Thyroid Nodules and Shear Wave Elastography: A New Tool in Thyroid Cancer Detection

SELFNet: Denoising Shear Wave Elastography Using Spatial-temporal Fourier Feature Networks

OBJECTIVE

Ultrasound-based shear wave elastography offers estimation of tissue stiffness through analysis of the propagation of a shear wave induced by a stimulus. Displacement or velocity fields during the process can contain noise as a result of the limited number of acquisitions. With advances in physics-informed deep learning, neural networks can approximate a physics field by minimizing the residuals of governing physics equations.

METHODS

In this research, we introduce a shear wave elastography Fourier feature network (SELFNet) using spatial-temporal random Fourier features within a physics-informed neural network framework to estimate and denoise particle displacement signals. The network uses a sparse mapping to increase robustness and incorporates the governing equations for regularization while simultaneously learning the mapping of the shear modulus. The method was evaluated in datasets from tissue-mimicking phantom of lesions and ex vivo tissue.

RESULTS

The findings indicate that SELFNet is capable of smoothing out the noise in phantom lesions with different stiffness and sizes, outperforming a reference Gaussian filtering method by 17% in relative ℓ2 error, 45% in reconstruction root-mean-square error. Furthermore, the ablation study suggested that SELFNet can prevent over-fitting through the Fourier feature mapping module. An ex vivo study confirmed its applicability to different types of tissue.

CONCLUSION

The implementation of SELFNet shows promise for shear wave elastography with limited acquisitions. In this context, subject to successful translation, it has the potential to be extended to clinical applications, such as the diagnosis of cancer or liver disease.

Use of Ultrasonographic Shear Wave Measurements to Diagnose Thyroid Metastasis from Breast Carcinoma

A metastatic thyroid tumor (MTT) arising from breast carcinoma (BC) is rare and sometimes difficult to diagnose. We present a case of MTT from BC; we suspected anaplastic thyroid carcinoma at initial presentation. The patient was a 58-year-old female with a hard nodule in the right anterior neck and a history of breast cancer. Computed tomography indicated tumors on both thyroid lobes, and ultrasonography (US) with shear wave measurement (SWM) showed malignant features. We performed fine needle aspiration cytology (FNAC), the results of which led us to strongly suspect MTT from BC. The surgically resected specimen was evaluated histopathologically, including by immunohistochemistry (IHC), and the diagnosis was confirmed. In addition to FNAC and IHC, SWM is useful to diagnose MTT from BC.

[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.

Associations of Real-Time Ultrasound and Strain and Shear Wave Elastography with Gastrointestinal Organs: A Systematic Review

Ultrasound elastography is gaining attention for its diagnostic potential across various medical fields, and its physical properties make it valuable in modern clinical medicine. However, its specific attributes, especially in the context of recent medical advancements, remain relatively unexplored. This study aimed to identify instrument-specific characteristics and applications of real-time ultrasound elastography, shear wave elastography, and strain elastography, particularly within gastroenterology. Following PRISMA guidelines, the study examined elastography articles on databases like PubMed, resulting in 78 included articles. Data on patient demographics, organ involvement, specificity, sensitivity, accuracy, positive predictive value, and negative predictive value were extracted. Statistical analysis involved SPSS version 21, with significance set at p < 0.05. The majority of patients were male (50.50%), with a mean age of 42.73 ± 4.41 years. Shear wave elastography was the most prevalent technique (48.7%), and liver investigations were predominant in gastroenterology (34.6%). Gastrointestinal applications showed higher sensitivity, positive predictive value, and negative predictive values (p < 0.05) but lower specificity (p < 0.05). Real-time ultrasound elastography exhibited increased specificity, accuracy, and predictive values (p < 0.05). Ultrasound elastography appears more accurate and effective in gastroenterological settings. Nonetheless, its performance depends on instrument-specific and operator-dependent factors. While promising, further studies are necessary to ascertain optimal utilization in both gastrointestinal and non-gastrointestinal conditions.

Differentiating benign and malignant thyroid nodules: A cross-sectional study on the comparison of diagnostic value of ultrasound elastography and fine needle aspiration biopsy

Background and Aim

This study examines the comparison of ultrasound elastography and fine needle aspiration (FNA) in diagnosing thyroid cancers and investigates the use of elastography as the initial diagnostic test of thyroid cancers to avoid the need for invasive diagnostic tests.

Methods

In this study, 28 patients with 48 thyroid nodules (TNs) who were candidates for FNA or surgery were examined within a period of 18 months. Cut-off and subsequently sensitivity and specificity for elastography results, compared to pathology results as the gold standard, were calculated using the receiver operating characteristic curve (ROC).

Results

Based on ROC, the cut-off point differentiating the tissue stiffness between benign and malignant TNs was 25.400 kilopascal (kPa) (sensitivity of 90.9% and specificity of 78.4%). It was observed that age affects the tissue stiffness; therefore, the cut-off was defined as 65.625 kpa for age groups under 50 years old (sensitivity of 100% and specificity of 100%) and 25.400 kpa for the age group above 50 years old (sensitivity of 88.9% and specificity of 70.4%).

Conclusion

Based on the high sensitivity and specificity of shear wave elastography in the differentiation of benign and malignant TNs, it can be employed as a stand-alone or in combination with other diagnostic techniques to reduce the need for inessential surgical operations. However, future studies or developments are needed on this promising diagnostic technique.

Can pre-operative ultrasound elastography predict aggressive features of solitary papillary thyroid carcinoma?

OBJECTIVE

To investigate whether pre-operative ultrasound elastography (USE) can be used to predict aggressive features of solitary papillary thyroid carcinomas (PTCs).

METHODS

Clinical and USE indices were retrospectively analyzed in 487 patients with surgically confirmed solitary PTCs. The patients were grouped per aggressive features on pathologic testing. Univariate and binary logistic regression analyses were performed to explore independent risk factors of aggressive features.

RESULTS

Univariate analysis revealed standard deviation (SD) values of the tumor shear-wave velocity (SWV) were associated with capsular invasion (p < 0.05). Further, shear-wave elasticity and SWV ratios correlated with extrathyroidal extension (all p < 0.05). The tumor shear-wave elasticity and SWV SD values were associated with cervical lymph node metastasis (CLNM) (all p < 0.05). Binary logistic regression analysis identified location and capsule contact as independent predictive risk factors for capsular invasion (all p < 0.05); size for extrathyroidal extension (all p < 0.05); and sex, age, margin, and suspected CLNM for CLNM (all p < 0.05). However, pre-operational USE indexes were not independent predictors of aggressive features (all p > 0.05).

CONCLUSION

Pre-operative USE indices were not independent risk factors of aggressive features of solitary PTCs. Thus, USE may have a limited value for predicting the aggressive features of PTC.

ADVANCES IN KNOWLEDGE

Pre-operative USE indices may have a limited value for predicting the aggressive features of PTC.

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.

Diagnosis of anomalies based on hybrid features extraction in thyroid images

Diagnosing benign and malignant glands in thyroid ultrasound images is considered a challenging issue. Recently, deep learning techniques have significantly resulted in extracting features from medical images and classifying them. Convolutional neural networks ignore the hierarchical structure of entities within images and do not pay attention to spatial information as well as the need for a large number of training samples. Capsule networks consist of different hierarchical capsules equivalent to the same layers in the convolutional neural networks. We propose a feature extraction method for ultrasound images based on the capsule network. Then, we combine those deep features with conventional features such as Histogram of Oriented Gradients and Local Binary Pattern together to form a hybrid feature space. We increase the accuracy percentage of a support vector machine (SVM) by balancing and reducing the data dimensions of samples. Since the SVM provides different training kernels according to the sample distribution method, the extracted textural features were categorized using each of these kernels to obtain the result. The parameters of classification evaluation using the researcher-made model have outperformed the other methods in this field. Experimental results showed that the combination of HOG, LBP, and CapsNet methods outperformed the others, with 83.95% accuracy in the SVM with a linear kernel.

