ standard deviation in 14 out of 16 myocardial segments (87.5%). Significant reduction of T₁ variance could be obtained in 7 segments (43.8%). DS significantly reduced myocardial T₁ variance in 16 out of 25 patients (64.0%). With conventional RF transmission, dielectric shading artefacts occurred in six patients causing diagnostic uncertainty. No according artefacts were found on DS images. DS image findings were in accordance with conventional T₁ mapping and late gadolinium enhancement (LGE) imaging. Phantom experiments demonstrated good correlation of myocardial T₁ time between DS MOLLI and spin echo imaging. Dual-source RF transmission enhances myocardial T₁ homogeneity in MOLLI imaging at 3.0 T. The reduction of signal inhomogeneities and artefacts due to dielectric shading is likely to enhance diagnostic confidence.