Elastography: new developments in ultrasound for predicting malignancy in thyroid nodules

TSE-GAN: strain elastography using generative adversarial network for thyroid disease diagnosis

Over the past 35 years, studies conducted worldwide have revealed a threefold increase in the incidence of thyroid cancer. Strain elastography is a new imaging technique to identify benign and malignant thyroid nodules due to its sensitivity to tissue stiffness. However, there are certain limitations of this technique, particularly in terms of standardization of the compression process, evaluation of results and several assumptions used in commercial strain elastography modes for the purpose of simplifying imaging analysis. In this work, we propose a novel conditional generative adversarial network (TSE-GAN) for automatically generating thyroid strain elastograms, which adopts a global-to-local architecture to improve the ability of extracting multi-scale features and develops an adaptive deformable U-net structure in the sub-generator to apply effective deformation. Furthermore, we introduce a Lab-based loss function to induce the networks to generate realistic thyroid elastograms that conform to the probability distribution of the target domain. Qualitative and quantitative assessments are conducted on a clinical dataset provided by Shanghai Sixth People's Hospital. Experimental results demonstrate that thyroid elastograms generated by the proposed TSE-GAN outperform state-of-the-art image translation methods in meeting the needs of clinical diagnostic applications and providing practical value.

Use of ultrasound elastography in differentiating benign from malignant thyroid nodules: a prospective study

Purpose

Elastography is a real-time non-invasive ultrasonography modality wherein the tissue stiffness is evaluated by calculating the degree of tissue distortion in response to an external force. This study was undertaken to assess the diagnostic value of elastography in differentiating benign from malignant thyroid nodules.

Methodology

In this prospective comparative study, a total of 52 thyroid nodules from 44 euthyroid patients undergoing fine needle aspiration cytology were assessed. Elastography was performed by a single experienced sonologist, wherein the nodules were graded as per elastography scoring (ES), and the strain ratio (SR) for each nodule was computed. Final histopathology findings of the patients undergoing surgery were compared to elastography findings, and measures of diagnostic accuracy to differentiate between benign and malignant nodules were determined for ES and SR.

Results

Thirty (68.2%) females and 14 (31.8%) males, with a mean age of 45.18 ± 11.23 years, were assessed. Fourteen (31.8%) patients underwent thyroidectomy, and histopathology was reported for 18 (34.6%) nodules. In all, nine (17.3%) nodules were malignant, and 43 (82.7%) nodules were considered benign. ES demonstrated a sensitivity of 88.9%, specificity of 88.3%, PPV of 61.5%, NPV of 97.4%, and accuracy of 88.5% to identify benign thyroid nodules. The mean SR for benign nodules was significantly lower as compared to malignant nodules (2.72 ± 0.62 vs. 4.52 ± 0.75, P < 0.0001). The optimal cut-point value for SR to differentiate benign and malignant thyroid nodules was determined to be 3.8, with the sensitivity, specificity, PPV, NPV, and accuracy being 88.9%, 95.4%, 80%, 94.6%, and 94.2%, respectively.

Conclusion

Ultrasound elastography (ES and SR) demonstrated good diagnostic efficacy to differentiate benign thyroid nodules from the malignant ones, and can be a good supplementary tool to gray-scale ultrasonography. It can also help in reducing the rates of unnecessary fine needle-aspiration biopsy.

[Elastography in thyroid nodules]

BACKGROUND

Elastography is an imaging method to examine the elasticity of tissue. In the meantime, various elastography methods have been developed, which are subdivided according to the type of stimulus applied. In principle, a distinction should be made between strain elastography (SE) and shear wave elastography (SWE). Both methods provide another means of assessing thyroid disease in addition to conventional B-mode sonography.

OBJECTIVE

The aim is to provide an overview of elastography techniques including physical basics and their importance in the clarification algorithm of thyroid nodules.

MATERIALS AND METHODS

International guidelines and recent publications on elastography were selectively assessed.

RESULTS

Elastography provides additional information compared to conventional B-mode sonography. The change in shear stiffness is the essential physical mechanism for tissue contrast in all elastograms. In addition to the qualitative assessment of elasticity in SE, quantification is possible with SWE. In the international literature, elastography was analyzed as a single method or in comparison or combination with conventional B-mode sonography and especially with standardization using a risk stratification system (RSS, TIRADS). The results are quite controversial. In nodules with unclear findings on fine-needle biopsy (Bethesda III/IV), the combination of morphologic criteria and elastography improved diagnostic accuracy. In particular, the high negative predictive value of soft nodules represents a relevant added value. This strength of the method can play an important role in the clarification of nodules with intermediate malignancy risk or of unclear FNB results. Elastography has previously only been incorporated into French-TIRADS. Although the procedure is mentioned in the EU-TIRADS as a complementary method, integration has not been described. Limitations of the method are idealized basic assumptions, dependence of manufacturer and examiner, and artifacts.

CONCLUSION

Elastography can be a useful adjunct to standard diagnostic procedures in the evaluation of thyroid nodules, especially in nodules with intermediate risk of malignancy and unclear results on fine needle aspiration.

Lightweight Force-Controlled Device for Freehand Ultrasound Acquisition

This study investigates a force-controlled auxiliary device for freehand ultrasound (US) examinations. The designed device allows sonographers to maintain a steady target pressure on the US probe, thereby improving the US image quality and reproducibility. The use of a screw motor to power the device and a Raspberry Pi as the system controller results in a lightweight and portable device, while a screen enhances user-interactivity. Using gravity compensation, error compensation, an adaptive proportional-integral-derivative algorithm, and low-pass signal filtering, the designed device provides highly accurate force control. Several experiments using the developed device, including clinical trials relating to the jugular and superficial femoral veins, validate its utility in ensuring the desired pressure in response to varying environments and prolonged US examinations, enabling low or high pressures to be maintained and lowering the threshold of clinical experience. Moreover, the experimental results show that the designed device effectively relieves the stress on the sonographer's hand joints during US examinations and enables rapid assessment of the tissue elasticity characteristics. With automatic pressure tracking between probe and patient, the proposed device offers potentially significant benefits for the reproducibility and stability of US images and the health of sonographers.

Differentiating thyroid nodules parathyroid lesions using 2D-shear-wave elastography: a novel approach for enhanced diagnostic accuracy

Differentiating between thyroid and parathyroid lesions by means of ultrasound can be a challenge in some cases. This study explores the diagnostic efficacy of bidimensional shear wave elastography planewave ultrasound (2D SWE PLUS) as an auxiliary technique in distinguishing these superficial structures. We evaluated 86 cases, presenting with concurrent thyroid nodules and hyperparathyroidism, through conventional ultrasound and 2D SWE PLUS, employing an Aixplorer Supersonic Mach30 with a 5-18 MHz linear probe. Statistically significant differences were observed for the elasticity index (EI) between parathyroid and normal thyroid tissue (p<0.0001, U=291), and between parathyroid lesions and thyroid nodules (p<0.0001, U=248.5). An area under the curve (AUC) of 0.961, with an optimal cut-off value of ≤8.9 kPa, was established to effectively distinguish parathyroid tissue from normal thyroid tissue (sensitivity of 91.9%; specificity of 97.5%). Furthermore, an AUC of 0.963 and an optimal cut-off of 9.24 kPa (sensitivity of 94.2%, specificity of 91.1%) were determined for parathyroid vs thyroid lesions. Elasticity values were significantly elevated in the cancer group compared to benign thyroid nodules (p<0.0001). Our findings suggest that 2D SWE PLUS is an effective tool in differentiating between thyroid nodules and parathyroid lesions, enhancing diagnostic performance in neck ultrasonography.

Elastography of the thyroid nodule, cut-off points between benign and malignant lesions for strain, 2D shear wave real time and point shear wave: a correlation with pathology, ACR TIRADS and Alpha Score

Objective

A prospective cross-sectional investigation of 170 thyroid nodules (TN) between January 2020 and December 2021 at Alpha Imagen was conducted to determine cut-off points (C/O) for elastography measurements and their diagnostic accuracy.

Methods

Nodules were categorized by ACR TI-RADS, Alpha Score (AS), and Bethesda; all were evaluated using 2D Shear Wave Real Time Elastography (RT-SWE), point Shear Wave (pSWE), and Strain Elastography (SE). Data was assessed with ROC curves, the Shapiro-Wilk test, T test, Chi-square test, and ANOVA.

Results

C/O were as follows: RTSWE Emax of 115kPa and 6.5 m/s, Emean of 47.5 kPa and 4.1 m/s, pSWE (average) of 52.4 kpa and 4.15 m/s; sensitivity of 81.2% and specificity of 57.6%, with a PPV of 72.4% and NPV of 70.0%. SE Value A had a C/O of 0.20%, with a sensitivity of 84%, specificity of 57%, PPV of 72.4% and NPP of 73.6%. The Strain Ratio nodule/tissue C/O was calculated as 2.69, with a sensitivity of 84%, specificity of 57%, PPV of 72.3%, and NPV of 73.5%. The RLBIndex quality control must be at least 92%; for pSWE, we suggest a mean interquartile ratio of ≤15.7% for kPa and 8.1% for m/s. The recommended depth is between 1.2 and 1.5 cm, and commonly used ROI boxes were 3x3 and 5x5mm.

