Real-time elastography and contrast-enhanced ultrasound for the assessment of thyroid nodules

Thyroid ultrasound and its ancillary techniques

Ultrasound (US) of the thyroid has been used as a diagnostic tool since the late 1960s. US is the most important imaging tool for diagnosing thyroid disease. In the majority of cases a correct diagnosis can already be made in synopsis of the sonographic together with clinical findings and basal thyroid hormone parameters. However, the characterization of thyroid nodules by US remains challenging. The introduction of Thyroid Imaging Reporting and Data Systems (TIRADSs) has improved diagnostic accuracy of thyroid cancer significantly. Newer techniques such as elastography, superb microvascular imaging (SMI), contrast enhanced ultrasound (CEUS) and multiparametric ultrasound (MPUS) expand diagnostic options and tools further. In addition, the use of artificial intelligence (AI) is a promising tool to improve and simplify diagnostics of thyroid nodules and there is evidence that AI can exceed the performance of humans. Combining different US techniques with the introduction of new software, the use of AI, FNB as well as molecular markers might pave the way for a completely new area of diagnostic accuracy in thyroid disease. Finally, interventional ultrasound using US-guided thermal ablation (TA) procedures are increasingly proposed as therapy options for benign as well as malignant thyroid diseases.

The predictive models based on multimodality ultrasonography for the differential diagnosis of thyroid nodules smaller than 10 mm

OBJECTIVE

The objective of this study was to establish a multimodality ultrasound prediction model based on conventional ultrasound (Con-US), shear wave elastography (SWE), and strain elastography (SE) and contrast-enhanced ultrasound (CEUS) and to explore their diagnostic values for thyroid nodules ≤ 10 mm.

METHODS

This retrospective study included 198 thyroid nodules (maximum diameter≤10 mm) in 198 thyroid surgery patients who were examined preoperatively with above-mentioned methods. The pathological findings of the thyroid nodules were used as the gold standard, and there were 72 benign nodules and 126 malignant nodules. The multimodal ultrasound prediction models were developed by logistic regression analysis based on the ultrasound image appearances. The diagnostic efficacy of these prediction models was then compared and internally cross-validated in a fivefold manner.

RESULTS

The specific features on CEUS (enhancement boundary, enhancement direction and decreased nodule area) and the parenchyma-to-nodule strain ratio (PNSR) on SE and SWE ratio were included in the prediction model. The Model one combining American College of Radiology Thyroid Imaging Reporting and Data Systems (ACR TI-RADS) score with PNSR and SWE ratio had the highest sensitivity (92.8%), while the Model three combining TI-RADS score with PNSR, SWE ratio and specific CEUS indicators had the highest specificity, accuracy, and AUC (90.2%,91.4%, and 0.958, respectively).

CONCLUSION

The multimodality ultrasound predictive models effectively improved the differential diagnosis of thyroid nodules smaller than 10 mm.

ADVANCES IN KNOWLEDGE

For the differential diagnosis of thyroid nodules ≤ 10 mm, both ultrasound elastography and CEUS could be effective complements to ACR TI-RADS.

The Role of CEUS in the Evaluation of Thyroid Cancer: From Diagnosis to Local Staging

Ultrasound often represents the first diagnostic step for thyroid nodule evaluation in clinical practice, but baseline US alone is not always effective enough to achieve thyroid nodule characterization. In the last decades new ultrasound techniques, such as CEUS, have been introduced to evaluate thyroid parenchyma as recommended by EFSUMB guidelines, for use in clinical research field, although its role is not yet clear. Several papers show the potential utility of CEUS in the differential diagnosis of benign and malignant thyroid nodules and in the analysis of lymph node involvement in neoplastic pathology. Therefore, we carried out an evaluation of the literature concerning the role of CEUS in three specific areas: the characterization of the thyroid nodule, the evaluation of minimally invasive treatment and loco-regional staging of the lymph node in proven thyroid cancer. According to evidence reported, CEUS can also play an operative role in nodular thyroid pathology as it is able to guide ablation procedures on thyroid nodule and metastatic lymph nodes, to assess the radicality of surgery, to evaluate disease relapse at the level of the margins of ablated regions and to monitor the clinical evolution of necrotic areas in immediate post-treatment setting.

Multimode ultrasonic technique is recommended for the differential diagnosis of thyroid cancer

Background

B-mode ultrasound is one of the most commonly used imaging techniques for evaluating thyroid nodules due to its noninvasive property and excellent performance in terms of discriminating between benign and malignant nodules. However, the accuracy of differential diagnosis strongly depends on the experience of ultrasonographers. In addition to B-mode ultrasound, the elastic mode and contrast-enhanced mode have shown complimentary value in the diagnosis of thyroid nodules. The combination of multiple modes in ultrasonic techniques may effectively undermine diagnostic subjectiveness and improve accuracy. In this study, we evaluated the diagnostic value of combining the three ultrasonic modes for differentiating thyroid cancers.

Methods

In this retrospective study, we analyzed a total of 196 thyroid nodules with suspected malignancies from 185 patients who gave informed consent. Xi’an Jiaotong University granted ethical approval (No. 2018200) to carry out the study within its facilities. All the patients received ultrasonic examinations with the B mode, elastic mode and contrast-enhanced mode, followed by histopathological confirmation by fine-need aspiration or surgery. A predictive multivariate logistic regression model was selected to integrate the variety of data obtained from the three modes.

Results

The combination of three ultrasonic techniques for differentiating malignant from benign thyroid nodules showed the highest diagnostic accuracy of 0.985 compared to the B mode alone (0.841) and the two-mode combination. The accuracy of the B mode combined with the elastic technique was 0.954, and the accuracy of the B mode combined with the contrast-enhanced technique was 0.960.

Discussion

Multimode ultrasonic techniques should be recommended to patients with suspected malignant thyroid nodules in routine clinical practice.

Contrast-enhanced ultrasound for the differential diagnosis of thyroid nodules: An updated meta-analysis with comprehensive heterogeneity analysis

The diagnostic accuracy of contrast-enhanced ultrasound (CEUS) for distinguishing malignant thyroid nodules from benign thyroid nodules remains controversial. This meta-analysis was performed to evaluate the overall diagnostic value of CEUS for the characterization of thyroid nodules. Relevant studies were identified by searching PubMed, Embase and the Cochrane Library until August 1th 2019 to assess the overall diagnostic accuracy of CEUS. 37 eligible studies were included in the present meta-analysis. The pooled sensitivity, specificity, positive likelihood rate, negative likelihood rate and diagnostic odds ratio of CEUS were 0.87, 0.83, 5.38, 0.17 and 38.94, respectively, with the AUC of 0.9263. Subgroup analysis showed the heterogeneity was greatly reduced in small nodules group (≤ 1 cm) (I2 = 0.0%), while heterogeneity was still observed in the group of variable sizes group (I2 = 69.5%). However, meta-regression analysis revealed that only diagnostic criterion was the major source of heterogeneity (p = 0.0259). The risk of publication bias was negligible (p = 0.35). CEUS exhibited high accuracy for the identification of thyroid nodules and might provide additional perfusion information for the current US imaging reporting systems.

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.

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.

