Figure 1
From: A novel approach to phase-contrast velocity offset correction by in vivo high-SNR acquisitions

Example of the 1st order surface fits for the original (a) and thicker slice high-SNR (b) pulse sequences, with the stationary tissue shown as blue dots. Improved SNR is clearly visible due to the thicker slice excited by the shorter RF pulse with no sequence timing or gradient alterations so the offset error does not change.