Thyrotoxicosis

Toxic diffuse goitre (Graves’ Disease)

  • Toxic diffuse goitre 1
  • Toxic diffuse goitre 2
  • Toxic diffuse goitre 3
  • Toxic diffuse goitre 4
99m Tc Thyroid scan99m Tc Thyroid scan large image

99m Tc Thyroid scan

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The 99m Tc thyroid scan in toxic diffuse goitre will show diffuse enlargement of the gland with diffusely increased uptake.

Note the diffusely enlarged gland with increased tracer uptake. Assymetry is often seen reflecting the assymetry of the normal gland.

 

99m Tc scan99m Tc scan large image

99m Tc scan

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The 20 minute uptake value is generally above the normal range unless the patient has been on medical treatment before the scan is performed.

 

99m Tc Scan with 20min uptake graph99m Tc Scan with 20min uptake graph large image

99m Tc Scan with 20min uptake graph

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In untreated Graves’ disease, the 20 min uptake is increased above the normal range (0.4-4%).

 

99m Tc Thyroid scan99m Tc Thyroid scan large image

99m Tc Thyroid scan

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A pyramidal lobe is not uncommonly seen on the 99mTc scan of patients with toxic diffuse goitre.