The scan uses high-frequency sound waves to produce images of the parotid gland. One of the major salivary glands, the parotid gland is located just beneath and in front of each ear. Your doctor may advise this scan to find out morphological and structural changes of the parotid gland. The scan helps the doctor to find out whether a lesion is located in the parotid gland or outside. Ultrasound imaging can also differentiate between benign and malignant parotid lesions.