Thyroid/Neck Ultrasound & Ultrasound-Guided Thyroid Fine Needle Aspiration (FNA) Biopsy

Thyroid/Neck Ultrasound & Ultrasound-Guided Thyroid Fine Needle Aspiration (FNA) Biopsy

At Associated Endocrinologists, we perform thyroid ultrasound and ultrasound-guided Thyroid Fine Needle Aspiration (FNA) Biopsy at our Farmington Hills location, often on the same day as your office appointment.

Thyroid Ultrasound

What is a Thyroid/Neck Ultrasound?

A thyroid ultrasound is a crucial test for the evaluation of thyroid nodules. This simple test uses high-frequency sound waves to image the thyroid. The sound waves are emitted from a small hand-held transducer passed over the thyroid. You will lie on the exam table with your neck hyperextended and a pillow under your shoulders for comfort.

Your radiographer applies lubricant jelly to the skin on your neck so that the sound waves transmit easier through the skin and into the thyroid and surrounding structures.

Sound waves can show thyroid volumes to ensure the thyroid is the correct size, blood flow, and abnormal growths within the thyroid. It can also show the thyroid’s adjacent structures to ensure that growths do not impact the trachea or esophagus.

A neck ultrasound can also provide images of the cervical lymph nodes. Abnormal lymph nodes can indicate the presence of metastatic cancer. Patients with metastatic lymph nodes have a high mortality rate; the key to successful treatment relies on early detection.

The neck ultrasound exam is quick, accurate, painless, inexpensive, and completely safe. It usually takes about 10 minutes, and the results can be known almost immediately.

Do I Need a Thyroid Ultrasound?

Your doctor manually palpates your thyroid and parathyroid glands during a physical exam to feel for abnormal lumps. A thyroid ultrasound is used as an additional diagnostic tool if your doctor detects an abnormality during a physical exam or if you show symptoms of thyroid diseases such as hypothyroidism, hyperthyroidism, or thyroid cancer.

A thyroid ultrasound exam can detect various types of nodules, including:

  • A benign lesion
  • Nodular goiter
  • Multinodular goiter
  • Incidental thyroid nodules
  • Thyroid cysts

Your doctor may also recommend a thyroid ultrasound as part of a routine exam if you have a family history of thyroid cancer like papillary thyroid carcinomas. They may also suggest an ultrasound as part of your regular screening if you have been diagnosed with a genetic disease, such as multiple endocrine neoplasia type 1 (MEN1), which often causes tumors on the parathyroid gland.

What are the Possible Results of a Thyroid Ultrasound?

Thyroid nodules detected during an ultrasound are typically classified using the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS). The ACR TI-RADS Classification System uses points assigned to symptoms to categorize nodules into one of five categories. It is used to determine whether you need additional diagnostic imaging or a biopsy to differentiate between types of thyroid nodules.

  • Benign (TR1)

A benign lesion or nodule is primarily spongiform or cystic, has a wider-than-tall shape, a smooth margin, and no comet-tail artifacts.

  • Not suspicious (TR2)

A benign lesion that exhibits the same characteristics as a TR1 classified nodule but may have a mixed or solid composition or macrocalcifications.

  • Mildly suspicious (TR3)

On the ultrasound image, mildly suspicious nodules may be lobed, have irregular margins, and appear hyperechoic (solid gray). Patients with mildly suspicious thyroid nodules may need a fine needle aspiration biopsy if the nodule is larger than 2.5 cm.

  • Moderately suspicious (TR4)

A moderately suspicious lesion may have irregular margins caused by peripheral calcifications, may be taller-than-wide, and have a solid or almost solid composition on the sonographic image. If the nodule is larger than 1.5 cm, you need additional diagnostic testing to establish whether it has a high risk for malignancy.

  • Highly suspicious (TR5)

Highly suspicious lesions display the same characteristics as TR4 nodules, extrathyroidal extensions and are more hyperechoic than adjacent parenchymal cells.

