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Table 4 Distribution of measurements of the flow volumes, mean velocity, and peak velocity for two different 2D flow phase-contrast acquisitions (orthogonal “through-plane” to the phantom vessel and misaligned) and two 4D flow phase-contrast sequences (GRAPPA2 and k-t-GRAPPA5) with angles between the longitudinal axis of the phantom vessel and the z-direction in 15° steps from 0 to 45°

From: Validation of two accelerated 4D flow MRI sequences at 3 T: a phantom study

Angle Pump reference 2D flow PC 4D flow PC GRAPPA2 4D flow PC k-t-GRAPPA5
Flow volume, L/min Mean velocity, cm/s Peak velocity, cm/s Flow volume, L/min Mean velocity, cm/s Peak velocity, cm/s Flow volume, L/min Mean velocity, cm/s Peak velocity, cm/s Flow volume, L/min Mean velocity, cm/s Peak velocity, cm/s
5.3 70 70 5.4 71 93 5.4 71 90 5.4 71 96
15° 5.3 70 70 5.4 64 89 5.3 70 90 5.3 72 93
30° 5.3 70 70 5.1 60 82 5.3 70 87 5.3 70 87
45° 5.3 70 70 4.8 51 82 5.2 68 90 5.3 71 89
  1. No significant differences between 4D flow measurements, orthogonal (“through-plane”) 2D flow measurements, and the pump reference (p = 0.999). In contrast, the misaligned 2D flow measurements demonstrated increasingly higher differences with the degree of misalignment
  2. 2D two-dimensional, 4D four-dimensional, cm/s centimetres per second, GRAPPA generalised autocalibrating partially parallel acquisition, L/min litres per minute, PC phase-contrast, Venc velocity encoding