An ultrasound is another test that may be used to aid in the diagnosis of tinnitus. An ultrasound uses reflected high-frequency sound waves and their echoes to create images of structures within the body. An ultrasound can reveal how blood flows within vessels, but is only useful for accessible vessels. It is not helpful for blood vessels within the skull.
A common cause of tinnitus is inner ear hair cell damage. Tiny, delicate hairs in your inner ear move in relation to the pressure of sound waves. This triggers cells to release an electrical signal through a nerve from your ear (auditory nerve) to your brain. Your brain interprets these signals as sound. If the hairs inside your inner ear are bent or broken, they can "leak" random electrical impulses to your brain, causing tinnitus.