In this post, Roxanne Matthews, our Physiotherapist and Certified Athletic Trainer, explains how ultrasound works.
Before one can understand how ultrasound (U/S) works, it is helpful to first understand what it is.
There are two main types of U/S: diagnostic U/S, and therapeutic U/S. Diagnostic U/S looks at the soft tissues in the body and portrays them on a screen. The purpose is to diagnose or rule out something, for example a pregnancy. U/S can also be used to diagnose damage to soft tissues, as is the case with muscle and ligament tears. Although a physiotherapist does not administer diagnostic U/S directly, he or she may suggest a referral for one, from your physician, when there is concern of an underlying soft tissue condition which may be hampering progress of therapy.
The U/S used in the physiotherapy clinic itself, however, is not used for the purposes of diagnoses. Physiotherapy utilizes what is called therapeutic U/S. Treatment sessions are brief, usually lasting about five minutes.
The method behind therapeutic U/S is the sound waves. First, the clinician will spread some cold, blue gel over the area of pain or swelling that he or she is going to treat. Next, a transducer, or “wand” is circled over the area. The end of the “wand” couples with the gel and sends sound waves beneath the surface of the skin where the soft tissue is then stimulated. The sound waves are of very high frequency that cannot be heard by the human ear. Similar to a microwave, U/S works from the inside out. This means that, unlike a hot pack, there should be no heat on the outer surface of your skin, but rather deeper in the tissues. U/S primarily works on tissues at the depth of 2-5cm beneath the skin.
So, what are the benefits of therapeutic U/S? U/S decreases pain by decreasing tissue swelling, which in turn decreases pain. Another benefit of U/S is it decreases scar tissue. Especially for people with repetitive muscle strains, or who are recently post-surgical, U/S assists in breaking down the scar tissue left as a result of trauma. Generally speaking, therapeutic U/S also brings an increase in blood flow to the area, which assists in healing.
Although not the be-all-end-all, therapeutic U/S can play a vital role in rehabilitative therapy.