Comparing shear wave elastography and fine needle aspiration in the diagnosis of solid thyroid nodules

This descriptive study was performed on individuals who were referred to Imam Reza Hospital for fine needle aspiration biopsy (FNAB) based on the results of gray scale ultrasound and the decision of the referring physician. In addition to determining the gray scale characteristics of the nodules, shear wave elastography (SWE) was also performed and the results were recorded. These were also taken from the patients FNAB results. Finally, the findings of SWE and FNAB methods were compared and analyzed using SPSS software version 16. Based on the results presented herein, a significant relationship was observed between the results of SWE and FNA in the diagnosis of malignancy in solid thyroid nodules. This agreement was found to be higher in men (K = 0.866) than women (K = 0.849). Taken together, our data suggest that shear wave elastography can replace FNA in the diagnosis of malignancy in solid thyroid nodules.

The European Institute of Oncology Thyroid Imaging Reporting and Data System for Classification of Thyroid Nodules: A Prospective Study

Background: To evaluate the performance, quality and effectiveness of “IEO-TIRADS” in assigning a TI-RADS score to thyroid nodules (TN) when compared with “EU-TIRADS” and the US risk score calculated with the S-Detect software (“S-Detect”). The primary objective is the evaluation of diagnostic accuracy (DA) by “IEO-TIRADS”, “S-Detect” and “EU-TIRADS”, and the secondary objective is to evaluate the diagnostic performances of the scores, using the histological report as the gold standard. Methods: A radiologist collected all three scores of the TNs detected and determined the risk of malignancy. The results of all the scores were compared with the histological specimens. The sensitivity (SE), specificity (SP), and diagnostic accuracy (DA), with their 95% confidence interval (95% CI), were calculated for each method. Results: 140 TNs were observed in 93 patients and classified according to all three scores. “IEO-TIRADS” has an SE of 73.6%, an SP of 59.2% and a DA of 68.6%. “EU-TIRADS” has an SE of 90.1%, an SP of 32.7% and a DA of 70.0%. “S-Detect” has an SE of 67.0%, an SP of 69.4% and a DA of 67.9%. Conclusion: “IEO-TIRADS” has a similar diagnostic performance to “S-Detect” and “EU-TIRADS”. Providing a comparable DA with other reporting systems, IEO-TIRADS holds the potential of being applied in clinical practice.

Impact of shear wave dispersion slope analysis for assessing the severity of myocarditis

This study aimed to elucidate the utility of a novel ultrasound-based technique, shear wave dispersion slope (SWDS) analysis, which estimates tissue viscosity, for evaluating the severity of myocardial inflammation. Experimental autoimmune myocarditis (EAM) at different disease phases [3-week (acute phase): n = 10, 5-week (subacute phase): n = 9, and 7-week (late phase): n = 11] were developed in male Lewis rats. SWDS was measured in the right and the left ventricular free walls (RVFW and LVFW) under a retrograde perfusion condition. Histological myocardial inflammation was evaluated by CD68 staining. The accumulation of CD68-positive cells was severe in the myocardium of the EAM 3-week group. The median (interquartile range) SWDS of RVFW was significantly higher in the EAM 3-week group [9.9 (6.5-11.0) m/s/kHz] than in the control group [5.4 (4.5-6.8) m/s/kHz] (P = 0.034). The median SWDS of LVFW was also significantly higher in the EAM 3-week group [8.1 (6.4-11.0) m/s/kHz] than in the control group [4.4 (4.2-4.8) m/s/kHz] (P = 0.003). SWDS and the percentage of CD68-positive area showed a significant correlation in RVFW (R2 = 0.64, P < 0.001) and LVFW (R2 = 0.73, P < 0.001). This study showed that SWDS was elevated in ventricular walls with acute inflammation and also significantly correlated with the degree of myocardial inflammation. These results suggest the potential of SWDS in estimating the histological severity of acute myocarditis.

US-Elastography With Different Techniques for Thyroid Nodule Characterization: Systematic Review and Meta-analysis

Background

Thyroid nodules are frequent in adult population and thyroid cancer incidence has increased dramatically over the past three decades. The aim of this systematic review and meta-analysis was to evaluate the US-Elastosonography (USE) diagnostic performance in assessing the thyroid nodules malignancy risk.

Methods

PubMed and Embase databases were searched from January 2011 to July 2021. We extracted data from selected studies and calculated the overall diagnostic accuracy of qualitative USE, semi-quantitative USE and quantitative USE. Summary receiver operating characteristic (ROC) curve was elaborated to show the results. All statistical tests were performed using Metadisc and Medcal software package.

Results

Finally 72 studies with 13,505 patients and 14,015 thyroid nodules (33% malignant) undergoing elastography were included. The pooled sensitivity, specificity and AUC were 84%, 81%, and 0.89 respectively for qualitative USE; 83%, 80%, and 0.93 for semi-quantitative USE and 78%, 81% and 0.87, for quantitative USE. The qualitative and semiquantitative USE present very similar diagnostic accuracy values and both better than the quantitative USE.

Conclusions

USE is a useful imaging tool for thyroid nodule characterization. In accordance with recent guidelines and meta-analyses, the USE could be used daily in thyroid nodule malignancy risk stratification.

Systematic Review Registration

PROSPERO: CRD42021279257.

Shear Wave Elastography and Thyroid Imaging Reporting and Data System (TIRADS) for the Risk Stratification of Thyroid Nodules-Results of a Prospective Study

Purpose: To compare the diagnostic performance of thyroid imaging reporting and data system (TIRADS) in combination with shear wave elastography (SWE) for the assessment of thyroid nodules. Methods: A prospective study was conducted with the following inclusion criteria: preoperative B-mode ultrasound (US) including TIRADS classification (Kwak-TIRADS, EU-TIRADS), quantitative SWE and available histological results. Results: Out of 43 patients, 61 thyroid nodules were detected; 10 nodules were found to be thyroid cancer (7 PTC, 1 FTC, 2 HüCC) and 51 were benign. According to Kwak-TIRADS the majority of benign nodules (47 out of 51, 92.2%) were classified in the low-risk- and intermediate-risk class, four nodules were classified as high-risk (7.8%). When using EU-TIRADS, the benign nodules were distributed almost equally across all risk classes, 21 (41.2%) nodules were classified in the low-risk class, 16 (31.4%) in the intermediate-risk class and 14 (27.4%) in the high-risk class. In contrast, most of the malignant nodules (eight out of ten) were classified as high-risk on EU-TIRADS. One carcinoma was classified as low-risk and one as intermediate-risk nodule. For SWE, ROC analysis showed an optimal cutoff of 18.5 kPa to distinguish malignant and benign nodules (sensitivity 80.0%, specificity 49.0%, PPV 23.5% and NPV 92.6%). The addition of elastography resulted in an increase of accuracy from 65.6% to 82.0% when using Kwak-TIRADS and from 49.2% to 72.1% when using EU-TIRADS. Conclusion: Our data demonstrate that the combination of TIRADS and SWE seems to be superior for the risk stratification of thyroid nodules than each method by itself. However, verification of these results in a larger patient population is mandatory.

Update on diagnosis and treatment of hyperthyroidism: ultrasonography and functional imaging

Ultrasonography and radionuclide imaging using [^99mTc]Pertechnetate or radioactive iodine isotopes are essential tools used during the diagnostic workup of hyperthyroidism with or without structural alterations of the thyroid. Color duplex sonography and ultrasound elastography may add important information to find the cause of the hormone excess. During the last few years, hybrid imaging using SPECT/-(CT) or PET-based methods, such as [¹²⁴]Iodine-PET/CT or [¹²⁴]Iodine-PET/ultrasound have been increasingly used, playing a role in the context of localizing ectopic thyroid tissue or in multinodular goiter. Recently, promising data has been published on the use of [^99mTc]MIBI imaging in amiodarone induced hyperthyroidism.

