Comparison of image quality before and after application of an echo-enhancing agent
| Artery | Without Echo Enhancement | With Echo Enhancement | P Value | ||||
|---|---|---|---|---|---|---|---|
| Grade 0 | Grade 1 | Grade 2 | Grade 0 | Grade 1 | Grade 2 | ||
| P1 PCA | 11 | 19 | 16 | 4 | 3 | 39 | <.001 |
| V4 VA | 13 | 25 | 8 | 8 | 6 | 32 | <.001 |
| BA | 6 | 13 | 4 | 3 | 5 | 15 | <.005 |
| Visibility of VA confluens | Not visible, n = 9 | Unilateral, n = 8 | Bilateral, n = 6 | Not visible, n = 2 | Unilateral, n = 10 | Bilateral, n = 11 | <.05 |
| Visibility of BA head | Not visible, n = 10 | Visible, n = 13 | Not visible, n = 2 | Visible, n = 21 | <.01 | ||
Note.—Data are number of vessels. See Methods for explanation of grades. V4 VA indicates V4 segment of the vertebral artery; BA, basilar artery.