Thyroid Imaging Recommendations

Initial Thyroid Imaging

The American College of Radiology recommends ultrasound as the first-line imaging modality for evaluating thyroid disease, with additional imaging modalities selected based on specific clinical scenarios 1, 2
Ultrasound is the most appropriate initial imaging for palpable thyroid nodules in euthyroid patients without goiter due to its superior sensitivity and specificity for nodule detection and characterization 1, 2

The American College of Radiology recommends ultrasound as the first-line imaging for suspected goiter to confirm thyroid origin and characterize goiter morphology 1, 3
CT without IV contrast should be added when there is suspicion for substernal extension, as CT is superior for evaluating the extent of tracheal compression 1, 3
MRI is an alternative to CT for goiter evaluation but is less preferred due to greater respiratory motion artifact 4, 3

The American College of Radiology recommends three equivalent first-line imaging options for thyrotoxicosis: thyroid ultrasound, I-123 radionuclide uptake and scan, and I-131 radionuclide uptake with Tc-99m pertechnetate scan 1, 4
Radionuclide uptake confirms that the entire goiter consists of thyroid tissue and helps identify hypofunctioning or isofunctioning nodules for biopsy 4

The American College of Radiology recommends ultrasound as the most appropriate preoperative imaging for differentiated thyroid cancer 1
CT with IV contrast should be added for higher-stage disease or when there are concerns about invasive features or bulky nodal disease 1, 2
For suspected recurrence of differentiated thyroid cancer, both ultrasound and I-123 whole-body scan are recommended as complementary procedures 1

The American College of Radiology notes that ultrasound has several advantages, including being the most sensitive for detecting thyroid nodules, superior specificity for cervical lymph node evaluation, and cost-effective and non-invasive 2
However, ultrasound has limitations, including being limited in evaluating inferior disease borders and mediastinal structure involvement, and may miss lymph node metastases in the central compartment and retropharyngeal space 2

The American College of Radiology recommends CT scans for evaluation of substernal goiter extension, assessment of tracheal compression, evaluation of invasive primary tumors, assessment of bulky lymph node involvement, and delineation of laryngeal, tracheal, esophageal, or vascular involvement 1, 3, 2

The American College of Radiology advises against relying solely on CT or MRI to differentiate between benign and malignant nodules, as these modalities have limited utility for this purpose, and against using imaging alone to predict malignancy 1