Why is an ultrasound performed on a thyroid gland in a patient with hyperthyroidism?

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Last updated: December 4, 2025View editorial policy

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Why We're Doing a Thyroid Ultrasound for Your Hyperthyroidism

I'm ordering an ultrasound to look at the structure of your thyroid gland and check for nodules, which helps me understand what's causing your hyperthyroidism and plan the best treatment for you. 1, 2

What the Ultrasound Shows Me

When you have hyperthyroidism (overactive thyroid), the ultrasound helps me see:

  • The size and shape of your thyroid gland – I need to know if it's enlarged uniformly or if one side is bigger than the other 1, 3
  • Whether you have nodules (lumps) – Some nodules can be "hot" (overactive) and cause your hyperthyroidism, particularly in conditions like toxic adenoma or toxic multinodular goiter 1, 2
  • The blood flow pattern in your thyroid – Using Doppler ultrasound, I can see if blood flow is increased (suggesting an overactive gland like Graves' disease) or decreased (suggesting inflammation or thyroiditis) 1
  • Any suspicious features – Even though we're focused on hyperthyroidism, I need to make sure there aren't any nodules that look concerning for cancer 1, 4

How This Guides Your Treatment

The ultrasound is particularly important because:

  • It works together with your radioactive iodine scan – The ultrasound confirms which nodules I see on the nuclear medicine scan and helps identify which ones might need a biopsy 1, 2
  • It helps me plan radioactive iodine treatment – If you need this therapy, the ultrasound measurements of your thyroid size help me calculate the correct dose 1
  • It distinguishes between different causes – Your hyperthyroidism could be from Graves' disease, toxic nodules, or thyroiditis, and the ultrasound appearance combined with blood flow patterns helps narrow this down 1, 2

Why Ultrasound First

Ultrasound is the best first imaging test because:

  • It's the most detailed way to see thyroid structure – It provides high-resolution images that other tests can't match 1, 4
  • It's safe – No radiation exposure, unlike CT scans or nuclear medicine studies 5
  • It's readily available and quick – I can get the information I need without delay 5

The American College of Radiology recommends that ultrasound should be the first imaging test after checking your thyroid blood tests (TSH) when evaluating hyperthyroidism 1, 2. This approach ensures we don't miss important findings and helps me give you the most appropriate treatment for your specific condition.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Thyroid Imaging Selection Guidelines

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Thyroid Disorders: Graves' Disease and Multinodular Goiter

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Thyroid Ultrasound: Diffuse and Nodular Disease.

Radiologic clinics of North America, 2020

Research

Thyroid ultrasound.

Endocrinology and metabolism clinics of North America, 2001

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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