Thyroid Artery Embolization

Thyroid artery embolization (abbreviated as TAE) is a minimally invasive treatment method based on the principle of blocking the blood flow to the thyroid gland at specific points. The aim is to reduce or diminish the overgrown or hyperfunctioning regions of the thyroid by decreasing the blood supply to these areas. Being much less invasive compared to conventional surgical interventions creates a significant advantage for many patients. It offers an alternative for patients with large nodular goiter or Graves’ disease, particularly for those with a high surgical risk or who do not wish to undergo surgery. Through embolization, it is possible to preserve the healthy parts of the thyroid while reducing or deactivating the problematic areas. This procedure is performed by injecting very small particles into the blood vessels and is usually carried out in specialized imaging environments such as an angiography laboratory. Thus, the control remains entirely in the physician’s hands and the risk of damaging non‑target tissues is kept to a minimum.

What Is Thyroid Artery Embolization and How Does It Work?

Thyroid artery embolization is a method used in interventional radiology that is based on occluding certain arteries supplying the thyroid gland. This can be compared to an irrigation system: just as if you were to shut off the water supply to a part of the garden where unwanted weeds are growing so that they dry up and shrink, in TAE the blood flow to the targeted thyroid tissue is cut off, rendering the overactive or nodular regions inactive. In this way, excessive hormone production and the overgrowth of the thyroid gland are prevented.

During the procedure, a thin catheter is first inserted into an artery via the groin (femoral) or sometimes the wrist (radial). Using a real-time imaging method called fluoroscopy, the catheter is directed into the main vessels supplying the thyroid. Then, small particles that are compatible with body tissues—or sometimes occlusive liquids—referred to as embolic agents, are injected. These tiny particles lodge in the target vessels, permanently or for a long time, blocking them. As a result of the blockage, the blood flow to that region is reduced or completely cut off, causing the tissues in that area to shrink, their function to decrease, or to cease entirely.

The greatest strength of this procedure is that it can target only the problematic parts of the thyroid without affecting the entire gland. When performed with the appropriate technique, the blood circulation to the healthy thyroid tissue is preserved, offering a more conservative approach compared to removing the entire gland surgically. Another important advantage is the relatively short recovery time after the procedure. Patients are usually discharged on the same day or the following day and can quickly return to their daily activities. However, as with any medical procedure, TAE requires special planning and expertise. With proper patient selection, detailed knowledge of vascular anatomy, and a careful procedural process, the risk of complications can be kept low.

Who Are the Ideal Candidates for Thyroid Artery Embolization?

As with every treatment method, TAE is considered more suitable for certain patient profiles. Traditionally, patients with large and multinodular goiter or conditions manifested by hyperthyroidism such as Graves’ disease—who wish to avoid the risks of surgery or have comorbidities that preclude surgery—are prioritized. Individuals with systemic conditions such as heart or lung disease, for whom general anesthesia poses a risk, can benefit greatly from TAE. Additionally, TAE may be preferred in cases of recurrent goiter, where a patient who has previously undergone thyroid surgery develops a “recurrence.” Due to tissue adhesions and anatomical changes, a second or third surgery may become riskier.

Some patients may also prefer to avoid surgery for personal reasons. For example, those concerned about neck scars or unwilling to have the entire thyroid removed may find TAE a good option. However, in cases where the nodules are very small or hormonal imbalances are at an advanced stage, the decision to perform the procedure should be made based on the joint evaluation of an endocrinology specialist and an interventional radiology team.

Furthermore, TAE may be considered in cases of “hyperthyroidism that cannot be controlled with medication.” Especially when the desired results cannot be achieved with antithyroid drugs and radioactive iodine (RAI) treatment is deemed unsuitable for various reasons, TAE can offer a viable option. Of course, factors such as the patient’s age, general health status, the size of the goiter or nodule, and hormonal test results must be taken into account. The physicians aim to determine which method will achieve the highest success with the lowest complication rate. When appropriately selected, TAE is an innovative method that can yield successful outcomes and rapidly improve the patient’s quality of life.

Which Conditions Can Be Treated with Thyroid Artery Embolization?

The most common indication for TAE is Graves’ disease. Graves’ disease is an autoimmune disorder in which the immune system mistakenly over-stimulates the thyroid, leading to excessive hormone production. In this condition, TAE helps to reduce hormone production by selectively restricting the blood flow to the overactive thyroid tissue. In addition, cases referred to as “toxic multinodular goiter,” where multiple nodules secrete excessive hormones and the thyroid may enlarge significantly, are also within the treatment spectrum of TAE.

