Fine needle aspiration is a relatively non-invasive, less painful and quicker method when compared to other methods of tissue sampling such as surgical biopsy. A cyst aspiration can also be achieved with a FNA, where the fluid is drained from a cyst with no need for analysis.
Information on re-publishing of our images. A fine needle aspiration biopsy is a simple and quick procedure. It is performed to collect a sample of cells or fluid from a cyst or solid mass, to allow the cells to be examined under a microscope. Local anaesthetic is not usually required for a fine needle aspiration, as the procedure should not be painful.
Fine needle aspirations may be performed on palpable lumps lumps which can be felt , or impalpable lumps which have been detected on ultrasound or x-ray.
Once the skin has been cleaned at the needle entry point, the lump is then examined. If the lump can be felt, your doctor or surgeon will palpate the lump to position it for the needle.
If the lump cannot be felt, imaging may be required to find the exact location. This can be done with ultrasound , where the surgeon will watch the needle on the ultrasound monitor and guide it to the area, or with a stereotactic mammogram for the breast which uses two mammograms at different angles and a computer to create exact coordinates.
The type of needle used for fine needle aspiration biopsy has a hollow interior and is much finer than a regular needle used to draw blood. You can see an example of what the needle may look like in the image to the right.
The insertion of the needle is said to be similar to the sensation of a blood test. A vacuum or negative pressure is created in the needle and with an in and out motion of the needle, the sample is taken. Several needle insertions may be required to ensure that the sample is adequate. Once the test is completed, a small bandage will be placed over the site and you can continue your normal activities.
There are generally no complications with this procedure, though you may experience some tenderness or bruising over the needle insertion site. If you experience any bleeding, swelling, fever or pain that is not relieved with paracetamol, contact your doctor immediately. It is not recommended that you use aspirin to relive pain as it may worsen any bruising. The samples taken are examined by a pathologist under a microscope.
Most people will not need this, though. In some cases, your healthcare provider might inject a local anesthetic to the area before inserting the needle.
Because the needle is so small, this is often not necessary. Your healthcare provider may perform the biopsy with the help of an ultrasound machine. This machine uses high-frequency sound waves to provide an ongoing image of the nodule. This enables your healthcare provider to guide the needle to exactly the right spot.
It also prevents damage to other structures. A gel-like substance will be applied to your neck, where the ultrasound detector will be used. After cleaning the area, your provider will insert the thin, fine needle into your thyroid gland.
This may hurt a little. He or she will slowly advance the needle into the nodule itself, moving it back and forth several times. The needle attaches to a syringe that can apply suction and remove some cells from the nodule. After the removal of the needle, these cells will be placed on a slide. Your healthcare provider might repeat this procedure a few times to obtain different samples from different parts of the nodule.
Sometimes the lump will be all or mainly fluid. The fluid can be removed during the biopsy. After the procedure, the cells will be sent to a pathology lab and analyzed for signs of cancer. A small bandage will be placed over the needle insertion site. Most people will be able to resume their normal activities right away. You can remove your bandage within a few hours. Most often, this is nothing to worry about, and the bleeding, bruising, and swelling go away over time.
A doctor called a pathologist will look at the biopsy tissue or fluid to find out if there are cancer cells in it. An FNA biopsy is the easiest type of biopsy to have, but it can sometimes miss a cancer if the needle does not go into the cancer cells, or if it doesn't remove enough cells. Even if an FNA does find cancer, there might not be enough cancer cells to do some of the other lab tests that are needed. When your doctor finds a nodule, they may order imaging tests to help determine if it is benign non-cancerous or malignant cancerous.
If imaging exams cannot clearly define the abnormality, a biopsy may be necessary. For biopsies performed in children, sedation may be used. Specific instructions will be given at the time of scheduling. The needle used is a thin, fine-gauge needle that is smaller in diameter than the needle used in most blood draws usually a 25 or 27 gauge 1. The aspiration may be done with a needle or with a needle that is attached to a syringe. The syringe may be in a plastic or metal holder to make it easier for the doctor to aspirate the cells.
Ultrasound is used to guide accurate placement of the needle within the thyroid nodule. Ultrasound machines consist of a computer console, video monitor and an attached transducer. The transducer is a small hand-held device that resembles a microphone.
Some exams may use different transducers with different capabilities during a single exam. The transducer sends out inaudible, high-frequency sound waves into the body and listens for the returning echoes. The same principles apply to sonar used by boats and submarines. The technologist applies a small amount of gel to the area under examination and places the transducer there. The gel allows sound waves to travel back and forth between the transducer and the area under examination. The ultrasound image is immediately visible on a video monitor.
The computer creates the image based on the loudness amplitude , pitch frequency , and time it takes for the ultrasound signal to return to the transducer. The physician inserts a fine gauge needle through the skin and advances it into the thyroid nodule.
Samples of the cells are then obtained and put on a slide for review by the pathologist. Image-guided, minimally invasive procedures such as fine needle aspiration of the thyroid are most often performed by a specially trained radiologist with experience in needle aspiration and ultrasound. The neck will be cleansed with antiseptic. Medicine to numb the area may or may not be used.
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