There are several options for imaging the thyroid in Graves’ disease.
- Iodine 123 scan
- Technetium 99 pertechnetate scan
In-office ultrasound is perhaps the easiest way to image the thyroid in Graves’ disease. Typically, what is seen is an overabundance of blood supply to the entire thyroid. The thyroid that is suffering from Graves’ disease has an increased blood supply. This is very evident during surgery as well. The high stimulation of the thyroid gland from the antibodies produces neovascularization, that is the thyroid has an abundant numbers of blood vessels and those blood vessels are dilated and high flow. This can easily be seen on a doppler imaging during a thyroid ultrasound examination.
Thyroid uptake scan -not always necessary!
Another option for evaluating the thyroid is the thyroid uptake scan, which is usually done at the hospital radiology department. In Graves’ disease, the entire gland is going to show an increased uptake of contrast material. This scan can be useful in distinguishing Graves’ disease from multinodular toxic goiter and toxic adenoma. Occasionally, hyperthyroidism is caused by thyroiditis in which case the uptake scan is going to show very little uptake. Perhaps the luckiest patients with hyperthyroidism are those that have a toxic adenoma. This is a single isolated area of the thyroid that is overproducing thyroid hormone, and this can be removed with a thyroid lobectomy. This not only cures the hyperthyroidism, but the remaining half functions normally. The result is that most patients would not require thyroid hormone supplementation after surgery. In multinodular toxic goiters, the entire thyroid would need to be removed in order to gain adequate control of the disease because the thyroid nodules tend to be on both sides of the thyroid. In some cases of Graves’ disease, particularly those with orbitopathy, imaging studies are not necessary as the diagnosis can be established clinically through either lab tests or through ultrasound. The need for thyroid uptake scans has diminished as the quality and the availability of ultrasound in the office setting has improved.