Patients’ vertebral artery parameters at different levels of the cervical spine.
| Level | C3 | C4 | C5 | C6 | C7 | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall bilateral | Right | Left | P-value | Overall bilateral | Right | Left | P-value | Overall bilateral | Right | Left | P-value | Overall bilateral | Right | Left | P-value | Overall bilateral | Right | Left | P-value | ||
| TDVA (mm) | 3.58±0.63 | 3.42±0.82 | 3.75±0.69 | 0.010 | 3.65±0.65 | 3.45±0.95 | 3.85±0.74 | 0.016 | 3.70±0.67 | 3.57±0.90 | 3.82±0.75 | 0.089 | 3.62±0.61 | 3.54±0.89 | 3.69±0.70 | 0.288 | 3.83±0.76 | 3.73±1.1 | 3.93±0.76 | 0.262 | |
| LDVA (mm) | 3.30±±0.62 | 3.15±0.88 | 3.46±0.63 | 0.020 | 3.38±0.56 | 3.22±0.90 | 3.54±0.56 | 0.029 | 3.59±0.63 | 3.51±0.92 | 3.68±0.67 | 0.226 | 3.66±0.70 | 3.57±0.97 | 3.74±0.76 | 0.236 | 3.75±0.76 | 3.59±0.99 | 3.89±0.82 | 0.039 | |
| FZ (mm) | 0.98±0.25 | 1.01±0.34 | 0.95±0.32 | 0.397 | 0.95±0.27 | 0.93±0.31 | 0.96±0.34 | 0.659 | 1.16±0.63 | 1.04±0.41 | 1.27±1.2 | 0.218 | 0.99±0.41 | 0.94±0.29 | 1.05±0.71 | 0.313 | N/A | N/A | N/A | N/A | |
| TDVA/ TTF (%) | 58.78±8.36 | 56.84 ±11.53 | 60.72 ±8.54 | 0.021 | 61.66±7.98 | 59.99±12.55 | 63.32±8.59 | 0.120 | 64.29±11.35 | 63.68±17.01 | 64.89±12.59 | 0.671 | 63.09±13.15 | 61.86 ±17.48 | 64.32±19.54 | 0.514 | N/A | N/A | N/A | N/A | |
SD - standard deviation; TDVA - transverse diameter of vertebral artery; LDVA - longitudinal diameter of vertebral artery; FZ - Free zone (see text for definition); N/A - not applicable