ARFI elastography for the evaluation of diffuse thyroid gland pathology: Preliminary results

Two-Dimensional Shear-Wave Elastography of the Thyroid in Clinically Healthy Dogs in Different Age Groups

The thyroid of dogs has not been extensively studied in 2D shear-wave elastography, making it challenging to apply this technique in the diagnosis of thyroid diseases in a non-invasive manner. The aim of this study is to evaluate the thyroid glands of healthy dogs using 2D shear-wave elastography in order to establish qualitative and quantitative parameters of tissue stiffness in dogs in different age groups. A total of 31 dogs of various breeds, sexes, and sizes were evaluated. Animals with clinical signs or ultrasound findings indicative of endocrine disease or thyroid lesions were excluded from the study. The shear-wave velocity data in meters per second (m/s) and color elastograms were evaluated and calculated using QelaXto™ 2D software. A healthy thyroid exhibits a blue-color elastogram, indicative of low stiffness. The reference range for the shear-wave velocity of thyroid tissue assessed by 2D shear-wave elastography can be between 1.6 and 2.0 m/s, with a variation of ±0.889 in adult and senior dogs.

Evaluation of thyroid congestion in patients with heart failure using shear wave elastography: An observational study

Shear wave elastography (SWE) is a noninvasive method for measuring organ stiffness. Liver stiffness measured using SWE reflects hepatic congestion in patients with heart failure (HF). However, little is known about the use of SWE to assess other organ congestions. This study aimed to evaluate the utility of SWE for assessing not only the liver but also thyroid congestion in patients with HF. This prospective study included 21 patients with HF who have normal thyroid lobes (age: 77.0 ± 11.0, men: 14). Thyroid and liver stiffness were measured by SWE using the ARIETTA 850 ultrasonography system (Fujifilm Ltd., Tokyo, Japan). SWE of the thyroid was performed on B-mode ultrasonography; a target region was identified within a region of interest. SWE was performed in each lobe of the thyroid gland. Five measurements were taken at the same location and the averages were recorded for comparison. We investigated the relationship between SWE for evaluating thyroid stiffness and the clinical characteristics of patients with HF. SWE of the thyroid was significantly correlated with SWE of the liver (R = 0.768, P < .001), thyroid stimulation hormone (R = 0.570, P = .011), free thyroxine (R = 0.493, P = .032), estimated right atrial pressure (RAP; R = 0.468, P = .033), and composite congestion score (R = 0.441, P = .045). SWE may be useful for evaluating thyroid stiffness and assessing the degree of thyroid congestion. Thyroid congestion may reflect the elevation of RAP and cause thyroid dysfunction through organ congestion.

Factors Affecting Thyroid Elastography in Healthy Children and Patients with Hashimoto’s Thyroiditis

OBJECTIVE

Hashimoto’s thyroiditis (HT) is the most common form of thyroiditis in childhood. In addition to thyroid ultrasonography, shear-wave elastography (SWE) can evaluate thyroid parenchyma tissue stiffness, and more detailed findings can be obtained with this method. We aimed to evaluate the relationship between SWE values and clinical, biochemical and hormonal parameters of patients with HT and in healthy individuals.

METHODS

We compared 46 newly diagnosed HT cases with 46 healthy controls. We examined the effect of all metabolic parameters and thyroid-related markers on SWE values.

RESULTS

The mean SWE values in those patients with euthyroid HT were 12.5±5.1 kilopascal (kPa), whereas it was 8.2±2.82 kPa in healthy controls (p<0.001). Although the clinical [age, gender and body mass index (BMI)] and laboratory parameters (such as thyroid function tests, homeostasis model assessment of insulin resistance, insulin-like growth factor-1 values, which we think may affect SWE scores) of those children with HT and the healthy controls were statistically similar (p>0.05), except for their thyroid autoantibodies and thyroglobulin, SWE values and thyroid volume were significantly higher in those individuals with HT (p<0.001). Multiple linear regression analysis was performed to evaluate the direction and degree of the effect of the variables on thyroid elasticity scores. It was observed that age (p=0.002), BMI standard deviation score (SDS) (p=0.04) and anti-thyroid peroxidase (p=0.008) levels were effective on the thyroid elasticity score in the regression model. We detected a SWE cut-off value of 9.68 kPa with 68% sensitivity and 72% specificity, a 70% positive predictive value, and a 69% negative predictive value in thyroid elastography when differentiating between cases with HT and healthy controls.

CONCLUSION

Our results show that no metabolic factor other than BMI SDS has any effect on SWE scores, especially in healthy children. There was a positive correlation between BMI SDS and SWE in healthy children (r=0.353; p=0.02), but not in those patients with HT (r=0.196; p=0.19). Likewise, age is another factor affecting SWE only in healthy children. We do not recommend routine evaluation of any laboratory parameters other than thyroid functions before thyroid elastography.

Can thyroid elastography with ultrasound be used to stage children with Hashimoto's thyroiditis?

OBJECTIVES

We aimed to evaluate the stiffness of the thyroid parenchyma with Shear wave elastography (SWE) in children with Hashimoto's thyroiditis (HT) and healthy controls.

METHODS

A total of 130 children with HT and 46 healthy controls were included in this study. The clinical and laboratory characteristics of the groups, thyroiditis stages in thyroid ultrasonography, and SWE scores which was obtained as kilopascal (kPa), were analysed.

RESULTS

We observed that SWE scores were significantly higher in children with HT compared to healthy controls, and SWE scores increased significantly in HT group, as the thyroiditis stage increased (p<0.001). Median, 1st (Q1) and 3rd (Q3) quartiles of SWE scores were as follows; healthy control: 7.4 kPa (6-10.6), stage 1 HT: 9.6 kPa (7.4-11.2), stage 2 HT: 15.2 kPa (10.8-19.9), stage 3 HT: 17.9 kPa (13.7-25.8), (p<0.001). Children with HT were divided into subgroups according to serum TSH and free T4 levels as euthyroid (103; 79.2% of children), euthyroid but subclinical TSH elevation (7; 5.4% of children), hypothyroidism (11; 8.5% of children) and hyperthyroidism (9; 6.9% of children). The SWE scores were significantly higher in children with hypothyroidism with HT compared to healthy controls 17.9 kPa (13.6-27.5) vs. 7.4 kPa (6-10.6), and in euthyroid children with HT compared to healthy controls 11.5 kPa (9.2-15.6) vs. 7.4 kPa (6-10.6), (p=0.006 and p<0.001, respectively).

CONCLUSIONS

The SWE scores increase as the thyroiditis stage increases in children with HT. There was no significant difference in SWE scores between stage 2 and stage 3 thyroiditis.

Quantitative Diagnosis Progress of Ultrasound Imaging Technology in Thyroid Diffuse Diseases

High-frequency ultrasound (HFUS), the imaging modality of choice for thyroid screening, is most commonly used in the study of diffuse thyroid disease (DTD) with Hashimoto's thyroiditis (HT) and Graves' disease (GD). DTD can involve thyroid function and severely affect life quality, so early diagnosis is important for the development of timely clinical intervention strategies. Previously, the diagnosis of DTD relied on qualitative ultrasound imaging and related laboratory tests. In recent years, with the development of multimodal imaging and intelligent medicine, ultrasound and other diagnostic imaging techniques have gradually become more widely used for quantitative assessment of the structure and function of DTD. In this paper, we review the current status and progress of quantitative diagnostic ultrasound imaging techniques for DTD.

Shear wave elastography as a quantitative method for thyroid gland elasticity assessment in pediatrics patients with autoimmune-related thyroid disease, diagnostic utility and laboratory correlation

Background

Autoimmune thyroiditis (AIT) is the most common thyroid pathology in pediatric patients among which Hashimoto’s thyroiditis has the highest prevalence. Along with size, measuring mechano-acoustic tissue elasticity is evolving as an important parameter in the evaluation of diffuse thyroid pathology. This study aims to investigate the role of shear wave elastography (SWE) in the diagnosis of autoimmune thyroid disease (AITD) in the pediatric population and also compare the elasticity between them and healthy individuals.