Conclusion

2D-SWE and pSWE with Emax and Emean demonstrated C/O with excellent diagnostic accuracy. To maximize the correct classification of TN, we suggest combining ACR TI-RADS and AS with any of the elastography measurements assessed here.

Can ultrasound strain elastography (USE) improve management of suspicious thyroid nodules measuring <10 mm? A systematic review

INTRODUCTION

Current UK guidelines state that suspicious thyroid nodules <10 mm do not require FNA. These are often followed up with serial ultrasound scans. Ultrasound Strain Elastography (USE) could provide a more accurate alternative and preclude the need for follow-up. Can USE identify nodules at greater risk of malignancy and streamline patient management?

METHODS

Systematic review methodology used. Inclusion criteria are: - Population: patients with suspicious thyroid nodules <10 mm.- Intervention: USE.- Comparator: Ultrasound features of nodules.- Outcome measure: FNA or surgical removal of nodules. Searches performed on 6 commercial databases, along with grey literature anddissertation databases. The QUADAS-2 diagnostic study checklist used for quality assessment.

RESULTS

8 studies included and a narrative analysis performed due to heterogeneity of results. The mean USE sensitivity is 74.3%, mean specificity 80.5%. Mean overall ultrasound sensitivity is 80.4%, specificity 71.0%. Results suggest that USE is not superior to ultrasound for detecting malignancy. Some study limitations, particularly the heterogeneity of reporting the ultrasound features preclude meaningful conclusion from being drawn.

CONCLUSION

USE is more accurate at identifying benign nodules than ultrasound. Nodules appearing benign on USE could be excluded from serial ultrasound follow-up. No significant difference was found between USE and ultrasound at identifying malignant nodules.

IMPLICATIONS FOR PRACTICE

As FNA is not recommended for suspicious thyroid nodules <10 mm, these are often followed up with multiple scans and clinician reviews. This increases pressure on healthcare systems and uncertainty for the patient. This review shows that USE is more accurate at identifying benign nodules than ultrasound alone, meaning that these nodules could potentially be excluded from serial follow up. This would streamline patient management, freeing-up vital resources in ENT and ultrasound departments.

Interobserver and Intraobserver Reliability in Sonoelastographic Assessment of Thyroid Nodules

BACKGROUND

Thyroid ultrasonography is the first and perhaps most fundamental step for the radiological distinction of benign and malignant nodules. In this study, 2 radiologists reviewed the sonoelastographic and Doppler images of thyroid nodules and evaluated for the intraobserver and interobserver reliability.

PURPOSE

We aimed to determine confusing nodule identifiers and sonographic features differently defined by observers.

METHODS

A total of 157 nodules in 91 patients (male/female, 72:19) with ages ranging from 18 to 72 years old were included in the study. Ultrasonographic images and video clips of the nodules were obtained and presented to 2 reviewers unaware of the cytopathology results. Two observers defined the characteristics of the nodules based on previously determined criteria. Then, intraobserver and interobserver correlation coefficients were calculated for each subcategory.

RESULTS

In the grayscale ultrasonographic examination, varying degrees from low to high interobserver correlation coefficients were obtained for different subcategories (between κ = 0.359 and κ = 0.821). In color Doppler examination, we obtained medium correlation coefficients ( κ = 0.493 and κ = 0.553). On the other hand, there was a high correlation coefficient in tissue compression elastography ( κ = 0.617 and κ = 0.638).According to our study results, elastographic pattern, shape of the nodule, presence of echogenic foci, and pathological lymph nodes are better predictors to determine the malignant potential of thyroid nodule with higher interobserver correlation. Therefore, these criteria may be used primarily for the evaluation of thyroid nodules. The intraobserver correlation coefficient was higher in the practitioner with longer experience, suggesting the importance of professional practice period on the decision-making process.

The role of elastography in the assessment of thyroid nodules in acromegaly

BACKGROUND

Nodular thyroid disease is a frequent finding seen in patients with acromegaly. Ultrasound-elastography (US-E) appears to be a helpful tool for the diagnosis of thyroid cancer. The aims of this study were to evaluate thyroid nodules in acromegaly and to assess the diagnostic accuracy of US-E in detecting thyroid cancer in this population.

METHODS

US-E was applied to 166 nodules detected in 102 acromegalic patients and to 105 nodules found in 95 nonacromegalic subjects. The lesions were classified according to the elasticity scores (ES) as soft (ES 1-2) or hard (ES 3-4).

RESULTS

: Mean age was 55.1 ± 12.47 years [59 (58%) women]. The prevalence of hard nodules (ES 3 and 4) was significantly higher in the group of acromegalic patients than in control subjects (48% to 20%, p < 0.001). Mean ES was higher in patients with acromegaly (2.45 to 2.22, p: 0.001), however, the mean strain index (SI) was similar between groups (1.53 to 1.65, p: 0.204).

DISCUSSION

Thyroid nodules in acromegaly patients have a higher elasto score and the prevalence of hard nodules is higher in active disease. However, increased stiffness of nodules by US-E in patients with acromegaly does not seem to estimate the malignancy of the nodules.

Conventional ultrasonography and elastosonography in diagnosis of malignant thyroid nodules: A systematic review and meta-analysis

Purpose

To evaluate the diagnostic value of conventional ultrasound and elastosonography in malignant thyroid nodules by meta-analysis.

Methods

The literature included in the Cochrane Library, PubMed, and Embase were searched by using "elastosonography, ultrasonography, thyroid nodules" as the keywords. The clinical studies using elastosonography and conventional ultrasound to diagnose thyroid nodules were selected, and histopathology of thyroid nodules was used as reference standards. The quality evaluation and heterogeneity test were performed on the literature that met the requirements, the combined specificity and sensitivity were pooled, and a comprehensive ROC curve analysis was performed. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool was utilized to evaluate the quality of each included study. Meta-DiSc version 1.4, StataSE 12 and Review Manager 5.4 were used.

Results

A total of nine studies assessed 3066 thyroid nodules (2043 benign and 1023 malignant). The pooled sensitivity, specificity, PLR, NLR, and DOR of conventional ultrasound for the diagnose of malignant thyroid nodules were 0.833 (95% CI 0.809-0.855), 0.818 (95% CI 0.801-0.835), 4.85 (95% CI 4.36-5.39), 0.20 (95% CI 0.17-0.23), and 29.38 (95% CI 23.28-37.08), respectively, with an AUC of 0.9068. Also, the pooled sensitivity, specificity, PLR, NLR, and DOR of elastosonography were 0.774 (95% CI 0.741-0.804), 0.737 (95% CI 0.715-0.758), 3.14(95% CI 2.85-3.47), 0.29 (95% CI 0.25-0.34), and 9.35 (95% CI 7.63-11.46), respectively, with an AUC of 0.8801. Three studies provided data regarding the conventional ultrasound and elastosonography. The pooled sensitivity, specificity, PLR, NLR, DOR, and AUC were 0.902 (95% CI 0.870-0.928), 0.649 (95% CI 0.616-0.681), 2.72 (95% CI 2.46-3.00), 0.14 (95% CI 0.11-0.19), 25.51 (95%CI 17.11-38.03), and 0.9294.

Conclusion

The existing evidence shows that elastosonography cannot completely replace conventional ultrasound in the diagnosis of malignant thyroid nodules, and the combination of elastosonography and conventional ultrasound gives a better diagnostic precision.

Systematic review registration

www.crd.york.ac.uk, identifier PROSPERO CRD42022375808.

Value of shear-wave elastography and cerebral-placental-uterine ratio in women diagnosed with preeclampsia and fetal growth restriction in prediction of adverse perinatal outcomes

PURPOSE

The aim of this study was to measure placental stiffness with shear-wave elastography technique and to evaluate the relationship with cerebral-placental-uterine ratio (CPUR) and adverse perinatal outcomes in patient groups diagnosed with preeclampsia (PE) and fetal growth restriction (FGR) in the second and third trimesters compared to the control group.

MATERIALS AND METHODS

This prospective cross-sectional study was conducted at our hospital between March 2019 and March 2020. The study groups were divided into three groups: PE, FGR, and low risk pregnancy (LRP) group. The study population had singleton pregnancies and the placental site was at the anterior wall. Both shear-wave elasticity (SWE) and shear-wave velocity (SWV) were measured in the placenta during pregnancy. CPUR was calculated for each group.

