Fig 3.

Scatterplots giving vessel-attribute measures in high-activity (light gray) and low-activity (dark gray) subjects. The 3 horizontal lines along each set of scatterplots represent the mean and the mean ± 1 SD. Stars indicate a significant difference (P < .05) between subjects of high and low activity as determined by at least 1 of the statistical measures used. A, Vessel number. B, Average vessel radius (AVR). C, Tortuosity measured by SOAM. D, Tortuosity measured by ICM. H indicates high; L, low; W.H., whole-head circulation; Ant, anterior cerebral circulation; Post, posterior circulation; Left, left middle cerebral circulation; Right, right middle cerebral circulation.