Practical Application of Elastography in the Diagnosis of Thyroid Nodules in Children and Adolescents

Ultrasound Elastography in Children

Ultrasound elastography is a novel ultrasound technique, being extensively researched in children in the last decade. It measures tissue elasticity with the observation of tissue response after an external stimulus. From research to clinical practice, ultrasound elastography has evolved significantly in liver fibrosis evaluation in children; however, several other applications of the technique are available in both clinical practice and research environments. Practically, in children any organ can be assessed, including the brain in early ages, along with muscle and connective tissue elasticity evaluation, spleen, kidney, skin, lymphatic tissue, etc. The elastography method, age, body mass index and technical points should be considered when performing ultrasound elastography. This review highlights its vast potential as a diagnostic tool in the pediatric population, where ultrasound is a dominant imaging tool; however, the indications and exam protocol for its clinical use in several fields in pediatrics have yet to be elucidated.

Elastographic Evaluation of Thyroid Nodules in Children and Adolescents with Hashimoto’s Thyroiditis and Nodular Goiter with Reference to Cytological and/or Histopathological Diagnosis

There are data indicating the coexistence of papillary thyroid carcinoma and autoimmune thyroiditis (AIT) in children. The aim of the study was elastographic evaluation of thyroid nodules in children and adolescents with AIT and nodular goiter in relation to cytological and/or histopathological diagnosis. We examined 215 children (57 boys and 158 girls) with 261 thyroid nodules (143 non-AIT and 118 AIT). All study participants underwent a conventional ultrasound examination with elastography followed by fine needle aspiration biopsy (FNAB). Abnormal Strain Ratio (SR ≥ 5) was observed in 36 non-AIT nodules and 15 AIT nodules. Papillary thyroid carcinoma was diagnosed in 5 patients (2% of all investigated nodules). SR of malignant thyroid nodules was statistically higher in comparison to SR of benign nodules both in the group of non-AIT (6 ± 4 vs. 3.67 ± 2.62, p = 0.024) and AIT nodules (6.3 ± 0.01 vs. 2.92 ± 1.89, p = 0.047). Comparison of non-AIT and AIT benign nodules revealed that SR was higher in non-AIT nodules (3.67 ± 2.62 vs. 2.92 ± 1.89, p = 0.01). We observed a strong positive correlation (R = 1) between TSH concentration and SR ratio in the group of all malignant thyroid nodules. Autoimmune inflammatory process of the thyroid gland does not limit the use of elastography in the diagnosis of thyroid nodules in children.

Ultrasound elastography in children - nice to have for scientific studies or arrived in clinical routine?

Ultrasound elastography (USE) is a modality that in addition to fundamental B-mode, Doppler, and contrast-enhanced sonography is suitable to make qualitative and quantitative statements about the stiffness of tissues. Introduced more than 20 years ago in adults, USE becomes now a diagnostic tool also in children. The aim of this paper is to describe current available techniques for USE in children. The significance for routine use in children is shown, and further interesting applications are reported.

Suspected Malignant Thyroid Nodules in Children and Adolescents According to Ultrasound Elastography and Ultrasound-Based Risk Stratification Systems-Experience from One Center

The risk of malignancy in thyroid nodules correlates with the presence of ultrasonographic features. In adults, ultrasound risk-classification systems have been proposed to indicate the need for further invasive diagnosis. Furthermore, elastography has been shown to support differential diagnosis of thyroid nodules. The purpose of our study was to assess the application of the American Thyroid Association (ATA), British Thyroid Association (BTA) ultrasound risk-classification systems and strain elastography in the management of thyroid nodules in children and adolescents from one center. Seventeen nodules with Bethesda III, IV, V and VI were selected from 165 focal lesions in children. All patients underwent ultrasonography and elastography followed by fine needle aspiration biopsy. Ultrasonographic features according to the ATA and BTA stratification systems were assessed retrospectively. The strain ratio in the group of thyroid nodules diagnosed as malignant was significantly higher than in benign nodules (6.07 vs. 3.09, p = 0.036). According to the ATA guidelines, 100% of malignant nodules were classified as high suspicion and 73% of benign nodules were assessed as low suspicion. Using the BTA U-score classification, 80% of malignant nodules were classified as cancerous (U5) and 20% as suspicious for malignancy (U4). Among benign nodules, 82% were classified as indeterminate or equivocal (U3) and 9% as benign (U2). Our results suggest that application of the ATA or BTA stratification system and elastography may be a suitable method for assessing the level of suspected malignancy in thyroid nodules in children and help make a clinical decision about the need for further invasive diagnosis of thyroid nodules in children.

