Thyroid Ultrasound
Thyroid ultrasound uses sound waves to create images of the thyroid gland — a painless, non-invasive, radiation-free test.
It is the primary imaging tool for evaluating thyroid nodules, goitre, and structural abnormalities.
Last medically reviewed: 1 November 2025
Key points
- Ultrasound assesses thyroid structure and nodules.
- It is painless and uses no radiation.
- Features are combined into a risk score such as TIRADS.
- Biopsy is used for suspicious nodules.
What it shows
Ultrasound reveals the gland’s size, texture (diffuse vs nodular), and any nodules — their number, size, composition (solid, cystic, mixed) and suspicious features like microcalcifications, irregular margins, or taller-than-wide shape.
It also detects cysts, inflammation patterns, and enlarged lymph nodes.
When it is needed
Ultrasound is indicated for palpable lumps, abnormal thyroid function tests, visible goitre, or suspicious symptoms. It is also used to guide fine needle aspiration biopsy and monitor nodules over time.
It is not routinely needed for uncomplicated hypothyroidism with a normal-feeling gland.
What the results mean
Most nodules seen on ultrasound are benign. Suspicious features prompt FNAC. Simple cysts need no treatment. Diffuse enlargement suggests goitre or thyroiditis. Normal ultrasound with abnormal function tests points toward functional (not structural) disease.
Ultrasound findings guide but do not replace clinical judgment — a specialist interprets them in context.
Frequently asked questions
Is thyroid ultrasound painful or harmful?
No — it is completely painless, non-invasive, and uses no radiation. A gel is applied to the neck and a probe glides over the area.
Can ultrasound tell if a nodule is cancer?
It identifies suspicious features that warrant biopsy, but cannot definitively diagnose cancer — FNAC provides the cellular diagnosis.
Do I need ultrasound if my TSH is abnormal?
Not always — if the gland feels normal and function tests suggest a functional disorder, ultrasound may not be needed. It is most useful when nodules or goitre are suspected.
References & further reading
This page is based on established medical knowledge and guidelines from authoritative sources. Always consult a qualified clinician for personal medical advice.
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