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.
Full Answer. Boys hit their growth spurt at about age 11, and they can grow up to 4 inches a year for two years. Most of a boy's growth takes place between ages 12 and 15. Boys experience other physical changes during puberty, including the development of facial, pubic and underarm hair.