RESULTS

A total of 147 patients were included in this study. The mean SWE (kilopascals) values in the PE group were significantly higher than in the FGR and controls (difference of means = 3.67, 9.45; 95% CI (1.23-6.1, 7-11.8); p < .05), respectively. The mean SWV values were significantly higher in PE and FGR groups than controls (p < .05). CPUR showed correlation with central maternal surface of placenta (p: .02, r: -0.184), central fetal surface of placenta (p < .001, r: -0.288), peripheral maternal surface of placenta (p: .002, r: -0.252), and peripheral fetal surface of placenta SWE values (p: .03, r: -0.181). NICU admission was correlated with central fetal surface of placenta SWE values (p: .002, r: 0.258).

CONCLUSION

In conclusion, we demonstrated increased placental stiffness in both the PE and the FGR group. Also, this difference was found to be more prominent in preeclampsia. This technique seems useful for assessment of placental function and may strengthen the utility of Doppler parameters for predicting adverse perinatal outcomes in high-risk pregnancies.

[Clinicopathologic analysis of micro and mini parotid gland tumors]

OBJECTIVE

To investigate the clinicopathological characteristics of micro and mini parotid gland tumors and to provide reference for their clinical diagnosis and treatment.

METHODS

Patients with parotid gland tumors treated in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from December 2012 to April 2020 were selected. Relevant clinical data of the patients with tumor diameter ≤20 mm detected by preoperative CT were collected to analyze the clinicopathological characteristics and prognosis of micro and mini parotid gland tumors. And the collected data were divided into two groups with diameter 11-20 mm and diameter ≤10 mm according to tumor diameter measured by preoperative CT. The clinicopathological differences between the two groups were statistically analyzed.

RESULTS

A total of 2 067 patients with primary epithelial parotid gland tumors were collected, and 685 patients with tumor diameter ≤20 mm were examined by CT, accounting for 33.1%. The ratio of male to female patients with micro and mini parotid gland tumors was 1 ∶1.93, the average age was (45.3±13.8) years (12-83 years), and the median course of disease was 12 months (1 week to 30 years). Among them, 635 cases (92.7%) were benign tumors, 50 cases (7.3%) were malignant tumors, and the ratio of benign to malignant was 12.7 ∶1. The most common benign tumor was pleomorphic adenoma, and the most common malignant tumor was mucoepidermoid carcinoma. The micro and mini parotid gland tumors were divided into 11-20 mm group (n=611) and ≤10 mm group (n=74), the clinical characteristics comparison of the two groups of gender ratio, average age, course of di-sease had no statistical difference (P>0.05). In the 11-20 mm diameter group, the percentage of benign and malignant tumor was 92.8% (567/611) and 7.2% (44/611) respectively, and the ratio of benign to malignant tumors was 12.9 ∶1. In the ≤10 mm diameter group, the percentage of benign and malignant tumor was 91.9% (68/74) and 8.1% (6/74) respectively, and the ratio of benign to malignant tumors was 11.3 ∶1. There was no significant difference between the two groups (P>0.05). Fifty patients with malignant tumor were followed up for the median follow-up period of 39.5 months (1-91 months). Local recurrence occurred in 2 patients with one death. The overall 2-year survival rate was 93.7% and the 5-year survival rate was 89.3%.

CONCLUSION

The majority of micro and mini parotid gland tumors was benign lesion. There was a good prognosis for micro and mini parotid gland carcinoma. Early surgical treatment was recommended for micro and mini parotid gland tumors.

Elastography and Doppler May Bring a New Perspective to TIRADS, Altering Conventional Ultrasonography Dominance

RATIONALE AND OBJECTIVES

The main aim of ultrasonography (US) examining thyroid nodules is to differentiate malignant nodules from benign nodules. Several professional societies and groups of investigators have defined guidelines such as Thyroid Imaging Reporting and Data System (TIRADS) to provide the standardized language and approach to thyroid nodules. This study is aimed to investigate the compatibility of such classification systems with the pathological diagnosis of nodules and evaluate the contribution of the Shear-wave elastography (SWE) and Doppler ultrasonography (DUS) findings.

MATERIALS AND METHODS

This is a prospective study. Patients with thyroid US exams between December 2017 and April 2019 were included. In the study, eligible 210 nodules from 210 patients were enrolled. For stratification, the conventional B-mode US, SWE and DUS were performed. According to Kwak, American College of Radiology (ACR), and European (EU)-TIRADS, Nodules were classified separately, and a new scoring system whose the criteria was put defined in the study has developed.

RESULTS

For SWE; Emean cut-off value was 33 kPa with a sensitivity and specificity of 95,6% (95% CI: 0,85-0,98) and 95% (95% CI:0,90-0,97) respectively (p <0.001). For spectral DUS; resistivity index (RI) cut-off value was 0.64 with a sensitivity and specificity of 73,3% (95% CI:0,59-0,83) and 80% (95% CI:0,73-0,85) respectively (p <0.001). Kwak TIRADS, American College of Radiology TIRADS, EU-TIRADS, and new system were compared by ROC curve analysis. The new system has the highest sensitivity, specificity, PPV, NPV, accuracy, and AUC compared to others.

CONCLUSIONS

The new scoring system has shown that SWE and DUS findings may alter the categorization in TIRADS and increase sensitivity and specificity.

Risk Stratification of Thyroid Nodules: From Ultrasound Features to TIRADS

Simple Summary

Thyroid nodules are a frequent clinical issue. Their incidence has increased mainly due to the widespread use of neck ultrasound scans. Most thyroid nodules are asymptomatic, incidentally discovered, and benign at cytology. Thyroid ultrasound is the most sensitive diagnostic tool to evaluate patients with nodular thyroid disease. It is therefore important to use the ultrasound features to select nodules that require a fine-needle aspiration cytology.

Abstract

Thyroid nodules are common in iodine deficient areas, in females, and in patients undergoing neck irradiation. High-resolution ultrasonography (US) is important for detecting and evaluating thyroid nodules. US is used to determine the size and features of thyroid nodules, as well as the presence of neck lymph node metastasis. It also facilitates guided fine-needle aspiration (US-FNA). The most consistent US malignancy features of thyroid nodules are spiculated margins, microcalcifications, a taller-than-wide shape, and marked hypoechogenicity. Increased nodular vascularization is not identified as a predictor of malignancy. Thyroid elastosonography (USE) is also used to characterize thyroid nodules. In fact, a low elasticity of nodules at USE has been related to a higher risk of malignancy. According to their US features, thyroid nodules can be stratified into three categories: low-, intermediate-, and high-risk nodules. US-FNA is suggested for intermediate and high-risk nodules.

Evaluation of the relationship between placental stiffness measured by shear wave elastography and perinatal outcomes in women with gestational diabetes mellitus

BACKGROUND

Recently, studies on placental elastography in high-risk pregnancies continue to increase. The shear wave technique can contribute to the management of gestational diabetes mellitus (GDM) and improve perinatal outcomes by measuring placental stiffness.Purpose: To evaluate the relationship between placental stiffness measured by shear wave elastography (SWE) and perinatal outcomes in women with GDM.Material and Methods: This prospective cross-sectional study was conducted at our hospital between March and October 2020. The participants were divided into three groups: GDM-A1 group (regulated by dietary modifications); GDM-A2 group (needed pharmacologic treatment); and low-risk pregnancy (LRP) group. Both SWE and shear wave velocity (SWV) were measured in the placenta during pregnancy.

RESULTS

In total, 111 women were included in the study. The mean SWE (kPa) values for the GDM-A1, GDM-A2, and LRP groups were 10.4 (range 3.1-23.3), 13 (range 4.3-29.6), and 8.3 (range 3.2-15.1), respectively. The mean HbA1c and fasting glucose values of diabetes groups showed strongly positive correlation with mean SWE and SWV values (P < 0.001, r=0.875; P < 0.001, r=0.856; P < 0.001, r=0.791; P < 0.001, r=0.740), respectively. The SWE values of central maternal and fetal surfaces of the placenta (P=0.01, r=0.242; P < 0.001, r=0.333) showed a moderately positive correlation with admission to the neonatal intensive care unit.

CONCLUSION

Placental stiffness has increased in the GDM-A2 group when compared to the GDM-A1 and LRP groups. We also observed a strong positive correlation between HbA1c, fasting glucose values, and increased elasticity values in diabetic patients with metabolic dysregulation that may have clinical value.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Ultrasound Elastography in Ocular and Periocular Tissues: A Review

Ultrasound elastography has become available in everyday practice, allowing direct measurement of tissue elasticity with important and expanding clinical applications. Several studies that have evaluated pathological and non-pathological tissues have demonstrated that ultrasound elastography can actually improve the diagnostic accuracy of the underlying disease process by detecting differences in their elasticity. Ocular and periocular tissues can also be characterized by their elastic properties. In this context, a comprehensive review of literature on ultrasound elastography as well as its current applications in Ophthalmology is presented.

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.