Recurrent goiters that regrow after surgical intervention can also be managed with TAE. In such cases, opting for a minimally invasive procedure instead of undergoing another surgery can offer a comfortable and safe alternative for patients. Surgery may not always be straightforward or without issues in patients who have previously undergone neck surgery or radiotherapy; TAE becomes an important option to overcome these challenges.

In some rare cases, benign thyroid nodules (for example, large cystic nodules) causing cosmetic concerns or compressive symptoms can be reduced in volume by blocking their blood supply with TAE. Consequently, symptoms that diminish the patient’s quality of life, such as visible swelling in the neck or shortness of breath, can be alleviated. Additionally, although very rarely, in cases where there is excessive vascularity or bleeding risk due to thyroid cancer, embolization can be used for symptom control or to reduce tumor vascularity prior to surgery.

Despite these wide applications, TAE is not mandatory in every case. Endocrinologists, interventional radiologists, and, if necessary, surgeons decide together which method will yield the best result. Since the success of the treatment is closely related to patient‑specific factors, the presence of a condition that can be treated with TAE always requires a comprehensive evaluation.

How Effective Is Thyroid Artery Embolization in the Treatment of Hyperthyroidism?

Hyperthyroidism is a condition in which there is an excessive amount of thyroid hormones in the blood. This condition can cause a wide range of symptoms from heart palpitations and weight loss to hand tremors and hot flashes. TAE is a method that has shown successful results, particularly in cases of hyperthyroidism caused by Graves’ disease. Studies have shown that after the procedure, many patients experience a normalization or significant reduction in thyroid hormone levels, along with a decrease in the excessive vascularity and hyperactivity of the thyroid. It is common to find data showing that thyroid hormone levels normalize after a certain period and that the patient’s clinical symptoms improve.

The effect of the procedure may exhibit some fluctuations during the first weeks, which are related to partial tissue damage in the thyroid and the subsequent self-regulation process. In the first few days, there may even be a temporary increase in thyroid hormone levels due to hormone release from damaged cells after the occlusion. However, this fluctuation is transient in most cases. Within approximately one to two months, hormone levels stabilize and become more consistent.

One of the advantages of TAE is its ability to selectively block the blood flow to the hyperfunctioning area while preserving the relatively healthy tissue. This means that, compared to surgery, there is a lower risk of causing hypothyroidism, where the thyroid no longer produces enough hormone. Nevertheless, it is not entirely without risk; in some patients, hormonal imbalances may persist or recur over the long term. When performed on appropriate cases and using the correct technique, TAE stands out as a realistic and effective option for controlling hyperthyroidism.

What Are the Benefits of Choosing Thyroid Artery Embolization Over Surgery?

Surgical intervention has long been used effectively in the treatment of thyroid diseases. However, for patients with a large goiter or those for whom surgery is considered high-risk due to other health problems, TAE can be a very attractive option. The primary benefit is that the procedure does not require general anesthesia. It is typically performed under local anesthesia and mild sedation, which is a major advantage for patients who are too high-risk for general anesthesia.

Secondly, issues such as incisions, sutures, and scarring associated with surgery are absent in TAE. The procedure is performed via a small catheter inserted through the groin or wrist. This allows patients who are not concerned about surgical scars and who prefer a shorter hospital stay to return to their daily lives more quickly. Some patients are also apprehensive about surgical complications such as damage to the nerves in the neck (for example, the recurrent laryngeal nerve) or injury to the parathyroid glands. TAE significantly reduces these types of complication risks.

Thirdly, after complete surgical removal of the thyroid gland, patients may need to use thyroid hormone replacement therapy for life. In contrast, TAE aims to reduce the vascularity of the overactive parts of the thyroid, allowing the healthy tissue to be preserved. This means that the risk of developing hypothyroidism after the procedure is lower compared to surgery. Although it is not possible to guarantee that no medications will be needed, statistically the need for medication does not arise as frequently as with surgery.

Lastly, an important advantage of TAE is that it can be repeated if necessary. The procedure can be performed again at certain intervals if required. Surgery, on the other hand, generally aims to remove the thyroid tissue completely in a single operation, and repeat surgeries become much more complex compared to the first one. All these advantages explain why TAE may be preferred over surgery in certain cases.

