Also, Doppler can detect abnormal blood flow within the heart, which can indicate a problem with one or more of the heart's four valves. Color Doppler. Color Doppler is an enhanced form of Doppler echocardiography. With color Doppler, different colors are used to designate the direction of blood flow.
Quick Answer. The age at which people grow armpit hair varies, but for boys it is often between the ages of nine and 14. Girls typically begin to grow this hair between eight and 13 years of age. Keep Learning.
Time Frame. Underarm hair can begin to grow as late as age 17, with 96 percent of teens seeing their first growth by the time they're 15, and 95 percent reporting full growth by the time they're 19. Growth occurs slowly, with an average of 3 to 4 years from the time that hair begins to grow until a complete region of growth is reported.