Predictor Analysis in Radiofrequency Ablation of Benign Thyroid Nodules: A Single Center Experience

Purpose

To confirm the efficacy of ultrasound (US) guided radiofrequency ablation (RFA) in the treatment of benign thyroid nodules, we evaluated as primary outcome the technical efficacy and clinical success in a single center dataset. The secondary outcome was to find a correlation between nodules' pre-treatment features and volume reduction rate (VRR) ≥75% at 12 months after RFA and during follow-up period.

Methods

This retrospective study included 119 consecutive patients (99 females, 20 males, 51.5 ± 14.4 years) with benign thyroid nodules treated in our hospital between October 2014 and December 2018 with a mean follow-up of 26.8 months (range 3-48). Clinical and US features before and after RFA were evaluated by a US examination at 1, 3, 6, 12 months and annually thereafter up to 48 months.

Results

The median pre-treatment volume was 22.4 ml; after RFA we observed a statistically significant volume reduction from the first month (11.7 ml) to the last follow-up (p < 0.001 for all follow-up times). The median VRR was 47.1, 55.3, 61.2, 67.6, 72.8, 71.3, and 62.9% at 1, 3, 6, 12, 24, 36, and 48 months of follow-up respectively, showing a progressive significant improvement up to 24 months (VRRs 1 vs 3 months, 3 vs 6 months and 6 vs 12 months p < 0.001, 12 vs 24 months p = 0.05) while no differences at 24 vs 36 and 36 vs 48 months were observed. Symptoms improved significantly (complete resolution 64.35%, partial resolution 35.65%), and neck circumference was reduced as compared to pre-treatment (p < 0.001). Lower pre-treatment neck circumference (37.5 vs 36.0 cm, p = 0.01) was a positive predictor of VRR ≥75% at 12 months. Macrocystic echostructure (HR 2.48, p 0.046) and pre-treatment volume >22.4 ml (HR 0.54, p 0.036) were found to be independent positive and negative predictors of VRR ≥75% respectively. One-month post RFA VRR ≥50% represented the best positive predictor of technical success.

Conclusions

This study confirmed the efficacy of RFA in the treatment of benign thyroid nodules. In particular we show that by selecting macrocystic nodules smaller than 22.4 ml better long-term response can be achieved, which is predicted by an early shrinkage of the nodule.

Retrospective analysis of the ultrasound features of resected thyroid nodules

PURPOSE

Several ultrasound (US) risk stratification systems (US-RSSs) have been proposed to stratify the risk of malignancy (ROM) of thyroid nodules. This risk might be overestimated due to selection bias and comparison with the cytological report alone. Our study aimed to compare ROM and diagnostic performance of three guidelines (ATA, AACE/ACE/AME, EUTIRADS) and evaluate the changes in unnecessary biopsy according to the nodule size cutoff for biopsy, using histology as gold standard.

METHODS

This retrospective observational study included 146 consecutive patients who underwent surgery after US and cytological characterization. We analyzed the effectiveness and accuracy of three US-RSSs.

RESULTS

46.6% of nodules were diagnosed as malignant. Applying US-RSS, the percentage of nodules that should have been analyzed by biopsy was 84.25% with ATA, 69.86% with EUTIRADS and 64.38% with AACE/ACE/AME systems. The ROM was 94.9%, 86.0%, 87.0% for high-risk category, 36.4%, 32.0%, 35.4% for intermediate-risk category and 22.9%, 0.0%, 22.9% for low-risk category by ATA, AACE/ACE/AME and EUTIRADS systems, respectively. EUTIRADS and AACE/ACE/AME systems were more accurate in differentiating malignant from benign cases. ATA score was the more sensitive US-RSS to identify malignant tumors within the high-risk category. About the unnecessary biopsies, in the intermediate-risk category, the application of the size criterion helps to increase specificity in all systems.

CONCLUSIONS

The US categorization of low and high-risk thyroid nodules using current US-RSSs helps alone to determine the optimal treatment option. Nodule size remains relevant to recommend biopsy for the intermediate-risk category.

Strain elastography for the assessment of skin nodules in dogs

BACKGROUND

Strain elastography (SE) is a modern imaging technology that provides an additional way of evaluating the changes in soft tissue elasticity caused by pathophysiological processes. Despite its widespread use in human medicine, only a few studies on the application of SE in veterinary medicine are available.

OBJECTIVES

To evaluate the potential usefulness of SE as an integrative imaging model in the standard ultrasound technique to better discriminate between inflammatory and neoplastic skin nodules in dogs.

ANIMALS

Fifty-one client-owned dogs with clinical evidence of single or multiple skin nodules detected during routine dermatological examination.

METHODS AND MATERIALS

Margins, echogenicity, echo-structure, calcification and vascularisation of 65 skin nodules were assessed with ultrasound, and SE was used to score qualitative (E-score, E-index, E2) and semiquantitative (SR) parameters. A comparison of diagnostic yields with cytological and histological findings as the gold standard was performed.

RESULTS

Mast cell and benign follicular tumours showed the highest E-scores and SRs among neoplastic nodules; statistically significant differences were not detected. Calcific and nonvascularised nodules showed significantly higher E-index values than the others. Overall, a negative correlation was observed between the longitudinal diameter of skin nodules and the qualitative elastic parameters.

CONCLUSIONS AND CLINICAL IMPORTANCE

In this study, SE proved to be useful to identify only a subset of nodules such as mast cells and hair follicular tumours. Although evidence supporting the use of SE in evaluating skin nodules was demonstrated to below, indicators to guide further research were developed.

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.

Decreased Size of Mammary Tumors Caused by Preoperative Treatment with Aglepristone in Female Domestic Dogs (Canis familiaris) Do Not Influence the Density of the Benign Neoplastic Tissue Measured Using Shear Wave Elastography Technique

Shear wave elastography (SWE) can be useful to discriminate between malignant and benign mammary tumors. In dogs with elevated progesterone levels compared to the baseline and fast-growing tumors, treatment with the use of aglepristone allows for tumor size reduction, which facilitates surgery. This study aimed to evaluate the influence of the preoperative treatment of benign mammary tumors (BMTs), performed with the use of aglepristone, on the density of the tumor tissue measured by SWE. Twelve female dogs with diagnosed BMTs and increased levels of progesterone were treated with aglepristone (Alizine, Virbac, France) at 10 mg/kg s.c. (Subcutaneous injection). twice, with a 24 h interval. The density of the tumor was evaluated by SWE before and after the treatment. The type of tumor was evaluated by fine needle aspiration cytology before treatment, and a histopathological examination was made after surgical removal, performed after the aglepristone treatment. In all the cases, a significant reduction in the mammary tumor's size was observed following treatment, with no influence on the density of the tumor's tissue measured by SWE. Similar studies on malignant mammary tumors are warranted to verify if in these cases, density will also be a constant parameter that is not dependent on the tumor size.

Ultrasound: The Extension of Our Hands to Improve the Management of Thyroid Patients

Ultrasonography (US) was introduced in the thyroid field in the 1980s to guide the biopsy of palpable, scintigraphically cold nodules [...].

Ultrasound elastography reveals the relation between body posture and soft-tissue stiffness which is relevant to the etiology of sitting-acquired pressure ulcers

OBJECTIVE

Sitting-acquired pressure ulcers (PUs) are common in wheelchair users. These PUs are often serious and may involve deep tissue injury (DTI). Investigating the mechanical properties of the tissues susceptible to DTI may help in guiding the prevention and early detection of PUs. In this study, shear wave elastography (SWE) was used to measure the normative mechanical properties of the soft tissues of the buttocks, i.e. skeletal muscle and subcutaneous fat, under the ischial tuberosities, in a convenient sample of healthy adults without weight bearing and with weight bearing of different times.

APPROACH

We compared the stiffness properties of these soft tissues between the lying prone and sitting postures, to determine whether there are detectable property changes that may be associated with the type of posture. We hypothesized that muscle contractions and 3D tissue configurations associated with the posture may influence the measured tissue stiffnesses.

MAIN RESULTS

Our results have shown that indeed, SWE values differed significantly across postures, but not over time in a specific posture or for the right versus left sides of the body.

SIGNIFICANCE

We have therefore demonstrated that soft-tissue stiffness increases when sitting with weight bearing and may contribute to increasing the potential PU risk in sitting compared to lying prone, given the stiffer behavior of tissues observed in sitting postures.

A Comparison Study of Conventional Ultrasound and Ultrasound Strain Elastography in the Evaluation of Myopathy

The aim of this study was to compare ultrasound strain elastography (USE) with conventional ultrasonography echogenicity (EL) in detecting muscle pathology. For conventional ultrasonography, biceps EL was obtained. For USE, elasticity index (EI) of biceps was represented as a range, from 0 (softest) to 6 (hardest). Muscle-to-fats elasticity ratio compared EI of muscle with that of surrounding fats. Color distribution of elastogram was analyzed using open-source ImageJ software showing % red, % green, and % blue within a region of interest. Increased biceps EL, decreased biceps EI, and elasticity ratio were observed in patients with myopathy. In the color elastogram, there is no significant difference in % green between healthy control and patient, but significance was observed in % red and % blue (P < 0.001). Utilization of USE parameters has increased sensitivity up to 100% compared with 63% with conventional US. It is a promising adjunct for the clinical diagnosis of myopathy.

