Table 3. MPI-calculated velocities in stenotic phantoms.
| Setting | Flow rate [ml/min] | Reference velocity [cm/s] | FDHM velcoties using intrinsic correction factor [cm/s] | Correction factor c [1] | Absolute error [cm/s]/Absolute relative error | FDHM velocities using correction factor from setting 2 | Absolute error [cm/s]/Absolute relative error | FDHM using correction factor from setting 3 | Absolute error [cm/s]/Absolute relative error |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 151 ± 24.5 | 20 ± 2.2 | 19.8 ± 2.0 | 25.30 ± 0.19 | 0.2/1.2% | ||||
| 21.5 ± 1.8 | 25.84 ± 0.08 | 1.5/7.7% | |||||||
| 19.0 ± 2.0 | 25.03 ± 0.14 | 1.0/5.1% | |||||||
| 19.8 ± 2.0 | 25.32 ± 0.19 | 0.2/0.8% | |||||||
| 2 | 680 ± 40.4 | 40 ± 3.6 | 42.7 ± 2.8 | 21.22 ± 0.13 | 2.7/6.8% | ||||
| 42.3 ± 2.9 | 21.18 ± 0.14 | 2.3/5.7% | |||||||
| 34.9 ± 3.1 | 20.49 ± 0.09 | 5.1/12.9% | |||||||
| 42.3 ± 2.9 | 21.18 ± 0.14 | 2.3/5.7% | |||||||
| 42.4 ± 2.9 | 21.19 ± 0.14 | 2.4/6.0% | |||||||
| 36.8 ± 3.1 | 20.69 ± 0.13 | 3.2/8.0% | |||||||
| 3 | 205 ± 26.2 | 12 ± 1.7 | 12.9 ± 1.6 | 17.09 ± 0.32 | 0.9/7.1% | 15.8 ± 1.1 | 3.8/31.6% | ||
| 9.0 ± 1.5 | 16.00 ± 0.25 | 3.0/25.2% | 11.8 ± 1.1 | 0.2/1.9% | |||||
| 12.9 ± 1.6 | 17.10 ± 0.32 | 0.9/7.5% | 15.8 ± 1.1 | 3.8/32.0% | |||||
| 15.2 ± 1.4 | 17.51 ± 0.29 | 3.2/26.6% | 18.2 ± 1.0 | 6.2/51.8% | |||||
| 16.1 ± 1.3 | 17.65 ± 0.27 | 4.1/34.4% | 19.2 ± 0.9 | 7.2/59.9% | |||||
| 9.1 ± 1.5 | 16.04 ± 0.26 | 2.9/24.2% | 11.9 ± 1.1 | 0.1/0.9% | |||||
| 4 | 410 ± 32.3 | 24 ± 2.5 | 22.7 ± 1.6 | 13.79 ± 0.06 | 1.3/5.6% | 34.5 ± 1.1 | 10.5/43.7% | 27.8 ± 1.3 | 3.8/15.7% |
| 25.2 ± 1.6 | 14.28 ± 0.11 | 1.2/4.8% | 37.0 ± 1.0 | 13.0/54.1% | 29.8 ± 1.3 | 5.8/24.0% | |||
| 24.3 ± 1.7 | 14.11 ± 0.17 | 0.3/1.1% | 36.1 ± 1.1 | 12.1/50.4% | 29.1 ± 1.3 | 5.1/21.1% |
This table shows the velocities for the FDHM method in comparison to the reference values for the four prior specified settings (1: 4 mm diameter, no stenosis; 2: 6 mm diameter, no stenosis; 3: 6 mm diameter, stenosis; 4: 6 mm diameter, stenosis, doubled flow rate as in 3). At first, FDHM velocities were calculated using the cross-correlated correction factor of the respective measurement series, representing the iCF. In a next step, FDHM velocities for setting 3 and 4 were calculated by using the correction factor of setting 2 to evaluate feasibility of non-stenotic tubes being used as a calibration for stenotic ones. Finally, the correction factor of setting 3 was used to calculate the FDHM velocities in setting 4 in order to assess calibration viability using stenotic tubes. TD-method was not used due to inferior performance in comparison to FDHM.