Table 1.
Distribution of two measurements of the flow volume for 2D flow and two 4D flow phase-contrast sequences (GRAPPA2 and k-t-GRAPPA5) with different rotational frequencies of the blood pump
| Rotational pump output, rpm | Venc, cm/s | Pump reference flow volume | 2D flow PC flow volume | 4D flow PC GRAPPA2 flow volume | 4D flow PC k-t-GRAPPA5 flow volume | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| L/min | L/min, mean ± SD | L/min (difference from the pump reference) | L/min, mean ± SD | L/min (difference from the pump reference) | L/min, mean ± SD | L/min (difference from the pump reference) | L/min, mean ± SD | ||||||
| Exam 1 | Exam 2 | Exam 1 | Exam 2 | Exam 1 | Exam 2 | Exam 1 | Exam 2 | ||||||
| 1,500 | 40 | 1.7 | 1.7 | 1.70 ± 0.0 | 1.7 (+ 0.0) | 1.7 (+ 0.0) | 1.70 ± 0.0 | 1.7 (+ 0.0) | 1.8 (+ 0.1) | 1.75 ± 0.1 | 1.8 (+ 0.1) | 1.7 (+ 0.0) | 1.75 ± 0.1 |
| 2,000 | 50 | 2.4 | 2.3 | 2.35 ± 0.1 | 2.4 (+ 0.0) | 2.4 (+ 0.1) | 2.40 ± 0.0 | 2.4 (+ 0.0) | 2.4 (+ 0.1) | 2.40 ± 0.0 | 2.3 (-0.1) | 2.4 (+ 0.1) | 2.35 ± 0.0 |
| 2,500 | 60 | 3.0 | 3.0 | 3.00 ± 0.0 | 3.1 (+ 0.1) | 3.1 (+ 0.1) | 3.10 ± 0.0 | 3.1 (+ 0.1) | 3.1 (+ 0.1) | 3.10 ± 0.0 | 3.1 (+ 0.1) | 3.2 (+ 0.2) | 3.15 ± 0.1 |
| 3,000 | 70 | 3.8 | 3.8 | 3.80 ± 0.0 | 3.8 (+ 0.0) | 3.8 (+ 0.0) | 3.80 ± 0.0 | 3.7 (-0.1) | 3.8 (+ 0.0) | 3.75 ± 0.1 | 3.8 (+ 0.0) | 3.9 (+ 0.1) | 3.85 ± 0.1 |
| 3,500 | 85 | 4.5 | 4.5 | 4.50 ± 0.0 | 4.6 (+ 0.1) | 4.6 (+ 0.1) | 4.60 ± 0.0 | 4.4 (-0.1) | 4.5 (+ 0.0) | 4.45 ± 0.1 | 4.6 (+ 0.1) | 4.7 (+ 0.2) | 4.65 ± 0.1 |
| 4,000 | 100 | 5.3 | 5.3 | 5.30 ± 0.0 | 5.4 (+ 0.1) | 5.4 (+ 0.1) | 5.40 ± 0.0 | 5.2 (-0.1) | 5.3 (+ 0.0) | 5.25 ± 0.1 | 5.4 (+ 0.1) | 5.5 (+ 0.2) | 5.45 ± 0.1 |
| 4,500 | 110 | 6.1 | 6.1 | 6.10 ± 0.0 | 6.2 (+ 0.1) | 6.2 (+ 0.1) | 6.20 ± 0.0 | 6.0 (-0.1) | 6.2 (+ 0.1) | 6.10 ± 0.1 | 6.2 (+ 0.1) | 6.3 (+ 0.2) | 6.25 ± 0.1 |
| 5,000 | 125 | 6.9 | 6.9 | 6.90 ± 0.0 | 7.0 (+ 0.1) | 7.1 (+ 0.2) | 7.05 ± 0.1 | 6.9 (+ 0.0) | 6.9 (+ 0.0) | 6.90 ± 0.1 | 7.0 (+ 0.1) | 7.1 (+ 0.2) | 7.05 ± 0.1 |
| 5,500 | 140 | 7.7 | 7.7 | 7.70 ± 0.0 | 7.8 (+ 0.1) | 7.9 (+ 0.2) | 7.85 ± 0.1 | 7.6 (-0.1) | 7.7 (+ 0.0) | 7.65 ± 0.1 | 7.8 (+ 0.1) | 7.9 (+ 0.2) | 7.85 ± 0.1 |
No significant differences between measurements and pump reference were observed (p = 0.994)
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, SD standard deviation of the mean, Venc velocity encoding