Diagnostic reliability of elastography in thyroid nodules reported as indeterminate at prior fine-needle aspiration cytology (FNAC): a systematic review and Bayesian meta-analysis

OBJECTIVES

To assess the diagnostic yields of elastography in thyroid nodules reported as indeterminate in FNAC according to guidelines.

METHODS

Databases of Medline, Embase, and Cochrane Central were searched till 31 October 2019. Two different reviewers check the studies and extracted the data. The diagnostic accuracy and yield were quantitatively synthesized using Bayesian bivariate model in R.

RESULTS

Twenty studies with 1734 indeterminate thyroid nodules undergoing elastography were included. The summary estimates of sensitivity and specificity were 0.766 (95% credible interval (CrI), 0.686-0.835) and 0.867 (95% CrI, 0.780-0.931), respectively. The summary estimate for diagnostic odds ratio (DOR) was 25.9 (95% CrI, 12.8-46.2). Summary receiver operating characteristic plots for elastography showed a right-diagonal curvilinear relationship, suggesting a trade-off between sensitivity and specificity, and the estimate of area under curve (AUC) was 0.743. The summary estimates for positive and negative likelihood ratios were 6.6 (95% CrI, 4.2-11.3) and 0.27 (95% CrI, 0.21-0.36), respectively.

CONCLUSIONS

Elastography had fair diagnostic yields in indeterminate thyroid nodules. Shear wave elastography and strain ratio elastography could be more efficient in diagnosis and should evolve in the next years while combing elastography with ultrasound would contribute more to sensitivity and specificity currently.

KEY POINTS

• Elastography has fair diagnostic yields in indeterminate thyroid nodules. • Shear wave elastography and strain ratio elastography are more efficient than real-time elastography. • Combining elastography and other ultrasound techniques improves evaluation of indeterminate thyroid nodules.

Ultrasound vibro-elastography for assessing mechanical properties of porcine reproductive tissues in an ex vivo model

BACKGROUND

The aim of this study was to use ultrasound vibro-elastography (UVE) for measuring surface wave speed and assessing mechanical properties of ex vivo porcine reproductive tissues, including the uterus, bladder, cornua and cervix.

METHODS

In UVE, a 0.1-s harmonic vibration at low frequency was generated on the tissue surface with a handheld shaker. A linear-array ultrasound probe was used to measure the resulting surface wave propagation. Surface wave speeds of tissues were measured in the frequency range of 100-300 Hz. Mechanical properties of the tissue were calculated based on wave speed dispersion with frequency.

FINDINGS

The obtained results showed that the surface wave speeds of porcine bladder, cervix, cornua and uterus increased with frequency. There were no statistically significant differences in the wave speeds or mechanical properties among the porcine bladder, cervix, cornua and uterus.

INTERPRETATION

Experimental data obtained in this study may be used as a reference to study in vivo surface wave speed or mechanical properties for porcine or human reproductive tissues.

Utility of sonoelastography for the evaluation of rotator cuff tendon and pertinent disorders: a systematic review and meta-analysis

OBJECTIVES

Sonoelastography has been increasingly used to investigate musculoskeletal disorders. The aim of this meta-analysis was to investigate the utility of sonoelastography in diagnosing rotator cuff tendon pathology and pertinent disorders.

METHODS

Searching through PubMed and Embase, we systemically reviewed clinical studies in which sonoelastography has been used for imaging rotator cuff tendon pathology and relevant disorders. The primary outcome was the standardized mean difference (SMD) of tendon elasticity between shoulders (or patients) with and without the designated pathological conditions.

RESULTS

A total of 11 cross-sectional studies were included in the meta-analysis. The supraspinatus and infraspinatus tendons assessed by shear wave sonoelastography were likely to be stiffer in shoulders with adhesive capsulitis, with a SMD of 2.103 (95% confidence interval (CI), - 0.151 to 4.357, p = 0.067) and a SMD of 1.548 (95% CI, - 0.032 to 3.127, p = 0.055), respectively. Regarding rotator cuff tendinopathy, there was no significant difference in the elasticity of supraspinatus tendons evaluated by shear wave velocity (SMD = - 0.107; 95% CI, - 0.524 to 0.310, p = 0.615) or strain ratios (SMD = 0.153, 95% CI, - 2.134 to 2.440, p = 0.896). Only one study used shear wave sonoelastography to investigate patients with rotator cuff tendon tears and found tendon that elasticity was similar between diseased and normal shoulders.

CONCLUSION

This meta-analysis revealed that supraspinatus and infraspinatus tendons tended to be stiffer in shoulders with adhesive capsulitis. Furthermore, no significant difference in tendon elasticity could be identified between shoulders with and without rotator cuff tendinopathy or tendon tears.

KEY POINTS

• Supraspinatus and infraspinatus tendons are likely to have decreased elasticity in shoulders with adhesive capsulitis, as assessed by shear wave sonoelastography. • There was no significant difference in tendon elasticity between shoulders with and without rotator cuff tendinopathy or tendon tears when evaluated by strain and shear wave sonoelastography.

Assessment of the cervix in pregnant women with a history of cervical insufficiency during the first trimester using elastography

INTRODUCTION

To investigate changes in first trimester cervical elastography, cervical length and endocervical canal width in pregnant women with a history of cervical insufficiency, and further discuss the possibility of using these markers as predictors of cervical insufficiency in early pregnancy.

MATERIAL AND METHODS

This was an observational ultrasound study of first trimester cervical changes in singleton pregnancies between January 2016 and June 2018. Cervical elastography, cervical length and endocervical canal width were measured during the first trimester. Strain elastography was used to estimate the softness of anterior and posterior cervical lips and was expressed as percentages (strain rate).

RESULTS

Of the 339 pregnant women enrolled, 24 had a history of cervical insufficiency. The anterior cervical lip was significantly softer in the cervical insufficiency group (strain rate: 0.19% ± 0.05% vs 0.11% ± 0.04%; P < .001). Cervical length was significantly shorter in the cervical insufficiency group (36.3 ± 4.8 mm vs 38.3 ± 3.8 mm; P = .014). Endocervical canal width was significantly wider in the cervical insufficiency group (5.7 ± 1.1 mm vs 5.2 ± 0.7 mm; P = .001). Receiver operating characteristic curve analyses revealed that the optimal cut-off values of anterior cervical lip, cervical length and endocervical canal width to confirm the diagnosis of cervical insufficiency were 0.15%, 35.5 mm and 5.75 mm, respectively. In multivariate logistic regression analysis, significant differences were still observed in anterior cervical strain rate (adjusted odds ratio [OR] 53.78, 95% [confidence interval [CI] 11-270; P < .001) and endocervical canal width (adjusted OR, 5.41, 95% CI,1.2-24.7; P = .029).

CONCLUSIONS

First trimester cervical elastography is a valuable tool in the assessment of women with a history of cervical insufficiency. The anterior cervical lip was significantly softer in women with a history of cervical insufficiency, and the sensitivity and specificity of anterior cervical lip strain were better than that of cervical length and endocervical canal width.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Elastography for the diagnosis of high-suspicion thyroid nodules based on the 2015 American Thyroid Association guidelines: a multicenter study

BACKGROUND

An accurate diagnosis for high-suspicion nodules based on the 2015 American Thyroid Association (ATA) guidelines would reduce unnecessary invasive examinations. Elastography is a useful tool for discriminating benign and malignant thyroid nodules. The aim of this study is to investigate the diagnostic efficiency of elastography for high-suspicion thyroid nodules based on the 2015 ATA guidelines in the Chinese population.

METHODS

Thyroid nodules with high-suspicion characteristics based on the 2015 ATA guidelines were subjected to conventional ultrasound (US) and ultrasound strain elastography (USE) examinations at 12 hospitals from 4 geographic regions across China. Cytology/histology of thyroid nodules was used as a reference method. Receiver operating characteristic (ROC) curves were plotted to evaluate the diagnostic performance of the elasticity score (ES) and strain ratio (SR). Logistic regression analysis was used to determine the predictors of malignancy.

RESULTS

Overall, a total of 1445 thyroid nodules (834 malignant, 611 benign) from 12 centers were included in the final analysis. The areas under the curve of the ES and SR were 0.828 and 0.732, respectively. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the ES were 92.4, 60.7, 79.0, 76.3 and 85.5%, respectively, and those of the SR were 81.1, 50.1, 68.9, 65.9 and 67.9%, respectively. The combination of the Thyroid Imaging Reporting and Data System (TI-RADS) and ES led to a significant increase in the sensitivity and NPV (97.1 and 91.9%, respectively) compared with the TI-RADS alone. Logistic regression analysis showed that microcalcifications (OR = 5.290), taller than wide (OR = 12.710), irregular margins (OR = 10.117), extrathyroidal extension (ETE; OR = 6.412), the ES (OR = 3.741) and the SR (OR = 1.083) were independent predictors of malignant thyroid nodules. The sensitivity, specificity, accuracy, PPV and NPV of the ES were all superior in nodules ≥1 cm than in those < 1 cm (95.0% vs 90.4, 68.8% vs 56.8, 85.9% vs 74.4, 85.2% vs 69.9, and 87.8% vs 84.2%, respectively).