Clinical diagnostic value of contrast-enhanced ultrasound and TI-RADS classification for benign and malignant thyroid tumors: One comparative cohort study

To evaluate the diagnostic efficacy and clinical value of contrast-enhanced ultrasonography (CEUS) plus TI-RADS classification in benign and malignant thyroid tumors compared with either method alone.The informed consent was signed all patients. A total of 370 patients with thyroid tumors of TI-RADS category 3 and 4 were recruited, with 432 thyroid nodules. They respectively received routine ultrasonography and CEUS. The nodules were reclassified according to CEUS scoring, and a combined diagnosis was made. The pathological results were taken as the gold standard. The sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and area under the ROC curve were calculated for the 3 diagnostic methods. The diagnostic efficacy was compared by using Student t test, Pearson chi-square (χ) test, McNemar chi-square (χ) test or Z test. Student t test and logistic regression were employed for comparing different imaging features of benign and malignant thyroid tumors on CEUS and risk analysis.Of 432 thyroid nodules, there were 258 malignant nodules (59.72%) and 174 benign ones (40.28%). By logistic regression, 6 suspicious features on CEUS were considered significant for differentiating malignant from benign tumors: slow entry of contrast agents during enhancement stage (OR = 15.610, P = .001), slow time to peak (OR = 7.416, P = .002), non-uniform enhancement (OR = 10.076, P = .023), enhancement pattern (irregular) (OR = 36.233, P = .002), enhancement boundary (unclear) (OR = 25.300, P = .012), and no ring-like enhancement (OR = 25.297, P = .004). CEUS plus TI-RADS classification showed a higher diagnostic efficacy for differentiating between benign and malignant thyroid tumors. The Se was 85.66% (0.806-0.896), Sp 83.33% (0.768-0.884), PPV 88.40% (0.836-0.919), NPV 79.67% (0.729-0.851), and AUC 0.867 ± 0.019 (0.815-0.889). The above indicators were of statistical significance as compared with TI-RADS classification or CEUS alone (P <.05).CEUS can more clearly visualize microvascular distribution of the nodules and offers a new approach to diagnose benign and malignant thyroid tumors. TI-RADS classification plus CEUS is more accurate than TI-RADS classification alone. This combined approach is worthy of clinical popularization.

The diagnostic accuracy of contrast-enhanced ultrasound for the differentiation of benign and malignant thyroid nodules: A PRISMA compliant meta-analysis

BACKGROUND

Contrast-enhanced ultrasound (CEUS) is a non-invasive method that has been used in the diagnosis of several diseases. Recently, CEUS has been used in the differentiation of benign and malignant thyroid nodules. However, the performance of CEUS in thyroid nodules has not been studied clearly.

METHODS

The databases of Pubmed, Embase, Cochrane library and the unpublished studies were systematically searched for candidate inclusions, with the use of CEUS in differentiating the benign and malignant thyroid nodules. The quality of included studies was assessed using Quality Assessment of Diagnostic Accuracy Studies (QUADAS) questionnaire. The pooled estimates of sensitivity, specificity, diagnostic odds ratio (DOR), positive and negative likelihood ratio (NLR) were calculated using STATA software version 14.0.

RESULTS

Totally 33 diagnostic studies were included for further analysis. The quality of included studies was relatively high using QUADAS method. The pooled estimates of sensitivity and specificity were 0.88 (95% CI 0.85, 0.91) and 0.88 (95% CI 0.83, 0.91), respectively. In addition, the DOR, the positive and NLRs were pooled positive LR and the negative LR were 54 (95% CI 33, 89), 7.1% (5.2%, 9.8%), and 0.13% (0.10%, 0.18%). No significant publication bias was observed.

CONCLUSIONS

Our meta-analysis further indicated that CEUS is a useful tool in differentiating benign and malignant thyroid nodules, with high sensitivity and specificity.

Value of Contrast-Enhanced Ultrasound and Acoustic Radiation Force Impulse Imaging for the Differential Diagnosis of Benign and Malignant Thyroid Nodules

Objectives: To assess the value of contrast-enhanced ultrasound (CEUS) and acoustic radiation force impulse (ARFI) imaging for the differential diagnosis of benign and malignant thyroid nodules.

Methods: CEUS was performed in eighty-eight thyroid nodules. The patterns of CEUS were analyzed, and ARFI was then performed. The shear wave velocities (SWVs) of the nodules and the surrounding normal thyroid tissue were obtained. The areas under the curve (AUCs) and cut-off value were obtained by a receiver operating characteristic (ROC) curve analysis. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic rate of each modality were assessed and compared using pathological diagnosis.

Results: Among 88 nodules, 29 nodules were malignant and 59 were benign. The sensitivity, specificity, PPV, NPV, and diagnostic rate of CEUS were 79.3, 91.5, 82.1, 90, and 87.5%, respectively. Using a cut-off value of 2.565 m/s for SWV, the sensitivity, specificity, PPV, NPV and diagnostic rate for malignancy were 75.9, 94.9, 88.0, 88.9, and 88.6%, respectively. The AUC was 0.878. The sensitivity, specificity, PPV, NPV and diagnostic rate of CEUS in combination with ARFI were 93.1, 89.8, 81.8, 96.3, and 90.9%, respectively.

Conclusion: Both CEUS and ARFI are valuable for the differential diagnosis of benign and malignant thyroid nodules. Combining these two methods can improve the diagnostic rate.

Ultrasound Elastography is a Useful Adjunct to Conventional Ultrasonography and Needle Aspiration in Preoperative Prediction of Malignancy in Thyroid Nodules: A Northern India Perspective

INTRODUCTION

Data on ultrasound elastography (USE) are scant from India. This study aimed to compare the sensitivity and specificity of USE with thyroid ultrasonography (USG) and fine-needle aspiration (FNA) as preoperative predictor of malignancy, using postoperative histopathology as gold standard.

MATERIALS AND METHODS

Consecutive patients with thyroid swelling/goiter underwent thyroid USG followed by USE. Patients with pure cystic nodules or eggshell calcification were excluded. Patients with nodules >10 mm with one or more high-risk USG features underwent FNA. Patients with no USG high-risk features, benign score on USE, and benign FNA were conservatively followed. All other patients underwent thyroidectomy.

RESULTS

246 consecutive patients underwent USG. Data from 97 patients (117 nodules) were analyzed. Median age of patients was 43 years with 85.4% females. All patients with USE score-1 had benign USG and FNA characteristics. Of 86 nodules having USE score-2, 18.6% nodules were hypoechoic and 16.28% had microcalcification. Hypoechogenicity and microcalcifications were observed in 66.67% nodules with USE score-3. All nodules with USE score-4 and 5 were hypoechoic and had microcalcifications. Histopathology was benign in 84 and malignant in 33 patients. Occurrence of malignancy in USE scores 1-5 was 0, 4.65, 100, 90.5, and 100%, respectively. All eight nodules with diagnosis of follicular adenoma had preoperative USE score-2. The sensitivity of preoperative USG, USE, and FNA in picking up malignancy was 66.67, 87.88, and 69.70%, respectively. Specificity of USG, USE, and FNA in detecting thyroid malignancy was 88.10, 100, and 97.6%, respectively. False positivity rates for USG, USE, and FNA in diagnosing thyroid malignancy was 11.9, 0, and 2.4%, respectively. The overall diagnostic accuracy of USG, USE, and FNA cytology in this study was 82.05, 96.58, and 89.74%, respectively.

CONCLUSION

USE may be better than USG for preoperative detection of malignancy in thyroid nodules.

Application of contrast-enhanced ultrasound for evaluation of thyroid nodules

Contrast-enhanced ultrasound (CEUS) is widely used to evaluate tumor microcirculation, which is useful in the differential diagnosis between benignity and malignancy. In the last 10 years, the applicability of CEUS to thyroid nodules has greatly improved due to technological refinements and the development of second-generation contrast agents. In this review, we summarize the applications of CEUS for thyroid nodules, focusing on the imaging findings of malignant and benign nodules in the existing literature and the use of those findings to predict malignancies, with an additional brief description of the utilization of CEUS for other thyroid-related diseases.