Results

This case–control analytical study was carried out on 64 pediatric subjects ranging in age from 7 to 17 years. All the cases were diagnosed as AIT by anti-thyroid antibodies, and their thyroid function was evaluated by thyroid hormones. We performed thyroid Ultrasonography and Shear wave elastography. Patients with AIT had significantly higher elasticity values (35.6 kPa, IQR 8.43–103.7 kPa) than the control group (9.35 kPa, IQR 5.73–13.21 kPa). There was no correlation of elasticity values of thyroid gland in patients with AIT with autoantibodies and thyroid function test, respectively. The cutoff value for elasticity was 12.317 kPa with sensitivity and specificity of 96.9% and 100%, respectively.

Conclusions

SWE is a highly sensitive imaging method integrating routine ultrasonography in the diagnosis of AITD which estimates the extent of fibrosis in numerical value.

Reliability of shear wave elastography in the evaluation of diffuse thyroid diseases in children and adolescents

PURPOSE

Thyroid diseases are common yet serious in children that lead to many metabolic and growth disorders; the most common among these are diffuse thyroid diseases (DTD). This study aimed to evaluate the reliability of shear wave elastography (SWE) to differentiate and diagnose DTD from normal thyroid tissue.

METHOD

This prospective study included normal participants and patients with DTD. The subjects were assessed by clinical evaluation, laboratory investigation, conventional ultrasound, and Doppler examination, followed by SWE assessments. Statistical analysis was performed using the t-test and one-way ANOVA test, as appropriate. Receiver operating characteristic (ROC) curves were used to determine the best cutoff values to differentiate healthy participants from those with DTD and to differentiate between different types of DTD.

RESULTS

The study included 74 patients with DTD and 20 healthy participants. The mean SWE values were 10.9 ± 1.78, 12.8 ± 2.1, 15.31 ± 2.95, and 17.26 ± 4.2 kPa for the normal participants and for patients with simple goiter, Hashimoto's thyroiditis (HT), or Grave's disease (GD), respectively. Statistically significant differences were noted between the mean SWE of the normal participants and that of patients with DTD, as well as between the mean SWE of patients with different types of DTD (P < 0.05). The best SWE cutoff values to differentiate a normal thyroid from DTD, HT from GD, HT from simple goiter, and GD from simple goiter were 12.8, 17.8, 13.4, and 13.9 kPa, respectively.

CONCLUSIONS

SWE is a reliable diagnostic tool for differentiating normal thyroid tissue from DTD, as well as for differentiating between different types of DTD.

Variation of Shear Wave Elastography With Preload in the Thyroid: Quantitative Validation

OBJECTIVES

Thyroid shear wave elastography (SWE) has been shown to have advantages compared to biopsy or other imaging modalities in the evaluation of thyroid nodules. However, studies show variability in its assessment. The objective of this study was to evaluate whether stiffness measurements of the normal thyroid, as estimated by SWE, varied due to preload force or the pressure applied between the transducer and the patient.

METHODS

In this study, a measurement system was attached to the ultrasound transducer to measure the applied load. Shear wave elastographic measurements were obtained from the left lobe of the thyroid at applied transducer forces between 2 and 10 N. A linear mixed-effects model was constructed to quantify the association between the preload force and stiffness while accounting for correlations between repeated measurements within each participant. The preload force effect on elasticity was modeled by both linear and quadratic terms to account for a possible nonlinear association between these variables.

RESULTS

Nineteen healthy volunteers without known thyroid disease participated in the study. The participants had a mean age ± SD of 36 ± 8 years; 74% were female; 74% had a normal body mass index; and 95% were white non-Hispanic/Latino. The estimated elastographic value at a 2-N preload force was 16.7 kPa (95% confidence interval, 14.1-19.3 kPa), whereas the value at 10 N was 29.9 kPa (95% confidence interval, 24.9-34.9 kPa).

CONCLUSIONS

The preload force was significantly and nonlinearly associated with SWE estimates of thyroid stiffness. Quantitative standardization of preload forces in the assessment of thyroid nodules using elastography is an integral factor for improving the accuracy of thyroid nodule evaluation.

Evaluation of the Stiffness of Thyroid Parenchyma With Shear Wave Elastography Using a Free-Region of Interest Technique in Graves Disease

OBJECTIVES

The first aim was to evaluate the stiffness of thyroid parenchyma with shear wave elastography (SWE) in patients with Graves disease (GD) and compare the elastographic values with those of asymptomatic volunteers. The second aim was to evaluate whether there was a correlation between SWE values and grayscale ultrasound (US) and laboratory parameters.

METHODS

In this prospective study, the thyroid gland parenchyma of 50 patients whose clinical and laboratory findings were indicative for GD and 54 asymptomatic participants with normal laboratory values was examined by SWE. Grayscale US images of the thyroid and submandibular gland were recorded. The volume of the thyroid gland was measured. Elastographic measurements were performed with a free region of interest. The quantitative SWE values (meters per second and kilopascals) of the patient and control groups were compared. A correlation analysis between the SWE values and grayscale US and laboratory parameters was performed.

RESULTS

The median (range) SWE values of the thyroid gland in patients with GD were significantly higher than those of the control group [17.34 (12.58-56.15) versus 12.05 (7.72-23.67) kPa and 2.28 (1.83-4.12) versus 1.92 (1.55-2.61) m/s; P < .001 for both comparisons]. When 14.5 kPa or 2.115 m/s was designated as the cutoff value, GD could be diagnosed with a high sensitivity and specificity. We showed a negative weak correlation between the SWE values and parenchymal echogenicity in the GD group.

CONCLUSIONS

Shear wave elastography can be used as an effective imaging method with high sensitivity and specificity rates in the diagnosis of GD.

Assessment of thyroid gland elasticity with shear-wave elastography in Hashimoto's thyroiditis patients

PURPOSE

We aimed to investigate the use and effectiveness of Shear-Wave Elastography (SWE) in Hashimoto's Thyroiditis (HT) diagnosis and compare the SWE values in HT patients with asymptomatic volunteers.

METHODS

The thyroid gland parenchyma of 74 patients whose clinical and laboratory findings and ultrasonography (US) features were indicative of HT and 75 healthy, asymptomatic participants with normal laboratory values were examined using SWE. Their thyroid parenchymal echoes and thyroid gland volume were measured using B-mode US examination. Elastographic measurements were made by plotting the boundaries of thyroid gland by hand, using Free Region of Interest (ROI). The quantitative SWE values [meters/second (m/s) and kilopascal (kPa)] were compared betweent the patients and the controls. The correlation analyses between the SWE measurements and the autoantibodies [Anti-thyroid peroxidase antibody (TPOAbs) and anti-thyroglobulin antibodies (TgAbs)], thyroid-stimulating hormone (TSH), freetriiodothyronine (fT3), free-thyroxine (fT4), and thyroglobulin levels were performed.

RESULTS

The mean thyroid SWE measurement values of HT group were significantly higher than the asymptomatic group (p < 0.001). This study proposes 29.45 kPa or 2.77 m/s as a sensitive-spesific cut-off value for HT. We revealed significant positive association between SWE values and TgAb levels, gland volume, TgAb, TPOAb levels, and a significant negative association between SWE and echogenicity (p < 0.001).

CONCLUSION

In the assessment of HT, SWE is a highly sensitive imaging method to estimate the degree of fibrosis and to provide objective numerical values.