CONCLUSIONS

Elastography combined with the ES is a valuable tool for the assessment of high-suspicion thyroid nodules based on the 2015 ATA guidelines, especially in nodules ≥1 cm.

Injectable Biomedical Devices for Sensing and Stimulating Internal Body Organs

The rapid pace of progress in implantable electronics driven by novel technology has created devices with unconventional designs and features to reduce invasiveness and establish new sensing and stimulating techniques. Among the designs, injectable forms of biomedical electronics are explored for accurate and safe targeting of deep-seated body organs. Here, the classes of biomedical electronics and tools that have high aspect ratio structures designed to be injected or inserted into internal organs for minimally invasive monitoring and therapy are reviewed. Compared with devices in bulky or planar formats, the long shaft-like forms of implantable devices are easily placed in the organs with minimized outward protrusions via injection or insertion processes. Adding flexibility to the devices also enables effortless insertions through complex biological cavities, such as the cochlea, and enhances chronic reliability by complying with natural body movements, such as the heartbeat. Diverse types of such injectable implants developed for different organs are reviewed and the electronic, optoelectronic, piezoelectric, and microfluidic devices that enable stimulations and measurements of site-specific regions in the body are discussed. Noninvasive penetration strategies to deliver the miniscule devices are also considered. Finally, the challenges and future directions associated with deep body biomedical electronics are explained.

Partially cystic thyroid cancer on conventional and elastographic ultrasound: a retrospective study and a machine learning-assisted system

Background

Thyroid carcinoma constitutes the vast majority of all thyroid cancer, most of which is the solid nodule type. No previous studies have examined combining both conventional and elastic sonography to evaluate the diagnostic performance of partially cystic thyroid cancer (PCTC). This retrospective study was designed to evaluate differentiation of PCTC from benign partially cystic nodules with a machine learning-assisted system based on ultrasound (US) and elastography.

Methods

Patients with suspicious partially cystic nodules and finally confirmed were included in the study. We performed conventional US and real-time elastography (RTE). The US features of nodules were recorded. The data set was entered into 6 machine-learning algorithms. Sensitivity, specificity, accuracy, and area under the curve (AUC) were calculated.

Results

A total of 177 nodules were included in this study. Among these nodules, 81 were malignant and 96 were benign. Wreath-shaped feature, micro-calcification, and strain ratio (SR) value were the most important imaging features in differential diagnosis. The random forest classifier was the best diagnostic model.

Conclusions

US features of PCTC exhibited unique characteristics. Wreath-shaped partially cystic nodules, especially with the appearance of micro-calcifications and larger SR value, are more likely to be malignant. The random forest classifier might be useful to diagnose PCTC.

Shear Wave Elastography versus Strain Elastography in Diagnosing Parathyroid Adenomas

OBJECTIVES

The aim of the study was to compare elastographic means in parathyroid adenomas, using shear wave elastography and strain elastography.

METHODS

This prospective study examined 20 consecutive patients diagnosed with primary hyperparathyroidism and parathyroid adenoma, confirmed by biochemical assay, technetium-99 sestamibi scintigraphy, and pathology report, after parathyroid surgery. All patients were examined on conventional 2B ultrasound, 2D shear wave elastography, and strain elastography. We determined using 2D shear wave elastography (SWE) the elasticity index (EI) in parathyroid adenoma, thyroid parenchyma, and surrounding muscle and examined using strain elastography the parathyroid adenoma, and determined the strain ratio with the thyroid tissue and muscle tissue.

RESULTS

All patients had positive sestamibi scintigraphy and underwent surgery, with confirmation of parathyroid adenoma in all cases. The mean parathormone (PTH) value before surgery was 153.29 pg/ml (36.5, 464.8) and serum calcium concentration was 10.5 mg/dl (9, 11.5). We compared using 2D-SWE and strain elastography parathyroid adenoma with thyroid tissue and with surrounding muscle. The mean EI measured by SWE in parathyroid adenoma was 4.74 ± 2.74 kPa and in thyroid parenchyma was 11.718 ± 4.206 kPa (mean difference = 6.978 kPa, p < 0.001), and the mean EI value in muscle tissue was 16.362 ± 3.829 kPa (mean difference = 11.622, p < 0.001). Using ROC analysis, we found that an EI below 7 kPa correctly identifies parathyroid tissue. We evaluated parathyroid adenomas using strain elastography by color mapping and strain ratio as a semiquantitative measurement; however, we could not find any statistical correlation comparing the strain ratio obtained from the parathyroid adenoma with the thyroid tissue (p=0.485).

CONCLUSION

Ultrasound elastography is a helpful tool in identifying parathyroid adenomas. A cutoff value below 7 kPa can be used in 2D-SWE. Color maps in strain elastography without adding strain ratio can be used, parathyroid adenoma being identified as score 1 in the Rago criteria.

Diagnostic value of shear wave sonoelastography in differentiation of benign from malignant thyroid nodules

PURPOSE

To study the efficacy of shear wave elastography (SWE), using both qualitative and quantitative methods, alone and in conjunction with other B-mode features.

METHOD

117 patients with 123 nodules were studied both by conventional ultrasonography and SWE. Size, echogenicity, margins, internal calcification (micro- or macro-calcification), composition, shape and color Doppler were assessed for each nodule. The elasticity was assessed both qualitatively and quantitatively. Velocity in the ROI (Region of Interest) was calculated in the stiffest portions for 3 times, and maximum and mean velocity were obtained. ROC curve was analyzed to calculate the best cut-off value of the SWV (Shear Wave Velocity). Univariate logistic regression was used to examine the maximum and mean SWV as discrete variables and the results were compared to key variables of conventional US (Ultrasound) features.

RESULT

123 nodules in 117 patients were evaluated. Poor margins, hypoechogenicity, micro-calcification, color Doppler grades III and IV, color map grades IV and V, maximum and minimum velocity had significant correlation with malignancy. The highest Nagelkerke R2 belonged to maximum and mean velocity (R2 = 41.2 and 39 respectively) which propose them as the strongest predictors of malignancy. The best cut-off point for differentiation of benign from malignant nodules was 3.63 m/s for maximum velocity (sensitivity of 90 %, specificity of 78.2 %,) and 3.44 m/s for mean velocity (sensitivity of 90 %, specificity of 76.4 %).

CONCLUSION

The Real-time SWE is a promising test for the preoperative malignancy risk stratification of patients and maximum velocity has the strongest predictive value for both conventional and elastography variables.

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.

Shear wave elasticity by tracing total nodule showed high reproducibility and concordance with fibrosis in thyroid cancer

Background

Although shear wave elastography (SWE) is reported to be useful in detecting malignant thyroid nodules, it shows a wide range of cut-off values of elasticity index (EI) in detecting malignant nodules. The cause of discrepancy remains unclear. Fibrosis of the tumors is known to increase the EI in SWE, and matching of SWE and surgical histopathology has not been fully illustrated in thyroid cancer. We aimed to evaluate the reproducibility of the new total nodular region of interest (ROI) method excluding the subjective features of focal circular ROI placement and to determine the lesion that causes the elevation of EI on SWE and on histopathology.

Methods

A total of 29 thyroid cancers from 28 patients were included. We evaluated the reproducibility of EI in the new total nodular ROI using Q-Box Trace program and compared the EI in focal nodular ROI using a 3-mm circular area. We analyzed the correlation between fibrosis and EI.

Result

The coefficient of variation (CV) of the intrarater assay was significantly lower in total nodular ROI than in focal nodular ROI within the image in rater 1 (1.7% vs. 13.4%, p < 0.001) and in rater 2 (1.4% vs. 16.9%, p < 0.001) and in different images in rater 1 (7.6% vs. 12.3%, p = 0.040) and in rater 2 (7.5% vs. 19.8%, p = 0.004). Moreover, CV of the interrater assay showed similar results (14.9% vs. 19%, p = 0.030). Interrater intraclass correlation coefficient showed better agreement in total nodular ROI than in focal nodular ROI (0.863 vs. 0.783). The degree of fibrosis on histopathology showed significant correlations with EI (E_Mean, p < 0.001; E_Max, p = 0.027), and the location of fibrosis was concordant with the high EI area on SWE.

Conclusion

Our study revealed that the new total nodular ROI method showed higher reproducibility and better agreement in intra- and interrater assay than the focal nodular ROI method, suggesting a valuable and standardized method in clinical practice. Moreover, our results showed that fibrosis in the histopathology increased EI on SWE and might lead to the discrepancy of the cut-off values in detecting thyroid cancer.