Reducing Unnecessary Biopsy of American College of Radiology Thyroid Imaging Reporting and Data System Category 4 Nodules

OBJECTIVES

To assess the effectiveness of strain elastography (SE), Virtual Touch tissue imaging and quantification (VTIQ; Siemens Medical Solutions, Mountain View, CA) and their combination (SE + VTIQ) in distinguishing benign from malignant American College of Radiology Thyroid Imaging Reporting and Data System category 4 nodules (TR4) to reduce unnecessary biopsy.

METHODS

In this retrospective study, 985 thyroid nodules from 920 patients were initially enrolled and examined with conventional ultrasound, SE, and VTIQ. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of SE, VTIQ, and SE + VTIQ were calculated respectively. An area under the receiver operating characteristic curve analysis was applied to evaluate the diagnostic efficiency of SE, VTIQ, and SE + VTIQ in the differentiation of benign and malignant TR4 nodules.

RESULTS

A total of 864 patients with 922 TR4 nodules were enrolled ultimately, as 63 thyroid nodules from 56 patients were excluded because they did not meet the inclusion criteria of this study. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of SE, VTIQ, and SE + VTIQ were 72.4% versus 86.3% versus 82.1%, 77.7% versus 80.5% versus 83.5%, 70.6% versus 76.1% versus 80.2%, 73.4% versus 76.3% versus 83.5%, and 75.5% versus 79.7% versus 82.8%, respectively. The areas under the receiver operating characteristic curve for the diagnosis of TR4 nodules by SE, VTIQ, and SE + VTIQ were 0.751, 0.817, and 0.844.

CONCLUSIONS

In spite of a slight decrease in the sensitivity, the application of combining SE and VTIQ techniques can improve the specificity and accuracy of TR4 nodule diagnosis, which can help reduce unnecessary biopsies of TR4 nodules.

Multimodal Ultrasound Including Virtual Touch Imaging Quantification for Differentiating Cervical Lymph Nodes

Defining the entity of cervical lymph nodes (LNs) is essential for the diagnosis and staging of head and neck malignancies. Virtual Touch imaging quantification (VTIQ) is a relatively new method of elastography that measures tissue stiffness quantitatively. A prospective study was conducted that included 108 patients (57 benign and 51 metastatic lymph nodes [MLNs]). Shear wave velocities (SWVs) were analyzed using VTIQ and were compared with the histopathological results. Both maximum and minimum SWVs within the LNs significantly differed between benign masses and MLNs (p < 0.001). Percentage areas of the node with SWVs >6 m/s and <3.5 m/s differed significantly (p < 0.001). Intralesional areas with SWVs ≤3.5 m/s of 0-29% (odds ratio: 93.7) and 30%-69% (odds ratio: 46.3) were predictive of malignant LNs as well as ill-defined tumor (odds ratio: 5.2). VTIQ can provide more information on the entity of cervical LNs.

Precision Medicine with 3D Ultrasound

Introduction: Currently, B-mode ultrasound (US) is the primary imaging modality in diagnosing thyroid nodules (TNs). B-mode is a two-dimensional US (2D US) imaging display. Recent studies suggest a role for strain and shear wave elastography for evaluating TN as well. Three-dimensional US (3D-US) has the potential to enhance the diagnostic accuracy and precision for thyroid cancer (TC) detection.

Materials and Methods: An experienced ultrasonographer (G.A.) evaluated the patient using the following techniques: B-mode, strain and shear wave elastography, and 3D-US followed by fine needle aspiration biopsy (FNAB). Laboratory measurements were performed at LabCorp. Informed consent was obtained.

Case: A 28-year-old woman referred for hypothyroidism. Her primary doctor initiated levothyroxine 50 mcg daily 6 months prior. At the time of her visit, her thyroid stimulating hormone (TSH) was 2.8 (0.45–4.5 uIU/mL) and both thyroid peroxidase and thyroglobulin antibodies were elevated, suggestive of Hashimoto's thyroiditis. Her thyroid US showed a heterogeneous gland with an isoechoic TN in the right lobe measuring 7.7 × 6.3 × 7 mm. Strain elastography showed diffuse and patchy tissue stiffness throughout the gland, suggestive of tissue fibrosis caused by Hashimoto's thyroiditis. This study did not distinguish target TN from the surrounding tissue. Shear wave elastography of the TN revealed moderately increased stiffness compared with surrounding tissue. The shear wave velocity (SWV) measurement for the TN was 3.1 m/s. 3D-US examination demonstrated an isoechoic TN with irregular margins, and the volume was 0.119 cm³. FNAB of the TN was performed. Cytopathology was diagnostic for papillary thyroid cancer (PTC), Bethesda Category VI. Subsequent total thyroidectomy confirmed a 7 mm PTC with positive surgical margins caused by thyroid capsule invasion and no clear-cut evidence of extra-thyroid extension.

Discussion: This case showcases the recent technological advances in TN imaging. Our objective is to provide an improved approach to TN management. The American College of Radiology Thyroid Imaging Reporting and Data System stratifies the malignancy risk of TN primarily based on the size and B-mode US features. This model does not recommend FNAB for any TN <10 mm regardless of malignancy risk.¹ This is our observation that with 3D-US the size cutoff of TN might not be an issue as with B-mode or elastography. Irregularities of the TN can be seen with 3D-US with small and large nodules equally. The finding of irregular margins on 3D-US and consulting with the patient lead us to perform FNAB. Recent publications in the journal of VideoEndocrinology showed utilizations of 3D-US in diagnosing parathyroid adenomas and TNs. 3D-US technology improves view of the target lesion by adding a third dimension, coronal view, to the transverse and longitudinal views of B-mode US.^2,3 B-mode imaging provides excellent view of TNs. However, it has a low sensitivity for predicting TC.⁴ Prospective TN studies have demonstrated that adding elastography to B-mode imaging improves sensitivity of US technology for detecting TC.^5–10 In a prospective study with 707 TN, we showed that a single cutoff analysis for predicting malignancy in TNs, a maximum SWV of 3.54 m/s had the best sensitivity. The mean SWV for benign nodules was 2.71 m/s. The mean SWV for malignant nodules was 3.96 m/s.⁶ In this particular case strain and shear wave were not as helpful. The discrepancy between the two systems has been described in cases with severe Hashimoto's thyroiditis associated with tissue fibrosis.⁶ In our experience, the presence of autoimmune thyroid disease increases the risk for malignancy. Recent publications reported an association between differentiated TC and autoimmune thyroid disease and/or TSH when all Bethesda classifications were included.^11–13

Conclusion: 3D-US technology in conjunction with B-mode may improve diagnostic accuracy in detecting TC.

No competing financial interests exist.

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Diagnostic Accuracy Evaluation of Two-Dimensional Shear Wave Elastography in the Differentiation Between Benign and Malignant Thyroid Nodules: Systematic Review and Meta-analysis

OBJECTIVES

To evaluate two-dimensional (2D) shear wave elastography (SWE) performance as an independent predictor of malignancy in the diagnostic differentiation of thyroid nodules (TNs), including subgroup analyses of different manufacturers and respective cutoffs points.

METHODS

The online databases MEDLINE (PubMed), Embase, and the Cochrane Library were searched for articles using 2D SWE in TN evaluation. After good-quality relevant thyroid-specific articles were selected, the main data, plus their sensitivity and specificity, were tabulated. Summary receiver operating characteristic curves were generated to verify the accuracy of data obtained from 3 manufactures. A meta-analysis was performed to evaluate whether clinical recommendations can be improved by the use of 2D SWE to differentiate TNs.