Patients with highly suspicious thyroid nodules have a higher risk of thyroid cancer. Your doctor will recommend a fine needle aspiration biopsy.

What are the Limitations of a Thyroid Ultrasound?

Thyroid ultrasounds have a high diagnostic accuracy of approximately 82% for identifying nodules based on echogenicity, margins, microcalcifications, size, shape, and abnormal neck lymph nodes. However, in some cases, a radiographer or endocrinologist may be able to differentiate between benign and malignant nodules using the ultrasound image alone.

If the ultrasound images prove inconclusive, your doctor may recommend an ultrasound-guided fine needle aspiration biopsy.

fine needle aspiration biopsy

What is Ultrasound-Guided Thyroid Fine Needle Aspiration (FNA) Biopsy?

Thyroid fine needle aspiration (FNA) biopsy is the only non-surgical method that can differentiate malignant and benign thyroid nodules.

Your doctor slides the ultrasound probe back and forth over your thyroid gland to determine precisely which area to biopsy. An injection of an anesthetic solution (lidocaine) is usually used to numb the skin first. You will feel a pinch and burn while the anesthetic begins to work.

Using ultrasound to guide the needle tip, your doctor then inserts a thin needle into your thyroid gland and removes a small amount of soft tissue, thyroid cells, and fluid through the needle. The ultrasound increases the quality of the biopsy specimens and allows the doctor to know where the needle tip is at all times.

After each pass with the needle, the material from your thyroid gland is placed on a glass microscope slide and sent to the cytology laboratory for examination. Your doctor may perform 4-6 passes of the thyroid nodule to get an adequate specimen.

During a needle biopsy, you may feel pressure or a brief, sharp pain in your neck as the needle enters your thyroid gland. Try not to swallow, cough, or make sudden movements when the needle is in your neck to prevent injury. You do not need to hold your breath during the biopsy, but stay calm and still.

There is usually no bleeding after the procedure. A small bandage is applied where the needle was inserted. The area may remain sore for up to 24 hours after the biopsy. Ice packs relieve pain in most cases, but Tylenol can also be used. Ibuprofen should be avoided as it could increase the risk of bleeding.

Do I Need an Ultrasound-Guided Fine Needle Aspiration Biopsy?

Patients with thyroid nodules may need to undergo an ultrasound-guided FNA biopsy if the thyroid nodule is larger than 1-1.5 cm (⅜-⅝ inch) and/or has any worrisome characteristics.

For high-risk patients (those who have had radiation exposure in the past or have a family member with thyroid cancer), nodules under 1 cm may need a biopsy.

How to Prepare for an Ultrasound-Guided FNA Biopsy

Your doctor will ask you to stop taking anticoagulants (or blood-thinners) like warfarin or heparin for several days before the biopsy to prepare for thyroid FNA. This reduces the risk of bleeding during and after treatment. You can continue to take any other essential medications. In most cases, you do not need to fast on the day of your treatment.

The ultrasound gel is water-based and non-toxic. However, you should avoid wearing jewelry around your neck and wear comfortable clothes on the day of your appointment to prevent accidental damage.

What are the Possible Results of an Ultrasound-Guided FNA Biopsy?

The specimens collected during a biopsy are analyzed by a cytopathologist and evaluated by your endocrinologist. The Bethesda System for Reporting Thyroid Cytopathology classifies your results into one of six categories.

  • Benign nodules

Benign thyroid nodules are the most common type of abnormal growth detected using a biopsy. If you have benign nodules, your doctor may continue to monitor them for several months.

If the nodules are large or causing you to experience difficulties breathing, speaking, or swallowing, your doctor may recommend a thyroid radiofrequency ablation (RFA) treatment to encourage cystic degeneration.

  • Malignant growths

In up to 7% of cases, the biopsy will show cancerous or malignant thyroid nodules. Most malignant thyroid nodules turn out to be papillary thyroid cancer and require a full or partial thyroidectomy or radioactive iodine treatment to eliminate the cancerous cells.