What Are the Risks and Complications Associated with Thyroid Artery Embolization?

As with every medical procedure, TAE carries some risks and side effects. However, serious complications are relatively rare. The most frequently reported complaint is mild to moderate pain in the neck area. This pain is generally considered part of the post‑embolization syndrome and is usually short‑lived. It can often be managed with painkillers. Additionally, transient complaints such as mild fever, fatigue, or a sensation of discomfort in the throat may also be observed. These symptoms are a natural result of the inflammatory process that occurs in the tissue after the occlusion.

Rarely, sudden hormone release situations such as “thyroid storm” or “thyroid crisis” may occur. This is a severe reaction by the body to an excessive load of thyroid hormones and requires emergency treatment. However, with appropriate patient selection and pre‑procedure preparation, this risk is kept very low. For example, it is generally recommended to lower the hormone levels to a certain range before the procedure or control them with antithyroid medications.

Vascular complications (such as damage to the vessel, bleeding, or hematoma in the groin area) are also potential risks during the procedure. Although the likelihood of the catheter causing weakening or perforation of the vessel is very low, an experienced interventional radiologist minimizes these risks as much as possible. Similarly, there is a risk of non‑target embolization, where particles may inadvertently migrate to surrounding tissues, potentially causing unwanted damage. However, with today’s advanced imaging techniques and precise catheter systems, such complications have been significantly reduced.

TAE is generally a well‑tolerated and relatively safe procedure. Nevertheless, factors such as the patient’s overall condition, additional comorbidities, and the experience of the team performing the procedure can affect the complication rates. It is important that the risks are thoroughly evaluated and that the patient is provided with detailed information. Physicians will recommend this method or direct the patient to alternative methods based on a careful assessment of the benefit‑risk balance.

How Long Is the Recovery Process After Thyroid Artery Embolization?

The recovery process after TAE is generally more comfortable and quicker compared to surgery. The procedure is usually performed under local anesthesia and the patient may be discharged on the same day or the following day. During the recovery period, there might be mild pain or bruising around the catheter insertion site in the groin or wrist, but this usually does not cause significant discomfort and resolves within a few days.

Most patients recover enough to resume their daily routines within approximately one week. Any possible neck pain or tenderness can also be alleviated with mild painkillers. Some patients may experience a mild fever, fatigue, or a sensation of discomfort in the throat for a few days. These symptoms, known as “post‑embolization syndrome,” are a natural response of the body to the procedure and usually resolve with rest and increased fluid intake.

In the long term, thyroid hormone levels gradually normalize. In some patients, there may be a transient increase in hormone release from the embolized tissues during the first few days, causing temporary fluctuations. However, in the majority of patients, hormone levels stabilize after a few weeks to one or two months. During this period, regular blood tests are performed by an endocrinology specialist to monitor thyroid hormone levels as needed. The final effects of TAE are often more clearly understood around six months after the procedure. A reduction in goiter size or nodule volume, alleviation of symptoms, and normalization of hormone levels indicate the success of the procedure. Long‑term follow‑up is important to evaluate the durability of TAE’s effects and the potential need for repeat treatments.

What Are the Success Rates of Thyroid Artery Embolization for Graves’ Disease?

Graves’ disease is a complex condition in which the immune system overstimulates the thyroid, leading to excessive hormone production. In these patients, TAE selectively reduces the blood flow to the overactive areas of the thyroid. This approach can be a promising solution, especially for patients who cannot undergo surgery or are reluctant to do so. Various clinical studies have reported that after TAE, a significant portion of Graves’ patients experience normalization or a marked reduction in hormone levels. Some studies have reported long‑term or permanent improvement in a large percentage of patients (ranging between 70–90%).

However, these success rates may not be uniform in every case. Factors such as the status of the patient’s immune system, the volume of the thyroid gland, and the presence of nodules can affect the outcomes. Moreover, since the underlying autoimmune process in Graves’ disease may persist, there is a possibility of recurrence over the long term. Therefore, patients are monitored with regular follow‑up appointments and blood tests. In some patients, even after TAE, there may be a need for a small dose of antithyroid medication or additional treatments.

What is important is that the gains achieved from the procedure—such as a reduction in hormone levels and control of symptoms like palpitations and sweating—contribute to an improved quality of life. TAE can often spare patients from undergoing more invasive procedures such as surgery. Additionally, in the pre‑surgical period, TAE may be chosen as a “bridge therapy” to quickly control thyroid hormone levels. The high success rates observed make TAE a serious alternative in Graves’ disease; however, as with every treatment option, individual factors must be taken into account.

