Comparison of image quality before and after application of an echo-enhancing agent

ArteryWithout Echo EnhancementWith Echo EnhancementP Value
Grade 0Grade 1Grade 2Grade 0Grade 1Grade 2
P1 PCA1119164339<.001
V4 VA132588632<.001
BA61343515<.005
Visibility of VA confluensNot visible, n = 9Unilateral, n = 8Bilateral, n = 6Not visible, n = 2Unilateral, n = 10Bilateral, n = 11<.05
Visibility of BA headNot visible, n = 10Visible, n = 13Not visible, n = 2Visible, 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.