Figure 1
From: Rapid phase contrast MRI with minimum time gradient waveform design using convex optimization
Pulse sequence diagrams for 2D through-plane PC-MRI sequences for VENC = 150 cm/s: (a) conventional flow compensated and flow encoded (FCFE) velocity encoded sequence (TEMIN = 2.68 ms, 1.8 mm × 1.8 mm spatial resolution, 38 ms temporal resolution) and (b) convex gradient optimized (CVX) velocity encoded sequence (TEMIN = 2.18 ms, 1.8 mm × 1.8 mm spatial resolution, 30 ms temporal resolution). Two separate CVX optimizations are conducted for each sequence as indicated by the gray regions within the pulse sequence diagrams. The two slice select gradients, the flow compensated readout gradient, and the phase encoding gradient are optimized during the time between RF transmission and data acquisition (Interval 1). The spoiler, readout ramp down, and phase encode rewinder gradients are optimized during the time between the end of data acquisition and the end of the TR (Interval 2).