Comparison of intraobserver and interobserver variability for CT perfusion values separately for the symptomatic and asymptomatic hemisphere
| Variability | SDDrel (%) | |||||
|---|---|---|---|---|---|---|
| Symptomatic Side | Asymptomatic Side | |||||
| CBV | CBF | MTT | CBV | CBF | MTT | |
| Intraobserver | ||||||
| ACA | 22 | 22 | 5 | 20 | 21 | 5 |
| MCA | 18 | 20 | 4 | 19 | 22 | 5 |
| Basal ganglia | 18 | 20 | 4 | 19 | 20 | 7* |
| PCA | 20 | 22 | 8 | 20 | 20 | 4 |
| Interobserver | ||||||
| ACA | 15 | 19 | 9 | 20* | 22 | 8 |
| MCA | 12 | 17 | 6 | 14 | 19 | 8 |
| Basal ganglia | 15 | 15 | 8 | 21 | 18 | 9 |
| PCA | 22 | 16 | 11 | 14 | 13 | 6 |
Note:—SDDrel indicates SDs of relative differences; CBV, cerebral blood volume; CBF, cerebral blood flow; MTT, mean transit time; ACA, anterior cerebral artery; MCA, middle cerebral artery; PCA, posterior cerebral artery.
* Difference between asymptomatic and symptomatic hemisphere significantly different (P < .05).