High-Resolution Ultrasound is Required for Thyroid Nodule Evaluation
Patients need a high-frequency ultrasound examination of the thyroid to properly evaluate for nodules, as this is the most accurate and cost-effective imaging method for thyroid nodule detection and characterization. 1, 2
Ultrasound Specifications and Technique
- High-frequency ultrasound is the preferred imaging modality for thyroid nodule evaluation due to its accuracy, safety, and ability to detect nodules as small as 5mm 3
- Complete ultrasound examination should include evaluation of both the thyroid gland and cervical lymph nodes to detect any suspicious features 4, 1
- Ultrasound should be performed by specialists with expertise in thyroid sonography to ensure optimal imaging quality and interpretation 5
- Routine thyroid ultrasound screening is not recommended for the general population but should be performed when there is clinical suspicion of thyroid disease 5
Key Ultrasound Features to Assess
- Solid vs. cystic composition (solid nodules carry higher malignancy risk) 1
- Echogenicity (hypoechoic nodules are more suspicious for malignancy) 1
- Margins (irregular or ill-defined margins suggest malignancy) 2
- Presence of calcifications (microcalcifications are concerning for malignancy) 1
- Vascularity pattern (intranodular vascularity is more suspicious) 2
- Size and shape of nodules (irregular shape is concerning) 1, 2
Follow-up After Ultrasound
- Fine-needle aspiration biopsy (FNAB) guided by ultrasound is the preferred next step for suspicious nodules 3, 1
- FNAB should be considered for nodules ≥1cm depending on ultrasound features 1, 5
- Smaller nodules (<1cm) may warrant FNAB if they have suspicious ultrasound features 1
- For nodules with indeterminate FNAB results, core needle biopsy (CNB) may be necessary 3
Special Considerations
- Ultrasound-guided FNAB has higher sensitivity, specificity, and accuracy than palpation-guided techniques 2
- Ultrasound guidance is particularly beneficial for nonpalpable nodules, multiple nodules, or when nodule palpation is difficult 2
- The relationship between nodule size and malignancy risk is complex - smaller nodules (<2cm) may actually have higher malignancy rates than larger ones 6
- Nodule size at ultrasound shows relatively good correlation with final pathologic size, which is important for treatment planning 6
Common Pitfalls to Avoid
- Relying solely on nodule size to determine malignancy risk (size alone is a poor predictor) 6
- Failing to evaluate cervical lymph nodes during the ultrasound examination 4
- Not using ultrasound guidance for FNAB, which can lead to sampling errors 1, 2
- Performing routine thyroid ultrasound screening in low-risk individuals without clinical indication 5, 7