Figure 1
Concentric rings. (a) 2D k-space is sampled with uniformly spaced concentric rings, where gradients are designed for the outermost ring and then scaled down to acquire one ring after each RF pulse. A time-efficient retracing design is used to acquire each ring through multiple revolutions. Each revolution captures the image at a different effective TEr (separation dTE) to enable fat-water separation. (b) Extension to a two-band design where only the inner half of k-space (shaded) is acquired with retracing. This can increase gradient power for the inner rings and decrease dTE. (c) Time-interleaved k-t undersampling for R = 2. Rings denoted by dotted lines are omitted, while a central region of N cal rings is always acquired for training. (d) The desired sets of rings for each frame are acquired over multiple heartbeats (HB) with interleaved segmentation. Temporal resolution is T frame .