RESULTS

The sensitivity and specificity parameters of 2D SWE for the differentiation between benign and malignant TNs according to different instruments were, respectively, as follows: Toshiba SWE (Toshiba Medical Systems, Tochigi, Japan), 0.77 (95% confidence interval [CI], 0.70-0.83) and 0.76 (95% CI, 0.72-0.81); Virtual Touch tissue imaging and quantification (Siemens Medical Solutions, Mountain View, CA), 0.72 (95% CI, 0.67-0.77) and 0.81 (95% CI, 0.78-0.84); and SuperSonic SWE (SuperSonic Imagine, Aix-en-Provence, France), 0.63 (95% CI, 0.59-0.66) and 0.81 (95% CI, 0.79-0.83). The summary receiver operating characteristic curves showed the following area under the curve syntheses: Toshiba SWE, 0.84 (Q* = 0.7707); Virtual Touch tissue imaging and quantification, 0.85 (Q* = 0.7809); and SuperSonic SWE, 0.88 (Q* = 0.8102). Positive and negative predictive values varied, respectively, from 16% to 94% and 29% to 100%, considering all included articles. The overall accuracy ranged from 53% to 93%.

CONCLUSIONS

Two-dimensional SWE is a relevant and an important tool that supports ultrasound in clinical practice in the diagnostic differentiation between benign and malignant TNs.

Diagnosis of Thyroid Nodule with New Ultrasound Imaging Modalities

Introduction: B-mode ultrasound (US) technology is an integral part of diagnosing and assessing risk stratification of thyroid nodules (TNs). The addition of shear wave elastography and three-dimensional (3D) US imaging may improve risk stratification for thyroid cancer (TC). Materials and Methods: The patient was evaluated in our clinic with US imaging including B-mode, shear wave elastography, 3D-US, and fine needle aspiration biopsy (FNAB). Laboratory measurements were performed at LabCorp. The patient gave informed consent. Case: A 20-year-old female referred for hypothyroidism who was on levothyroxine 25µg daily. Her thyroid-stimulating hormone (TSH) was 3.870 (0.45-4.5 µIU/mL). Thyroid peroxidase antibody and thyroglobulin antibody were elevated, suggestive of Hashimoto's thyroiditis. Her thyroid ultrasongraph showed a heterogeneous thyroid gland with a hypoechoic TN in the right lobe measuring 9.2 × 8.9 × 9 mm. Shear wave elastography examination was suggestive of a hard TN. The shear wave velocity (SWV) measurements for the target TN was 3.9 m/s. 3D-US examination demonstrated a hypoechoic TN with irregular margins and a volume of 0.322 cm³. FNAB of right TN was performed. The cytopathology was read as malignant (Bethesa Category VI), diagnostic for papillary thyroid cancer (PTC). She underwent total thyroidectomy. Surgical pathology report showed an 8 mm PTC in the right lobe and 2 mm PTC in the left lobe with a background of Hashimoto's thyroiditis. There were 3/10 positive lymph nodes (LNs) for metastases. The largest metastatic LN measured 5 mm at level 6. Discussion: This case illustrates recent advances in US technology. For decades, clinicians relied on B-mode US to assess the risk for TC. This case illustrates important challenges and advances in US technology. Current ACR-TIRADS guideline for TN management is based on B-mode US features and TN size.¹ In our experience, including additional factors such as elastography, 3D-US, and laboratory evaluation helps to improve our diagnostic accuracy. In this case, her laboratory was suggestive of autoimmune thyroid disease. This information was helpful to put this patient in a higher risk category. Recent large studies reported an association between differentiated TC and autoimmune thyroid disease and/or TSH when all Bethesda classifications were included.^2-4 Shear wave elastography examination showed that this TN had a high SWV, suggestive of a hard TN, which is suspicious for malignancy. Several recent publications have reported that elastography can assess the malignant potential of TN.^5-10 In our prospective study, we reported that in a single cutoff analysis for predicting malignancy in TNs, a maximum SWV of 3.54 m/s had the best sensitivity. With greater SWV values, specificity increased but sensitivity decreased.⁶ 3D-US technology enhances our ability to visualize the target lesion because of adding a new dimension, coronal view, to the existing B-mode that consists of transverse and longitudinal views. In this case, irregular margins of the TN are seen much better with 3D-US. This is a preliminary report, and more studies need to be done. Conclusion: Adding SWE and 3D-US technology to B-mode US may enhance our ability for risk stratification for TN before FNAB. 3D-US may improve our ability to visualize the margins of TN. No competing financial interests exist. Runtime of video: 2 mins 5 secs.

Diagnostic Performance of a Combination of Shear Wave Elastography and B-Mode Ultrasonography in Differentiating Benign From Malignant Thyroid Nodules

Objectives

This study was conducted to compare clinicopathologic and radiologic factors between benign and malignant thyroid nodules and to evaluate the diagnostic performance of shear wave elastography (SWE) combined with B-mode ultrasonography (US) in differentiating malignant from benign thyroid nodules.

Methods

This retrospective study included 92 consecutive patients with 95 thyroid nodules examined on B-mode US and SWE before US-guided fine-needle aspiration biopsy or surgical excision. B-mode US findings (composition, echogenicity, margin, shape, and calcification) and SWE elasticity parameters (maximum [E_max], mean, minimum, and nodule-to-normal parenchymal ratio of elasticity) were reviewed and compared between benign and malignant thyroid nodules. The diagnostic performance of B-mode US and SWE for predicting malignant thyroid nodules was analyzed. The optimal cutoff values of elasticity parameters for identifying malignancy were determined. Diagnostic performance was compared between B-mode US only, SWE only, and the combination of B-mode US with SWE.

Results

On multivariate logistic regression analysis, age (odds ratio [OR], 0.90; P=0.028), a taller-than-wide shape (OR, 11.3; P=0.040), the presence of calcifications (OR, 15.0; P=0.021), and E_max (OR, 1.22; P=0.021) were independent predictors of malignancy in thyroid nodules. The combined use of B-mode US findings and SWE yielded improvements in sensitivity, the positive predictive value, the negative predictive value, and accuracy compared with the use of B-mode US findings only, but with no statistical significance.

Conclusion

When SWE was combined with B-mode US, the diagnostic performance was better than when only B-mode US was used, although the difference was not statistically significant.

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.

Ultrasound elastography: a novel tool for the differential diagnosis of pleural effusion

INTRODUCTION

Traditional thoracic ultrasound (TUS) is often the initial tool used to help diagnose malignant pleural effusion (MPE). Ultrasound elastography, a relatively new technique, has been used to differentiate malignant disease from benign disease by evaluating tissue "stiffness". However, no studies evaluating the efficacy of ultrasound elastography for diagnosing MPE are available. We assessed the value of ultrasound elsatography for diagnosing MPE prospectively.

METHODS

All 244 enrolled patients were divided into a development set and a validation set in chronological order. The cut-off elasticity index was established using a receiver operating characteristic curve constructed from the continuous data of the patients in the development set. The diagnostic performance of ultrasound elastography was compared with that of TUS in the validation set.

RESULTS

In the development set, the mean elasticity index (47.25 kPa) was the optimal cut-off. In the validation set, pleural ultrasound elastography had a sensitivity of 83.64%, a specificity of 90.67%, a positive predictive value of 86.79%, a negative predictive value of 88.31%, a positive likelihood ratio of 8.96 and a negative likelihood ratio of 0.18 for diagnosing MPE. The sensitivity of ultrasound elastography was significantly higher (p=0.006) than that of TUS (60%).

CONCLUSION

Pleural ultrasound elastography is a better technique than TUS for differentiating MPE from benign pleural disease.

Ultrasound elastography in the evaluation of thyroid nodules: evolution of a promising diagnostic tool for predicting the risk of malignancy

The elastic properties of tissue have always been of interest in clinical practice. In the past, the identification of structures that were stiffer on physical palpation would raise the suspicion that "there was something wrong". With the development and advancement of medicine, there proved to be a true correlation in the prediction of malignancy of a lesion: malignant disease tends to stiffen the affected tissue, either by increased cell proliferation or fibrosis. Palpation is the oldest method for the detection of thyroid nodules, which is informed by the knowledge that malignant thyroid lesions tend to be much harder than benign ones. Unfortunately, palpation is a highly subjective method that is dependent on the size and location of the lesion, as well as on the skill of the physician. In cases where these nodules are very small or are located in deep regions, their detection by palpation is difficult or even impossible. In addition, although a malignant lesion differs in terms of elasticity, it may not have echogenic properties, preventing its detection by conventional ultrasound. Imaging that indicates the stiffness or deformation of tissues, through the use of ultrasound elastography techniques, adds new information related to their structural formation. In this article, we review the basic physical principles of elastography and the evolution of the method for the evaluation of thyroid nodules, as well as the limitations of and future perspectives for its use.