Role of Virtual Touch Tissue Quantification in Hashimoto's Thyroiditis

We investigated the role of the virtual touch tissue quantification (VTQ) technique in diagnosing Hashimoto's thyroiditis (HT) and in distinguishing various HT-related thyroid dysfunctions. Two hundred HT patients and 100 healthy volunteers (the control group) were enrolled. The diagnostic performance of VTQ in predicting HT was calculated as the area under the receiver operating characteristic curve (A_Z). The HT patients were further classified into three subgroups on the basis of serologic tests of thyroid function: hyperthyroidism, euthyroidism and hypothyroidism. Comparisons of shear wave velocity (SWV) between three subgroups were evaluated by analysis of variance. The mean SWV of the control group was significantly lower than that of the HT group (1.93 ± 0.33 m/s vs. 2.32 ± 0.49 m/s, p <0.001). A_z was 0.734 with a cut-off value of 1.86 m/s for performance of SWV in distinguishing between HT and a healthy thyroid; the sensitivity and specificity were 82.5% and 50.0%, respectively. Mean SWV values in the three HT subgroups (hyperthyroidism [2.07 ± 0.37 cm/s] vs. euthyroidism [2.20 ± 0.40 cm/s] vs. hypothyroidism [2.49 ± 0.46 cm/s]) were significantly different (p <0.05). Our results suggest that VTQ is a promising technique for assessing HT and HT-related thyroid dysfunction.

Advantages of Routine Ultrasound Combined With Contrast-Enhanced Ultrasound in Diagnosing Papillary Thyroid Carcinoma

This study aimed to evaluate the advantages of routine ultrasound (US), contrast-enhanced US (CEUS), and the combination of these 2 methods in diagnosing papillary thyroid carcinoma (PTC). We subjected 89 patients with calcified thyroid nodules to conventional US and CEUS and then retrospectively analyzed the US and CEUS features of 89 patients with single, solid PTC. On this basis, we then evaluated the ability of US, CEUS, and their combination to diagnose PTC. In the 89 patients with thyroid nodules, US findings differed significantly from CEUS findings (P < 0.05). In the US group, the diagnostic sensitivity, specificity, and accuracy were 87.5%, 78.8%, and 88.0%, respectively; in the CEUS group, these values were 92.9% (P < 0.05), 87.9% (P < 0.05), and 92.9% (P < 0.05), respectively; and when the methods were combined, the diagnostic sensitivity, specificity, and accuracy were 96.7%, 92.7%, and 94.9%, respectively. A typical PTC nodule can be definitively diagnosed using US and CEUS; more specifically, the features of slow progression, late enhancement, and low enhancement were highly associated with a diagnosis of PTC. When these features were combined, they exhibited higher diagnostic performance than any individual method.

The Value of Peripheral Enhancement Pattern for Diagnosing Thyroid Cancer Using Contrast-Enhanced Ultrasound

BACKGROUND

Contrast-enhanced ultrasound (CEUS) scanning can detect differences between thyroid tumors and surrounding tissues. However, enhancement patterns within nodules are insufficient for the diagnosis of thyroid carcinomas. The peripheral enhancement patterns of nodules may provide useful diagnostic information. The objective of this study was to investigate the diagnostic accuracy of the peripheral enhancement patterns during CEUS scanning of thyroid nodules.

MATERIAL AND METHODS

120 nodules with peripheral rings during CEUS and definite pathology confirmed by surgery were included in this study. The internal and peripheral CEUS enhancement patterns of these nodules were assessed, and the diagnostic value of CEUS was compared with the conventional ultrasound. The relationship of types of peripheral rings and sizes of nodules was analyzed, respectively.

RESULTS

There were 78 benign and 42 malignant nodules. Peripheral irregular ring performs well in detecting malignancy. It improves the diagnostic performance of CEUS by combining with internal enhancement patterns (diagnostic sensitivity of 97.6%, specificity of 98.7%, and accuracy of 98.3%) and adds value to conventional ultrasound (95.2%, 70.5%, and 79.2%). The sizes of the nodules with regular high-enhanced rings (2.34 ± 1.33 cm) were larger than the other three types of peripheral rings (P < 0.05).

CONCLUSIONS

Features of peripheral ring on CEUS are important for the diagnosis of thyroid cancer; they can further contribute to the accuracy combining with the internal enhancement pattern, which could avoid the unnecessary biopsy.

Real-time elastography in autonomously functioning thyroid nodules: relationship with TSH levels, scintigraphy, and ultrasound patterns

BACKGROUND

Real-time elastography has been proposed to increase the sensitivity of ultrasound and improve the detection of thyroid nodules at risk of malignancy. To date sparse data on real-time elastography assessment of autonomously functioning thyroid nodules exist. Here, we investigated the potential role of real-time elastography in autonomously functioning thyroid nodule assessment. Specifically, the correlation between serum hormones and real-time elastography score, as well as other clinical and ultrasound features, was analyzed.

METHODS

Patients with autonomously functioning thyroid nodule identified by I-123 scintigraphy from September 2015 to July 2016 and undergoing ultrasound, real-time elastography, and thyroid function evaluation were selected. All autonomously functioning thyroid nodule were classified as RTE I (prevalence of red or green color with blue in up to 25% of the nodule area), RTE II (blue in 25-75%), or RTE III (blue in more than 75%). The association between suppressed thyroid stimulating hormone and patient's age, nodule's size, ultrasound presentation, and real-time elastography scoring was analyzed by Odds Ratio in univariate fashion and multivariate model.

RESULTS

A number of 47 subjects with single autonomously functioning thyroid nodule were enrolled. Median age of 63 years, median size of 2.0 cm, and suppressed thyroid stimulating hormone levels in 32% of cases were found. Those nodules classified by ultrasound at high risk underwent fine-needle aspiration cytology and cancer was excluded. At real-time elastography evaluation, a 45% of autonomously functioning thyroid nodule had a hard appearance (RTE III) and had thyroid stimulating hormone significantly lower than the other (p < 0.0001). A model of multivariate logistic regression including nodule's size, ultrasound characteristics, and elastographic presentation showed that only RTE III was significantly associated with suppressed thyroid stimulating hormone (Odds Ratio of 50).

CONCLUSIONS

Autonomously functioning thyroid nodule may have variable elasticity at real-time elastography examination, being hard score associated with reduced/suppressed thyroid stimulating hormone. For clinical practice, the presence of autonomously functioning thyroid nodule should be considered in patients with hard lesions. Also, as quoted by the most recent ATA guidelines, elastography should not be accounted for risk stratification of thyroid nodules.

Diagnostic potential of real-time elastography (RTE) and shear wave elastography (SWE) to differentiate benign and malignant thyroid nodules: A systematic review and meta-analysis

BACKGROUND

Real-time elastography (RTE) and shear wave elastography (SWE) are noninvasive and easily available imaging techniques that measure the tissue strain, and it has been reported that the sensitivity and the specificity of elastography were better in differentiating between benign and malignant thyroid nodules than conventional technologies.

METHODS

Relevant articles were searched in multiple databases; the comparison of elasticity index (EI) was conducted with the Review Manager 5.0. Forest plots of the sensitivity and specificity and SROC curve of RTE and SWE were performed with STATA 10.0 software. In addition, sensitivity analysis and bias analysis of the studies were conducted to examine the quality of articles; and to estimate possible publication bias, funnel plot was used and the Egger test was conducted.

RESULTS

Finally 22 articles which eventually satisfied the inclusion criteria were included in this study. After eliminating the inefficient, benign and malignant nodules were 2106 and 613, respectively. The meta-analysis suggested that the difference of EI between benign and malignant nodules was statistically significant (SMD = 2.11, 95% CI [1.67, 2.55], P < .00001). The overall sensitivities of RTE and SWE were roughly comparable, whereas the difference of specificities between these 2 methods was statistically significant. In addition, statistically significant difference of AUC between RTE and SWE was observed between RTE and SWE (P < .01).

CONCLUSION

The specificity of RTE was statistically higher than that of SWE; which suggests that compared with SWE, RTE may be more accurate on differentiating benign and malignant thyroid nodules.

Thyroid Cancer: Ultrasound Imaging and Fine-Needle Aspiration Biopsy

Ultrasound is critical in detection, diagnosis, and management of thyroid nodules. Ultrasound detection of regional nodal metastatic disease is based on abnormal nodal morphology rather than size and is critical to initial surgical and long-term management of thyroid cancer. Fine-needle aspiration biopsy is the gold standard for malignancy diagnosis in thyroid cancer. Thyroglobulin assay of nodal aspirates improves accuracy in diagnosis of metastases. Reporting lexicons assign risk levels to thyroid nodules with the goal of improving and standardizing patient management. Surveillance ultrasound in papillary microcarcinomas is being evaluated and compared with surgical management.

