To the left is an ultrasound of a normal liver. You can clearly see the gallbladder. To the right is an ultrasound of a liver with a tumor.
Ultrasounds can differentiate between cysts and tumors based on the echoes the two give off. To the left is an ultrasound of breast cancer, and to the right is an ultrasound of a cyst within the breast.
Ultrasounds are also used to monitor the progress of babies. To the left is an ultrasound of a male baby. To the right is a 3-d ultrasound of a baby. How cute...