Ultrasound Real-Time Tissue Elastography Improves the Diagnostic Performance of the ACR Thyroid Imaging Reporting and Data System in Differentiating Malignant from Benign Thyroid Nodules: A Summary of 1525 Thyroid Nodules

BACKGROUND

To explore the correlation between the ultrasound elasticity score (ES) of real-time tissue elastography (RTE) and the malignant risk stratification of the Thyroid Imaging Reporting and Data System (TI-RADS) and to evaluate the added value of RTE to TI-RADS in differentiating malignant nodules from benign ones.

METHODS

A total of 1,498 patients (885 women and 613 men; mean age of 43.5 ± 12.4 years) with 1,525 confirmed thyroid nodules (D = maximum diameter, D ≤ 2.5 cm) confirmed by fine-needle aspiration (FNA) and/or surgery were included. The nodules were divided into four groups based on their sizes (D ≤ 0.5 cm, 0.5 < D ≤ 1.0 cm, 1.0 < D ≤ 2.0 cm, and 2.0 < D ≤ 2.5 cm). We assigned an ES of RTE and malignant risk stratification of the TI-RADS category to each nodule. The correlation between the ES of RTE and the malignant risk stratification of TI-RADS category was analyzed by the Spearman's rank correlation. The diagnostic performances of RTE, TI-RADS, and their combination were compared by the receiver operator characteristic (ROC) analysis.

RESULTS

The ES of RTE and the malignant risk stratification of TI-RADS showed a strong correlation in the size intervals of 0.5 < D ≤ 1.0 cm, 1.0 < D ≤ 2.0 cm, and 2.0 < D ≤ 2.5 cm (r = 0.768, 0.711, and 0.743, respectively). The diagnostic performance of their combination for each size interval was always better than RTE or TI-RADS alone (for all, P < 0.001).

CONCLUSIONS

Overall, The ES of RTE was strongly correlated with the malignant risk stratification of TI-RADS. The diagnostic performance of the combination of RTE and TI-RADS outperformed RTE or TI-RADS alone. Therefore, RTE may be an adjunctive tool to the current TI-RADS system for differentiating malignant from benign thyroid nodules.

Thyroid imaging reporting and data system combined with Bethesda classification in qualitative thyroid nodule diagnosis

OBJECTIVE

We aimed to investigate the value of the combined use of high-resolution ultrasound thyroid imaging reporting and data system (TI-RADS) classification and thyroid fine needle aspiration cytology (Bethesda classification) for the qualitative diagnosis of benign and malignant thyroid nodules.

METHODS

We enrolled 295 patients with 327 thyroid nodules who were scheduled to undergo thyroid nodule surgery. Before surgery, all the patients underwent ultrasound and scoring with the TI-RADS classification, along with thyroid fine needle biopsy cytology under ultrasound guidance (US-FNAC) and scoring with the Bethesda classification. After surgery, the TI-RADS and Bethesda classification scores, separately and in combination, were compared with the postoperative pathological results in terms of the differential diagnosis of thyroid nodules.

RESULTS

TI-RADS classification score 4 exhibited the highest diagnostic value for thyroid cancer; the sensitivity, specificity, and accuracy were 92.7%, 70.7%, and 87.1%, respectively, whereas the Kappa and receiver-operating characteristics (ROC) values were 0.651 and 0.817, respectively. Moreover, Bethesda classification score 3 exhibited the highest diagnostic value for thyroid cancer; the sensitivity, specificity, and accuracy were 90.0%, 94.3%, and 91.1%, respectively, whereas the Kappa and ROC values were 0.78 and 0.914, respectively. With regard to the combined diagnostic method, a score of 7 exhibited the highest diagnostic value for thyroid cancer; the sensitivity, specificity, and accuracy were 97.3%, 92.0%, and 95.9%, respectively, whereas the Kappa and ROC values were 0.893 and 0.946, respectively.

CONCLUSION

The combination of high-resolution ultrasonography TI-RADS classification and US-FNAC (Bethesda classification) can improve the accuracy of malignant thyroid nodules diagnosis.

Combination of contrast-enhanced ultrasound and strain elastography to assess cytologically non-diagnostic thyroid nodules

The aim of the present study was to investigate the benefits of combining contrast-enhanced ultrasound (CEUS) and strain elastography (SE) for the diagnosis of thyroid nodules with non-diagnostic fine-needle aspiration cytology (FNAC) results. Between October 2013 and March 2017, CEUS and SE were performed in 226 patients (236 thyroid nodules) with non-diagnostic FNAC results prior to thyroidectomy. The diagnostic value of CEUS, SE and their combination (CEUS+SE) in distinguishing malignant from benign thyroid nodules was evaluated, using surgical pathology as a reference. Receiver operating characteristic curve analysis was used to assess the diagnostic performance of CEUS, SE and CEUS+SE in determining malignant thyroid nodules. Subsequently, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of CEUS, SE and CEUS + SE were calculated. The malignancy rate in patients with thyroid nodules and non-diagnostic FNAC results was 26.3% in the present study. The sensitivity, specificity, PPV, NPV, accuracy and area under the curve in predicting malignant thyroid nodules were 80.6, 85.6, 66.7, 92.5, 84.3 and 0.831%, respectively, using SE alone; 59.7, 95.9, 84.1, 86.9, 86.4 and 0.778%, respectively, using CEUS alone; and 83.9, 89.1, 73.6, 94.5, 88.1 and 0.865%, respectively, using the combination of CEUS and SE. Overall, the combination of CEUS with SE resulted in higher sensitivity, NPV and accuracy in the diagnosis of cytologically non-diagnostic thyroid nodules compared with CEUS or SE alone.

Which Is the Best Reference Tissue for Strain Elastography in Predicting Malignancy in Thyroid Nodules, the Sternocleidomastoid Muscle or the Thyroid Parenchyma?

OBJECTIVES

This study aimed to compare 2 types of strain ratios (SRs) in thyroid nodules. Two reference points were used: the sternocleidomastoid (SCM) muscle and the thyroid parenchyma.

METHODS

A total of 101 nodules in 83 patients were prospectively enrolled in the study. For the semiquantitative analysis, 2 types of SRs were used: SR1, the ratio of the SCM muscle strain to the thyroid nodule strain; and SR2, the ratio of the surrounding normal thyroid tissue strain to the thyroid nodule strain. For each nodule, the SR1 and SR2 elastographic values were calculated, and their averages were compared.

RESULTS

Eighty-one (80.2%) of 101 thyroid nodules were benign, and 20 (19.8%) were malignant. In both benign and malignant histopathologic types, the SR1 averages were significantly higher than the SR2 averages (P = .001; P < .001, respectively). Both the SR1 and SR2 values were found to be significantly successful in differentiating benign from malignant histopathologic types (P < .001 for both). The areas under the curve were then compared for the methods, and the difference was found to be statistically significant (P = .046). The diagnostic accuracy of the SR1 was superior to that of the SR2.

CONCLUSIONS

The SR1 and SR2 are effective adjunctive diagnostic tools for identifying malignant thyroid nodules. Using the SCM muscle as a reference point instead of thyroid tissue may be a more valuable way to measure SRs.

Strain Elastography as a Valuable Diagnosis Tool in Intermediate Cytology (Bethesda III) Thyroid Nodules

Fine needle aspiration (FNA) is considered the gold standard in the diagnostic of thyroid nodules. Using the recommended BETHESDA reporting system, up to 20% of results are classified as intermediate cytology. As there is no consensus whether ultrasound evaluation, lobectomy or surgery is the best treatment option, intermediate cytology results are considered a grey zone of the FNA. The main aim of our study was to evaluate the performance of combined advanced ultrasound techniques in the process of diagnosis and evaluation of the intermediate cytology cases after FNA. We evaluated 54 consecutive cases with intermediate cytology on FNA, using conventional B-mode ultrasound (2B), and strain elastography, using a linear multifrequency 6-13 MHz linear probe (Hitachi Prerius Machine, Hitachi Inc, Japan). All nodules were classified with our Thyroid Imaging Report and Data System (TI-RADS) proposed model, considering: vertical appearance, with antero-posterior diameter bigger than the transvers diameter, the so called taller than wide shape, irregular borders, intranodular inhomogeneity, marked hypoecogenicity, micro calcifications, the presence of suspect lymph nodes, and increased stiffness as suspicious for malignancy. The classification outcomes were compared with the pathology results, considered the gold standard diagnosis. The prevalence of cancer was 28.8%, with 13/45 cases having a clear diagnostic of cancer. Six cases were diagnosed with borderline follicular neoplasia, a category with unclear evolution, also considered as malignant in the analysis of the imaging results. In total, 16/19 cancer cases had increased stiffness on elastography. The cancer prevalence increased with TI-RADS category, being 25% in TI-RADS 4b category and 92.8% in TI-RADS 5 category. The AUROC (Area Under Receiver Operating Curve) of elastography alone, in differentiation of malignant thyroid nodules was 74.9%; the combination of elastographic and conventional ultrasound characteristics generated an even better AUROC, of 84.5%. The combined conventional ultrasound and elastography identified thyroid cancer in cases with intermediate cytology with a sensitivity of 89.5% with a specificity of 50%. High risk thyroid nodules, identified by combined high risk conventional ultrasound characteristics and increased stiffness, on strain elastography, are highly predictive for malignancy, in the intermediate cytology cases.