Shear wave elastography in differentiating between benign and malignant cervical lymph nodes in patients with oral carcinoma

OBJECTIVES

To evaluate shear wave elastography in differentiating between benign and malignant cervical lymph nodes in patients with oral carcinoma.

METHODS

77 patients with oral squamous cell carcinoma were examined by B-mode and shear wave elastography with a 14 MHz linear transducer. The integrated shear wave elastography software allowed the operator to place regions of interest of various sizes within the elastography window, and automatically displayed shear elastic modulus data (kPa) for each region of interest. The relationship between size and shear elastic modulus of cervical lymph nodes was assessed by Pearson's rank correlation test. The shear elastic modulus of cervical lymph nodes in benign and malignant were evaluated using the Mann-Whitney U test. The analyses were used with a 5% significance level.

RESULTS

We plotted shear elastic modulus (X) against minimal axial diameter of cervical lymph nodes (Y), and observed a significant correlation [ Y = 0.091 X + 4.648 (R² = 0.603, p = 0.000, N = 77)]. Furthermore, the shear elastic modulus of the malignant cervical lymph nodes (105.9 ± 5.2 kPa) was higher than that of benign (11.9 ± 4.4 kPa, p = 0.000).

CONCLUSIONS

The shear wave elastography is an effective technique for the objectively and quantitatively diagnosis of cervical lymph node metastases of the oral carcinoma.

Comparative Diagnostic Accuracy of Contrast-Enhanced Ultrasound and Shear Wave Elastography in Differentiating Benign and Malignant Lesions: A Network Meta-Analysis

Background: We performed a network meta-analysis to compare the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) and shear wave elastography (SWE) in differentiating benign and malignant lesions in different body sites.

Methods: A computerized literature search of Medline, Embase, SCOPUS, and Web of Science was performed using relevant keywords. Following data extraction, we calculated sensitivity, specificity, positive likelihood ratio (LR), negative LR, and diagnostic odds ratio (DOR) for CEUS, and SWE compared to histopathology as a reference standard. Statistical analyses were conducted by MetaDiSc (version 1.4) and R software (version 3.4.3).

Results: One hundred and fourteen studies (15,926 patients) were pooled in the final analyses. Network meta-analysis showed that CEUS had significantly higher DOR than SWE (DOR = 27.14, 95%CI [2.30, 51.97]) in breast cancer detection. However, there were no significant differences between CEUS and SWE in hepatic (DOR = −6.67, 95%CI [−15.08, 1.74]) and thyroid cancer detection (DOR = 3.79, 95%CI [−3.10, 10.68]). Interestingly, ranking analysis showed that CEUS achieved higher DOR in detecting breast and thyroid cancer, while SWE achieved higher DOR in detecting hepatic cancer. The overall DOR for CEUS in detecting renal cancer was 53.44, 95%CI [29.89, 95.56] with an AUROC of 0.95, while the overall DOR for SWE in detecting prostate cancer was 25.35, 95%CI [7.15, 89.89] with an AUROC of 0.89.

Conclusion: Both diagnostic tests showed relatively high sensitivity and specificity in detecting malignant tumors in different organs. Network meta-analysis showed that CEUS had higher diagnostic accuracy than SWE in detecting breast and thyroid cancer, while SWE had higher accuracy in detecting hepatic cancer. However, the results were not statistically significant in hepatic and thyroid malignancies. Further head-to-head comparisons are needed to confirm the optimal imaging technique to differentiate each cancer type.

Evaluation of Normal and Varicocele-Bearing Testes Using Real-time Strain Elastography

OBJECTIVES

To evaluate testes in patients with varicocele using real-time strain elastography and to correlate the results with the patients' clinical, seminal, and hormonal profiles.

METHODS

Fifty patients with left varicocele and 20 age-matched control participants were included in the study. All participants were evaluated via a historical interview, clinical examination, including testicular volume and varicocele grade, hormonal assay (total and free testosterone, luteinizing hormone, and follicle-stimulating hormone), computer-assisted semen analysis, and testicular assessment using real-time strain elastography to define the strain ratio and elasticity score.

RESULTS

Testicular volume and sperm parameters were significantly lower (P < .001), whereas the follicle-stimulating hormone level, strain ratio, and elasticity score were significantly higher (P < .01; P < .001; P < .001, respectively), in the varicocele group. Other hormone levels in the endocrine profile were not significantly different between the groups. Significant negative correlations were found between the elasticity score and testicular volume and the percentage of normal forms (P = .029; P = .005). The varicocele grade showed significant positive correlations with both the strain ratio and elasticity score (P < .001).

CONCLUSIONS

Strong correlations were found between real-time strain elastography and the testicular volume, varicocele grade, and sperm morphologic characteristics. Real-time strain elastography is a simple, noninvasive investigative modality that can potentially be used to study the structure and function of the testicular tissue in varicocele.

Evaluation of Reconstruction Parameters for 2-D Comb-Push Ultrasound Shear Wave Elastography

Shear wave elastography (SWE) is a noninvasive ultrasound imaging modality used in the assessment of the mechanical properties of tissues such as the liver, kidney, skeletal muscle, thyroid, and the breast. Among the methods used to perform SWE is the comb-push ultrasound shear elastography method. This method uses multiple focused ultrasound beams to generate push beams with acoustic radiation force. Applying these push beams generates propagating shear waves. The propagation motion is measured with ultrafast ultrasound imaging. The shear wave motion data are directionally filtered, and a 2-D shear wave velocity (SWV) algorithm is applied to create group velocity maps. This algorithm uses a moving window and a specified patch for performing cross-correlations of time-domain signals. We performed a parametric study of how the choice of the patch and window size affected the reconstruction of the SWV in homogeneous and inclusion phantoms. We quantified the mean velocity and coefficient of variation in the homogeneous phantoms. We measured the contrast-to-noise ratio and bias in the inclusion phantoms. In each of these cases, we found that particular combinations of the patch and window provided optimal values of these evaluation metrics for the phantoms tested. This study provides a basis to construct algorithms to produce optimal SWV reconstructions for various clinical applications.

Narrowband Shear Wave Generation Using Sinusoidally Modulated Acoustic Radiation Force

Most transient ultrasound elastography methods use high-intensity ultrasound "push" pulses that generate a shear wave with a wide frequency spectrum. However, it is difficult to control how the energy of the wave is distributed within that spectrum. For this reason, the shear-wave group velocity may not match that of harmonic methods like magnetic resonance elastography (MRE). The objective of this study was to introduce a narrowband shear wave generation method produced by "push" pulses with sinusoidally modulated intensity. The method, named harmonic shear wave imaging (HSWI), successively transmits a series of push pulses with a periodic change in duration. The excited shear waves form a continuous shear wave with a known main frequency that can be controlled by the user. Push pulses are interleaved with imaging pulses so only one clinical transducer is used to generate and record the shear waves. The proposed method was compared to MRE and a transient shear wave elastography method using phantoms and in vivo measurements. It was found that HSWI produces narrowband waves with a speed that closely matches that measured by MRE. Measurement of the acoustic output parameters indicated that the acoustic intensities in HSWI are suitable for clinical applications. The ability of HSWI to generate narrowband shear waves using a single linear array transducer makes it amenable for clinical translation. HSWI can potentially use the same thresholds as MRE for diagnosis of diseases affecting the stiffness of soft tissues.

