Fig. 1.

Pulse sequence for electrocardiogram (ECG) and navigator gated 3D T1ρ and accelerated k-space sampling order schema. a Image gating is synchronized with end-systole to achieve maximum myocardial wall thickness during this cardiac no motion period. Three heartbeats are shown. Sampling occurs every other heartbeat to allow for longitudinal relaxation of magnetization. b T1ρ and magnetization stabilization (ramp) followed by spatial encoding of a k-space subset is performed during the end-systolic time. c Enhanced view of the balanced steady-state free-precession kernel used during ramp and spatial encoding. d K-space sample ordering is shown. In this example, a subset of kspace (i.e. 48 k-space phase encoding lines) are acquired per heartbeat. K-space sample ordering is performed to assure that center spatial encoding frequencies are collected in the same heartbeat as much as possible. The color bar indicates the k-space ordering index