Blood tests can provide physicians with a picture of how a patient's thyroid functions, but an ultrasound can show the gland's physical appearance. Getting a view of the thyroid's anatomy can allow doctors to detect the presence of growths on the gland, called nodules.
Most people with nodules don't even know they have them. They typically don't cause any symptoms unless the nodules become quite large. In those cases, enlarged nodules can affect the patient's ability to swallow or breathe and may cause pain or hoarseness when speaking.
When Is An Ultrasound Requested?
Doctors may request an ultrasound of a patient's thyroid if he or she feels nodules during a physical examination. By palpating the area in the front of the patient's neck between the clavicle, the doctor and detect irregular lumps by touch. Nodules are often harmless, but their presence can indicate additional tests may be needed to determine whether the growths are benign or cancerous. The ultrasound will also show if the size, position, and shape of the thyroid gland is normal.
What More Is Considered?
A study published in 2013 in JAMA Internal Medicine investigated more than 11,000 thyroid ultrasounds to assess the risk of cancer when nodules were present on the thyroid. Nodules were present in all but three percent of the patients diagnosed with thyroid cancer. In patients without cancer, 56 percent had nodules. Despite the prevalence of nodules in the patients who participated in this study, only one percent of these patients were diagnosed with thyroid cancer. Because of the low incidence of cancer in thyroid nodules, doctors look closely at the different characteristics in order to determine the likelihood that the nodules could be malignant.
Ultrasounds can detect features such as size, shape, blood flow, calcification, texture, irregular borders, and if the nodule is solid or fluid-filled. The investigators studied the correlation between three characteristics of thyroid nodules and the risk of cancer: size, solidity, and macrocalcification. They found that solid nodules, greater than 2 cm, with evidence of microcalcification indicated high risk for thyroid cancer. If ultrasound shows nodules with suspicious features, further testing may be necessary. According to the National Thyroid Association, fine needle aspiration biopsy is the preferred method to determine if nodules are cancerous or benign. Ultrasound is often used during these biopsies to assist the doctor in guiding the needle. If nodules are found to be cancerous as a result of biopsy, surgery is required to remove all or part of the thyroid gland.
For more information, check with a facility like Kenai Peninsula Imaging Center, LLC.