Strain Elastography - How To Do It?

Tissue stiffness assessed by palpation for diagnosing pathology has been used for thousands of years. Ultrasound elastography has been developed more recently to display similar information on tissue stiffness as an image. There are two main types of ultrasound elastography, strain and shear wave. Strain elastography is a qualitative technique and provides information on the relative stiffness between one tissue and another. Shear wave elastography is a quantitative method and provides an estimated value of the tissue stiffness that can be expressed in either the shear wave speed through the tissues in meters/second, or converted to the Young's modulus making some assumptions and expressed in kPa. Each technique has its advantages and disadvantages and they are often complimentary to each other in clinical practice. This article reviews the principles, technique, and interpretation of strain elastography in various organs. It describes how to optimize technique, while pitfalls and artifacts are also discussed.

Improvement of diagnostic efficiency in distinguishing the benign and malignant thyroid nodules via conventional ultrasound combined with ultrasound contrast and elastography

We aimed to evaluate the diagnostic values of conventional ultrasound (US), ultrasound contrast (UC) and ultrasound elastography (UE) in distinguishing the benign and malignant thyroid nodules. A total of 100 patients with thyroid nodules receiving operative treatment were selected; they underwent the conventional US, UE and UC examinations before operation, respectively. The nodules received pathological examination after operation to distinguish benign from malignant lesions. The sensitivity, specificity and diagnostic accordance rate of each diagnostic method was evaluated by receiver operating characteristic (ROC) curve, and the area under the curve (AUC) of ROC was calculated. The manifestations of malignant thyroid nodules in conventional US examination were mostly the hypoecho, heterogeneous echo, irregular shape, unclear boundary, aspect ratio <1, microcalcification and irregular peripheral echo halo, and there were statistically significant differences compared with the benign nodules (P<0.05). UE showed that the differences between benign and malignant nodules in 2, 3 and 4 points were statistically significant (P<0.05). The manifestations of malignant nodules in UC were mostly the irregular shape, obscure boundary, no obvious enhancement, heterogeneous enhancement and visible perfusion defects, and there were statistically significant differences compared with the benign nodules (P<0.05). ROC curve showed that both sensitivity and specificity of UE and UC were superior to those of conventional US. AUC was the largest (AUC = 0.908) and the diagnostic value was the highest in the conventional US combined with UE and UC. Conventional US combined with elastography and UC can significantly improve the sensitivity, specificity and accuracy of diagnosis of benign and malignant thyroid nodules.

Analysis of arterial dynamic micro-vascularization with contrast-enhanced ultrasound (CEUS) in thyroid lesions using external perfusion software: First results

AIM

To determine different perfusion characteristics of histo-pathologically proven adenomas and carcinomas of the thyroid gland with CEUS and perfusion software.

MATERIAL AND METHODS

Retrospective perfusion analysis of 25 patients with carcinomas and 41 cases of adenomas of the thyroid gland (30 males, 36 females; aged 18 - 85 years, mean 56 years). All cases were histologically analyzed. Perfusion analysis was independently performed using external perfusion software (VueBox®). TTP, mTT, Peak and Rise time were calculated.

RESULTS

Lesions' sizes ranged from 0.2 to 10.2 cm in carcinomas (mean 2.18 cm), and from 0.6 to 5.0 cm in adenomas (mean 2.25 cm). In 20 out of 25 carcinomas that were evaluated with CEUS, a complete wash-out in the late venous phase was found. Adenomas showed wash-out at the border.Perfusion analysis in VueBox® revealed some parameters which tend to show differences between adenomas and carcinomas, however did not reach the level of significance.Median Peak in carcinomas was highest at the margins (2945 rU), and lowest in the surroundings (1110 rU). Mean Transit Time (mTT) values showed no differences between center, margin and surrounding.In adenomas healthy tissue showed higher mTT values compared to the center (24.6 vs. 20.7 sec). Median Peak was highest in the surrounding tissue and lowest in the margins (1999 vs. 1129 rU). No statistical differences could be found in the comparisons.

CONCLUSION

CEUS with perfusion analysis offers new possibilities for the dynamic evaluation of micro-vascularization in thyroid adenomas and carcinomas. Using VueBox® the perfusion analysis of the arterial phase provides new parameters that help determine a lesion's malignancy or benignity. However a final assessment regarding malignancy and benignity of thyroid lesions using only CEUS and perfusion analysis of the arterial phase is not yet possible.

Quality measurement on shear wave speed imaging: diagnostic value in differentiation of thyroid malignancy and the associated factors

To evaluate the associated factors for quality measurement (QM) on shear wave speed (SWS) imaging and the additional value of QM for differentiation of thyroid nodules. A consecutive series of 238 patients with 254 thyroid nodules were enrolled. They were all evaluated by conventional ultrasound and SWS imaging and were finally proven pathologically. QM was used to assess whether SWS propagation was authentic and was classified as high QM and Low QM. Twelve variables were analyzed to evaluate the associated factors for QM using binary logistic regression. Receiver operating characteristic (ROC) curve was plotted on SWS and SWS+QM. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and area under ROC curve (AUC) were calculated. The study included 170 benign thyroid nodules (160 high QM and 10 low QM) and 84 malignant thyroid nodules (56 high QM and 28 low QM) (P < 0.001). The mean SWS of benign and malignant nodules were 2.51 ± 0.47 m/s and 3.43 ± 1.21 m/s respectively (P < 0.001). The sensitivities, specificities, PPVs, NPVs, accuracies and AUCs were 77.4%, 80.0%, 65.7%, 87.7%, 79.1%, 0.82 for SWS alone with SWS ≥ 2.78 m/s; 33.3-34.5%, 91.2-94.1%, 65.9-73.7%, 73.8-74.1%, 72.4-74.0%, 0.63-0.64 for QM alone and 84.5-85.7%, 72.4-75.9%, 60.5-63.4%, 90.8-91.0%, 76.8-78.7%, 0.79-0.80 for SWS+QM. Nodule depth was identified to be the strongest associated factor for QM of SWS, followed by malignancy and SWS. In conclusion, QM for thyroid nodule is associated with nodule depth, malignancy, and SWS. QM improves the specificity in comparison with SWS alone, whereas SWS+QM does not improve the overall diagnostic performance.

An Algorithm of Image Heterogeneity with Contrast-Enhanced Ultrasound in Differential Diagnosis of Solid Thyroid Nodules

Enhancement heterogeneity on contrast-enhanced ultrasonography (CEUS) is used to differentiate between benign and malignant thyroid nodules. In this study, we used an algorithm to quantify enhancement heterogeneity of solid thyroid nodules on CEUS. The heterogeneity value (HV) is calculated as standard deviation/mean intensity × 100 (using Adobe Photoshop). The heterogeneity ratio (HR) is calculated as the ratio of the HV of the nodule to that of the surrounding parenchyma. Three phases-ascending, peak and descending phases-were studied. HV values at ascending (HV_a) and peak (HV_p) phases were significantly higher in malignant nodules than in benign nodules (95.57 ± 43.87 vs. 73.06 ± 44.04, p = 0.009, and 32.53 ± 10.73 vs. 26.44 ± 8.25, p = 0.002, respectively). HR_a, HR_p and HR_d were significantly higher in malignant nodules than in benign nodules (1.93 ± 1.03 vs. 1.00 ± 0.47, p = 0.000, 1.43 ± 0.51 vs. 1.09 ± 0.28, p = 0.000, and 1.33 ± 0.40 vs. 1.08 ± 0.33, p = 0.001, respectively). HR_a achieved optimal diagnostic performance on receiver operating characteristic curve analysis. The algorithm used for assessment of image heterogeneity on CEUS examination may be a useful adjunct to conventional ultrasound for differential diagnosis of solid thyroid nodules.