Diagnostic Performance of Ultrasound Strain Elastography in Transverse and Longitudinal Views in Predicting Malignant Thyroid Nodules

Agreement between ultrasound strain elastography (SE) scores of transverse and longitudinal views of thyroid nodules was investigated, and the diagnostic performance of these scores in predicting thyroid malignancy was assessed. From December 2016 to February 2017, a total of 250 thyroid nodules in 232 patients (62 males and 188 females, mean age: 45 y [20-75 y]) were enrolled. Diagnostic agreement between SE scores obtained in different views was assessed. Sensitivity, specificity, area under the receiver operating characteristic curve (Az) of the SE score in different criteria (criterion 1, SE score ≥4 from any view is defined as suspicious; criterion 2, SE score ≥4 as in only transverse view; and criterion 3, SE score ≥4 only from longitudinal view) were evaluated. Diagnostic agreement between SE scores of different views was fair (κ = 0.227). The Az value for criterion 1 (0.770, 95% confidence interval [CI]: 0.713, 0.820) was the highest among the three criteria, significantly higher than that of criterion 2 (0.692, 95% CI: 0.631, 0.749) (p < 0.001), but not statistically significantly different from that of criterion 3 (0.768, 95% CI: 0.711, 0.819) (p = 0.909). However, the Az value for criterion 3 was higher than that for criterion 2 (p < 0.005). The results indicated that criterion 1 had high sensitivity (80.0%) and criterion 2 had high specificity (68.0%). Our study found that the agreement between SE scores of different views was fair. SE scores ≥4 in either view were most sensitive for predicting malignant thyroid nodules.

Diagnostic value of multimodal ultrasound imaging in differentiating benign and malignant TI-RADS category 4 nodules

Background

Differential diagnosis of benign and malignant thyroid imaging reporting and data system category 4 (TI-RADS-4) nodules can be difficult using conventional ultrasound (US). This study aimed to evaluate whether multimodal ultrasound imaging can improve differentiation and characterization of benign and malignant TI-RADS-4 nodules.

Methods

Multimodal ultrasound imaging, including US, superb microvascular imaging (SMI), and real-time elastography (RTE), were performed on 196 TI-RADS-4 nodules (78, benign; 118, malignant) in 170 consecutive patients. The sensitivity, specificity, accuracy, false negative rate (FNR), and false positive rate (FPR) of each single method and that of multimodal US imaging were determined by comparison with surgical pathology results.

Results

The sensitivity, specificity, accuracy, FNR, and FPR for US were 65.25%, 69.23%, 66.84%, 34.75%, 30.77%, respectively; for SMI were 77.97%, 93.59%, 84.18%, 22.03%, 6.41%, respectively; RTE, 80.51%, 84.62%, 82.14%, 19.49%, 15.38%; and for multimodal US imaging were 94.08%, 87.18%, 91.33%, 6.93%, 12.82%, respectively. The areas under the received operating characteristic curve for US, SMI, RTE, and multimodal US imaging in evaluating benign and malignant TI-RADS-4 nodules were 67.2%, 84.40%, 86.60%, and 95.50%, respectively.

Conclusions

The initial clinical results suggest that multimodal US imaging improves the diagnostic accuracy of TI-RADS-4 nodules and provides additional information for differentiating malignant and benign nodules.

Risk stratification of the thyroid nodule with Bethesda indeterminate cytology, category III, IV, V on the one surgeon-performed US-guided fine-needle aspiration with 27-gauge needle, verified by histopathology of thyroidectomy: the additional value of one surgeon-performed elastography

BACKGROUND

The aim is to assess the value of strain elastography (SE) in differentiating likelihood of malignancy for the thyroid nodules, possessing the Bethesda Category III, IV, and V indeterminate cytology.

METHODS

The data was obtained by ultrasonography (US)-guided fine-needle aspiration (US-g-FNA) via 27-gauge needle, with the verification of indicated thyroidectomies in a retrospective analysis, from April 2010 to April 2014, by enrolling the documents of 262 consecutive patients, with 327 thyroid nodules, subjected to one-surgeon performed neck US, SE, and US-g-FNA with 27-G needle to rule out the malignancy.

RESULTS

122 of 327 cases were Bethesda Category III, IV, and V with histopathologically benign, 110 (90.2%); PTC, 7 (5.7%); FTC, 4 (3.3%); HCC, 1 (0.8%). Tsukuba Elasticity Score (TES) 1, 2, 3, 4, and 5 were detected as 38 (31.1%), 8 (6.6%), 59 (48.4%), 4 (3.3%), and 13 (10.7%), respectively for the cases with the indeterminate cytology. No significant difference was detected between TES 4 and 5 and malign histopathology by McNemar test (p = .727) with a good level of concordance, the kappa coefficient, 0.737.

CONCLUSION

SE may be a useful tool in differentiating malign from benign thyroid nodules by selecting surgery adaptation even for Bethesda indeterminate cytology on FNAC.

Value of contrast-enhanced ultrasound combined with elastography in evaluating cervical lymph node metastasis in papillary thyroid carcinoma

BACKGROUND

Cervical lymph node metastasis in papillary thyroid carcinoma (PTC) affects the treatment and prognosis of patients. Ultrasound is a common imaging method for detecting cervical lymph nodes in PTC patients; however, it is not accurate in determining lymph node metastasis.

AIM

To evaluate the value of contrast-enhanced ultrasound combined with elastography in evaluating cervical lymph node metastasis in PTC.

METHODS

A total of 94 patients with PTC were recruited. According to pathological results, lymph nodes were divided into two groups: metastatic group (n = 50) and reactive group (n = 63). The routine ultrasound findings, contrast-enhanced ultrasound and elastography data were recorded and compared. Logistic regression was used to generate predictive probability distributions for the diagnosis of lymph node metastasis with different indicators. Receiver operating characteristic curve analysis was used to test the efficacy of contrast-enhanced ultrasound combined with elastography based on routine ultrasound in evaluating PTC cervical lymph node metastasis.

RESULTS

The ratio of long diameter/short diameter (L/S) ≤ 2, irregular marginal morphology, missing lymphatic portal, peripheral or mixed blood flow distribution, peak intensity (PI), non-uniform contrast distribution and elasticity score in the metastatic group were significantly higher than those in the reactive group (P < 0.05). L/S ratio, missing lymphatic portal, PI and elasticity score had a significant influence on the occurrence of PTC cervical lymph node metastasis (P < 0.05). Furthermore, the area under the curve (AUC) for lymph node metastasis diagnosed using the combination of PI ratio, elasticity score, missing lymphatic portal and LS was 0.936, which was significantly higher than the AUC for PI ratio alone. The difference was statistically significant (P < 0.05). The fitting equation for the combined diagnosis was logit(P) = -12.341 + 1.482 × L/S ratio + 3.529 × missing lymphatic portal + 0.392 × PI + 3.288 × elasticity score.

CONCLUSION

Based on the gray-scale ultrasound, the combination of contrast-enhanced ultrasound and elastography can accurately assess PTC cervical lymph node metastasis.

Nodular Thyroid Disease in the Era of Precision Medicine

Management of thyroid nodules in the era of precision medicine is continuously changing. Neck ultrasound plays a pivotal role in the diagnosis and several ultrasound stratification systems have been proposed in order to predict malignancy and help clinicians in therapeutic and follow-up decision. Ultrasound elastosonography is another powerful diagnostic technique and can be an added value to stratify the risk of malignancy of thyroid nodules. Moreover, the development of new techniques in the era of "Deep Learning," has led to a creation of machine-learning algorithms based on ultrasound examinations that showed similar accuracy to that obtained by expert radiologists. Despite new technologies in thyroid imaging, diagnostic surgery in 50-70% of patients with indeterminate cytology is still performed. Molecular tests can increase accuracy in diagnosis when performed on "indeterminate" nodules. However, the more updated tools that can be used to this purpose in order to "rule out" (Afirma GSC) or "rule in" (Thyroseq v3) malignancy, have a main limitation: the high costs. In the last years various image-guided procedures have been proposed as alternative and less invasive approaches to surgery for symptomatic thyroid nodules. These minimally invasive techniques (laser and radio-frequency ablation, high intensity focused ultrasound and percutaneous microwave ablation) results in nodule shrinkage and improvement of local symptoms, with a lower risk of complications and minor costs compared to surgery. Finally, ultrasound-guided ablation therapy was introduced with promising results as a feasible treatment for low-risk papillary thyroid microcarcinoma or cervical lymph node metastases.