A thyroid ultrasound is a non-invasive imaging test that uses high-frequency sound waves to create real-time pictures of the thyroid gland, located in the front of the neck. This diagnostic procedure evaluates the structure of the gland and surrounding tissues. Its purpose is to check for physical abnormalities such as changes in size, the presence of nodules, or cysts. It can also be used to monitor known growths, classify them, and guide instruments for a fine-needle aspiration biopsy if necessary.
Preparing for the Ultrasound
Preparing for a thyroid ultrasound is generally simple, requiring no special diet or fasting beforehand. Patients can typically eat, drink, and take all their usual medications. Specific instructions from the imaging facility should always be followed, as a few may request a period of fasting.
The most important preparation involves clothing and accessories to ensure clear access to the neck area. Wear loose, comfortable clothing, such as a shirt with an open or wide collar, allowing the technician to easily reach the entire neck. Any jewelry around the neck, such as necklaces or large earrings, should be removed before the appointment to prevent interference.
Step-by-Step Guide to the Scan
The first step involves patient positioning to ensure the technician has the best view of the thyroid gland. You will be asked to lie flat on your back on a padded examination table. A small pillow or support is often placed under your shoulders or neck to gently extend the neck backward, which helps position the thyroid for scanning.
The technologist will then apply a water-based gel directly onto the skin of your neck, covering the area over the thyroid gland. This gel is clear, non-toxic, and acts as a coupling agent, eliminating any air pockets between the skin and the scanning device. While the gel is sometimes warmed, it may feel cool upon initial contact.
The technician uses a handheld device called a transducer, pressing it gently but firmly against the gel-covered skin and moving it across the neck. The transducer emits high-frequency sound waves, which travel into the body and bounce off the thyroid tissue. As the echoes return, a computer processes them instantly to create a real-time, two-dimensional image on a monitor.
The technician systematically scans the thyroid, including both lobes and the connecting isthmus, taking images in transverse and longitudinal planes. Color Doppler technology may be applied to assess blood flow within the gland or detected nodules, aiding in characterization. You may be asked to hold still, briefly hold your breath, or swallow to help capture clear images and measurements. The entire scanning process typically lasts about 20 to 30 minutes.
What Happens After the Examination
Once the required images are captured, the technologist will wipe the gel from your neck. The water-based gel does not stain clothing, and any residue is easily cleaned. Since the procedure is non-invasive and uses no radiation, there are no side effects, and you can return to your normal daily activities immediately.
The technologist is specifically trained to acquire the images but is not authorized to provide a diagnosis or discuss the findings with you. The pictures and any recorded video clips are sent to a board-certified radiologist or a specialist who is trained to interpret the complex images. This specialist will analyze the characteristics of the thyroid gland, noting the size, shape, and the internal structure of any nodules or cysts.
The radiologist compiles a detailed report of their findings, which is sent to the physician who originally ordered the test. The ordering physician typically receives this report within a few days. Your doctor will then contact you to discuss the results, which may indicate a goiter, inflammation, benign cysts, or suggest the need for further testing, such as a biopsy for suspicious growths.