Quantitative Assessment of Thyroid Glands in Healthy Children With Shear Wave Elastography

The local shear wave speed (in meters per second) and Young modulus (in kilopascals) of normal thyroid glands were defined in healthy children to determine reference values.This prospective study assessed 107 pediatric cases (age interval, 3-17 years; mean, 9.37 ± 3.68 years), including 52 boys and 55 girls. The study group included children without thyroid gland disease (autoimmune, infectious, or neoplastic). Data about the sex, age, weight, height, and body mass index (BMI) of the subjects were recorded for all subjects. Elasticity values were measured from 3 different sites in both thyroid lobes and averaged.Median values for elasticity and shear wave velocity measured in bilateral thyroid lobes were 6.38 ± 1.97 kPa (range, 3.00-12.5 kPa) and 1.45 ± 0.21 m/s (range, 1.03-2.04 m/s) on the right and 8.81 ± 3.00 kPa (range, 3.80-22.6 kPa) and 1.69 ± 0.26 m/s (range, 1.13-2.68 m/s) on the left. There was no significant difference between the elasticity values for the right and left thyroid lobes between boys and girls. There was a positive correlation between right thyroid lobe mean elasticity (in kilopascals) and shear wave velocity (in meters per second) values with age, BMI, and right thyroid lobe volume in the whole group. No significant correlation was found between left thyroid lobe mean elasticity (in kilopascals) and shear wave velocity (in meters per second) values with age, BMI, and left thyroid lobe volume in the study population.This study determined mean elasticity and shear wave velocity values for thyroid gland in healthy children. This information can be used as a baseline for the investigation of thyroid diseases.

Acoustic Radiation Force Impulse Imaging With Virtual Touch Tissue Quantification Enables Characterization of Mild Hypoxic-Ischemic Brain Damage in Neonatal Rats

OBJECTIVES

The aim of this study was to investigate whether the measurement of brain tissue stiffness using acoustic radiation force impulse (ARFI) elastography with virtual touch tissue quantification can improve the early detection of neonatal hypoxic-ischemic brain damage in rats.

METHODS

Seven-day-old Sprague-Dawley rats were randomly assigned to 3 groups: the mild asphyxia (n = 30), moderate asphyxia (n = 30), and sham control (n = 10) groups. Rats in the mild and moderate asphyxia groups were exposed to 8% oxygen (hypoxia) for 30 and 60 minutes, respectively, at 1 hour after ligation of the right common carotid artery. An ultrasound diagnostic instrument was used to obtain 2-dimensional ultrasound images, and ARFI with virtual touch tissue quantification was used to measure shear wave velocity preoperatively and at 12, 24, 48, and 72 hours postoperatively. Hematoxylin-eosin staining was used to evaluate brain damage.

RESULTS

Two-dimensional ultrasound imaging detected swelling and increased echogenicity at 48 to 72 hours in the mild asphyxia group and at 24 to 72 hours in the moderate asphyxia group. The shear wave velocity substantially increased from 0.65 ± 0.04 m/s preoperatively to 0.78 ± 0.07 m/s at 72 hours in the moderate asphyxia group and from 0.64 ± 0.04 m/s preoperatively to 0.70 ± 0.03 m/s at 72 hours in the mild asphyxia group. The changes in the shear wave velocity coincided with the histopathologic changes in the brain, which included neuronal demyelination, hyperplasia, and necrosis; edema around vascular structures; and hemorrhage in the ependymal and periventricular areas.

CONCLUSION

Shear wave velocity data obtained with the virtual touch tissue quantification technique may be used for early diagnosis of neonatal hypoxic-ischemic brain damage.

Evaluation of Normal Thyroid Tissue and Autoimmune Thyroiditis in Children Using Shear Wave Elastography

OBJECTIVE

Shear wave elastography (SWE) is a user-independent ultrasonographic technique that evaluates tissue elasticity. It is used especially in the evaluation of thyroiditis and thyroid nodules when it is capable of distinguishing malignant from benign thyroiditis in adults. To date, no studies have evaluated SWE in pediatric thyroid patients. The aim of this study was to measure the elasticity of normal thyroid tissue in children and adolescents using SWE and to investigate its role in the diagnosis of pediatric autoimmune thyroiditis.

METHODS

In total, 113 healthy children of whom 66 (58.4%) were girls and 57 children with autoimmune thyroiditis of whom 45 (78.9%) were girls were evaluated by SWE after B-mode ultrasound. The quantitative evaluation of normal thyroid tissue in healthy children and those with autoimmune thyroiditis was performed using shear wave velocity (SWV) values (m/s). Thyroid antibodies were consistent with autoimmune thyroiditis. Data were compared using descriptive and analytical statistics and receiver-operating characteristic curves.

RESULTS

The mean ± standard deviation (range) of SWV value in thyroid parenchyma of the healthy children was 1.82±0.3 m/s (1.32-2.37) m/s. There was a significant positive correlation between age and SWV values which increased with age. The average SWV value of thyroid parenchyma in children with autoimmune thyroiditis was 3.7±1.2 (2.59-6.25) m/s which was statistically significantly greater than in healthy children (p=0.00). The cut-off value for elasticity with the highest diagnostic accuracy was 2.39 m/s; sensitivity and specificity were 97.4% and 100% respectively. There was no correlation between elasticity, thyroid function tests and autoantibody concentrations (p>0.05).

CONCLUSION

SWE is a useful imaging method that can be used with routine ultrasonography in evaluation of the thyroid in children.

Multifactor Analysis of Thyroid Stiffness in Graves Disease: A Preliminary Study

OBJECTIVE. The aim of this study was to evaluate the value of shear wave elastography (SWE) in Graves disease (GD) and to identify the potential factors influencing thyroid stiffness. MATERIALS AND METHODS. A total of 207 subjects were enrolled and underwent SWE examination in the study, including 162 patients with GD and 45 healthy volunteers with normal thyroids, matched for age and sex. For all subjects, five measurements of elastic modulus values (SWE mean, SWE minimum, and SWE maximum of a 9-mm ROI) were performed on each thyroid lobe, and a mean value was calculated. The indicators including free three-triiodothyronine (FT₃), free thyroxine (FT₄), thyroid-stimulating hormone (TSH), thyroid size, isthmus thickness, anti-thyroid peroxidase (TPO) antibodies (Abs), and antithyroglobulin (TG) Abs were detected in the 162 patients with GD, among whom 88 patients underwent initial TSH receptor (TR) Ab examination. RESULTS. The elastic modulus values for patient with GD were significantly higher than those for healthy control subjects. The ROC AUC values for GD by SWE mean was 0.656, and the cutoff value was 15.45 kPa. The sensitivity and specificity were 56.8% and 71.1%, respectively. The duration of disease, thyroid size, isthmus thickness, and levels of TPO Ab, TG Ab, and TR Ab were positively correlated with SWE mean in GD. However, there was no correlation between age, FT₃, FT₄, TSH, and SWE mean. CONCLUSION. Quantitative SWE helps in the diagnosis of GD. The duration of disease, thyroid size, isthmus thickness, and levels of thyroid autoantibodies (TPO Ab, TG Ab, and TR Ab) could influence thyroid stiffness of GD.

Ultrasound elastography of the thyroid: principles and current status

Ultrasound (US) elastography has been introduced as a non-invasive technique for evaluating thyroid diseases. This paper presents a detailed description of the technical principles, peculiarities, and limitations of US elastography techniques, including strain elastography and shear-wave elastography. This review was conducted from a clinical perspective, and aimed to assess the usefulness of US elastography for thyroid diseases in specific clinical scenarios. Although its main focus is on thyroid nodules, the applications of US elastography for other thyroid diseases, such as diffuse thyroid diseases and thyroiditis, are also presented. Furthermore, unresolved questions and directions for future research are also discussed.