  • Suspicious for malignancy

If a biopsy shows that the tissue is suspicious for malignancy, there is a 65-70% chance that the malignant thyroid nodules are cancerous. The tissue specimen may display malignant characteristics like microcalcifications or irregular margins and benign features such as a uniform halo and no vascular structures.

  • Non-diagnostic

A non-diagnostic result means that there were insufficient cells available for diagnosis. This can occur when there is too much blood or cystic fluid in the sample and not enough thyroid follicular cells. If your results are non-diagnostic, your doctor may recommend a repeat biopsy.

  • Follicular neoplasm or Suspicious for follicular neoplasm

The follicular neoplasm is indicative of both cancerous and non-cancerous growth and is often referred to as indeterminate. This could suggest that the patient has a benign adenomatoid nodule, a follicular adenoma, or a non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP).

It could also indicate that the patient has a growth with a high risk for malignancy, such as follicular carcinoma or a follicular variant of papillary thyroid carcinoma.

Your doctor may recommend repeat biopsies or genetic testing to confirm the diagnosis.

  • Atypia of Undetermined Significance (AUS) or Follicular Lesion of Undetermined Significance (FLUS)

These results are also referred to as indeterminants. Indeterminate specimens show characteristics of benign thyroid nodules and malignant thyroid nodules and require further testing.

Genetic Markers for Indeterminate Thyroid Nodules

An ultrasound-guided FNA biopsy has more than 95% diagnostic accuracy. However, the diagnosis is still unclear when a patient has a thyroid FNA biopsy with an indeterminate result.

Indeterminate results on thyroid FNA samples are common (5-15% of biopsies). The American Thyroid Association recommends that most nodules require surgical removal if repeated biopsies also prove indeterminate.

Are There Any Risks of a Thyroid FNA Biopsy?

A thyroid FNA biopsy is a very safe procedure and is recommended by the American Thyroid Association as the standard non-surgical diagnostic tool for confirming malignant growths.

However, there are some minor risks associated with the procedure, including:

  • Bleeding at the needle insertion site
  • Mild infection
  • Damage to structures close to the thyroid

Thyroid Cancer Diagnosis and Treatment Options

If your endocrinologist has confirmed a thyroid cancer diagnosis with an ultrasound and FNA biopsy, they’ll proceed to stage the cancer’s development so that your medical care team can create an optimal treatment plan which may include surgical removal, radioactive iodine ablation, and radiotherapy or chemotherapy.

There are two common types of thyroid cancers, papillary and follicular thyroid cancer, making up approximately 95% of all thyroid cancers. These cancers are staged into two categories if you are under 55.

  • Stage I: Cancer is contained within the neck
  • Stage II: Cancer has spread outside the neck to other organs

If you are over 55, thyroid cancer is categorized into several stages:

  • Stage I: Any thyroid cancer less than 2 cm that is not growing outside the thyroid and has not spread to the body’s cervical lymph nodes or other areas.
  • Stage II: The thyroid cancer is between 2 and 4 cm but is not growing outside the thyroid or spreading to nearby lymph nodes or other areas of the body.
  • Stage III: thyroid cancer is larger than 4 cm or has grown slightly outside the thyroid (T3). The It may or may not have spread to nearby lymph nodes or other areas of the body.
  • Stage IV: The cancer has grown beyond the thyroid gland and into nearby neck tissues. It might or might not have spread to nearby lymph nodes, including the upper chest (superior mediastinal nodes) and throat (retropharyngeal nodes).
    It also may or may not have spread to other areas of the body. The cancer may have also grown either back toward the spine or nearby large blood vessels. Stage IV thyroid cancer has the highest mortality rate and requires extensive surgical and non-surgical treatment.

Contact Associated Endocrinologists

If you experience thyroid nodule symptoms, contact Associated Endocrinologists for an appointment. Our experienced healthcare professionals can perform a thyroid scan, thyroid ultrasound, or guided FNA biopsy to help with the evaluation of thyroid nodules. We can also discuss treatment options such as radioactive iodine or thyroid RFA to eliminate malignant lesions and noncancerous nodules.

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