What is a thyroid ultrasound?
Thyroid ultrasound is a procedure that allows the physician to visualize the thyroid gland using high frequency inaudible sound waves as he or she is examining the neck. It produces "live" images of the thyroid and surrounding structures such as lymph nodes and parathyroid glands. Because of its sensitivity, ultrasound can detect nodules and cysts as small as 2-3 millimeters in size that are too small to feel on physical examination. Ultrasound is able to measure the size of thyroid nodules very accurately in order to determine if there is a change in size. Ultrasound is also used to detect recurrent or metastatic thyroid cancer in patients who have undergone surgery for this disease. Ultrasound is now used for performing most thyroid biopsies to assure proper placement of the needle and to decrease the risk of an inadequate specimen being obtained.
How is ultrasound performed?
Ultrasound is done while the patient is lying down with the head extended back to expose the neck. A transducer is placed on the neck and a jelly is used to make contact with the skin. The physician moves the transducer over the neck watching the picture on a computer screen while examining the neck.
What are the risks associated with ultrasound?
The procedure is painless, quick, less expensive than other forms of imaging, and, most importantly, does not involve radiation. Therefore it can be performed during pregnancy and as many times as necessary.
What can I expect from a thyroid ultrasound?
Ultrasound will provide your physician with much more detailed anatomy of the neck than is possible by physical examination alone. Although certain ultrasound characteristics will tell if a nodule is suspicious for cancer or benign, a FNA biopsy is required to confirm the diagnosis. An exception is a nodule under one centimeter, which can simply be observed to determine if it grows.
Why would I need a FNA biopsy?
A FNA biopsy is indicated when there is a lump or nodule in the thyroid gland. A nodule in the thyroid may result from several different causes including inflammation, cyst formation, excessive growth of normal tissue, a benign tumor, or cancer. Treatment depends upon the exact nature of the nodule. Fine needle aspiration is a simple biopsy procedure that can provide that information. It is the best way to assess a thyroid nodule because it is reliable, fast, safe and causes only minimal discomfort.
How is FNA performed?
After cleansing the skin overlying the nodule, a very small needle (smaller than a needle used to draw blood) is passed through the skin into the mass. Most biopsies are done under ultrasound guidance to assure the proper placement of the needle and to decrease the risk of an inadequate specimen being obtained. During the procedure, which takes only a few minutes, the patient may briefly feel discomfort. After the biopsy, the patient will be able to drive, return to work, or perform any other normal activity. The biopsy does not affect medication schedules; nor does medication affect the biopsy results. The tissue is stained and sent to a cytopathologist to be examined. Results usually take 72 hours.
What risks are associated with FNA biopsy?
Fine needle aspiration biopsy poses no significant risk. Some patients have expressed concern that passage of a needle through a tumor might cause it to spread. Physicians at several universities have examined this concern and such tumor spread has never been reported.
What can I expect from the biopsy?
About 80 percent of the time, biopsy results can tell the exact nature of a nodule. However, about 20 percent of the time, the biopsy can tell something about the nodule but may not give all the information that is needed for a definite diagnosis and other tests may be required.
What treatment is available for thyroid cysts?
Thyroid cysts account for approximately 10% of all thyroid nodules. Draining the cysts is usually a temporary treatment because the cysts rapidly refill with fluid. Permanent treatment required removing half the thyroid gland. Recently it was discovered that injecting alcohol (100% ethanol) after removing the fluid would eliminate the cyst. This treatment (percutaneous ethanol injection) has now replaced surgery as the treatment of choice for cystic nodules in many thyroid clinics.
What follow-up care is available for patients with Thyroid Cancer?
Although thyroid cancer is generally considered one of the most curable types of cancer, it is known to recur many years later. At least 20% of patients will have a recurrence of their thyroid cancer during their lifetime. Surveillance of patients to detect early recurrence and provide early treatment is extremely important. Routine whole body scans using radioiodine are no longer recommended for most patients because of their poor sensitivity in detecting recurrent cancer, expense, and discomfort caused by stopping thyroid hormone before the scan. A more useful method of monitoring for early recurrent cancer is measurement of the blood thyroglobulin level and a careful ultrasound examination of the lymph nodes of the neck by a physician on an annual basis.
What is a Radioiodine Thyroid Uptake Test?
This test is used to measure how much iodine is taken up by the thyroid gland. Hypothyroid patients usually take up too little iodine and hyperthyroid patients take up too much iodine. The test is performed by giving a tracer dose of radioiodine by mouth. The iodine is concentrated in the thyroid gland or excreted in the urine over the next few hours. When the patient returns, the amount of iodine that went to the thyroid can be measured by a detector placed over the neck. This is called the "thyroid uptake". Of course patients who are taking thyroid medication will not take up iodine in their thyroid gland because their own thyroid gland is turned off and not functioning. At other times the gland will concentrate iodine normally but will be unable to convert iodine into thyroid hormone; therefore, interpretation of the thyroid uptake is done in conjunction with blood tests. A thyroid uptake is done prior to treatment with radioiodine in order to determine how much iodine is needed for treatment.
What is radioiodine treatment?
Radioiodine-131 has been used in the treatment of thyroid disease for over fifty years. Since its first use before World War II, it has become the treatment of choice for patients with hyperthyroidism. Treatment of patients with this condition has been made more comfortable, safer, and less expensive by using radioiodine-131 instead of surgery or long-term antithyroid medications. Radioiodine-131 is also used in treating patients with thyroid cancer after surgery. This has decreased the recurrence of cancer in such patients.
How is radioiodine treatment administered?
Radioiodine is given as a single capsule by mouth. After it is swallowed, it goes into the blood from which it is concentrated almost exclusively by the thyroid gland. Since it does not remain in other tissues, the radioiodine not taken up by the thyroid gland is rapidly eliminated in the urine.
What are the risks of radioiodine treatment?
In the past fifty years, over one million people with hyperthyroidism have been treated with radioiodine-131, and, to date, no known side effects have occurred. The frequency of thyroid cancer, leukemia or other types of cancer is not increased after the administration of radioiodine-131. Infertility is not increased by treatment, nor has there been an increase in birth defects in children of women who have been treated. Few medications or treatments used in medicine have a better safety record than radioiodine-131.
What can I expect from radioiodine treatment?
Patients are cautioned not to expect immediate results because virtually nothing happens the first month after treatment. Symptoms of hyperthyroidism and blood tests begin to improve the second month, and the hyperthyroidism should be cured by the end of the third month. Rarely (less than 5%) is a second treatment is needed. Once a patient is cured, he or she needs to be monitored for hypothyroidism. Over 50% of patients become hypothyroid the first year and most of the others will become hypothyroid in the future. It is important that patients be followed closely the first year and have a thyroid blood test annually after that. Once hypothyroidism occurs, patients take a daily thyroid supplement for the rest of their lives.