Quantitative Assessment of Thyroid, Submandibular, and Parotid Glands Elasticity With Shear-Wave Elastography in Children

Tissue elasticity is becoming a more commonly used parameter in evaluation of parenchyma in inflammatory diseases. Considering the changes in the thyroid and salivary glands with adolescence, determination of mean elasticity ranges with a function of age is necessary to apply ultrasound elastography more widely in the pediatric population.The thyroid, submandibular, and parotid glands of 127 healthy volunteers (66 males, 61 females; mean age = 10.3 ± 3.9 years; range = 3-17 years) were evaluated with shear-wave elastography.The mean elasticity values for the thyroid, submandibular, and parotid glands were 14.6 ± 3.3, 11.8 ± 2.2, and 11.8 ± 2.6 kPa, respectively. There was a significant positive correlation between age and elasticity of the thyroid, submandibular, and parotid glands. There was a significant correlation between age and elasticity value of the thyroid gland adjusted for weight and height.This study provided the baseline quantitative elasticity measures of thyroid, submandibular, and parotid glands, which would be a reference for upcoming studies. In addition, an increase in elasticity value in thyroid gland as a function of age independent of change in weight and height was demonstrated.

Clinical efficacy of novel elastography using acoustic radiation force impulse (ARFI) for diagnosis of malignant thyroid nodules

Objective

Acoustic radiation force impulse (ARFI) imaging is a recent ultrasound elastography technique; consequently, its efficacy is not fully known. In this study, we compared ARFI imaging with conventional strain elastography (SE) and shear wave velocities (SWVs) to evaluate the utility of ARFI imaging for diagnosing thyroid nodules.

Subjects and Methods

In this study we examined 233 thyroid nodules (183 benign nodules and 50 malignant nodules) isolated from human patients. The nodules were evaluated with SE and ARFI imaging, and SWVs of the nodules were simultaneously measured. ARFI images were classified using a four‐point score based on grayscale intensity of the images. The sensitivity, specificity, and diagnostic accuracy were compared between SE and ARFI imaging. Finally, SWVs for each score of SE and ARFI imaging were compared.

Results

The new scoring system for ARFI imaging can be divided into four virtual touch imaging (VTI) scores. Nodules with a VTI score of 3 or 4 as determined by ARFI imaging were determined to be malignant. The sensitivity, specificity, and diagnostic accuracy, respectively, were 63.2%, 66.3%, and 65.6% for SE, compared with 80.0%, 86.3%, and 85.0% for ARFI imaging. The median SWVs of the nodules were 1.57 m/s, 1.73 m/s, 1.88 m/s, and 2.09 m/s for VTI scores of 1, 2, 3, and 4, respectively. The SWVs of VTI scores 3 and 4 were significantly higher than those of VTI scores 1 and 2.

Conclusions

The diagnostic accuracy of ARFI imaging for differentiating malignant thyroid nodules was higher than that of SE. The VTI scores of the nodules accurately reflected their SWVs.

Level of Evidence

4

Acoustic Radiation Force Impulse Quantification in the Evaluation of Thyroid Elasticity in Pediatric Patients With Hashimoto Thyroiditis

OBJECTIVES

To evaluate the parenchymal elasticity of the thyroid gland with acoustic radiation force impulse imaging in pediatric patients with Hashimoto thyroiditis and to compare it with healthy volunteers.

METHODS

Twenty-six patients with Hashimoto thyroiditis and 26 healthy volunteers between 6 and 17 years were included. The shear wave velocity (SWV) values of both thyroid lobes in both groups were evaluated.

RESULTS

The age and sex characteristics of the controls and patients with Hashimoto thyroiditis were similar. The SWV of the thyroid gland in patients with Hashimoto thyroiditis (mean ± SD, 1.67 ± 0.63 m/s) was significantly higher than that in the control group (1.30 ± 0.13 m/s; P < .001). There was no significant difference between the thyroid lobes in both groups. A receiver operating characteristic curve analyses showed an optimal cutoff value of 1.41 m/s, with 73.1% sensitivity, 80.8% specificity, a 79.2 % positive predictive value, and a 75.0% negative predictive value (area under the curve, 0.806; P < .001). In patients with Hashimoto thyroiditis, there was a positive correlation between the SWV values versus anti-thyroperoxidase (Pearson r = 0.46; P = .038). There were no correlations between age, body mass index, thyroid function test results, and anti-thyroglobulin values and versus SWV values. Also, no significant differences were seen between the groups for gland size, gland vascularity, and l-thyroxine treatment.

CONCLUSIONS

Acoustic radiation force impulse elastography showed a significant difference in the stiffness of the thyroid gland between children with Hashimoto thyroiditis and the healthy group. Using acoustic radiation force impulse elastography immediately after a standard ultrasound evaluation may predict chronic autoimmune thyroiditis.

Shear wave elastography in the diagnostics of parathyroid adenomas-new application of the method

PURPOSE

Shear wave elastography (SWE) was described as valuable tool in the diagnostics of distinct types of thyroid lesions, thyroiditis and several other non-thyroidal conditions, such as liver inflammation and fibrosis or diagnostics of breast lesions. The aim of the current study was to assess the appearance of parathyroid adenomas in SWE and to check prospectively if SWE can be valuable additional tool in the diagnostics of pathologically enlarged parathyroids.

METHODS

Patients with parathyroid adenomas confirmed by histopathology were included. Subjects with benign thyroid lesions were enrolled to the control group. Elasticity of parathyroid adenomas and benign thyroid nodules was measured and compared.

RESULTS

Sixty five patients with parathyroid adenomas and 35 patients with 51 benign thyroid nodules were included. Parathyroid adenomas where significantly more elastic than benign thyroid nodules-mean elasticity of the lesion was 5.2 ± 7.2 vs. 24.3 ± 33.8 kPa, respectively. Relative mean elasticity (in comparison with surrounding thyroid tissue) was 0.30 ± 0.36 and 2.8 ± 3.9, respectively.

CONCLUSIONS

SWE can be useful tool in the diagnostics of parathyroid adenomas. Enlarged parathyroids are significantly more elastic than benign thyroid lesions. Low elasticity of the lesion constitutes feature with high negative prognostic value, allowing for reliable exclusion of suspicion of parathyroid adenomas.

Principles of ultrasound elastography

Tissue stiffness has long been known to be a biomarker of tissue pathology. Ultrasound elastography measures tissue mechanical properties by monitoring the response of tissue to acoustic energy. Different elastographic techniques have been applied to many different tissues and diseases. Depending on the pathology, patient-based factors, and ultrasound operator-based factors, these techniques vary in accuracy and reliability. In this review, we discuss the physical principles of ultrasound elastography, discuss differences between different ultrasound elastographic techniques, and review the advantages and disadvantages of these techniques in clinical practice.

The diagnostic performances of conventional strain elastography (SE), acoustic radiation force impulse (ARFI) imaging and point shear-wave speed (pSWS) measurement for non-calcified thyroid nodules

BACKGROUND

Non-calcified thyroid nodules are relatively difficult to diagnose only relying on features of at conventional US images.

OBJECTIVE

To investigate the diagnostic performances of conventional strain elastography (SE), acoustic radiation force impulse (ARFI) SE and point shear-wave speed (pSWS) measurement for non-calcified thyroid nodules.

METHODS

A total of 201 non-calcified thyroid nodules in 195 patients were studied. They were examined with conventional ultrasound (US), conventional SE, ARFI SE and pSWS measurement. Their diagnostic performances and multivariable models were assessed with receiver operating characteristic (ROC) curve and logistic regression analyses respectively.

RESULTS

There were 156 benign and 45 malignant non-calcified nodules proven by histopathology or cystology. The mean diameters of the nodules were 21.2±10.8 mm. Areas under receiver operating characteristic curve (AUCs) of elastography features (ranged, 0.488-0.745) were all greater than that of US (ranged, 0.111-0.332). At multivariate analysis, there were three predictors of malignancy for non-calcified nodules, including pSWS of nodule (odds ratio [OR], 34.960; 95% CI, 11.582-105.529), marked hypoechogenicity (OR, 16.223; 95% CI, 1.761-149.454) and ARFI SE grade (OR, 10.900; 95% CI, 3.567-33.310). US+SE+pSWS owned the largest AUC (0.936; 95% CI, 0.887-0.985; P < 0.05), followed by US+pSWS (0.889; 95% CI, 0.823-0.955), and the poorest was US (0.727; 95% CI, 0.635-0.819).