Thyroid Cancer Risk Factors in Children with Thyroid Nodules: A One-Center Study

Thyroid nodules are common in the adult population (13%), but in childhood, they are relatively rarely diagnosed (0.2–5%). The risk factors and diagnostic and therapeutic algorithms are well-known and effectively used in adults, but no clear procedures supported by scientific research are available in the pediatric population. Our aim in this study was to identify predictive factors for thyroid cancer in a pediatric population. We retrospectively analyzed 112 children (80 girls and 32 boys, aged 0.6–18 years, with an average group age of 13.4 ± 4.5 years) with thyroid nodules who presented or were referred between 2010 and 2021. A total of 37 children qualified for partial or total thyroidectomy. After histopathological nodule examination, the most common cases were benign lesions in 23 patients (57.5%) and malignant lesions in 14 children (32.5%). Solitary benign thyroid nodules were found in 16 children (40%). Malignancy risk was higher in children with increased nodule diameter (greater than 7 mm; p = 0.018) or hypoechogenic lesions in ultrasound (p = 0.010), with no correlation between increased blood flow in the vessels and tumor diagnosis. The relative risk of developing thyroid cancer for class III was found to be higher in comparison to adults and 11.1 times higher than for classes I and II combined.

Accuracy of shear wave elastography in characterization of thyroid nodules in children and adolescents

BACKGROUND

Thyroid nodules are an important health problem in children and adolescents. They possess a higher risk of malignancy in comparison to adults. This fact forms a great dilemma for clinicians. The aim of this study was to evaluate the reliability of shear wave elastography (SWE) as a non-invasive technique in the characterization of thyroid nodules in children and adolescents.

METHODS

This prospective study included 56 patients with thyroid nodules. All the patients underwent clinical assessment, laboratory investigations, ultrasound, and Doppler examination, followed by an SWE assessment. Statistical analysis was performed and the best cut-off value to differentiate benign from malignant nodules was determined using the ROC curve and AUC.

RESULTS

Seventy-two nodules were detected in the examined patients (ages ranged from 11 to 19 years, with mean age of 14.89 ± 2.3 years). Fifty-eight nodules (80.6%) were benign, and fourteen nodules (19.4%) were malignant (histopathologically proved). Highly suspicious criteria for prediction of malignancy by ultrasound and Doppler were hypoechoic echopattern, internal or internal and peripheral vascularity, microcalcifications, taller-than-wide dimensions, irregular outlines, and absence of halo (p < 0.05). The diagnostic performance for their summation was 70.69% sensitivity, 82.8% specificity, 80.45% accuracy, a 63.79% positive predictive value (PPV), and 87.9% negative predictive values (NPV). Regarding SWE, our results showed that 42.2 kPa was the best cut-off value, with AUC = 0.921 to differentiate malignant from benign nodules; the diagnostic performance was 85.71% sensitivity, 94.83% specificity, 93.06% accuracy, 76.9% PPV, and 93.2% NPV.

CONCLUSION

Shear wave elastography is a non-invasive technique that can assist in the diagnosis of malignant thyroid nodules among children and adolescents.

Pediatric thyroid ultrasound: a radiologist's checklist

Ultrasonography (US) is the imaging method of choice for evaluating the pediatric thyroid gland, complemented by scintigraphy and thyroid function tests, especially when evaluating children with suspected congenital hypothyroidism, goiter, infectious or autoimmune diseases, or neoplasm. Diagnostic considerations in newborns with congenital hypothyroidism mainly include dysgenesis, dyshormonogenesis, transient hypothyroidism and central (hypophyseal) hypothyroidism. The midline of the neck should be scrutinized for thyroid tissue from the floor of the mouth to the thoracic inlet. Cystic and echogenic ultimobranchial remnants should not be misinterpreted as orthotopic thyroid tissue. Diffuse thyroid diseases affect older children; these comprise Hashimoto and Graves diseases and infectious thyroiditis and exhibit features similar to those in adults. It is important to note that the diffuse sclerosing variant of papillary thyroid cancer can complicate thyroiditis and should not be confused with Hashimoto disease. In children with solid nodules the threshold for fine-needle aspiration biopsy or surgery should be lower compared to adults because of a higher likelihood of malignancy compared with adults. Biopsy should be considered in nodules with suspicious ultrasonographic features, even when smaller than 1 cm. Adult classification systems of thyroid nodules, although useful, are not sufficient to safely discriminate the nodules' likelihood of malignancy in children. We describe key sonographic findings and suggest a standard checklist that might be considered while performing and interpreting thyroid US in neonates and children.

