How to Understand Thyroid Gland Biopsy and Imaging Tests

The two ways in which a diseased thyroid gland can be more thoroughly analyzed are through studies of tissue samples from the gland (biopsy) and by taking detailed images of the gland (imaging tests). The following 3 points can help bring understanding to these medical lab procedures.

1. Fine Needle Aspiration (Tissue Biopsy)

When a thyroid gland has suspicious looking nodules within it (small tumors) that might contain malignancy, meaning cancer cells, with papillary and follicular thyroid cancers being the most common types, a biopsy sample might be extracted from the gland for analysis. This can either be done surgically or by use of a less invasive procedure called a "fine needle aspiration" (FNA).

The FNA is performed usually as an in-office, out-patient procedure, using a hypodermic needle to extract tissue from a specific area of the thyroid gland. If for example, a nodule is of a significant size or has a firmness to it (solid nodule), a doctor with experience in FNA, can extract a sample of tissue from the tumor itself, to rule-out or confirm the presence of malignant cells.

The procedure can also detect the presence of thyroid autoimmunity, such as Hashimoto's thyroiditis -- a condition in which the thyroid gland is being destroyed by auto-antibodies from the immune system, also referred to as "chronic lymphocytic thyroiditis". This disease is at-times elusive to detection by blood testing analysis, especially during early stages of the disease and the FNA can detect it, despite negative auto-antibodies in a patient's blood.

2. Thyroid Imaging Tests

When doctors examine patient's thyroid glands by palpation (fingertip feel) they will sometimes find that a goiter is present (swelling) or that there are nodules within it. They can also feel the texture of the gland and whether it is unusually firm, when pressed upon. When a goiter is mild or nodules that are felt within the gland are small or several are found (single nodules are considered more suspicious than multiples), a doctor may not feel that further testing is merited. If however, a goiter is large enough to obstruct a patient's breathing or swallowing or if a thyroid nodule is large or very solid, imaging tests of the thyroid gland might then be ordered.

3. Types of Thyroid Scans

Depending on the type of problem that is suspected to be affecting the thyroid gland, a doctor might order one or more of three types of tests. These would be "Thyroid Ultrasound", Radioactive Iodine Uptake Scan", CT Scan or an MRI (Magnetic Resonance Imaging).

Ultrasound

With a Thyroid Ultrasound, a lab technician will use a small handheld device covered with a lubricating substance and they will run it across the front of the neck, in the area of the thyroid gland. A monitor will pick up sensitive sound waves that are sent to the thyroid gland and that return as an image on the screen (echo). This imaging will pick up a great amount of detail, including shapes and textures within the gland. The sonogram technology is the same as is used to monitor the fetuses of expectant mothers. While a continuous image will appear on the screen during this procedure, the technician can also take occasional still-images at the appropriate times, for review by medical doctors.

Uptake Scan

A Radioactive Iodine Uptake Scan (RAIU) is an imaging test that utilizes radiology imaging, by giving the patient a carefully-measured dose of radioactive iodine. The substance is then absorbed by the thyroid gland, so that when imaging is taken, the tissue being observed will appear brighter and in more detail. There are two basic purposes for thyroid uptake scans and often these are done in-combination, the one being to observe how much healthy thyroid tissue is present and capable of absorbing iodine and the other, to scan the imaging results for abnormal-looking thyroid tissue or nodules.

CT Scan

A CT Scan (computed tomography or "cat scan) is a sophisticated type of x-ray imaging that takes images from a number of different angles simultaneously, so that the images can be compared for a more thorough evaluation than would simple x-rays that involve only one or two angle/views.

MRI

An MRI is also an imaging method that will show greater detail but rather than only scanning the thyroid gland, it will also scan surrounding areas of the body and other glands related to thyroid function, such as the pituitary gland that is found in the brain (the origin of Thyroid Stimulating Hormone). In the case of MRI, very powerful magnets are used to scan areas of the body to produce these detailed images and in some cases; a dose of an additional enhancer is given to patients, called "contrast" (gadolinium - a type of die).

In Conclusion:

Thyroid testing is available to detect all forms and types of thyroid disorders and diseases, including imaging tests, tissue biopsy and blood analysis. If symptoms of thyroid hormone imbalance are being experienced or an abnormal size or texture is discovered within the gland (i.e. goiter and/or thyroid nodules), further evaluation by a qualified medical doctor is important and should not be delayed.

The vast majority of thyroid disease cases are successfully treated but timely diagnosis can be a key to better treatment outcomes.

Sources:

Medscape Today News: WebMD
Link: http://www.medscape.com/viewarticle/536309_5