How Does Thyroid Artery Embolization Compare to Radioactive Iodine Treatment?

One of the most commonly used methods in the treatment of hyperthyroidism is radioactive iodine (RAI) therapy. RAI works by gradually destroying the hyperfunctioning thyroid tissue through the uptake of a radioactive substance by the thyroid cells. Although it is a highly effective treatment, some patients may eventually develop thyroid failure (hypothyroidism), necessitating lifelong thyroid hormone replacement therapy. In addition, certain radiation safety precautions must be followed during and after RAI treatment.

TAE offers a more targeted approach compared to RAI. In TAE, specific vessels are occluded to block the blood flow to the affected area. This leads to a reduction or inactivation of the overactive nodules or tissue. Some patients may find the process following RAI to be lengthy or have concerns about radiation exposure. In TAE, radiation is used only for fluoroscopic imaging during angiography; it is the embolic materials, not radiation, that are used to destroy the cells.

Another difference is that the incidence of hypothyroidism after TAE is generally lower compared to RAI, because TAE can target only the problematic areas rather than the entire thyroid tissue. RAI is usually absorbed by the whole thyroid gland, and the resulting tissue destruction may spread uncontrollably. However, for some cases RAI remains the gold standard; for example, in the treatment of thyroid cancer, RAI is often used in combination with surgery. Therefore, when comparing TAE and RAI, factors such as the patient’s clinical picture, the size of the goiter, cancer risk, and other factors should be considered. Both methods have their own pros and cons, and the final decision should be based on the patient’s specific condition.

What Are the Long-Term Effects of Thyroid Artery Embolization on Thyroid Function?

TAE aims to reduce the size and function of the thyroid tissue in certain areas by cutting off their blood supply. The long‑term effects are generally reflected in the stabilization of the patient’s hormone levels and structural shrinkage of the thyroid tissue. In many patients suffering from hyperthyroidism, thyroid function tests such as T3, T4, and TSH tend to normalize within a few months after the procedure. However, since every tissue reacts differently, in some patients the recovery process may take a bit longer.

The degree to which the thyroid tissue shrinks and the extent of involvement of specific regions depend on factors such as the type of embolic agent used, the volume of the injection, and the variability of the vascular anatomy. In autoimmune conditions like Graves’ disease, because the stimulatory effect of the immune system does not completely cease, there is a low but present possibility of recurrence over the long term. Therefore, regular follow‑up and periodic blood tests remain important.

In the long run, compared to surgery, TAE has the advantage of preserving the remaining healthy thyroid tissue. This means that the risk of developing hypothyroidism is lower. Of course, some patients may still require partial hormone replacement therapy because if a portion of the thyroid tissue loses its function, the normal hormonal balance may not be fully restored. Additionally, after the procedure, the necrotic thyroid tissue heals over time with fibrosis, resulting in the formation of a firmer tissue. Although the fibrotic tissue is unlikely to cause significant additional symptoms in the long term, some patients might experience a mild stiffness in the neck.

Overall, the long‑term results achieved with TAE are quite satisfactory when proper patient selection and regular follow‑up are maintained. It can be effective both in controlling thyroid hormone levels and in achieving long‑term or permanent reduction in goiter size. For these reasons, the use and popularity of TAE have been steadily increasing in recent years.

Can Thyroid Artery Embolization Be Used for a Large Multinodular Goiter?

A large multinodular goiter is characterized by the presence of multiple nodules in various parts of the thyroid gland. These nodules may sometimes be “silent,” causing symptoms only due to their size, or they may trigger excessive hormone production, referred to as “toxic.” The conventional approach is surgical removal of these nodules or complete excision of the gland. However, in cases where surgery is not preferred or possible for various reasons, TAE can become an important alternative.

The treatment of a large multinodular goiter can also be supported by TAE during the preoperative period. In some cases, when the goiter has reached enormous dimensions and its vessels are highly vascularized, there is a significant risk of severe bleeding during surgery. To reduce this risk, TAE may be performed before the operation to partially occlude the thyroid vessels and reduce blood flow. This helps decrease blood loss during surgery.

