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.
1 Pubic hair, armpit and leg hair usually begin to grow at about age 9 or 10, and reach adult patterns at about 13 to 14 years.  Menarche (the beginning of menstrual periods) typically occurs about 2 years after early breast and pubic hair appear. It may occur as early as age 9, or as late as age 16.