Thyroid Radiology

Question 1

Types of imagining used to study thyroid gland

Answer 1

• US
• CT
• MRI
• PET scan
• Fxnal imaging

Question 2

Characteristics of US use to study thyroid

Answer 2

• US: best for detecting and characterizing nodules
• Can use doppler to tell if node is vascularized
• Normal appearance → homogeneous
• Nodule is discrete area within gland that is distinct from normal/surrounding thyroid parenchyma

Question 3

Characteristics of types of nodules seen on US

Answer 3

• Solid → discrete well-defined nodule
• Cystic → discrete well-defined fluid filled
• Complex → discrete nodule with both fluid and solid comp
• Cancer → punctate very small heterogeneous clarifications

Question 4

Characteristics of CT use in thyroid imaging

Answer 4

• useful to define extension to lymph nodes and distant metastases
• Normal → hyperdense and hypervascular, homogeneous

Question 5

Characteristics of MRI use in thyroid imaging

Answer 5

• Useful for observing tissue invasion from metatasis
• Useful for infiltrative disease, especially in post surgery where anatomy is distorted
• Detection of deep nodal disease
  
  • Can’t differentiate b/w solid vs cystic nodule
• T2: Thyroid is slightly hyperintense

Question 6

Characteristics of PET scan and functional imaging use in thyroid imaging

Answer 6

• PET scan: thyroid cancer staging - look for metastatic disease
  
  • Detects hypermetabolic adenopathy
• Functional imaging: Iodine scan → evaluate the function of the gland
  
  • Use radiotracer for diagnostic/therapeutic purposes

Question 7

Dx?

Answer 7

Normal thyroid US

Question 8

Characteristics of thyroid on CT Neck

Answer 8

• hyperdense
• hypervascular

Question 9

Dx?

Answer 9

Normal CT

Question 10

Dx?

Answer 10

Solid nodule

Question 11

Dx?

Answer 11

Cystic nodule

Question 12

Dx?

Answer 12

Complex nodule

Question 13

Dx?

Answer 13

Thyroid cancer

Question 14

Dx?

Answer 14

Hashimoto’s disease

Question 15

Dx?

Answer 15

• hot nodule
• malignancy unlikely

Question 16

Dx?

Answer 16

• Cold nodule = possibly malignant
• US + FNAB to determine malignancy

Question 17

Common disease states seen on thyroid imaging

Answer 17

• Hot large thyroid gland → Graves disease (123I thyroid scan)
• Cold nodules: solid, cystic, cancer
• Hot nodules
• Thyroid Cancer → hypermetabolic adenopathy on CT/PET
  
  • Therapy: 131I radioactive iodine