Table 2.
Coefficients of repeatability (CoR) of blood flow velocities and pulsatility index
| Region | V mean (cm/s) | V max (cm/s) | V min (cm/s) | Pulsatility indexa | ||||
|---|---|---|---|---|---|---|---|---|
| Average | CoR (%) | Average | CoR (%) | Average | CoR (%) | Average | CoR (%) | |
| CSO | 0.63 ± 0.19 | 0.46/73 | 0.82 ± 0.19 | 0.46/56 | 0.44 ± 0.16 | 0.47/107 | 0.28 ± 0.07 | 0.14/50 |
| BG | 4.6 ± 0.64 | 1.9/41 | 5.7 ± 0.91 | 2.1/37 | 3.3 ± 0.45 | 2.1/62 | 0.40 ± 0.09 | 0.15/38 |
| M1 | 42 ± 8.0 | 10/24 | 55 ± 9.1 | 15/27 | 32 ± 6.8 | 9.6/30 | 0.56 ± 0.09 | 0.24/43 |
The pulsatility index (PI) is defined in Equation 1, and was derived from the normalised velocity curve over all vessels per region, per individual.
For V mean, V max, V min and PI, the average value ± standard deviation (SD) of all subjects combined is displayed in the left column (determined per individual, and then averaged over all individuals). In the right column, the coefficient of repeatability is displayed as an absolute value (left) and relative to the average of all individuals (right).
BG, basal ganglia; CSO, semioval centre; M1, M1 segment of the middle cerebral artery; V mean, V max, V min, mean, maximum and minimum velocity during the cardiac cycle, determined per vessel.