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.

Application of high-resolution ultrasound, real-time elastography, and contrast-enhanced ultrasound in differentiating solid thyroid nodules

High-resolution ultrasound (HRUS) is a sensitive tool for identifying thyroid nodules. Real-time elastography (RTE) and contrast-enhanced ultrasound (CEUS) are newly developed methods which could measure tissue elasticity and perfusion features. The aim of the present study was to evaluate and compare the diagnostic efficiency of HRUS, RTE, CEUS and their combined use in the differentiation of benign and malignant solid thyroid nodules.In total, 111 consecutive patients with 145 thyroid nodules who were scheduled for surgery were included in the study. All of them underwent HRUS, RTE, and CEUS examination. The independent ultrasound (US) predictors for malignancy were determined and quantified using logistic regression analysis, based on which a risk-scoring model was established for each method. The diagnostic efficiency of each method was assessed by receiver operating characteristic (ROC) curve analysis.HRUS showed the best diagnostic efficiency among the 3 US methods, with 74.6% sensitivity and 87.8% specificity. CEUS had higher sensitivity (85.7%), whereas RTE alone did not show much advantage. Combined use of RTE and HRUS increased the sensitivity (92.1%). The HRUS-RTE-CEUS combination could increase both the sensitivity and specificity (87.3%, 91.5%), with the best AUC (0.935) among all the methods.The overall diagnostic value of HRUS in predicting malignancy is the best among the 3 US methods. Combined use of RTE and CEUS and HRUS could improve the diagnostic efficiency for solid thyroid nodules.

Shear wave elastography and contrast-enhanced ultrasonography in the diagnosis of thyroid malignant nodules

The aim of the present study was to evaluate the value of shear wave elastography (SWE) and contrast-enhanced ultrasonography (CEUS) in the diagnosis of thyroid malignant nodules. A total of 253 patients with 319 thyroid nodules were subjected to two-dimensional ultrasound (2DUS) and CEUS examinations prior to thyroidectomy between March, 2014 and December, 2015. Young's modulus value for each nodule on 2DUS and CEUS images were recorded. The sensitivity, specificity and accuracy of 2DUS, SWE and CEUS in the diagnosis of thyroid malignant nodules were assessed. The results demonstrated that, of the 319 nodules that were pathologically confirmed, 183 were malignant and 136 were benign. The area under the receiver operating characteristic curve as a result of SWE diagnosis was 0.77. When the threshold of the Young's modulus value was ≥27.65 kPa in the diagnosis of malignant thyroid nodules, SWE exhibited a sensitivity of 84.55% (115/136), a specificity of 84.15% (154/183) and an accuracy of 84.32% (269/319). US contrast imaging of malignant thyroid nodules revealed a major tendency for early hypoenhancement and hypoenhancement. CEUS exhibited a sensitivity of 87.5% (119/136), a specificity of 86.33% (158/183) and an accuracy of 86.83% (277/319) in the diagnosis of malignant thyroid nodules. Compared with 2DUS, SWE, CEUS and their combined use exhibited statistically significant differences in the diagnosis of thyroid malignant nodules in terms of sensitivity, specificity and accuracy (χ²=9.220,15.310 and 40.296, respectively; P=0.000); SWE or CEUS did not differ significantly in the diagnosis of thyroid malignant nodules in terms of sensitivity, specificity or accuracy (χ²=0.737;P=0.542); Compared with the use of SWE or CEUS alone, their combination exhibited statistically significant differences in the diagnosis of malignant thyroid nodules in terms of sensitivity, specificity and accuracy (χ²=12.264 and 6.939, respectively; P=0.000,0.005). In conclusion, the high accuracy of the combined use of SWE and CEUS in the diagnosis of malignant thyroid nodules is of great clinical value.

Usefulness of combined use of contrast-enhanced ultrasound and TI-RADS classification for the differentiation of benign from malignant lesions of thyroid nodules

Purpose

To study the thyroid image reporting and data system (TI-RADS) classification and the contrast-enhanced ultrasound (CEUS) enhancement pattern of thyroid nodules, and to determine whether combined use of both methods is helpful in the diagnosis of thyroid nodules.

Methods

A total of 319 thyroid nodules in 246 patients were assessed with TI-RADS, CEUS and a combination of both methods. The diagnostic performance of TI-RADS, CEUS and a combination of both methods was compared.

Results

The accuracy in the diagnosis of thyroid nodules was 90.3 % for TI-RADS, 90.0 % for CEUS and 96.0 % for a combination of both methods respectively. A statistically significant difference was not observed in the diagnostic accuracy of CEUS and TI-RADS (P > 0.05). However, a significant difference was observed between a combination of both methods and either alone (P < 0.01). A combination of both methods showed high sensitivity, specificity and accuracy for TI-RADS classifications of 4a and 4b thyroid nodules compared with TI-RADS alone (P < 0.01) and a statistically significant difference was not observed for thyroid nodules classified as 2, 3, and 5 (P > 0.05).

Conclusions

The improved TI-RADS, when combined with CEUS, could significantly improve the diagnostic accuracy for thyroid nodules, especially for TI-RADS class-4 thyroid nodules.

Key Points

• TI-RADS can be used as the primary diagnostic standard for thyroid nodules

• CEUS can be used as an important complement to TI-RADS

• The improved TI-RADS can significantly improve the qualitative diagnostic accuracy

Diagnostic value of contrast-enhanced ultrasound in solid thyroid nodules with and without enhancement

We aimed to investigate different enhancement patterns of solid thyroid nodules on contrast-enhanced ultrasound (CEUS) and then to evaluate the corresponding diagnostic performance in the differentiation of benign and malignant nodules with and without enhancement. 229 solid thyroid nodules in 196 patients who had undergone both conventional ultrasound and CEUS examinations were classified into enhancement and non-enhancement groups. Besides, different enhancement patterns in the enhancement group were characterised with five indicators including arrival time, mode of entrance, echo intensity, homogeneity, and washout time. Then aforementioned indicators were compared between benign and malignant nodules of different sizes (<10 mm and >10 mm), and diagnostic performance of significant enhancement indicators was calculated. As for the enhancement group, there were statistically significant differences of <10 mm subgroup among three CEUS indicators including arrival time, mode of entrance, and washout time between malignant and benign thyroid nodules (p < 0.05), while all CEUS indicators showed statistically significant differences in the total group and ≥10 mm subgroup (p < 0.05). All the five CEUS indicators displayed better diagnostic performance with specificity (92.86, 92.14, 95.71, 90.71, and 90.71 %, respectively) and diagnostic accuracy (80.79, 79.48, 74.67, 75.11, and 81.66 %, respectively), while the sensitivity and negative predictive value of non-enhancement were 95.51 and 95.83 %, respectively, with an accuracy of 77.29 %. CEUS is a very promising diagnostic technique that could improve the diagnostic accuracy of identifying benign thyroid lesions to spare a large number of patients an unnecessary invasive procedure.

