Thyroid Radiology

Question 1

Imaging modalities

Answer 1

Anatomic imaging: US is the best modality.
Functional Imaging
PET/CT scan

Question 2

Anatomic imaging:

Answer 2

• Ultrasound, CT and MRI.
• Indicated to detect or characterize palpable or incidentally found thyroid nodule on other modalities.
• US is the best modality.

Question 3

Functional Imaging

Answer 3

Iodine ( I123 or I131) scan. To evaluate for function of the thyroid gland or nodule in patient with abnormal thyroid function. Evaluate for distant metastatic disease.

Question 4

PET/CT scan

Answer 4

scan- Staging and restaging of differentiated thyroid cancer

Question 5

Radiograph

Answer 5

• Not useful to detect thyroid disease
• May incidentally suggest a thyroid lesion by noting mass effect on the soft tissues (often more obvious clinically) or on tracheal air column

Question 6

The best modality to detect and characterize thyroid nodule.

Answer 6

US

Question 7

Best modality to detect lymph node metastasis in postop patient of thyroid cancer.

Answer 7

US

Question 8

incidentalomas

Answer 8

Nonpalpable nodules detected on US or other anatomic imaging studies

Question 9

CT

Answer 9

Useful to define extension to lymph nodes and distant metastasis.
Good anatomic evaluation of the thyroid bed
Thyroid is:
-Hyperdense
-Hypervascular

Question 10

MRI use

Answer 10

Useful in identifying infiltrative disease particularly in post-therapy neck where anatomy is distorted
Detection of deep nodal disease.

Question 11

MSI results

Answer 11

Thyroid slightly hyperintense on T2.
Can’t differentiate solid vs. cystic nodule.
Can’t visualize microca.

Question 12

Iodine Scan

Answer 12

• I 123 scan- To evaluate function of the thyroid gland and thyroid nodule in patient with abnormal thyroid function.
• I131 scan- Diagnostic and therapeutic role.
• Detect local and distant thyroid cancer metastasis.
• Treatment of hyperthyroidism as well as for well differentiated thyroid cancer.

Question 13

T of F: No imaging modality can reliably differentiate between benign and malignant thyroid disease.

Answer 13

True. Tissue diagnosis by FNA should be obtained on suspicious lesions.

Question 14

T or F: Nonpalpable nodules have the same risk of malignancy as palpable nodules with the same size.

Answer 14

True

Question 15

Hot nodules prognosis

Answer 15

almost always benign, Cold nodule 15-25% cancer risk in the nodule

Question 16

If cold nodule is found on I-123 scan, what is the next imaging test?

Answer 16

Ultrasound

Question 17

What is the best imaging test to differentiate solid vs. cystic nodule?

Answer 17

Ultrasound

Question 18

What is the first imaging test if TSH is low?

Answer 18

I 123 scan-

Question 19

What is the first imaging test if TSH is normal or high?

Answer 19

I 123 scan-