CONCLUSIONS

ARFI SE and pSWS measurement had better diagnostic performances than conventional SE and US. When US combined with SE and pSWS measurement, it could achieve an excellent diagnostic performance and might contribute a better decision-making of FNA for non-calcified thyroid nodules.

Comparison of Virtual Touch Tissue Quantification and Virtual Touch Tissue Imaging Quantification for diagnosis of solid breast tumors of different sizes

BACKGROUND

Acoustic radiation force impulse imaging (ARFI) with Virtual Touch Tissue Quantification (VTQ) or Virtual Touch Tissue Imaging Quantification (VTIQ) measures shear wave velocity (SWV), which is proportional to tissue stiffness, a diagnostic parameter for malignancy.

OBJECTIVE

To compare the performance of VTQ and VTIQ in diagnosing solid breast tumors.

METHODS

Conventional ultrasound, VTQ and VTIQ were used to examine 246 solid breast tumors from 230 patients. Tumors were grouped according to size: <10 mm, 10-20 mm, >20 mm. Pathological diagnoses were via histological examination of biopsies. ROC curves were used to assess diagnostic performance and optimal cut-off points for VTQ and VTIQ.

RESULTS

For all sizes, SWVVTQ and SWVVTIQ were higher for malignant versus benign tumors (P < 0.05). SWVVTQ and SWVVTIQ were both higher for tumors≥10 mm (P < 0.05). Areas under the ROC curves (diagnostic performance index; 0.860-0.952) did not differ significantly between VTQ and VTIQ. Optimal cut-off values for SWVVTQ and SWVVTIQ were higher for tumors≥10 mm.

CONCLUSION

The diagnostic performance of VTQ and VTIQ was moderate to good for solid breast tumors. Although both methods have higher sensitivities in tumors≥10 mm, their overall diagnostic performance was similar for all sizes.

WFUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography: Part 4. Thyroid

The World Federation for Ultrasound in Medicine and Biology (WFUMB) has produced guidelines for the use of elastography techniques including basic science, breast and liver. Here we present elastography in thyroid diseases. For each available technique, procedure, reproducibility, results and limitations are analyzed and recommendations are given. Finally, recommendations are given based on the level of evidence of the published literature and on the WFUMB expert group's consensus. The document has a clinical perspective and is aimed at assessing the usefulness of elastography in the management of thyroid diseases.

In Vitro Comparison of Five Different Elastography Systems for Clinical Applications, Using Strain and Shear Wave Technology

Several different platforms providing ultrasound elastography have emerged in recent years. In this in vitro study on a single tissue-mimicking phantom (CIRS Model 49), we aimed to compare the performance of quantitative elastography measurements from platforms running strain elastography and others running shear wave elastography. We evaluated five different elastography platforms using both linear and curvilinear probes. All measurements were performed in parallel by two independent investigators who recorded the elasticity quantitatively. We investigated intra- and inter-observer agreement by intra-class correlation analysis and coefficient of variation, by correlation and limits of agreement. The reproducibility of elasticity measurements was good to excellent for shear wave and strain elastography. All five elastography platforms had high intra-observer (intra-class correlation coefficient: 0.932-1.0) and inter-observer correlation (intra-class correlation coefficient: 0.845-0.996). All inclusions could be differentiated by quantitative elastography by all systems (p < 0.001). The use of a linear probe yielded more reproducible measurements compared with use of a convex probe in 3/4 platforms.

Calcification of thyroid nodules increases shear-wave speed (SWS) measurement: using multiple calcification-specific SWS cutoff values outperforms a single uniform cutoff value in diagnosing malignant thyroid nodules

Conventional ultrasound cannot satisfactorily distinguish malignant and benign thyroid nodules. Shear-wave elastography (SWE) can evaluate tissue stiffness and complement conventional ultrasound in diagnosing malignant nodules. However, calcification of nodules may affect the results of SWE. The purposes of this study are to compare the differences of shear-wave speed (SWS) measurement among different calcification groups and compare the diagnostic performance between using a single uniform SWS cutoff value and multiple individual calcification-specific cutoff values using technique of point SWS measurement. We retrospectively identified 517 thyroid nodules (346 benign and 171 malignant nodules) examined by conventional ultrasound and point SWS measurement. There were 177 non-calcified, 159 micro-calcified and 181 macro-calcified nodules. The diagnostic performance was evaluated by receiver operating characteristic (ROC) curve and area under the curve (AUC) was computed. The mean SWS in malignant nodules more than doubled that of benign nodules (4.81±2.03 m/s vs. 2.29±0.99 m/s, p<0.001). The mean SWS of nodules progressively increased from the non-calcification (2.60±1.49 m/s), to micro-calcification (3.27±1.85 m/s) and to macro-calcification (3.68±2.26 m/s) groups (p<0.001), which was true in both the benign and malignant nodules. If we used individual SWS cutoff values for non- (SWS >2.42 m/s), micro- (SWS >2.88 m/s) and macro-calcification (SWS >3.59 m/s) nodules in the whole group, the AUC was 0.859 (95% confidence interval [CI], 0.826-0.888), which was significantly better than the AUC of 0.816 (95% CI, 0.780-0.848) if a single uniform cutoff value (SWS >2.72 m/s) was applied to all the nodules regardless of calcification status (p=0.011). The cutoff values of SWS for different calcified nodules warrant future prospective validation.

Effect of liposomal local therapy on salivary glands in acoustic radiation force impulse imaging in Sjögren's syndrome

The purpose of this study was to evaluate the utility of acoustic radiation force impulse (ARFI) imaging as a monitoring tool for the effect of a liposomal local therapy in patients with dry mouth symptoms due to primary Sjögren's syndrome (pSS). Fifty patients with pSS, diagnosed according to the American-European Consensus Group (AECG) criteria, were included. Clinical data were collected, and sonographic examination including ARFI imaging of the parotid and submandibular glands was performed. Subjective symptoms were evaluated via visual analogue scales (VAS), and the unstimulated whole salivary flow was measured. After a two-month period of liposomal local therapy, sonographic examination was repeated and both subjective and objective symptoms were re-evaluated. Before local treatment, the mean ARFI value of parotid glands was 2.96 m/s (SD 0.97). Mean ARFI value of the submandibular glands was 2.09 m/s (SD 0.71). After the two-month treatment period, a significant decline of ARFI values in the parotid glands to a value of 2.34 m/s (SD 0.70, p < 0.001) could be observed. The submandibular glands did not show any significant change. Further, a significant reduction of the subjective sensation of dry mouth symptoms could be observed (p = 0.0001). With the application of ARFI imaging, a decline in parotid gland stiffness could be observed in patients with primary Sjögren's Syndrome accompanied by a significant improvement of the subjective sensation of dry mouth symptoms. The seromucous submandibular glands did not show any changes compared to the serous parotid glands.

ARFI: from basic principles to clinical applications in diffuse chronic disease-a review

Abstract

The many factors influencing the shear wave velocity (SWV) measured with Acoustic Radiation Force Impulse (ARFI) are examined in order to define the most correct examination technique. In particular, attention is given to the information achieved by experimental models, such as phantoms and animal studies. This review targets the clinical applications of ARFI in the evaluation of chronic diffuse disease, especially of liver and kidneys. The contribution of ARFI to the clinical workout of these patients and some possible perspectives are described.

Teaching Points

• Stiffness significantly varies among normal and abnormal biological tissues.

• In clinical applications physical, geometrical, anatomical and physiological factors influence the SWV.

• Elastographic techniques can quantify fibrosis, which is directly related to stiffness.

