Elastography of the thyroid

• Published in: Diagnostic and interventional imaging Vol. 94; no. 5; pp. 535 - 544
• Main Authors: Monpeyssen, H, Tramalloni, J, Poirée, S, Hélénon, O, Correas, J.-M
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01-05-2013
• Subjects: Adenocarcinoma, Follicular - diagnostic imaging; Adenocarcinoma, Follicular - pathology; Adenocarcinoma, Papillary - diagnostic imaging; Adenocarcinoma, Papillary - pathology; Biopsy, Fine-Needle; Cancer; Carcinoma, Medullary - diagnostic imaging; Carcinoma, Medullary - pathology; Diagnosis, Differential; Elasticity Imaging Techniques - methods; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Lymphatic Metastasis - diagnostic imaging; Lymphatic Metastasis - pathology; Quasi-static elastography; Radiology; Sensitivity and Specificity; Shear wave elastography; Thyroid; Thyroid Gland - diagnostic imaging; Thyroid Gland - pathology; Thyroid Neoplasms - diagnostic imaging; Thyroid Neoplasms - pathology; Thyroid Nodule - diagnostic imaging; Thyroid Nodule - pathology; Ultrasonography, Interventional; Shear wave elastography; Quasi-static elastography; Thyroid; Cancer
• ISSN: 2211-5684; 2211-5684
• DOI: 10.1016/j.diii.2013.01.023

Abstract Thyroid nodules are very common, while thyroid cancer is rare and has a very good prognosis. Thyroid nodule ultrasound characterization performed by experienced clinicians allows the selection of the tumours to be punctured and guiding fine needle aspiration (FNA). FNA provide cytology information able to differentiate benign tumours from cancer in approximately 80% of cases. However, it remains difficult to identify thyroid cancers with ultrasound imaging, as demonstrated by the very low rate of cancers detected in all of the carried out FNA (approximately 5%). As a majority of thyroid cancers are hard, the stiffness evaluation has become part of nodular characterization. Since 2005, elastography has been used for the evaluation of thyroid nodules; quasi-static elastography was the first technique available and used, at first, an external pressure induced by the probe, which was then replaced by carotid internal excitation allowing improvement in sensitivity. Semi-quantitative analysis allows comparison of tissue elasticities between tissue with elasticity anomalies and normal tissue and provides therefore useful analytic information. Shear wave elastography (SWE) provides a map of the elasticity in a region and allows stiffness quantification of lesions in kilopascals in order to reinforce the predictive value of malignancy. A tumour whose stiffness is greater than 65 kPa or for which the stiffness ratio is greater than 3.7 compared to surrounding healthy tissue is highly suspicious. SWE may enable the detection of malignant follicular tumours that currently escape detection by the ultrasound-guided ultrasound/aspiration cytology couple. Lymph node metastasis of papillary thyroid cancer can also be detected by elastography due to its increased stiffness.