Contrast-enhanced ultrasound and real-time elastography in the differential diagnosis of malignant and benign thyroid nodules

The diagnostic value of contrast-enhanced ultrasound (CEUS) or real-time elastography (RTE) alone, as well as a combination of CEUS and RTE, in distinguishing benign from malignant thyroid nodules was investigated. Between August 2012 and June 2014, a total of 97 consecutive patients (50 male and 47 female patients; mean age, 48.6±12.4; age range, 27-70 years) with thyroid nodules referred for surgical treatment were examined by CEUS and RTE. The final diagnosis was obtained based on histological findings. Image analysis of the CEUS and RTE scans was performed. Considering the postoperative pathological results as the golden standard, a receiver operating characteristic (ROC) curve was constructed. Subsequently, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of CEUS alone, RTE alone and CEUS + RTE combination were calculated. Pathological examination showed 66 papillary carcinomas and 43 benign lesions, including 21 adenomas and 22 nodular goiters. The sensitivity, specificity, PPV, NPV and accuracy of CEUS were 81.82, 90.70, 93.10, 90.70 and 85.32%, respectively. In the case of RTE, the sensitivity, specificity, PPV, NPV and accuracy were 80.30, 88.37, 91.38, 88.37 and 83.49%, respectively. Furthermore, the combination of CEUS + RTE had a sensitivity of 95.45%, specificity of 95.35%, PPV of 96.92%, NPV of 95.35% and accuracy of 95.41%. Therefore, the CEUS + RTE combination showed a significantly higher sensitivity and specificity compared with CEUS or RTE alone (all P<0.05). Based on ROC analysis, the area under the curve (AUC) for CEUS, RTE and CEUS + RTE combination was 0.883, 0.863 and 0.959, respectively. The AUC of RTE alone was significantly lower compared with that of the CEUS + RTE combination. In conclusion, our results demonstrate that CEUS + RTE combination significantly increases the diagnostic performance for differential diagnosis of malignant and benign thyroid nodules compared with CEUS or RTE alone.

Contrast-enhanced sonography for the identification of benign and malignant thyroid nodules: Systematic review and meta-analysis

PURPOSE

The use of contrast-enhanced sonography (CEUS) has yielded promising results in the differentiation of thyroid nodules. We conducted this meta-analysis to assess its performance in identifying and distinguishing between benign and malignant thyroid nodules.

METHODS

PubMed, Medline, Embase, and the Cochrane Library were searched for studies published through the end of December 2013. Sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, and area under the curve were calculated.

RESULTS

A total of 13 studies were included in this meta-analysis. For the diagnosis of malignant thyroid nodules worldwide, the overall mean rates of sensitivity and specificity of CEUS were 90% (95% confidence interval [CI], 88-93%) and 86% (95% CI, 83-89%), respectively. The summary diagnostic odds ratio was 52.83 (95% CI, 21.71-128.55), and the area under the curve for the summary receiver operating characteristic curve was 0.94 (95% CI, 0.90-0.98).

CONCLUSIONS

This meta-analysis indicates that CEUS may be a valuable supplemental method, with high rates of sensitivity and specificity, to use for identifying and distinguishing between benign and malignant thyroid nodules.

Application of Sonoelastography in Differential Diagnosis of Benign and Malignant Thyroid Nodules

Background:

Sonoelastography is a new ultrasound method which could be helpful to determine which thyroid nodule is malignant. We designed this study to evaluate the accuracy of sonoelastography in differentiating of benign and malignant thyroid nodules in Iranian patients.

Methods:

Forty thyroid nodules in forty consecutive patients who had been referred for sonography-guided fine-needle aspiration biopsy were evaluated. Gray scale ultrasound and elastosonography by real-time, freehand technique applied for all patients. Elastography findings were classified into four groups. Nodules which were classified as patterns 1 or 2 in elastogram evaluation were classified as benign and probably malignant if elastogram scans were patterns 3 and 4 of elastogram scan.

Results:

Mean age ± standard deviation (SD) was 42.2 ± 12.6 years, and mean ± SD thyroid-stimulating hormone level was 1.4 ± 1.9 IU/ml. Thirty-five cases (87.5%) were female and 5 (12.5%) were male. Histological examination indicated 27 (67.5%) benign and 13 (32.5%) malignant nodules. The most elastogram score was 2 (50%) followed by score 3. The cut-off point of 2 considered as the best value to differentiate benign and malignant thyroid nodules with sensitivity and specificity of 61% and 78% (area under the curve = 0.76, 95% confidence interval: 0.6–0.92, P = 0.007).

Conclusions:

Sonoelastography could help to differentiate benign and malignant thyroid nodules. As our sample size was limited, larger studies are recommended.

Diagnostic value of contrast-enhanced ultrasound in papillary thyroid microcarcinoma

The aim of the present study was to explore the value and characteristics of contrast-enhanced ultrasound (CEUS) in the diagnosis of papillary thyroid microcarcinoma (PTMC). By analyzing CEUS information of 130 nodules obtained from 106 patients with PTMC, who had been diagnosed by surgery and pathological analysis, CEUS characteristics of PTMC nodules were concluded. Based on the results, the PTMC nodules were divided into three groups as follows: 32 nodules (24.62%) were found to be enhanced earlier than the surrounding normal thyroid tissue, 95 nodules (73.08%) were enhanced at the same time as the normal thyroid tissue and 3 nodules (2.30%) were enhanced later than the normal thyroid tissue. The results also demonstrated that the peak enhancement intensity of the 130 nodules was lower compared with the irregular intensity of the normal parenchyma in corresponding thyroids, and that PTMC enhancement washed out faster than in normal thyroid parenchyma. In conclusion, the PTMC characteristics that CEUS can detect may improve the diagnostic accuracy and provide valuable information for the treatment of the disease.

Reliability of real-time elastography to diagnose thyroid nodules previously read at FNAC as indeterminate: a meta-analysis

The main limit of thyroid fine-needle aspiration cytology (FNAC) is represented by indeterminate report. Recently, real-time elastography (RTE) has been described in the management of these cases. Here, we performed a meta-analysis of published studies specifically focused on the use of RTE in indeterminate thyroid nodules. A comprehensive literature search of PubMed/MEDLINE and Google Scholar databases was conducted by using the combination of the terms "thyroid" and "indeterminate" and "elastography." Pooled sensitivity, specificity, accuracy, PPV and NPV of RTE as predictor of malignancy in thyroid nodules with indeterminate FNAC were calculated, including 95% confidence intervals (95% CI). The area under the summary ROC curve (AUC) was also assessed. Databases found 572 papers, and eight were included in the meta-analysis. Of these, six studies had prospective design and two were retrospective. Pooled malignancy rate was 31%. As common denominator, all studies set the prevalence of hardness within the nodule as risk factor for malignancy of the lesion. Sensitivity of RTE ranged from 11 to 89% (pooled estimate of 69%; 95% CI 55-82%), specificity varied from 6 to 100% (pooled estimate of 75%; 95% CI 42-96%), and accuracy was comprised between 35 and 94% (pooled estimate of 73%; 95% CI 54-89%). The AUC was 0.77. RTE has suboptimal diagnostic accuracy to diagnose thyroid nodules previously classified as indeterminate. Then, RTE alone should not be used for selecting these patients for surgery or not. We advice for further studies using other elastographic approaches and combined RTE and B-mode ultrasonography.

Quantification of carotid plaque elasticity and intraplaque neovascularization using contrast-enhanced ultrasound and image registration-based elastography

It is valuable for evaluation of carotid plaque vulnerability to investigate the relation between intraplaque neovascularization (IPN) and plaque elasticity. The contrast-enhanced ultrasound (CEUS) has been used in IPN measurement, but it cannot assess plaque elasticity. The aim of this study was to develop an ultrasound elastography technique based on registration of CEUS sequential images and to use this technique for direct comparison between IPN and plaque elasticity. We employed a nonrigid image registration method using the free-form deformation model to register a pair of clinical CEUS images at systole and diastole. The 2D displacement field of the plaque was estimated and then utilized to calculate the axial and lateral strain distributions within the plaque, from which quantitative strain parameters were obtained. The IPN was measured semiquantitatively with visual assessment and quantitatively with the time-intensity curve analysis and the analysis of contrast agent spatial distributions. Histopathology with CD34 staining for quantification of microvessel density (MVD) was performed on plaques excised by carotid endarterectomy. Simulation experiments showed that the mean absolute error and the root mean squared error of the displacement estimation were 0.325±0.180 pixel (7.2%±3.8%) and 0.556±0.284 pixel (12.3%±6.1%), respectively, demonstrating high accuracy of the elastography technique. Thirty-eight plaques in 29 patients met the inclusion criteria for the elastography and image analysis, where ten plaques underwent endarterectomy. The 95th percentile (A95) and standard deviation (Asd) of the axial strains exhibited significant differences between the low and high grades of IPN visually assessed (p<0.01). A95 (R=0.579; p<0.001) and Asd (R=0.609; p<0.001) were correlated with the enhanced intensity of plaque, and also correlated with the MVD (R=0.793 and 0.817, respectively; p<0.01), suggesting that plaque became softer and more elastically heterogeneous as IPN increased. These findings provide direct and quantitative evidence for the associations between plaque strains and IPN and might be helpful for evaluation of carotid plaque vulnerability and for plaque risk stratification.