• ARFI can be useful in chronic diffuse disease of liver and kidney.

Sonographic Elastography of the Thyroid Gland

Thyroid gland disorders include benign and malignant thyroid nodules and diffuse thyroid disorders. The incidence of malignant thyroid nodules is low and the prognosis is good. The diagnosis of thyroid cancer and diffuse parenchymal disorders is generally based on clinical manifestations and histopathological evaluation. Ultrasonography has its place in the diagnostics and follow-up of thyroid disorders. Ultrasonographic elastography is a new, developing method that shows increase in clinical practice. In this study, we aimed to review the data on thyroid ultrasound elastography.

Ultrasound elastographic techniques in focal liver lesions

Elastographic techniques are new ultrasound-based imaging techniques developed to estimate tissue deformability/stiffness. Several ultrasound elastographic approaches have been developed, such as static elastography, transient elastography and acoustic radiation force imaging methods, which include point shear wave and shear wave imaging elastography. The application of these methods in clinical practice aims at estimating the mechanical tissues properties. One of the main settings for the application of these tools has been liver stiffness assessment in chronic liver disease, which has been studied mainly using transient elastography. Another field of application for these techniques is the assessment of focal lesions, detected by ultrasound in organs such as pancreas, prostate, breast, thyroid, lymph nodes. Considering the frequency and importance of the detection of focal liver lesions through routine ultrasound, some studies have also aimed to assess the role that elestography can play in studying the stiffness of different types of liver lesions, in order to predict their nature and thus offer valuable non-invasive methods for the diagnosis of liver masses.

Assessment of the Stiffness of Major Salivary Glands in Primary Sjögren's Syndrome through Quantitative Acoustic Radiation Force Impulse Imaging

The purpose of the study described here was to evaluate salivary gland stiffness in primary Sjögren's syndrome (pSS) via acoustic radiation force impulse imaging, including Virtual Touch tissue quantification (VTQ) and Virtual Touch tissue imaging quantification (VTIQ). Twenty-one patients with pSS and 11 healthy patients were included, and the paired parotid and submandibular glands of all of the patients were examined using VTQ and VTIQ. Differences between the two groups were compared with independent and paired t-tests. The VTQ value for the parotid in the pSS group was significantly higher than that obtained for the control group (1.33 ± 0.22 and 1.18 ± 0.04 m/s, respectively, p < 0.01). The VTIQ values for the parotid and submandibular gland were both significantly higher in the pSS group than in the control group (p < 0.05). In the pSS group, a positive correlation was observed between the VTQ and VTIQ results for the parotid and submandibular glands. In summary, the stiffness of the major salivary glands in patients with pSS was increased compared with that of patients with normal glands. This finding indicates that VTQ and VTIQ imaging may be valuable adjuncts to gray-scale ultrasonography for the clinical diagnosis of pSS.

Diagnostic performance of thyroid ultrasonography screening in pediatric patients with a hypothyroid, hyperthyroid or euthyroid goiter

BACKGROUND

Goiter is frequently the first indicator of thyroid disease in children.

OBJECTIVE

To evaluate the usefulness of ultrasonography (US) in the identification of potential malignant nodules and autoimmune thyroiditis in children with diffuse goiter.

MATERIALS AND METHODS

This study consisted of 113 patients <20 years with a diffuse goiter who underwent thyroid US. Parenchymal echogenicity and the presence of nodules and abnormal lymph nodes were evaluated on US; if a thyroid nodule was detected, its characteristics were analyzed. The diagnostic accuracy of the US findings in the diagnosis of autoimmune thyroid disease was assessed.

RESULTS

Thyroid nodules were detected on US in 72 of the 113 (63.7%) patients. Of these, 65 (90.3%) had probably benign nodules and 4 (5.6%) patients had nodules suspicious of malignancy. The remaining had indeterminate nodules only. In one child with suspected malignant nodules, papillary thyroid cancer with coexisting autoimmune thyroiditis was confirmed. Hypoechogenicity was visualized in 23 (88.5%) patients with autoimmune thyroiditis and 12 (85.7%) with Graves disease. The sensitivity and specificity of micronodulation for autoimmune thyroiditis were 53.9% and 98.3%, respectively.

CONCLUSION

Although the potential for malignant nodules is relatively low in children with diffuse goiter, US can detect focal thyroid disease and characterize the nodules. US thus plays a useful role in excluding autoimmune thyroiditis in this population.

Impact of Fibrotic Tissue on Shear Wave Velocity in Thyroid: An Ex Vivo Study with Fresh Thyroid Specimens

We sought to elucidate the correlation between shear wave velocity (SWV) and fibrosis in thyroid by precisely assessing pathological structures inside 5 × 5 mm(2) regions of interest (ROIs) of resected specimens, under conditions that excluded physical artifacts. The materials were unselected thyroid and lymph node specimens resected during thyroid surgery. Immediately after surgery, fresh unfixed thyroid and metastatic lymph node specimens were suspended in gel phantoms, and SWV was measured. Upon pathological examination of each specimen, the extent of fibrosis was graded as none, moderate, or severe. A total of 109 specimens were evaluated: 15 normal thyroid, 16 autoimmune thyroiditis, 40 malignant nodules, 19 benign thyroid nodules, and 19 metastatic lymph nodes. When all specimens were classified according to the degree of fibrosis determined by pathological imaging, the mean SWV was 1.49 ± 0.39 m/s for no fibrosis, 2.13 ± 0.66 m/s for moderate fibrosis, and 2.68 ± 0.82 m/s for severe fibrosis. The SWVs of samples with moderate and severe fibrosis were significantly higher than those of samples without fibrosis. The results of this study demonstrate that fibrosis plays an important role in determining stiffness, as measured by SWV in thyroid.

Quantitative Shear Wave Velocity Measurement on Acoustic Radiation Force Impulse Elastography for Differential Diagnosis between Benign and Malignant Thyroid Nodules: A Meta-analysis

The aim of this study was to evaluate the diagnostic performance of quantitative shear wave velocity (SWV) measurement on acoustic radiation force impulse (ARFI) elastography for differentiation between benign and malignant thyroid nodules using meta-analysis. The databases of PubMed and the Web of Science were searched. Studies published in English on assessment of the sensitivity and specificity of ARFI elastography for the differentiation of thyroid nodules were collected. The quantitative measurement of ARFI elastography was evaluated by SWV (m/s). Meta-Disc Version 1.4 software was used to describe and calculate the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and summary receiver operating characteristic curves. We analyzed a total of 13 studies, which included 1,854 thyroid nodules (including 1,339 benign nodules and 515 malignant nodules) from 1,641 patients. The summary sensitivity and specificity for differential diagnosis between benign and malignant thyroid nodules by SWV were 0.81 (95% confidence interval [CI]: 0.77-0.84) and 0.84 (95% CI: 0.81-0.86), respectively. The pooled positive and negative likelihood ratios were 5.21 (95% CI: 3.56-7.62) and 0.23 (95% CI: 0.17-0.32), respectively. The pooled diagnostic odds ratio was 27.53 (95% CI: 14.58-52.01), and the area under the summary receiver operating characteristic curve was 0.91 (Q* = 0.84). In conclusion, SWV measurement on ARFI elastography has high sensitivity and specificity for differential diagnosis between benign and malignant thyroid nodules and can be used in combination with conventional ultrasound.

Different extent of hypoxic-ischemic brain damage in newborn rats: histopathology, hemodynamic, virtual touch tissue quantification and neurobehavioral observation

OBJECTIVE

To explore the correlation between pathological and ultrasound changes applying conventional ultrasound, Color Doppler ultrasound andVirtual Touch Tissue Quantification (VTQ) technique in newborn hypoxic-ischemic brain damage (HIBD) rat models. To provide theoretical basis for early diagnosis and treatment of HIBD neonatal.

