Effect of aliasing on phase-contrast cine CMR (PC CMR) flow measurements. Sixteen-year-old patient with surgically repaired tetralogy of Fallot and mild pulmonary valve stenosis. PC CMR was performed in the main pulmonary artery with the velocity range (venc) set incorrectly at 200 cm/sec (top row) and then with the venc set correctly at 300 cm/sec (bottom row). Magnitude (A, D) and phase images (B, E) in systole, and the resulting flow curves (C, F) generated from analyzing the region of interest (yellow contour) are shown. Because the peak velocity is 260 cm/sec, aliasing (B) and flow underestimation (C) are seen with a venc of 200 cm/sec but not with a venc of 300 cm/sec (E and F).