Clinical value of elasticity imaging and contrast-enhanced ultrasound in the diagnosis of papillary thyroid microcarcinoma

The present study aimed to evaluate the value of elasticity imaging and contrast-enhanced ultrasonography (CEUS) in the differential diagnosis of papillary thyroid microcarcinoma (TMC). In total, 73 patients exhibiting a total of 80 small thyroid nodules, which were difficult to diagnose using conventional ultrasonography, underwent elasticity imaging and CEUS. The diagnostic findings were subsequently clarified by intraoperative and pathological examination, and the accuracy of the 2 diagnostic methods was compared. The correct diagnostic rate of CEUS was 85% (68/80 nodules), of which 6 cases of TMC were misdiagnosed as benign lesions and 6 benign nodules were misdiagnosed as TMC. By contrast, the accuracy rate of the elasticity imaging, based on the 5-point diagnostic method, was 92.5% (74/80 nodules), of which 3 cases of TMC were misdiagnosed as benign nodules and 3 benign nodules were misdiagnosed as TMC. Furthermore, elasticity imaging in the diagnosis of TMC was determined to have sensitivity, specificity and accuracy rates of 94.0, 90.0 and 92.5%, respectively, whereas the corresponding rates for CEUS were 88.0, 80.0 and 85.0%, respectively. Thus, ultrasonographic elasticity imaging exhibited significant advantages in the diagnosis of TMC compared with CEUS (P<0.05). The use of CEUS demonstrates no evident advantage in the diagnosis of TMC; however, an elasticity score of ≥3 is of high clinical value as a diagnostic criterion for TMC.

Association between real-time contrast-enhanced ultrasound characteristics and thyroid carcinoma size

The aim of the present study was to discuss the various appearances of thyroid carcinomas on real-time contrast-enhanced ultrasound (CEUS) in association with tumor size. The appearances of 68 thyroid carcinomas confirmed by pathology were retrospectively analyzed. The lesions were divided into 3 groups by maximum diameter <10, 10-20 and >20 mm, respectively. For each lesion, absolute enhancement beginning time, relative enhancement beginning time, homogeneity, with or without perfusion defect, enhancement order, enhancement intensity and enhancement margin type were evaluated by CEUS. The majority of thyroid carcinomas were enhanced later than the surrounding thyroid gland. The predominant enhancement pattern of all the 68 thyroid carcinomas in the 3 groups was mainly heterogeneous and concentric enhancement, and the lesions mostly showed less clear or poorly defined enhancement margins. There was no significant difference among the 3 groups (P>0.05). Thyroid carcinoma with diameters <10 and 10-20 mm exhibited low enhancement, while thyroid carcinomas with diameters >20 mm showed high enhancement. With the increase of the lesion's maximum diameter, the probability of perfusion defect increased by 28.57, 54.29 and 75.00%, respectively, and there was a significant difference among the 3 groups (P<0.05). CEUS characteristics are associated with tumor size to a certain extent, and can provide valuable information for clinical diagnosis.

Diagnostic performance of elastography in cytologically indeterminate thyroid nodules

Cytological examination of material from fine-needle aspiration biopsy is the mainstay of diagnosis of thyroid nodules, thanks to its remarkable accuracy and scarcity of complications. However, follicular lesions (also called indeterminate lesions or Thy3 in the current classification), a heterogeneous group of lesions in which cytology is unable to give a definitive diagnosis to, represent its main limit. Elastography has been proposed as a potential diagnostic tool to define the risk of malignancy in the aforementioned nodules, but at present there is no conclusive data due to the small number of specifically addressed studies and the lack of concordance among them. The objective of our study was to evaluate the role of real-time elastography (RTE) for refining diagnosis of Thy3 nodules, by integrating diagnostic information provided by traditional ultrasound (US). The study included 108 patients with Thy3 nodules awaiting for surgery, which were evaluated by US (considering hypoecogenicity, irregular margins, microcalcifications, halo sign, and intranodular vascularization) and RTE. Nodules were classified at RTE using a four-class color scale. At histologic examination, 75 nodules were benign and 33 malignant. As expected, none of the ultrasound parameters alone was adequate in predicting malignancy or benignity of the nodules; in the presence of at least two US risk factors, we obtained 61 % sensitivity, 83 % specificity, and 77 % accuracy with 6.8 OR (95 % CI 2.4-20.4). RTE scores 3 and 4 showed 76 % sensitivity, 88 % specificity, 74 % PPV, and 89 % NPV with diagnostic accuracy of 84 %; the data are statistically significant (p < 0.0001) with a OR of 21.9 (95 % CI 7.1-76). By combining RTE with US parameters, the presence of at least 2 characters of suspicion had 88 % sensitivity and 94 % NPV with 23.8 OR (95 % CI 7-106.3). The use of combined RTE and US leads to the identification of two patients subpopulations which have a significantly different malignancy risk (6 vs. 63 %); further studies are needed to verify if it is possible to send only the first group to thyroidectomy and the other to follow-up.

Qualitative elastography can replace thyroid nodule fine-needle aspiration in patients with soft thyroid nodules. A systematic review and meta-analysis

CONTEXT

Only a minority of thyroid nodules is malignant; nevertheless, many invasive diagnostic procedures are performed to distinguish between benign and malignant nodules. Qualitative ultrasound elastography is a non-invasive technique to evaluate thyroid nodules.

OBJECTIVE

To investigate the diagnostic value of qualitative elastography in distinguishing benign from malignant thyroid nodules in patients referred for fine-needle aspiration (FNA).

DATA SOURCES

A systematic literature search (PubMed, Embase and Cochrane Library) was performed.

STUDY SELECTION

Included studies reported thyroid nodule elastography color scores and the related cytologic or histologic findings in patients with a thyroid nodule referred for FNA.

DATA EXTRACTION

Two independent reviewers extracted study data and assessed study quality. Pooled sensitivities and specificities of different populations were calculated using a bivariate Bayesian framework.

DATA SYNTHESIS

Twenty studies including thyroid nodules were analyzed. Pooled results of elastography indicate a summary sensitivity of 85% (95% confidence interval [CI], 79-90%) and specificity of 80% (95% CI, 73-86%). The respective pooled negative predictive and positive predictive values were 97% (95% CI, 94-98%) and 40% (95% CI, 34-48%). The pretest probability of a benign nodule was 82%. Only 3.7% of the false-negative nodules was a follicular thyroid carcinoma. A pooled negative predictive value of 99% (95% CI, 97-100%) was found when only complete soft nodules (Asteria elastography 1) were classified as benign, which included 14% of the studied population.

CONCLUSIONS

Elastography has a fair specificity and sensitivity for diagnostic accuracy. Its major strength entails the detection of benignity, especially when only completely soft nodules are qualified as benign. The outcomes of our analysis show that FNA could safely be omitted in patients referred for analysis of their thyroid nodule when elastography shows it to be completely soft (Asteria elastography 1). This could prevent unnecessary invasive diagnostic procedures in a substantial portion of patients.

The use of semi-quantitative ultrasound elastosonography in combination with conventional ultrasonography and contrast-enhanced ultrasonography in the assessment of malignancy risk of thyroid nodules with indeterminate cytology

Background

The pre-surgical selection of thyroid nodules with indeterminate cytology (Thy 3 according to British Thyroid Association) after fine-needle aspiration biopsy (FNAB) is currently required in order to reduce unnecessary total thyroidectomy. The objective of our study was to use a surgical series of Thy 3 nodules to evaluate the predictive role of ultrasound elastosonography (USE) and contrast-enhanced ultrasonography (CEUS) in pre-surgical diagnoses of malignancy.

