TABLE 2.
Flow‐rate assessment for steady flow in a straight tube (experiment 1)
| Acquisition | Volumetric flow rate (mL/s) | MRI‐assessed flow rate (mL/s) | Relative difference (%) (ΔVolumetric) | MRI‐assessed max velocity (cm/s) | Relative difference (%) (Δ4DGRE) | MRI‐assessed flow rate (mL/s) | Relative difference (%) (ΔVolumetric) | MRI‐assessed max velocity (cm/s) | Relative difference (%) (Δ4DGRE) |
|---|---|---|---|---|---|---|---|---|---|
| Tube 1 (diameter 1.0 cm) | Tube 2 (diameter 0.7 cm) | ||||||||
| 4DEPI5_ro_coronal | 50 | 53.6 | 7.2 | 96 | 9.1 | 44.0 | −12.0 | 216 | −1.4 |
| 4DEPI5_bp_coronal | 50 | 53.0 | 6.1 | 97 | 10.2 | 45.0 | −10.0 | 216 | −1.4 |
| 4DEPI5_nbp_axial | 50 | 52.5 | 5.0 | 98 | 11.4 | 48.0 | −4.0 | 215 | −1.8 |
| 4DEPI3_ro_coronal | 50 | 54.0 | 8.0 | 88 | 0.0 | 49.1 | −1.8 | 233 | 6.4 |
| 4DEPI3_bp_coronal | 50 | 52.3 | 4.6 | 93 | 5.7 | 50.0 | 0 | 215 | −1.8 |
| 4DEPI3_nbp_axial | 50 | 51.6 | 3.1 | 92 | 4.5 | 46.7 | −6.6 | 229 | 4.6 |
| 4DGRE_coronal | 50 | 49.4 | −1.2 | 88 | – | 47.8 | −4.4 | 219 | – |
| 4DEPI5_ro_coronal | 23 | 24.3 | 5.7 | 44 | 2.3 | ||||
| 4DEPI5_bp_coronal | 23 | 24.4 | 6.1 | 46 | 7.0 | ||||
| 4DEPI5_nbp_axial | 23 | 23.9 | 3.9 | 42 | −2.3 | ||||
| 4DGRE_coronal | 23 | 24.4 | 3.0 | 43 | – | ||||
4DEPIx_ro refers to acquisition with EPI factor (5 or 3) with the readout gradient aligned parallel to the main flow direction; 4DEPIx_bp refers to EPI acquisition with the blip phase‐encoding gradient aligned parallel to the main flow direction; and 4DEPIx_nbp refers to EPI acquisition with the readout and blip phase‐encoding gradient both perpendicular to the main flow direction.