used extensively to investigate valve defects, arteriosclerosis, and hypertension, particularly in the heart, but also in the abdominal aorta and the portal vein of the liver.
The newest addition to this test is the addition of color. Adding color to the image shows the direction and rate of blood flow more clearly.
Cranial ultrasonography is also performed on adults during brain surgery to help identify the location of brain tumors
The test is widely used because it is noninvasive, uses no x rays, and gives excellent images. It is harmless, painless, and widely available.
The frequencies of sound waves used in ultrasonography are between about one million and 15 million Hz (or one and 15 MHz)