METHODS

A total of 90 newborn Wistar rats were divided into ischemia, asphyxia and control group according to different HIBD molding methods. Conventional ultrasound, Color Doppler ultrasound and VTQ were applied on 3 h, 12 h, 24 h, 48 h and 72 h postoperative. After the observation of 72 h, 10 rats in each group were randomly selected for pathological specimens production. The rest rats were raised for 30 days for neuroethology detection.

RESULTS

In ischemia group and asphyxia group, there were 4 deaths and 6 deaths in the modeling process; the mortality rate was 13.33% (4/30) and 20.00% (6/30) respectively. For ischemia group, the systoli velocity (Vs), diastolic velocity (Vd) and resistance index (RI) of right middle cerebral artery (MCA) were significantly decreased after operation (P<0.05). For asphyxia group, the Vs and RI of right MCA were significantly decreased after operation (P<0.05), while the Vd of right MCA was significantly increased after operation (P<0.05), which lead to the postoperative RI value in each time point was all significantly lower than that in ischemia group (P<0.05). For ischemia group and asphyxia group, the VTQ results increased significantly postoperative (P<0.05), and compared with ischemia group and control group, the postoperative VTQ value in each time point was all significantly higher in asphyxia group (P<0.05). The neuroethology results were significantly lower in the ischemia group and asphyxia group (P<0.05), and the results in ischemia group were significantly higher than those of asphyxia group (P<0.05). And the results are consistent with the pathological findings.

CONCLUSION

There is a consistent correlation among histopathological changes, hemodynamic changes, VTQ values and neuroethology results in HIBD animal models. As noninvasive quantitative ultrasound elastography methods, Color Doppler ultrasound and VTQ can assess the extent of HIBD damages in newborn rats with specific values. This study provides basic research and theory to early diagnosis and early treatment of neonatal hypoxic-ischemic brain damage.

Acoustic Radiation Force Impulse Elastography in the Diagnosis of Thyroid Nodules: Useful or Not Useful?

The goal of this study is to evaluate the diagnostic performance of acoustic radiation force impulse (ARFI) elastography for differentiating benign from malignant thyroid nodules. One hundred and seventy-four pathologically proven thyroid nodules (139 benign, 35 malignant) in 154 patients (mean age: 49.2 ± 12.1 y; range: 16-72 y) were included in this study. Conventional ultrasound (US) and ARFI elastography using virtual touch tissue imaging (VTI) and virtual touch tissue quantification (VTQ) were performed to examine the thyroid nodules. Two blinded readers with different amounts of experience independently scored the likelihood of malignancy on the basis of a five-point scale in three different image-reading sets. The diagnostic performances among different image-reading sets and between the two readers were compared. The diagnostic specificity of both readers improved significantly after reading the VTI images or both VTI and VTQ images (all p < 0.05). After review of the results of both VTI and VTQ, the numbers of correctly diagnosed nodules increased in nodules <1.0 cm for both readers and in both nodular goiter and papillary thyroid carcinoma for the junior reader (p < 0.05). The nodules with definite diagnoses (i.e., confidence levels including definite benign and definite malignant cases) increased after review of VTI and VTQ images versus conventional US for the senior reader (p < 0.05). In conclusion, adding ARFI elastography improves the specificity in diagnosing malignant thyroid nodules compared with conventional US on its own. ARFI elastography particularly facilitates the specific diagnosis for thyroid nodules smaller than 1.0 cm. ARFI elastography is also able to increase the diagnostic confidence of the readers.

Correlation between quantitative shear wave elastography and pathologic structures of thyroid lesions

The aim of this study was to determine the correlation between shear wave velocity (SWV) generated by acoustic radiation force impulse and the pathologic structure of thyroid lesions. A total of 599 thyroid tissue samples were divided into four groups based on pathologic structure: 254 normal thyroid tissue samples as a control, 128 with chronic autoimmune thyroiditis (CAT) that demonstrated diffuse fibrosis, 165 with benign nodules that had high cell density and 52 with papillary thyroid carcinoma (PTC) that showed high cell density and fibrosis. The mean SWVs in each group were as follows: 1.60 ± 0.18 m/s in normal thyroid, 2.55 ± 0.28 m/s in CAT, 1.72 ± 0.31 m/s in benign nodules and 2.66 ± 0.95 m/s in PTC. The SWVs of CAT and PTC were significantly higher than those of normal thyroid, (p < 0.001). SWV was significantly affected by fibrosis.

Utility of Shear Wave Elastography for Diagnosing Chronic Autoimmune Thyroiditis

The aims of this study were to evaluate the utility of shear wave elastography (SWE) using acoustic radiation force impulse (ARFI) for diagnosing chronic autoimmune thyroiditis (CAT) and to verify the effect of fibrotic thyroid tissue on shear wave velocity (SWV). The subjects were 229 patients with 253 normal thyroid lobes (controls) and 150 CAT lobes. The SWV for CAT (2.47 ± 0.57 m/s) was significantly higher than that for controls (1.59 ± 0.41 m/s) (P < 0.001). The area under the receiver operating characteristics (ROC) curve for CAT was 0.899, and the SWV cut-off value was 1.96 m/s. The sensitivity, specificity, and diagnostic accuracy were 87.4%, 78.7%, and 85.1%, respectively. Levels of anti-thyroperoxidase antibodies and thyroid isthmus thickness were correlated with tissue stiffness in CAT. However, there was no correlation between levels of anti-thyroglobulin antibodies and tissue stiffness. Quantitative SWE is useful for diagnosing CAT, and it is possible that SWE can be used to evaluate the degree of fibrosis in patients with CAT.

Real-time shear wave elastography may predict autoimmune thyroid disease

OBJECTIVE

To evaluate and compare the values of the elasticity index as measured by shear wave elastography in healthy subjects and in patients with autoimmune thyroid disease, in order to establish if this investigation can predict the occurrence of autoimmune thyroid disease.

METHODS

A total of 104 cases were included in the study group: 91 women (87.5%), out of which 52 (50%) with autoimmune thyroid disease diagnosed by specific tests and 52 (50%) healthy volunteers, matched for age and gender. For all the subjects, three measurements were performed on each thyroid lobe and a mean value was calculated. The data were expressed in kPa. The investigation was performed with an Aixplorer system (SuperSonic Imagine, France), using a linear high-resolution 15-4 MHz transducer.

RESULTS

The mean value for the elasticity index was similar in the right and the left thyroid lobes, both in normal subjects and in patients with autoimmune thyroid disease: 19.6 ± 6.6 vs. 19.5 ± 6.8 kPa, p = 0.92, and 26.6 ± 10.0 vs. 25.8 ± 11.7 kPa, p = 0.71, respectively. This parameter was significantly higher in patients with autoimmune thyroid disease than in controls (p < 0.001). For a cut-off value of 22.3 kPa, which resulted in the highest sum of sensitivity and specificity, the elasticity index assessed by shear wave elastography had a sensitivity of 59.6% and a specificity of 76.9% (AUROC = 0.71; p < 0.001) for predicting the presence of autoimmune thyroid disease.

CONCLUSION

Quantitative elasticity index measured by shear wave elastography was significantly higher in autoimmune thyroid disease than in normal thyroid parenchyma and may predict the presence of autoimmune thyroid disease.

Shear Wave Velocity: A New Quantitative Index to Estimate the Status of Thyroid in Diffuse Thyroid Disease

Objective. The purpose of the study was to assess the application value of VTQ in DTD. Research Design and Methods. Thirty healthy subjects and 74 DTD patients were involved. The thyroid stiffness, which was expressed by SWV, was measured by VTQ and compared between the patients and healthy people. The relationship between SWV and thyroid serological indexes was also analyzed. Results. The thyroid SWVs of DTD patients were higher than those of the healthy (2.56 ± 1.33 m/s versus 1.74 ± 0.16 m/s, P = 0.011). There was no significant difference between the thyroid SWVs in GD and HT patients (P = 0.168). The SWVs in patients with GD and HT were both higher than those of the healthy (P < 0.05). The area under the ROC curve was 0.938 for SWV to distinguish between DTD and healthy thyroid. With a cutoff value of 2.02 m/s, the sensitivity and specificity were 81.12% and 100.00%, respectively. Additionally, we found a positive liner correlation between thyroid SWV and TSH in DTD patients (P < 0.001). Conclusion. SWV is a good indicator of the thyroid tissue stiffness, which might be considered helpful in screening DTD. What is more, SWV might have a potential in assessing the thyroid function.