In addition, TAE can be used on its own to reduce the volume of the goiter. The vessels supplying the multiple nodules are identified and the appropriate areas are embolized. After the procedure, a reduction in the volume of the nodules and alleviation of compressive symptoms may be observed. Patients suffering from difficulties in swallowing, breathing difficulties, or cosmetically concerning neck swelling may experience relief after TAE. Although complete disappearance of the nodules is not guaranteed, a significant reduction is often achievable.

On the other hand, if there is an irregular arrangement of many nodules or a complex vascular structure, the feasibility of TAE may be limited. Therefore, in such cases a comprehensive imaging study and expert evaluation are required. However, when the conditions are appropriate, TAE offers a less invasive and repeatable alternative to surgery for the treatment of a large multinodular goiter.

What Role Does Imaging Play in Thyroid Artery Embolization Procedures?

Imaging techniques are at the heart of TAE. It is vital to deliver the correct amount of embolic material to the appropriate vessel. This is akin to setting out on a journey without a map; if the vascular map is not clearly visualized, the risk of deviating into the wrong pathway and causing damage to non‑target tissues increases. Before TAE, various imaging methods such as ultrasound, magnetic resonance imaging (MRI), or computed tomography (CT) are used to understand the structure of the thyroid and the size of the nodules. This allows the identification of the truly problematic areas and the course of the vessels.

During the procedure, angiography comes into play. A thin catheter inserted via the groin or wrist is advanced to the neck vessels, and real‑time X‑ray monitoring using fluoroscopy is utilized. By injecting a contrast agent, the manner in which a particular vessel supplies the thyroid tissue can be observed in real time. At this stage, the target vessel is identified and the embolic agent is injected into that vessel. With fluoroscopic guidance, the success of the occlusion can be monitored live.

Imaging is also important after the procedure. Follow‑up imaging with ultrasound or other cross‑sectional techniques is performed to assess the degree of reduction in the nodules or to evaluate how the hormone levels have been affected, as well as to verify whether complete occlusion of the targeted vessels has been achieved. If there is recurrence of goiter growth or return of symptoms later on, similar imaging methods are used to investigate the source of the problem. Without imaging technologies, performing TAE would be nearly impossible. For this reason, an experienced interventional radiology team and up‑to‑date imaging capabilities are among the most critical factors for the success of TAE.

Is Thyroid Artery Embolization a Suitable Option for Elderly Patients?

Surgical procedures performed under general anesthesia always carry a certain degree of additional risk in elderly patients. Reduced cardiac, pulmonary, or renal function, slower wound healing, and the presence of comorbidities (such as diabetes or hypertension) may increase the risk of surgical complications. It is precisely in these circumstances that TAE offers a relatively less traumatic alternative for elderly patients. The procedure can be performed under local anesthesia and mild sedation, meaning it can be done without general anesthesia. In addition, the hospital stay after the procedure is short and the patient can quickly return home.

In elderly patients with a large goiter or hyperthyroidism, performing TAE to reduce the size or vascularity of the thyroid prior to surgery can significantly mitigate surgical risks. Particularly in cases where the goiter is highly vascularized and prone to heavy bleeding during surgery, embolization to partially block these vessels makes the surgical phase safer and easier. For some patients, it is even possible to achieve a degree of improvement with TAE alone, avoiding surgery altogether.

It is important to note whether TAE alone will be sufficient. In some elderly patients, due to additional comorbidities and high risks, even a small invasive procedure must be carefully evaluated. TAE is less invasive than surgery but it does not promise “zero risk.” For instance, in elderly patients with very fragile vascular structures or those with long‑standing uncontrolled heart disease, meticulous preparation and a multidisciplinary approach are required.

Nevertheless, as experience and technological capabilities increase, the use of TAE in the elderly population is becoming more widespread and its success rates are rising accordingly. Therefore, for elderly patients who are reluctant or unable to undergo surgery, thyroid artery embolization stands out as an effective treatment option that should certainly be considered by the medical team.

Prof. Dr. Özgür KILIÇKESMEZ

Prof. Dr. Özgür Kılıçkesmez graduated from Cerrahpaşa Medical Faculty in 1997. He completed his specialization at Istanbul Education and Research Hospital. He received training in interventional radiology and oncology in London. He founded the interventional radiology department at Istanbul Çam and Sakura City Hospital and became a professor in 2020. He holds many international awards and certificates, has over 150 scientific publications, and has been cited more than 1500 times. He is currently working at Medicana Ataköy Hospital.