An ultrasound uses sound waves to develop images, and it is the most sensitive imaging modality available for examining the thyroid gland. A thyroid ultrasound also has the benefit of being non-invasive, it doesn’t use ionizing radiation, and it is less expensive than other imaging techniques such as an MRI and CT scan. But does this mean that everyone with a suspected or confirmed thyroid or autoimmune thyroid condition should consider getting a thyroid ultrasound? I’ll of course answer this and other questions you may have in this blog post.
When I was diagnosed with Graves’ Disease, the endocrinologist [1] I saw didn’t want to do a thyroid ultrasound. After palpating my thyroid gland she didn’t detect any thyroid nodules, and while I appreciated her trying not to recommend any unnecessary tests, I talked her into doing a thyroid ultrasound. Other than some thyroid swelling it came back clean, as I had no thyroid nodules.
Since I requested a thyroid ultrasound even though my endocrinologist didn’t think it was necessary, does this mean that I recommend for everyone with a thyroid or autoimmune thyroid condition to get an ultrasound? I can’t say that I recommend for all of my patients to order a thyroid ultrasound.
The reason I chose to get a thyroid ultrasound is because I don’t think that palpating the thyroid gland is always sufficient to detect thyroid nodules. But even if I had one or more thyroid nodules show up on an ultrasound, would I have done anything differently while taking a natural treatment approach? The honest answer is probably not. And even if I had one or more thyroid nodules, I probably would not have had them biopsied, although this would depend on the characteristics, which I’ll talk about shortly.
When Is A Thyroid Ultrasound Indicated?
According to the American Association of Clinical Endocrinologists (AACE), a thyroid ultrasound is indicated in the following situations (1) [2]:
1. To confirm the presence of a thyroid nodule when the physical examination is equivocal. So if the physical exam is inconclusive for thyroid nodules then a thyroid ultrasound would be indicated.
2. To characterize a thyroid nodule. In other words, to measure the dimensions accurately and to identify internal structure and vascularization.
3. To determine whether a thyroid nodule is benign or malignant. Although an ultrasound can’t always differentiate between a malignant and thyroid nodule, sometimes this can be determined based on the appearance of the nodule.
4. To differentiate between thyroid nodules and other cervical masses. While thyroid nodules are the main focus of a thyroid ultrasound, other masses that can show up include enlarged lymph nodes, a thyroglossal cyst, or a cystic hygroma.
5. To evaluate diffuse changes in the thyroid parenchyma. What is the thyroid parenchyma? The thyroid parenchyma is simply the tissues that comprise the thyroid gland.
6. To detect post-operative residual or recurrent thyroid tumor or metastases to the neck lymph nodes. For example, if someone has thyroid surgery to remove a malignant nodule, then a follow-up thyroid ultrasound would understandably be indicated.
7. To screen high risk patients for a thyroid malignancy. This includes people with a family history of thyroid cancer, or perhaps if someone had radiation exposure to their neck in childhood.
8. To guide diagnostic and therapeutic interventional procedures. For example, if someone needs to get a biopsy of a thyroid nodule then an ultrasound may be used to help guide the placement of the needle within a nodule.
Getting Back To My Situation…
If you read the eight indications above then you’ll notice that the first one mentions that a thyroid ultrasound is indicated “to confirm the presence of a thyroid nodule when the physical examination is equivocal”. When I received my thyroid examination the endocrinologist seemed pretty confident that I didn’t have any thyroid nodules, yet I overruled her and asked for a thyroid ultrasound anyway. And even though I paid out of pocket for the ultrasound, I didn’t have any regrets, as I didn’t want to rely on the palpation skills of the endocrinologist, and I had peace of mind knowing that I didn’t have thyroid nodules.
But what approach would I have taken if the ultrasound revealed thyroid nodules? Earlier I mentioned that if the thyroid ultrasound I received revealed one or more thyroid nodules I probably wouldn’t have done anything different with regards to the natural treatment protocol I followed. I also mentioned how I probably wouldn’t have had a biopsy done. However, one benefit is that I could have done a follow-up ultrasound in the future to monitor the thyroid nodules and make sure that they weren’t getting larger.
Ultimately the decision to request a thyroid ultrasound is up to you. If the endocrinologist you are working with recommends an ultrasound due to one of the indications I listed above, then it probably is a good idea to get one. On the other hand, if after palpating your thyroid gland they are confident that you don’t need a thyroid ultrasound, then it’s fine not to get one. If you’re skeptical like I was and want to get one anyway then of course there is nothing wrong with politely asking the doctor.
You might think that the endocrinologist I was working with was willing to order the thyroid ultrasound because I’m a chiropractor, but I actually didn’t tell her my profession, and I didn’t put it down on the health history form. The reason I didn’t let her know my profession is because I wanted to see how she treated someone who wasn’t a healthcare professional. And I must admit that she was very pleasant to work with, although I only saw her for that single visit. Probably the main reason she was willing to order a thyroid ultrasound is because not only did I ask her politely for it, as I told her that it would give me peace of mind, but she also knew that I was paying out of pocket for it. As a result, from a health insurance perspective there was no concern as to whether the ultrasound was medically necessary.
Hashimoto’s, Graves’ Disease, and Thyroid Ultrasounds
What I’d like to do next is specifically talk about both Hashimoto’s Thyroiditis and Graves’ Disease, and when a thyroid ultrasound should be considered. But wait, shouldn’t the indications I listed above apply to these two autoimmune thyroid conditions? Well yes, these indications do apply, but there are other circumstances when getting a thyroid ultrasound might be a good idea, especially with Hashimoto’s Thyroiditis.
