Melanie McColgan, lead sonographer at Altnagelvin Hospital, explains the process of detecting thyroid cancer through ultrasound imaging.
By recognising the key ultrasound findings associated with thyroid cancer, sonographers can play a pivotal role in aiding accurate diagnosis and timely intervention.
This article will outline six key points followed by five reflection points to enhance your expertise in detecting thyroid carcinoma through ultrasound imaging.
Six key points:
1. Thyroid cancer is the most common endocrine cancer and is usually asymptomatic until the patient presents with a neck swelling. It is sometimes an incidental finding during an ultrasound scan of the carotid arteries.
2. All neck scans performed should be performed by practitioners who are competent in full neck ultrasound assessment such as the 7 sweep technique (BMUS, 2021).
3. All thyroid nodules should be assessed for shape, size, outline, echogenicity and vascularity.
4. Nodules should be classified using the British Thyroid Association (BTA) Guidelines (2014):
U1 Normal (no nodules)
U2 Benign
U3 Indeterminate/Equivocal
U4 Suspicious
U5 Malignant
Benign features:
Thin-walled micro-cysts giving a spongiform appearance
Hyperechoic foci with ‘ring-down’ sign of colloid within a cystic nodule
Eggshell (peripheral) calcification
Peripheral vascularity with colour or power Doppler
Hyperechoic or isoechoic lesion in relation to thyroid parenchyma, often with a hypoechoic halo
Malignant characteristics:
Solid hypoechoic nodule
Micro calcifications
Disrupted peripheral calcification of a solid hypoechoic nodule
Shape of the nodule (‘taller rather than wide’), with ‘tall’ being defined as increased anterior posterior diameter
Irregular outline
Marked intra-nodular vascularity
5.With mixed solid/cystic nodules, the solid portion should be analysed for malignant characteristics. With multinodular disease, the score given should be that of the most suspicious nodule. Retrosternal extension or tracheal deviation should be noted.
6. Full assessment of the neck for nodal disease is essential, particularly with U3 – U5 nodules. Patients with nodules that are characterised as U3 / U4 / U5 should be assessed by ENT and have FNA of the nodule to confirm diagnosis.
Reflection prompts:
What characteristics would you look at to assess a thyroid nodule?
Which scanning method is used in your department and are all ultrasound practitioners using the same technique?
What are common benign features of a thyroid nodule?
What are the ultrasound features associated with malignancy?
What other neck anatomy should be assessed at time of scan on discovering an equivocal, suspicious or malignant nodule?
What course of action would you take in your local department, on discovering a U3 – U5 nodule?
Further reading:
Ahuja, A. (2019) Diagnostic Ultrasound: Head and Neck, 2nd Edition. Canada, Amirsys. ISBN: 978-0-323-62572-2
BMUS (2021) Head and neck ultrasound practice standards. Available at: https://www.bmus.org/static/uploads/resources/Neck_Standards_and_Competencies_2021.pdf
eLearning for Healthcare: My eLearning > Clinical Imaging> 20 Ultrasound – Head and Neck 20_01 Thyroid and Parathyroid
National Institute for Health and Care Excellence (2022) Thyroid cancer: assessment and management. NICE guideline [NG230]. Available at: https://www.nice.org.uk/guidance/ng230
Perros P, Boelaert K, Colley S, Evans C, Evans RM, Gerrard Ba G, Gilbert J, Harrison B, Johnson SJ, Giles TE, Moss L, Lewington V, Newbold K, Taylor J, Thakker RV, Watkinson J, Williams GR; British Thyroid Association. Guidelines for the management of thyroid cancer. Clin Endocrinol (Oxf). 2014 Jul;81 Suppl 1:1-122. doi: 10.1111/cen.12515. PMID: 2498989.
(Image: Photo by Science Photo Library via GettyImages)