Subjects and methods

We enrolled 63 patients with Thy 3 nodules in which cytological–histological correlation was available. The ELX 2/1 strain index was obtained by means of semi-quantitative USE, which was performed before surgery in addition to conventional ultrasonography (US) and contrast-enhanced US (CEUS) on the Thy 3 nodules. The ELX 2/1 strain index, a five-item US score and both peak (P) index and time to peak (TTP) index from CEUS were correlated with the histological results. After surgical diagnosis, the data were analysed by using a receiver-operating characteristic (ROC) curve.

Results

Histology was benign in 50 and malignant in 13 Thy 3 nodules. No difference in maximal diameter was noted between benign (22.8 ± 1.6 mm) and malignant (18.9 ± 2.9 mm) nodules. Significant correlations were found between histology and cumulative US findings (p=0.005), ELX 2/1 index (p=0.002), P index (p=0.01) and TTP index (p=0.02). On analysing data from US, USE and CEUS, significant ROC areas under the curve were observed (p<0.0001). A cut-off value was set for US (>2), ELX 2/1 (>0.95), P index (<0.99) and TTP index (>0.98) scores. The diagnostic power of the cumulative pre-surgical analysis of Thy 3 nodules with US, USE and CEUS, considering the experimental cut-off points obtained from the ROC curves was: sensitivity 64%, specificity 92%, PPV 75% and accuracy 84%.

Conclusion

The ELX 2/1 index in conjunction with the US score can be useful in orienting surgical strategies in Thy 3 nodules. The information added by CEUS is less sensitive than that provided by US and USE. The use of a cut-off based on histology can reduce thyroidectomy. Observation should be the first choice when not all instrumental results are suspect.

Elastography can effectively decrease the number of fine-needle aspiration biopsies in patients with calcified thyroid nodules

When calcification, frequently found in both benign and malignant nodules, is present in thyroid nodules, non-invasive differentiation with ultrasound becomes challenging. The goal of this study was to evaluate the utility of elastography in differentiating calcified thyroid nodules. Consecutive patients (165 patients with 196 nodules) referred for fine-needle aspiration who had undergone both ultrasound elastography and B-mode examinations were analyzed retrospectively. Calcification was present in 45 benign and 20 malignant nodules. On 65 calcified nodules, elastography had 95% sensitivity, 51.1% specificity, 46.3% positive predictive value and 95.8% negative predictive value in detecting malignancy. Twenty-three of 45 benign calcified nodules were correctly diagnosed with elastography compared with 4 of 45 by B-mode ultrasound. Although it is difficult to differentiate benign and malignant calcified thyroid nodules solely with B-mode ultrasound, elastography has the potential to reduce the number of fine-needle aspiration biopsies performed on calcified nodules.

Elastography in clinical practice

Elastography is a new technique that evaluates tissue stiffness. There are two elastography methods, strain and shear wave elastography. Both techniques are being used to evaluate a wide range of applications in medical imaging. Elastography of breast masses and prostates have been shown to have high accuracy for characterizing masses and can significantly decrease the need for biopsies. Shear wave elastography has been shown to be able to detect and grade liver fibrosis and may decrease the need for liver biopsy. Evaluation of other organs is still preliminary. This article reviews the principles of elastography and its potential clinical applications.

Gray-scale ultrasonography combined with elastography imaging for the evaluation of papillary thyroid microcarcinoma: as a prognostic clinicopathology factor

Ultrasonography (US) is the preferred imaging modality for papillary thyroid microcarcinoma (PTMC). The aim of this study was to evaluate the importance of gray-scale ultrasound combined with elastography to predict extrathyroidal extension and cervical lymph node (LN) metastasis in patients with PTMC. We retrospectively evaluated gray-scale ultrasonic and elastographic results from 119 consecutive cases of PTMC with 138 nodules and correlated the histopathological findings. The results indicated that pathological extrathyroidal extension was significantly associated with T staging on US, extrathyroidal extension on US, bilaterality on US, boundary, strain ratio and hard malignancy as measured with the Rago score. Central LN metastasis on pathology was significantly associated with central LN metastasis on US, lateral LN metastasis on US, multifocality on US and bilaterality on US. Lateral LN metastasis on US was significantly associated with lateral LN metastasis on pathology. On multivariate analysis, T staging on US, extrathyroidal extension on US and hard malignancy as measured with the Rago score were significantly associated with pathological extrathyroidal extension. Lateral LN metastasis on US and bilaterality on US were independent factors in predicting central LN metastasis on pathology. Lateral LN metastasis on US was the predictive factor for lateral LN metastasis on pathology. US should be helpful in the diagnosis of PTMC and in the evaluation of possible PTMC recurrence on US in routine clinical practice.

Conventional ultrasonography and real time ultrasound elastography in the differential diagnosis of degenerating cystic thyroid nodules mimicking malignancy and papillary thyroid carcinomas

BACKGROUND

To evaluate the diagnostic utility of conventional ultrasonography and real time ultrasound elastography in differentiating degenerating cystic thyroid nodules mimicking malignancy from papillary thyroid carcinoma.

METHODS

We retrospectively analyzed conventional ultrasonographic and elastographic characteristics of 19 degenerating cystic thyroid nodules mimicking malignancy in 19 patients, with 30 surgically confirmed PTCs as controls. Based on size, the nodules had been grouped into less than 10mm (group A) and greater than 10 mm (group B). We evaluated conventional parameters and elasticity pattern. Color-scaled elastograms were graded as to stiffness of nodules using an elasticity pattern from I (soft) to IV (stiff).

RESULTS

Degenerating cystic thyroid nodules were similar to PTCs in conventional ultrasonographic findings, but the former frequently showed oval to round in shape (group A, 69.2% vs 18.8%, P=0.017; group B, 66.7% vs 7.14%, P=0.017) and punctuate hyperechoic foci (group A, 61.5% vs 0, P<0.001; group B, 50% vs 0, P<0.001). On real time ultrasound elastography, 7 of 13 degenerating cystic thyroid nodules in group A were pattern I, 5 were pattern II, 1 was pattern III. One degenerating cystic thyroid nodule in group B was pattern II, 5 were pattern III. The area under the curve for elastography was 0.98 in group A (sensitivity 92.3%, specificity 100%, P = 0.002), and 0.88 in group B (sensitivity 16.7%, specificity 100%, P = 0.014).

CONCLUSIONS

As a dependable imaging technique, elastography helps increase the performance in differential diagnosis of degenerating cystic thyroid nodule and malignancy.

Diagnosis of hyperfunctional thyroid nodules: impact of US-elastography

AIM

Several studies described the ultrasound based real-time elastography (USE) having a high sensitivity, specificity and negative predictive value in the diagnosis of suspicious thyroid nodules. Recently published studies called these results into question. Until now the usefulness of USE in the diagnosis of scintigraphically hyperfunctional thyroid nodules is not examined.

PATIENTS, METHODS

This study included 135 hyperfunctional thyroid nodules of 102 consecutive patients. The following attributes of the nodules were analyzed: stiffness with the USE using scores of Rago or Asteria and ultrasound criteria using TIRADS.

RESULTS

94 of the examined thyroid nodules (70%) were rated as hard (suspicious for malignancy) and 41 nodules (30%) as soft (not suspicious) with a specificity of 30%. The scoring systems of Rago and Asteria showed no significant difference. Applying the TIRADS criteria 44 nodules (33%) have a higher risk for malignancy (33 nodules TIRADS 4a, 11 nodules TIRADS 4b). Combining USE and TIRADS 32 nodules (24%) are categorized as suspicious (intersection of hard nodules that are categorized as TIRADS 4a or 4b).

CONCLUSION

Ultrasound based real-time elastography cannot identify scintigraphically hyperfunctional thyroid nodules as benign nodules reliably. Its accuracy in the assessment of at least "hot" thyroid nodules is to be questioned.