3D joint T₁/T_{1 ρ}/T₂ mapping and water-fat imaging for contrast-agent free myocardial tissue characterization at 1.5T

To develop a novel, free-breathing, 3D joint $$ / $$ / $$ mapping sequence with Dixon encoding to provide co-registered 3D $$ , $$ , and $$ maps and water-fat volumes with isotropic spatial resolution in a single $$ min scan for comprehensive contrast-agent-free myocardial tissue characterization and simultaneous evaluation of the whole-heart anatomy.

An interleaving sequence over 5 heartbeats is proposed to provide $$ , $$ , and $$ encoding, with 3D data acquired with Dixon gradient-echo readout and 2D image navigators to enable $$ respiratory scan efficiency. Images were reconstructed with a non-rigid motion-corrected, low-rank patch-based reconstruction, and maps were generated through dictionary matching. The proposed sequence was compared against conventional 2D techniques in phantoms, 10 healthy subjects, and 1 patient.

The proposed 3D $$ , $$ , and $$ measurements showed excellent correlation with 2D reference measurements in phantoms. For healthy subjects, the mapping values of septal myocardial tissue were $$ , $$ , and $$ for the proposed sequence, against $$ , $$ , and $$ for 2D MOLLI, 2D $$ -prep bSSFP and 2D $$ -prep bSSFP, respectively. Promising results were obtained when comparing the proposed mapping to 2D references in 1 patient with active myocarditis.

The proposed approach enables simultaneous 3D whole-heart joint $$ / $$ / $$ mapping and water/fat imaging in $$ 7 min scan time, demonstrating good agreement with conventional mapping techniques in phantoms and healthy subjects and promising results in 1 patient with suspected cardiovascular disease.