How can an ultrasound help figure out what is wrong with my foot?

Soft tissue injury. Ultrasound is used to diagnose soft tissue injuries of the foot and ankle and abnormal masses. The most common use for ultraound in the foot is inflamation of tendons and fluid filled masses such as ganglions.
Foot ultrasound. Ultrasound is a noninvasive test that allows us to look for cysts, masses, and foreign bodies. In addition, there is no radiation. Used in conjunction with radiographs (xrays), ct, and mri, we're able to diagnose most foot ailments.