Sonographic Characteristics of Papillary Thyroid Carcinoma with Coexistent Hashimoto's Thyroiditis: Conventional Ultrasound, Acoustic Radiation Force Impulse Imaging and Contrast-Enhanced Ultrasound

Our objective was to provide the various sonographic characteristics of papillary thyroid carcinomas for Hashimoto's thyroiditis (HT) patients, including conventional ultrasound (US), acoustic radiation force impulse Virtual Touch imaging and quantification (ARFI-VTIQ) and contrast-enhanced ultrasound (CEUS). Sixty-nine HT patients with 85 thyroid nodules (TNs) (49 malignant and 36 benign) were enrolled in this study. We evaluated the size, shape, margin, echogenicity, presence of halo, calcification, vascularity and ARFI-VTIQ and CEUS parameters for each nodule and compared the findings with the reference standards of histopathological and/or cytologic results. Univariate analysis indicated that compared with benign TNs with HT, papillary thyroid carcinomas with HT more often had taller-than-wider shapes, ill-defined margins, microcalcifications, peripheral vascularity, relatively harder stiffness with a higher shear wave speed, hypo-enhancement, peak intensity index <1 and area under the curve index <1 at pre-operative US, ARFI-VTIQ and CEUS. Multivariate analysis revealed that ill-defined margins, microcalcifications and peak intensity index <1 are independent characteristics related to malignant TNs for their differentiation from benign TNs (all p < 0.05). Our study indicated that pre-operative multiparameter US characteristics may serve as a useful tool to identify malignant TNs in HT patients.

Ultrasound elastography of the thyroid: principles and current status

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

Usefulness of shear wave elastography in the diagnosis of oral and maxillofacial diseases

Purpose

To evaluate the usefulness of shear wave elastography in the diagnosis of oral and maxillofacial diseases.

Materials and Methods

Ten patients with oral and maxillofacial diseases and 28 volunteers drawn from our student doctors were examined by shear wave elastography with a 14-MHz linear transducer using an Aplio 300 apparatus (Canon Medical Systems, Otawara, Japan). A statistical analysis of the shear elastic modulus (kPa) of healthy tissue (the sublingual gland, submandibular gland, anterior belly of the digastric muscle, and geniohyoid muscle) in the 28 volunteers was performed using 1-way repeated measures analysis of variance with the Tukey honest significant difference test. The maximum shear elastic modulus (kPa) of 8 patients with squamous cell carcinoma (SCC) and 2 patients with benign lesions was evaluated with the Mann-Whitney U test. The analysis used a 5% significance level.

Results

The mean shear elastic modulus of the sublingual gland (9.4±3.7 kPa) was lower than that of the geniohyoid muscle (19.2±9.2 kPa, P=.000) and the anterior belly of the digastric muscle (15.3±6.1 kPa, P=.004). The maximum shear elastic modulus of the SCCs (109.6±14.4 kPa) was higher than that of the benign lesions (46.4±26.8 kPa, P=.044).

Conclusion

Our results demonstrated the usefulness of shear wave elastography in the diagnosis of oral and maxillofacial diseases. Shear wave elastography has the potential to be an effective technique for the objective and quantitative diagnosis of oral and maxillofacial diseases.

Shear wave elastography in the evaluation of renal parenchymal stiffness in patients with chronic kidney disease

OBJECTIVE

To investigate the use of shear wave elastography (SWE)-derived estimates of Young's modulus (YM) as an indicator to detect abnormal renal tissue diagnosed by estimated glomerular filtration rate (eGFR).

METHODS

The study comprised 106 chronic kidney disease (CKD) patients and 203 control subjects. Conventional ultrasound was performed to measure the kidney length and cortical thickness. SWE imaging was performed to measure renal parenchymal stiffness. Diagnostic performance of SWE and conventional ultrasound were correlated with serum creatinine, urea levels and eGFR.

RESULTS

Pearson's correlation coefficient revealed a negative correlation between YM measurements and eGFR (r = -0.576, p < 0.0001). Positive correlations between YM measurements and age (r = 0.321, p < 0.05), serum creatinine (r = 0.375, p < 0.0001) and urea (r = 0.287, p < 0.0001) were also observed. The area under the receiver operating characteristic curve for SWE (0.87) was superior to conventional ultrasound alone (0.35-0.37). The cut-off value of less or equal to 4.31 kPa suggested a non-diseased kidney (80.3% sensitivity, 79.5% specificity).

CONCLUSION

SWE was superior to renal length and cortical thickness in detecting CKD. A value of 4.31 kPa or less showed good accuracy in determining whether a kidney was diseased or not. Advances in knowledge: On SWE, CKD patients show greater renal parenchymal stiffness than non-CKD patients. Determining a cut-off value between normal and diseased renal parenchyma may help in early non-invasive detection and management of CKD.

Retrospective cytological evaluation of indeterminate thyroid nodules according to the British Thyroid Association 2014 classification and comparison of clinical evaluation and outcomes

The cytology of 130 indeterminate nodules (Thy 3) was retrospectively reviewed according to the British Thyroid Association 2014 classification. Nodules were divided into Thy 3a (atypical features) and Thy 3f (follicular lesion) categories. Histology was available as a reference for 97 nodules. Pre-surgical evaluations comprised biochemical tests, color-Doppler ultrasonography (US), semi-quantitative elastography-US (USE), contrast-enhanced US (CEUS), and mutation analysis from cytological slides. Thyroid malignancy was the final diagnosis for 19% of surgically-treated nodules. No statistically significant difference in the risk of malignancy was found between Thy 3a (26%) and Thy 3f (14%) nodules. Histology of the Thy 3a and Thy 3f nodules showed a higher incidence of Hurtle cell adenomas in Thy 3f (29%) than in Thy 3a (3%) nodules (P=0.01). The only pre-surgical difference concerned the BRAF V600E mutation, which was positive in some Thy 3a but not in any Thy 3f nodules (P=0.04). Receiver-operating characteristic (ROC) analysis was used to obtain cut-off values from US (score), USE (ELX 2/1 strain index), and CEUS (time-to-peak index and peak index) data. The cut-off values were similar for Thy 3a and Thy 3f nodules. Data showed that malignancy can be suspected if the US score is >2, ELX 1/2 strain index >1, time-to-peak index >1, and peak index <1. In a sub-group of 24 revised nodules (12 Thy 3a and 12 Thy 3f) with histology as a reference, the diagnostic power of cumulative pre-surgical analysis by means of US, USE, and CEUS showed high positive and negative predictive values (83% and 100%, respectively) for the presence of malignancy in Thy 3a and Thy 3f nodules. In conclusion, in our series of revised Thy 3 nodules, malignancy was low and displayed no significant differences between Thy 3a and Thy 3f categories. The use of cut-offs based on histology as a reference could reduce surgery. Our data support the conviction that, in mutation-negative Thy 3a and Thy 3f nodules, observation should be the first choice when not all instrumental results are suspect.

Combination of Sonoelastography and TIRADS for the Diagnostic Assessment of Thyroid Nodules

To evaluate the diagnostic performance of elastography alone and combined with Thyroid Imaging Reporting And Data System (TIRADS) for the assessment of non-autonomous thyroid nodules. We included 244 thyroid nodules and analyzed the visual elasticity scores, strain value (SV) and TIRADS classification. Histologic examination revealed 38 malignant (16%) and 206 benign nodules. The SV was lower in malignant nodules than in benign with an optimal cutoff ≤0.225. The visual elasticity scores showed a better diagnostic performance than the SV measurement. The risk for malignancy increased with higher TIRADS category. The sensitivity, specificity, positive predictive value and negative predictive value of TIRADS were superior to sonoelastography. The combination of TIRADS ≥4C and SV ≤0.225 showed the highest odds ratio to predict malignancy. Kwak-TIRADS classification is superior to elastography for the differentiation of benign and malignant thyroid nodules. Our data demonstrate that a high TIRADS class alone is predictive for thyroid carcinoma and the clinical relevance of sonoelastography is negligible.