Imaging and Imaging-Based Management of Pediatric Thyroid Nodules

Thyroid nodules are less frequent in children than adults. Childhood thyroid nodules carry specific features, including a higher risk of malignancy than nodules in adults, rendering them unique in terms of management. Subsequently, they should be considered a distinct clinical entity with specific imaging recommendations. Initial evaluation requires a thorough workup, including clinical examination, and a detailed personal and familial history to determine the presence of possible risk factors. Laboratory and radiologic evaluation play an integral part in the diagnostic algorithm, with ultrasonography (US) being the first diagnostic test in all patients. US elastography has been recently introduced as an incremental method, reducing the subjectivity of the clinical diagnosis of nodule firmness associated with increased malignancy risk. However, fine-needle aspiration biopsy (FNAB) remains the mainstay in the diagnostic work-up of thyroid nodules and is documented to be best method for differentiating benign from malignant thyroid nodules. In addition, thyroid scintigraphy provides functional imaging information, which has a role both in the diagnostic management of thyroid nodules and during follow up in malignancies. Finally, despite providing additional information in certain clinical scenarios, ¹⁸F-fludeoxyglucose Positron Emission Tomography (¹⁸F-FDG-PET), computed tomography (CT), and magnetic resonance imaging (MRI) imaging are not routinely recommended for the evaluation of patients with newly detected thyroid nodules or in all cases of thyroid cancer. The objective of this review is to summarize the concepts in imaging and imaging-based management of nodular thyroid disease in the pediatric population, acknowledging the unique features that this patient group carries and the specific approach it requires.

Elastography for the evaluation of thyroid nodules in pediatric patients

Objective

To evaluate the usefulness of elastography (using manual compression) as an additional diagnostic tool for children and adolescents with thyroid nodules.

Materials and Methods

This was a prospective study conducted between September 2012 and August 2013 at a hospital in Brazil. We performed elastography, ultrasound, and fine-needle aspiration biopsy in 32 patients between 6 and 18 years of age who had, in total, 38 thyroid nodules.

Results

The elastography findings correlated with the histopathological diagnosis in 78.5% of cases. In three patients, an unnecessary thyroidectomy could have been avoided if the elastography results had been prioritized. Only one malignant thyroid nodule was found to show high elasticity.

Conclusion

Our results suggest that high elasticity of a nodule on elastography is associated with a low risk of thyroid cancer. If further confirmed in other studies, elastography may prove useful as a complementary test for screening thyroid nodules in children.

The Influence of the Manner of Performing the Thyroid Ultrasound Examination on the Reliability of the Assessment of the Thyroid Size in School-Aged Children

BACKGROUND/AIMS

Goitre incidence in school-aged children evaluated using ultrasonography is one of the essential indicators of iodine intake in a given area. The aim of the study was to examine what the difference is between the volume of the thyroid gland measured in the supine and sitting position and to determine the intra-observer, inter-observer, and inter-position variations.

METHODS

The survey was conducted among 87 children (56 girls and 31 boys aged 7-13 years, mean age 10.44 ± 1.72 years).

RESULTS

The thyroid volume measured in a sitting position was significantly lower than that measured in the supine position. The intra-observer variations for the total thyroid volume equalled 9.56-9.65%. The inter-observer variations were significantly higher and amounted to 34.5-35.7%.

CONCLUSIONS

The way in which ultrasound evaluation is performed is important for the analysis of the results. It is crucial to aim for the smallest inter-observer variation, which can be achieved by strictly defining the methods of the thyroid measurement and comparing one's measuring techniques with the reference method. The use of standards in ultrasound evaluation performed in the supine position, as well as the use of standards without a strict determination of the study method, can lead to erro-neous conclusions.

Utility of adult-based ultrasound malignancy risk stratifications in pediatric thyroid nodules

BACKGROUND

Individual ultrasound (US) features have limited ability to distinguish benign from malignant thyroid nodules. Adult-based systems have been developed to integrate the sonographic features in an effort to improve diagnostic accuracy. None, however, has been validated in children, in whom the likelihood of malignancy is 2-5 times higher than adults.

OBJECTIVE

To assess the performance of two adult-based sonographic (US) stratification methods for assessment of thyroid nodules in children.

MATERIALS AND METHODS

This retrospective study comprised 124 children who underwent thyroid US. Three radiologists reviewed the US data using the American Thyroid Association (ATA) and the Thyroid Image Reporting and Data System (TI-RADS). Radiologists' accuracy and agreement was assessed. The reference standard was histopathology/cytology or 2-year follow-up of clinical outcome for nonoperative cases.

RESULTS

We assessed 71 benign and 52 malignant nodules and excluded 1 nodule. Using the ATA pattern descriptions, 80% of malignant nodules were classified as "high" 36/52 (69%) or "intermediate" 6/52 (11%) likelihood of malignancy. A total of 20/71 (28%) benign nodules were also classified within these two categories. Using the TI-RADS, malignant nodules were classified as 2, 3, 4a, 4b, 4c and 5, with rate of malignancy of 0%, 0%, 7/52 (13.5%), 7/52 (13.5%), 32/52 (61.5%) and 6/52 (11.5%), respectively. Benign nodules were also classified in the 4a (26/71; 36.6%), 4b (17/71; 24%), 4c (14/71; 19.7%) and 5 (1/71; 1.4%) categories. The positive and negative predictive values were 68.0% and 87.5% for ATA, and 71.7% and 80.0% for TI-RADS.

CONCLUSION

We validated the use of ATA and TI-RADS methods in children and showed that they have test characteristics similar to those in adults, although neither is independently sufficient to discriminate nodules' likelihood of malignancy.