Hashimoto’s Thyroiditis. Although the diagnosis of Hashimoto’s is usually confirmed by an elevated TSH combined with the presence of thyroid peroxidase and/or thyroglobulin antibodies, these antibodies are not always positive in those with Hashimoto’s. When this is the case, getting a thyroid ultrasound can be beneficial, as many times this can confirm the presence of Hashimoto’s Thyroiditis.
Graves’ Disease. Just as is the case with Hashimoto’s, most cases of Graves’ Disease are characterized by elevated thyroid antibodies…specifically TSH receptor antibodies, with the most common type being thyroid stimulating immunoglobulins. While I can’t say that everyone with Graves’ Disease needs to get a thyroid ultrasound, I did want to mention that many doctors recommend for people with hyperthyroidism to get a radioactive iodine uptake test [3]. This involves taking a small dose of radioactive iodine [4], and the justification for this test is that a high uptake reading can confirm Graves’ Disease, and this test can also reveal if someone has thyroid nodules, and give an idea as to whether they are benign or malignant.
The reason why I’m not a big fan of this test is because 1) Graves’ Disease can usually be diagnosed by the presence of elevated thyroid stimulating immunoglobulins, and 2) a thyroid ultrasound can detect the presence of thyroid nodules, and can also give a good idea as to whether the nodules are benign or malignant. And of course the thyroid ultrasound is less invasive than the radioactive iodine uptake test, which is why I’m more in favor of getting an ultrasound.
Understanding Ultrasound Terminology
Remember that ultrasound involves waves, which are formed in the head of the instrument the doctor or radiologist applies to the body, which is also known as a transducer. Echogenicity of the tissue refers to the ability to reflect or transmit ultrasound waves in the context of surrounding tissues (2) [5]. Based on echogenicity, a structure can be characterized as hyperechoic (white on the screen), hypoechoic (gray on the screen) and anechoic (black on the screen) (2) [5]. Cartilage appears hypoechoic, including thyroid cartilage, and on an ultrasound Hashimoto’s Thyroiditis usually presents as diffuse enlargement of the thyroid gland, along with heterogeneous and hypoechoic parenchymal echo pattern. Graves’ Disease actually presents with a similar pattern. Thyroid blood vessels appear black or anechoic.
The thyroid gland is highly vascular, and certain types of ultrasound devices (i.e. Doppler ultrasound) can measure the vascularization of the thyroid gland, and so you might also see this on an ultrasound report. Hypervascularization means that there is an increased blood flow to the area, while hypovascularization refers to a decreased blood flow. Graves’ Disease is usually characterized by very high vascularity on an ultrasound. While you might expect Hashimoto’s and hypothyroidism to be of low vascularity, most cases of hypothyroidism are also characterized by high vascularity. If the ultrasound shows a small atrophied gland then this usually indicates that the person has had extensive damage to the thyroid gland, and this is sometimes referred to as “end stage” Hashimoto’s Thyroiditis.
What’s The Thyroid Ultrasound Pattern for Multinodular Goiter?
Although most of my patients have either Graves’ Disease or Hashimoto’s Thyroiditis, multinodular goiter [6] is the most common cause of diffuse asymmetric enlargement of the thyroid gland (1) [2]. Not surprisingly, in people with multinodular goiter a thyroid ultrasound will reveal a diffusely enlarged thyroid gland, along with multiple nodules. I spoke about the vascularity of Graves’ Disease and Hashimoto’s, and the vascularity can help to differentiate multinodular goiter from a carcinoma, as someone who has thyroid nodules with an increased blood flow has a higher risk of malignancy (3) [7].
More About Thyroid Nodules…
Although I have written separate articles on thyroid nodules [8] and I don’t want to focus too much on this here, I do want to add that it is very common to have thyroid nodules. So while I requested a thyroid ultrasound from my endocrinologist because I was concerned about having thyroid nodules, what I didn’t realize at the time was that more than 50% of people will have thyroid nodules on an ultrasound (4) [9]. The good news is that most of these thyroid nodules are benign. And so please don’t get stressed out if you have one or more thyroid nodules show up on an ultrasound.
While a thyroid biopsy [10] is used to confirm whether a suspicious thyroid nodule is benign or malignant, one of the indications I listed earlier mentioned how a thyroid ultrasound can give an idea as to whether a thyroid nodule is benign or malignant. And the way it does this is by looking at the following characteristics:
- The size of the nodule
- The presence of microcalcifications
- Irregular margins
- Solid composition
- Marked hypoechogenicity
So while a biopsy might be indicated to confirm whether a “suspicious” thyroid nodule is benign or malignant, most people who have one or more thyroid nodules don’t need to get a biopsy. Plus, keep in mind that biopsies aren’t perfect, as they don’t always confirm or rule out a malignancy. One more thing I want to add is that the presence of multiple nodules doesn’t increase the likelihood of a malignancy. In other words, if someone has five thyroid nodules, each nodule will have an equal risk of being benign or malignant when compared to someone who has one or two nodules.
In summary, an ultrasound is the most sensitive imaging modality used to examine the thyroid gland. Some of the indications for a thyroid ultrasound include to confirm the presence of a thyroid nodule when the physical exam is inconclusive, to characterize a thyroid nodule, and to differentiate between thyroid nodules and other cervical masses. Many people with Graves’ Disease are told to get a radioactive iodine uptake scan when many times a thyroid ultrasound (along with testing the thyroid stimulating immunoglobulins) would be sufficient. And sometimes an ultrasound can be used to diagnose Hashimoto’s Thyroiditis when the person has negative thyroid antibodies.