This page explains how a thyroid ultrasound works, what it can and cannot show, and how doctors use ultrasound images to check for thyroid nodules, goiter, and other thyroid changes.
If your doctor has ordered a thyroid ultrasound, you might wonder:
What is it for?
What does it show?
Is it safe?
This page explains everything and makes it simplified.
A thyroid ultrasound is:
➡ A painless imaging test that uses sound waves to create pictures of your thyroid gland.
It lets doctors see the thyroid directly instead of just relying on blood tests.
Ultrasounds are commonly ordered to:
Look at the size of the thyroid
Check for thyroid nodules
Evaluate lumps felt in the neck
Monitor known nodules
Investigate a goiter
Look for inflammation or structural changes
It is one of the most helpful tools for thyroid evaluation.
A thyroid ultrasound can show:
The overall size of the thyroid
Whether it is enlarged
If nodules are present
The shape and texture of nodules
Cysts (fluid-filled areas)
Solid masses
Signs of inflammation
It gives a detailed picture of the structure of the thyroid.
An ultrasound does not show:
How well the thyroid is working
Hormone levels
Whether you are hypo- or hyperthyroid
That information still comes from blood tests like TSH and Free T4.
Doctors commonly order an ultrasound if:
You have a lump in your neck
Your thyroid feels enlarged
Blood tests suggest a problem
You have known thyroid nodules
You have symptoms of thyroid disease
A nodule needs to be monitored over time
Ultrasound reports usually describe things like:
Size of the thyroid
Number of nodules
Size of each nodule
Whether nodules are solid or cystic
Whether any features look suspicious
The report might say things like:
“Normal thyroid size”
“Small benign-appearing nodule”
“Multiple nodules present”
“Enlarged thyroid consistent with goiter”
Most findings are non-cancerous and not urgent.
No.
An ultrasound can suggest whether a nodule looks:
Low risk
Intermediate risk
Higher risk
But it cannot diagnose cancer by itself.
If something looks concerning, the next step is usually:
➡ Fine Needle Aspiration Biopsy (FNA)
A thyroid ultrasound is very simple.
You lie on your back
A small wand is placed on your neck
Gel is used to help the image
The test usually takes 15–30 minutes
There are no needles or radiation
It is safe, painless, and quick.
If you have nodules, doctors may recommend:
Repeat ultrasound in 6–12 months
Then every 1–2 years
Or sooner if something changes
This helps make sure nodules are stable.
After an ultrasound, the next step depends on what it shows.
No further testing may be needed
Often just monitoring over time
A biopsy may be recommended
Blood tests and follow-up evaluation
Ultrasound shows the structure of the thyroid
It is painless and safe
It helps evaluate nodules and goiter
It does not measure thyroid hormone levels
Most findings are benign
The next page will explain:
➡ Thyroid Biopsy (FNA) Explained
This will help you understand what happens if a nodule needs closer evaluation.