Shear wave elastography and Afirma™ gene expression classifier in thyroid nodules with indeterminate cytology: a comparison study

PURPOSE

To compare shear wave elastography (SWE) and Afirma™ gene expression classifier (GEC) for diagnosis of malignancy in thyroid nodules (TNs) with Bethesda Classification (BC) III or IV indeterminate cytology.

METHODS

This preliminary single-center prospective study was approved by the Institutional Review Board. We evaluated 151 consented patients with 151 indeterminate TNs (123 BC III, 28 BC IV) on fine-needle aspiration biopsy (FNAB). B-mode ultrasound, vascularity, and SWE were performed prior to FNAB. TN stiffness was measured as shear wave velocity (SWV) in meters per second (m/s). The stiffest area of the TN was selected for SWV measurement. GEC testing was performed with a second FNAB. Surgery was recommended for GEC-suspicious TNs, or GEC-benign TNs with two or more worrisome B-mode US features.

RESULTS

Surgical pathology confirmed 31 malignant TNs. Among the GEC-suspicious group, 28 of 59 TNs were malignant. The SWV value of ≥3.59 m/s was the best cut-off for malignancy risk based on the receiver operating curve (ROC). Twenty-six malignant TNs had SWV ≥ 3.59 m/s. The sensitivity and specificity for SWV ≥ 3.59 m/s were 83.9 and 79.2%, respectively. Positive predictive value (PPV) was 51.0% and negative predictive value (NPV) was 95.0%. For the GEC-suspicious group, sensitivity, specificity, PPV, and NPV were 90.3, 74.2, 47.5, and 96.7%, respectively. In multivariate analysis, SWV and GEC-suspicious were significant predictors of malignancy, but B-mode features and vascularity were not.

CONCLUSION

This preliminary study indicates that SWE and GEC are independent predictors of malignancy in TNs with BC III or IV.

Assessment of Virtual Touch Tissue Imaging Quantification and the Ultrasound Thyroid Imaging Reporting and Data System in Patients With Thyroid Nodules Referred for Biopsy

OBJECTIVES

To evaluate the diagnostic performance of Virtual Touch tissue imaging quantification (VTIQ; Siemens Medical Solutions, Mountain View, CA) in combination with the Thyroid Imaging Reporting and Data System (TI-RADS) for assessing thyroid nodules referred for biopsy.

METHODS

A total of 197 surgically or cytologically proven thyroid nodules in 187 patients were included. Nodules evaluated by conventional ultrasound (US) and VTIQ examinations were classified into US TI-RADS categories. The shear wave velocity (SWV) on VTIQ was assessed, and the cutoff value was obtained from a receiver operating characteristic curve analysis. Diagnostic performances of conventional US, VTIQ, and their combination were compared.

RESULTS

There were 134 benign and 63 malignant nodules. The sensitivity and specificity for the US TI-RADS were 98.4% and 20.1%, respectively. The areas under the receiver operating characteristic curves for the mean, maximum, minimum, and ratio of the SWV were 0.818, 0.805, 0.799, and 0.728. With a cutoff value of 2.90 m/s, the sensitivity and specificity of the mean SWV were 71.4% and 82.8%. By applying this value or less as a standard for downgrading TI-RADS category 4a to category 3 lesions, the specificity significantly rose from 20.1% to 47.0% (P < .001) without a loss of sensitivity.

CONCLUSIONS

The additional application of VTIQ can improve the specificity of the TI-RADS for evaluating thyroid nodules without a loss of sensitivity.

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.

The diagnostic performance of shear wave speed (SWS) imaging for thyroid nodules with elasticity modulus and SWS measurement

To evaluate the diagnostic performance of a new technique of shear wave speed (SWS) imaging for the diagnosis of thyroid nodule with elasticity modulus and SWS measurement. 322 thyroid nodules in 322 patients (216 benign nodules, 106 malignant nodules) were included in this study. All the nodules received conventional ultrasound (US) and SWS imaging (Aplio500, Toshiba Medical Systems, Japan) before fine-needle aspiration (FNA) and/or surgery. The values of E-max and E-mean with elastic modulus (61.27 ± 36.31 kPa and 31.89 ± 19.11 kPa) or SWS (4.45 ± 1.49 m/s and 3.26 ± 2.71 m/s) in malignant nodules were significantly higher than those in benign lesions (29.18 ± 18.62 kPa and 15.85 ± 6.96 kPa, or 2.98 ± 0.85 m/s and 2.19 ± 0.42 m/s, all P < 0.001). No significant differences in area under the curve (AUC) between the SWS imaging parameters were found (all P > 0.05). In multivariate logistic regression analysis, E-max (m/s) with SWS was identified to be the strongest independent predictor for malignant nodules (odds ratio [OR] = 16.760), followed by poorly-defined margin (OR = 7.792), taller-than-wide shape (OR = 3.160), micro-calcification (OR = 2.422), and E-max (kPa) with elastic modulus (OR = 0.914). The AUC was 0.813 for E-max with SWS (m/s) and 0.796 for E-max with elastic modulus (kPa). With cut-off SWS value of 3.52 m/s in E-max, sensitivity of 69.8%, specificity of 81.5%, and accuracy of 77.6% were achieved. SWS imaging is a valuable tool in predicting thyroid malignancy. E-max with SWS measurement is the strongest independent predictor for thyroid malignancy.

US Elastography Using Carotid Artery Pulsation May Increase the Diagnostic Accuracy for Thyroid Nodules with US-Pathology Discordance

This study evaluated the diagnostic performance of ultrasound elastography (USE) using carotid arterial pulsation and determined the reproducibility of USE for thyroid nodules. A total of 148 patients with 173 thyroid nodules participated. The mean elasticity contrast index (ECI) was significantly higher in malignant nodules (3.1 ± 1.5) than in benign nodules (1.7 ± 0.8) (p < 0.001). When a cut-off ECI value of 3.5 was used, the diagnostic accuracy (78.6%) of gray-scale ultrasound (US) + ECI was the highest compared with that of the gray-scale US (76.9%) and ECI (67.1%). In 16 of 43 nodules (37.2%) with US-pathology, discordance could be correctly reclassified as benign (8 of 11) or malignant (8 of 32). The intra-class correlation coefficient for inter-observer agreement was 0.96, and those for intra-observer agreement were 0.97 and 0.98. Thyroid nodules with ECI values of >3.5 may have an additional value to increase the diagnostic accuracy for nodules with US-pathology discordance with reproducible results.

Correlation of ultrasound bladder vibrometry assessment of bladder compliance with urodynamic study results

Purpose or objective

The objective of this study is to assess correlation between bladder wall mechanical properties obtained by ultrasound bladder vibrometry (UBV) and urodynamic study (UDS) measurements in a group of patients undergoing clinical UDS procedure.

Materials and methods

Concurrent UBV and UDS were performed on 70 patients with neurogenic bladders (56 male and 14 female). Bladder wall mechanical properties measured by UBV at different filling volumes were correlated with recorded detrusor pressure (Pdet) values. Mean, median and standard deviation of correlation values were calculated and the significance of these observations was tested.

Results

Bladder wall mechanical properties obtained by UBV as group velocity squared and elasticity showed high correlations with Pdet measured at different volumes (median correlation 0.73, CI: 0.64–0.80 and 0.72, CI: 0.56–0.82 respectively). The correlation of group velocity squared and elasticity with Pdet were both significantly higher than 0.5.

Conclusions

The results of this study suggest that UBV can closely monitor changes in bladder wall mechanical properties at different volumes in a group of patients undergoing UDS. The high correlation between UBV parameters and detrusor pressure measurements suggests that UBV can be utilized as a reliable and cost-effective tool for assessment of the bladder wall mechanical changes in a noninvasive fashion.

Comparison of Virtual Touch Tissue Imaging & Quantification (VTIQ) and Virtual Touch Tissue Quantification (VTQ) for diagnosis of thyroid nodules

OBJECTIVE

The aim of this study was to compare the diagnostic performance of Virtual Touch Tissue Imaging & Quantification (VTIQ) and Virtual Touch Tissue Quantification (VTQ) in differentiating benign from malignant thyroid nodules (TNs).