The value of real-time ultrasound elastography in chronic autoimmune thyroiditis

OBJECTIVE

Chronic autoimmune thyroiditis (CAT) (chronic lymphocytic thyroiditis-Hashimoto's thyroiditis), which is the most common inflammatory disorder of the thyroid gland, causes hypothyroidism. Ultrasound elastography is a newly developed sonographic technique that provides an estimation of tissue elasticity by measuring the degree of tissue displacement under the application of an external force. In this study, our aim was to evaluate the accuracy of strain index ratio with real-time ultrasound elastography and to calculate the cut-off point for the diagnosis of CAT. Our aim was also to lead further studies on other pathological changes such as lymphoma, malign nodules etc. based on CAT by using this cut-off point. The gains from this study and further studies will assist clinical diagnoses and follow-up.

METHODS

Aplio™ 500 ultrasound machine (Toshiba Medical Systems Co. Ltd, Otawara, Japan) with linear 4.8-11.0 MHz transducers and elastography software was used. Routine B-mode (dimensions and parenchymal echogenicity) ultrasound evaluation was performed prior to the ultrasound elastography.

RESULTS

A total of 31 randomized patients (3 males, 28 females) with a mean age of 39.13 ± 10.16 years (range, 16-58 years) with CAT and 21 healthy controls (6 males, 15 females) with mean age of 34.67 ± 16.31 years (range, 14-81 years) were prospectively examined. The mean values of thyroid-stimulating hormone (TSH; normal TSH value is 0.27-4.20 IU ml(-1)) and anti-thyroid peroxidase (anti-TPO; normal anti-TPO value is 0-34 IU ml(-1)) were 3.40 ± 2.70 and 373.66 ± 148.94 IU ml(-1), respectively. No correlation was detected between serum TSH and thyroid tissue strain index (Spearman r coefficient of TSH was -0.290). Positive-sided correlation was detected between anti-TPO values and thyroid tissue strain index ratio (Spearman r coefficient of anti-TPO was 0.682). The median strain index ratio of patients with CAT (1.39 ± 0.72) was significantly higher than the mean ratio of the controls (0.76 ± 0.55). The area under the receiver operating characteristic curve was 0.775 (95% confidence interval). The optimal cut-off value (in which the sum of sensitivity and specificity was highest) for the prediction of diffuse thyroid pathology was 0.677. For this cut-off ratio, thyroid stiffness had 96% sensitivity and 67% specificity. A total of 30 of 31 patients (96%) and a total of 7 of 21 healthy controls (33%) exceeded the cut-off points.

CONCLUSION

The strain index ratio was higher in CAT than in normal thyroid parenchyma in real-time ultrasound elastography. Thus, it seems to be a useful method for the assessment of CAT with real-time ultrasound elastography, and further studies assessing the correlation of sonoelastography findings and histopathological subtypes of CAT would enrich the findings of the present study.

ADVANCES IN KNOWLEDGE

In our study, we detected the stiffness ratio of the thyroid tissue in patients with CAT. The cut-off value should be helpful for diagnosis or follow-up of the recently developed lesions such as lymphoma, malign nodule, etc. based on CAT. This study should also encourage new studies about CAT and ultrasound elastography.

Factors associated with the impossibility to obtain reliable liver stiffness measurements by means of Acoustic Radiation Force Impulse (ARFI) elastography--analysis of a cohort of 1,031 subjects

INTRODUCTION

Acoustic Radiation Force Impulse (ARFI) elastography is a non-invasive technique for liver fibrosis assessment.

AIM

To assess the feasibility of ARFI elastography in a large cohort of subjects and to identify factors associated with impossibility to obtain reliable liver stiffness (LS) measurements by means of this technique.

METHODS

Our retrospective study included 1031 adult subjects with or without chronic liver disease. In each subject LS was assessed by means of ARFI elastography. Failure of ARFI measurements was defined if no valid measurement was obtained after at least 10 shots and unreliable in the following situations: fewer than 10 valid shots; or median value of 10 valid measurements with a success rate (SR)<60% and/or an interquartile range interval (IQR) ≥ 30%.

RESULTS

Failure of LS measurements by means of ARFI was observed in 4 subjects (0.3%), unreliable measurements in 66 subjects (6.4%), so reliable measurements were obtained in 961 subjects (93.3%). In univariant analysis, the following risk factors were associated with failed and unreliable measurements: age over 58 years (OR=0.49; 95% CI 0.30-0.80, p=0.005), male gender (OR=0.58; 95% CI 0.34-0.94, p=0.04), BMI>27.7 kg/m(2) (OR=0.23, 95% CI 0.13-0.41, p<0.0001). In multivariate analysis all the factors mentioned above were independently associated with the risk of failed and unreliable measurements.

CONCLUSIONS

Reliable LS measurements by means of ARFI elastography were obtained in 93.3% of cases. Older age, higher BMI and male gender were associated with the risk of failed and unreliable measurements, but their influence is limited as compared with Transient Elastography.

Comparative study of acoustic radiation force impulse imaging with real-time elastography in differential diagnosis of thyroid nodules

The aims of this study were to evaluate whether acoustic radiation force impulse (ARFI) imaging of the thyroid gland and thyroid nodules yields reliable results and to compare the values of ARFI imaging with those of real-time elastography (RTE) in the differential diagnosis of thyroid nodules. RTE and ARFI were performed in 30 patients with 58 thyroid nodules. The results were compared with pathologic findings. Receiver operating characteristic curves were drawn to evaluate the diagnostic results. The area under the curve for RTE (0.78) was smaller than that for ARFI (0.94) (p < 0.01). ARFI imaging of thyroid tissue yields more reliable results than RTE.

Comparison of diagnostic value of conventional ultrasonography and shear wave elastography in the prediction of thyroid lesions malignancy

INTRODUCTION

Thyroid nodular disease (TND) is a very common disorder. However, since the rate of malignancy is reported to be 3-10%, only a minority of patients require aggressive surgical treatment. As a result, there is a need for diagnostic tools which would allow for a reliable differentiation between benign and malignant nodules. Although a number of conventional ultrasonographic (US) features are proved to be markers of malignancy, Shear Wave Elastography (SWE) is considered to be an improvement of conventional US. The aim of this study was to compare conventional US markers and SWE diagnostic values in the differentiation of benign and malignant thyroid nodules.

MATERIALS AND METHODS

All patients referred for thyroidectomy, irrespective of the indications, underwent a US thyroid examination prospectively. Patients with TND were included into the study. Results of the US and SWE examinations were compared with post-surgical histopathology.

RESULTS

One hundred and twenty two patients with 393 thyroid nodules were included into the study. Twenty two patients were diagnosed with cancer. SWE turned out to be a predictor of malignancy superior to any other conventional US markers (OR=54.5 using qualitative scales and 40.8 using quantitative data on maximal stiffness with a threshold of 50 kPa).

CONCLUSIONS

Although most conventional US markers of malignancy prove to be significant, none of them are characterized by both high sensitivity and specificity. SWE seems to be an important step forward, allowing for a more reliable distinction of benign and malignant thyroid nodules. Our study, assessing SWE properties on the highest number of thyroid lesions at the time of publication, confirms the high diagnostic value of this technique. It also indicates that a quantitative evaluation of thyroid lesions is not superior to simpler qualitative methods.