It means the blood in both the carotid arteries in the neck is flowing forward like it is supposed to flow. That is good news, that is what you want.
However, if you have plaque build-ups along the walls of your arteries, that will mess up the flow. Think of your arteries just like your plumbing in your house. If your pipes get clogged up with gunk, the water doesn't drain down the sink very good. It may drain down the sink slowly or not at all. Then you have to call a plumber to come and use the snake thing to unclog your pipes.
If your arteries get clogged up with plaques and debris, the same thing happens... The blood flow is not as good as it is supposed to be...and you can suffer a stroke or heart attack. So you need to have surgery to clean out the arteries, just like the plumber does with the pipes.
However, if you have plaque build-ups along the walls of your arteries, that will mess up the flow. Think of your arteries just like your plumbing in your house. If your pipes get clogged up with gunk, the water doesn't drain down the sink very good. It may drain down the sink slowly or not at all. Then you have to call a plumber to come and use the snake thing to unclog your pipes.
If your arteries get clogged up with plaques and debris, the same thing happens... The blood flow is not as good as it is supposed to be...and you can suffer a stroke or heart attack. So you need to have surgery to clean out the arteries, just like the plumber does with the pipes.