MATERIALS AND METHODS

In this study 107 TNs in 107 patients were enrolled and analyzed. All of them were detected by conventional ultrasound (US) and confirmed by fine-needle aspiration (FNA) biopsy or surgery. VTIQ and VTQ examinations were performed on each nodule. Thereafter the median and mean of shear wave speed (SWS) values in lesions on VTIQ and VTQ were computed (SWS-median and SWS-mean). With cytological results of FNA and histological results adopted as the reference standard, area under the receiver operating characteristic (AUROC) curve analysis was performed to evaluate the diagnostic efficiency of VTIQ and VTQ in differentiation of TNs.

RESULTS

Among the 107 lesions, 19 were papillary thyroid carcinomas (PTCs), 1 was medullary thyroid carcinoma (MTC) and 87 were benign. In total lesions, AUROC-median in VTIQ was significantly higher than that in VTQ (0.851 vs.0.759; p < 0.05).

CONCLUSION

VTIQ and VTQ were equivalent in diagnosing TNs when using SWS-mean, whereas VTIQ showed better performance in comparison with VTQ when using SWS-median.

Preliminary Evaluation of Virtual Touch Tissue Imaging Quantification for Differential Diagnosis of Metastatic and Nonmetastatic Cervical Lymph Nodes

OBJECTIVES

Virtual Touch tissue imaging quantification (VTIQ; Siemens Medical Solutions, Mountain View, CA) is useful for assessing tissue hardness. This study aimed to investigate the value of VTIQ in differential diagnosis of cervical lymph nodes.

METHODS

We retrospectively analyzed conventional sonograms and VTIQ images of 85 pathologically confirmed patients with superficial lymph node lesions. Conventional sonography was first performed, with 2-dimensional images described. Then VTIQ shear wave velocity (SWV) values of superficial lymph nodes were measured. With pathologic diagnosis as the reference standard, a receiver operating characteristic curve was generated to evaluate VTIQ efficacy in differential diagnosis of metastatic and nonmetastatic cervical lymph nodes.

RESULTS

Of the 85 nodes, 44 and 41 were metastatic and nonmetastatic, respectively. The latter group included 24 and 17 hematologic/lymphatic system disease and reactive hyperplastic nodes, respectively. Shear wave velocity values of metastatic nodes were significantly higher than those of their nonmetastatic counterparts (P < .001). With an area under the curve (AUC) of 0.953 and SWV cutoff of 3.27 m/s, accuracy, sensitivity, and specificity were 89.4%, 88.6%, and 90.2%, respectively, for distinguishing metastatic and nonmetastatic nodes. An AUC of 0.943 and SWV cutoff of 3.23 m/s yielded accuracy, sensitivity, and specificity of 88.2%, 88.6%, and 87.5% for differentiating metastatic from hematologic/lymphatic system disease nodes. Finally, an AUC of 0.968 and SWV cutoff of 3.27 m/s yielded accuracy, sensitivity, and specificity of 90.2%, 88.6%, and 94.1% for differentiating metastatic from reactive hyperplastic nodes.

CONCLUSIONS

Virtual Touch tissue imaging quantification is efficient in differential diagnosis of metastatic and nonmetastatic cervical lymph nodes.

Virtual touch tissue imaging and quantification (VTIQ) in the evaluation of thyroid nodules: the associated factors leading to misdiagnosis

To evaluate the associated factors leading to misdiagnosis with VTIQ for differentiation between benign from malignant thyroid nodules (TNs). The study included 238 benign TNs and 150 malignant TNs. Conventional ultrasound (US) features and VTIQ parameters were obtained and compared with the reference standard of histopathological and/or cytological results. Binary logistic regression analysis was performed to select independent variables leading to misdiagnosis. The maximum shear wave speed (SWS) (SWS-max), mean SWS (SWS-mean), SWS-ratio and standard deviation of SWS (SWS-_SD) were significantly higher for malignant TNs compared with benign TNs (all P < 0.001). SWS-mean achieved the highest diagnostic performance with a cut-off value of 3.15 m/s. False positive rate was 13.4% (32/238) while false negative rate was 35.3% (53/150). Intranodular calcification (OR: 1.715) was significantly associated with false positive VTIQ findings, while nodule size (OR: 0.936) and echotexture of the thyroid gland (OR: 0.033) were negatively associated with them. Nodule depth (OR: 0.881) and TI-RADS category (OR: 0.563) were negatively associated with false negative VTIQ findings. These US characteristic of TNs should be taken into consideration when interpreting the results of VTIQ examinations.

Virtual Touch Tissue Imaging and Quantification in the Evaluation of Thyroid Nodules

OBJECTIVES

To investigate the diagnostic performance of a 2-dimensional shear wave elastographic technique (Virtual Touch tissue imaging and quantification [VTIQ]; Siemens Medical Solutions, Mountain View, CA) for predicting thyroid malignancy.

METHODS

A total of 302 thyroid nodules underwent conventional sonography and VTIQ before fine-needle aspiration examination or surgery. Compared with histopathologic or cytologic results in combination with follow-up, the diagnostic performance of various shear wave speed (SWS) indices (minimum [SWS_min ], maximum [SWS_max ], and mean [SWS_mean ]) on VTIQ as well as conventional sonographic features for predicting thyroid malignancy was evaluated in all of the nodules.

RESULTS

Sixty-five malignant and 237 benign thyroid nodules were histopathologically or cytologically confirmed. All SWS indices on VTIQ were lower in benign nodules than thyroid malignancy (all P < .001). For discrimination between malignant and benign nodules, all VTIQ SWS indices were better than conventional sonographic features, such as a solid component, a taller-than-wide shape, microcalcification, a poorly defined margin and hypoechogenicity, in predicting thyroid malignancy (all P < .05). By applying a cutoff SWS_mean value of 2.60 m/s, VTIQ achieved sensitivity and negative predictive values of 84.6% and 94.3%, respectively, for differentiating nodules. The areas under the receiver operating characteristic curve of SWS_max (0.862 versus 0.717), SWS_min (0.866 versus 0.717), and SWS_mean (0.891 versus 0.725) for nodules larger than 10 mm were higher than those for nodules of 10 mm or smaller (all P < .05). Interoperator and intraoperator reproducibility was proven to be excellent, with all interclass correlation coefficient values higher than 0.80 (range, 0.813-0.905) CONCLUSIONS: Virtual Touch tissue imaging and quantification is a useful and reproducible tool for predicting thyroid malignancy.

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.

Optical coherence elastography assessment of corneal viscoelasticity with a modified Rayleigh-Lamb wave model

The biomechanical properties of the cornea play a critical role in forming vision. Diseases such as keratoconus can structurally degenerate the cornea causing a pathological loss in visual acuity. UV-A/riboflavin corneal collagen crosslinking (CXL) is a clinically available treatment to stiffen the cornea and restore its healthy shape and function. However, current CXL techniques do not account for pre-existing biomechanical properties of the cornea nor the effects of the CXL treatment itself. In addition to the inherent corneal structure, the intraocular pressure (IOP) can also dramatically affect the measured biomechanical properties of the cornea. In this work, we present the details and development of a modified Rayleigh-Lamb frequency equation model for quantifying corneal biomechanical properties. After comparison with finite element modeling, the model was utilized to quantify the viscoelasticity of in situ porcine corneas in the whole eye-globe configuration before and after CXL based on noncontact optical coherence elastography measurements. Moreover, the viscoelasticity of the untreated and CXL-treated eyes was quantified at various IOPs. The results showed that the stiffness of the cornea increased after CXL and that corneal stiffness is close to linear as a function of IOP. These results show that the modified Rayleigh-Lamb wave model can provide an accurate assessment of corneal viscoelasticity, which could be used for customized CXL therapies.