Table 2.
Magnitude of flow change with and without offset correction
| No correction | Optimized ST correction | 1st order correction | 2nd order correction | 3rd order correction | P-value῀ no vs. opt. |
P-value ‡ no vs. 1st |
P-value ‖ no vs. 2nd |
P-value $ no vs 3rd |
|
|---|---|---|---|---|---|---|---|---|---|
| Medis QFlow | |||||||||
| Net flow (ml/m2)a | 48 ± 13 | – | 47 ± 13 | – | – | – | – | – | – |
| Velocity offset (cm/s) | 0.0 ± 2.0 | – | − 0.5 ± 1.8 | – | – | – | < 0.001 | – | – |
| Absolute velocity offset (cm/s) | 1.0 ± 1.7 | – | 1.3 ± 1.2 | – | – | – | < 0.001 | – | – |
| Difference in net flow with phantom correction (%)b | |||||||||
| Difference | 0.2 ± 15.4 | – | −3.2 ± 12.8 | – | – | – | < 0.001 | – | – |
| Absolute difference | 3.3 (1.2 to 7.3) | – | 6.1 (3.0 to 11.2) | – | – | – | < 0.001 | – | – |
| Range of difference | − 78 to 155 | – | −66 to 74 | – | – | – | – | – | – |
| Clinically significant differences (> 10%) | 65 (19%) | – | 103 (30%) | – | – | – | < 0.001 | – | – |
| MASS | |||||||||
| Net flow (ml/m2)a | 48 ± 13 | 48 ± 12 | 47 ± 13 | 49 ± 13 | 48 ± 12 | – | – | – | – |
| Velocity offset (cm/s) | 0.1 ± 2.0 | 0.0 ± 1.5 | −0.3 ± 1.8 | 0.3 ± 1.6 | 0.3 ± 1.6 | 0.247 | < 0.001 | 0.082 | 0.276 |
| Absolute velocity offset (cm/s) | 1.0 ± 1.7 | 0.9 ± 1.2 | 1.3 ± 1.3 | 1.1 ± 1.2 | 1.1 ± 1.1 | 0.418 | < 0.001 | 0.013 | 0.003 |
| Difference in net flow with phantom correction (%)b | |||||||||
| Difference | 0.8 ± 15.6 | −0.1 ± 11.1 | −2.0 ± 13.0 | 2.7 ± 13.4 | 1.8 ± 12.2 | 0.379 | < 0.001 | 0.060 | 0.281 |
| Absolute difference | 3.2 (1.3 to 7.2) | 3.7 (1.5 to 8.5) | 5.6 (2.4 to 10.4) | 4.3 (1.6 to 9.3) | 4.6 (2.2 to 9.2) | 0.342 | < 0.001 | 0.015 | 0.004 |
| Range of difference | −78 to 161 | −35 to 101 | −65 to 69 | −58 to 101 | − 37 to 120 | – | – | – | – |
| Clinically significant differences (> 10%) | 62 (18%) | 67 (19%) | 93 (27%) | 74 (21%) | 79 (23%) | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| Circle cvi42 | |||||||||
| Net flow (ml/m2)a | 47 ± 13 | 47 ± 13 | 45 ± 12 | 47 ± 13 | 47 ± 13 | – | – | – | – |
| Velocity offset (cm/s) | 0.0 ± 2.2 | −0.2 ± 2.0 | − 0.7 ± 2.2 | − 0.1 ± 2.1 | − 0.1 ± 2.2 | 0.063 | < 0.001 | 0.607 | 0.566 |
| Absolute velocity offset (cm/s) | 1.2 ± 1.9 | 1.4 ± 1.5 | 1.7 ± 1.6 | 1.4 ± 1.6 | 1.5 ± 1.6 | 0.006 | < 0.001 | 0.014 | < 0.001 |
| Difference in net flow with phantom correction (%)b | |||||||||
| Difference | 0.0 ± 16.0 | −1.8 ± 14.3 | −4.8 ± 15.0 | − 0.5 ± 15.2 | −0.7 ± 15.5 | 0.046 | < 0.001 | 0.640 | 0.563 |
| Absolute difference | 4.1 (1.4 to 9.2) | 6.0 (2.2 to 11.9) | 8.0 (4.3 to 13.6) | 5.3 (2.2 to 12.1) | 6.1 (2.2 to 13.2) | 0.005 | < 0.001 | 0.011 | < 0.001 |
| Range of difference | −93 to 131 | −62 to 59 | −66 to 59 | − 85 to 71 | −80 to 75 | – | – | – | – |
| Clinically significant differences (> 10%) | 80 (23%) | 103 (30%) | 137 (40%) | 107 (31%) | 115 (33%) | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
Values are presented as mean ± standard deviation, median (interquartile range), range minimum to maximum or number (percentage)
Opt. Optimized stationary tissue (ST) correction
῀ p-values no correction versus optimized ST correction, ‡ p-values no correction versus first order correction, ‖ p-values no correction versus second order correction, $ p-values no correction versus third order correction
a Indicates net flow per heartbeat, with phantom correction the mean net flow was 48 ± 11 ml/ m2 in all software packages, b Minus indicates flow was lower compared to phantom flow measurements