A Novel Profile/View Ordering With a Non-Convex Star Shutter for High-Resolution 3D Volumetric T1 Mapping Under Multiple Breath-Holds

Purpose: To examine a novel non-convex star ordering/shutter for reducing the number of breath-holds in cardiac three-dimensional (3D) T-1 Mapping MRI with multiple breath-holds. Methods: A novel ordering, Non-Convex Star (NCS) was designed to acquire 3D volumes in a modified look-locker inversion recovery (MOLLI) T-1 mapping sequence to provide more spatial resolution and coverage in fewer breath-holds. The proposed 3D-MOLLI approach using NCS was first validated in two phantoms using artifact power (AP) measurement against the fully sampled phantom. This was followed by an in vivo study in seven swine, in which the T-1 values of the left ventricular (LV) myocardium divided into the American Heart Association (AHA) 16-segment model was compared against the reference multislice two-dimensional (2D) clinical reference and 3D volume without NCS breath-hold reduction. Results: NCS breath-hold reduction yielded less AP compared with the matched SENSE accelerated phantom volume (P < 0.0005), and was shown to be optimal at 25% fewer breath-holds. Calculated T-1 values from 3D in vivo volumes with/without NCS were comparable in all AHA segments (P = NS), whereas 3D-NCS yielded significantly higher T1 values than 2D at midslice of the LV myocardium in each AHA segment (P < 0.05). Conclusion: We successfully demonstrate the feasibility of the NCS approach for a 3D T-1 mapping acquisition requiring fewer breath-holds. (C) 2016 International Society for Magnetic Resonance in Medicine