Flashcards in EXAM #1: IMAGING OF THE THYROID Deck (18):
In the normal individual, what happens to the thyorid gland with age?
Gland naturally becomes more nodular
Why would you image the thyroid gland?
1) Evaluate abnormality of thyroid function test
2) Morphologic abnormality
What is the role of imaging in hypothyroidism?
What test should I order for the hyperthyroid patient?
Nuclear medicine iodine uptake and scan
What type of rays are given off from the decay of the radioactive iodide?
*These are in the same spectrum as x-rays i.e. a gamma camera
What determines whether a nuclear scan is normal or not?
Uptake of radioactive iodine
(10-25% uptake is normal)
What is the gross appearance of the thyroid in Graves' Disease?
Large, beefy, symmetric, and red
What is the classic nuclear scan finding in Graves' Disease?
What is the nuclear med finding in a toxic adenoma?
- Normal range uptake
- BUT a very strong focus of activity
How will a multinodular goiter appear on nuclear scan?
- Many areas of focal uptake
- Total uptake can be in the normal range
How will the nuclear med scan appear in the setting of thyroiditis?
*LOW uptake--looks like nothing
What is the difference between a goiter and a thyroid nodule?
Goiter= prominent thyroid gland
Nodule= single spot that is enlarged
In general, it is more high yield to image a diffuse enlargement of the thyroid vs. focal nodule?
*Goiter/ diffuse enlargement is rarely associated with cancer
What are the three etiologies for a distinct thyroid nodule?
2) Benign adenoma
What test is best to evaluate morphologic disease of thyroid?
What kind of radiation is associated with US?
*Electrons won't be liberated; can't cause DNA damage
What is the major limitation of thyroid US?
No way to distinguish between benign and malignant