Three-Dimensional Shear Wave Elastography for Differentiating Benign From Malignant Thyroid Nodules

Incorporation of CEUS and SWE parameters into a multivariate logistic regression model for the differential diagnosis of benign and malignant TI-RADS 4 thyroid nodules

PURPOSE

To investigate the diagnostic value of contrast-enhanced ultrasound (CEUS) quantitative analysis parameters combined with shear wave elastography (SWE) quantitative parameters in the differentiation of benign and malignant ACR TI-RADS category 4 thyroid nodules and to provide a more effective reference for clinical work.

METHODS

We analyzed 187 category 4 nodules, including 132 nodules in the development cohort and 55 nodules in the validation cohort, divided the development cohort into benign and malignant groups, and analyzed the differences in all CEUS and SWE quantitative parameters between the two groups. We selected the highest AUC of the two parameters, performed binary logistic regression analysis with the ACR TI-RADS score and constructed a diagnostic model. ROC curves were applied to evaluate their diagnostic efficacy.

RESULTS

1) The diagnostic model had an AUC of 0.926, sensitivity of 87.5%, specificity of 86.8%, diagnostic threshold of 3, accuracy of 87.12%, positive predictive value of 86.15%, and negative predictive value of 88.06%. 2) The diagnostic model had an AUC of 0.890 in the validation cohort, sensitivity of 81.5%, specificity of 79.6%, and accuracy of 80.00%.

CONCLUSION

The combined multiparameter construction of the nodule diagnostic model can effectively improve the diagnostic efficacy of 4 types of thyroid nodules and provide a new reference index for clinical diagnostic work.

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.

Diagnostic performance of shear wave elastography in thyroid nodules with indeterminate cytology: A systematic review and meta-analysis

Purpose

Thyroid nodules classified as indeterminate in previous fine-needle aspiration cytology often necessitate additional evaluation to determine their histology, while shear wave elastography (SWE) offers an alternative option in this regard. The objective of this study was to assess the diagnostic effectiveness of SWE in evaluating indeterminate nodules.

Methods

The PubMed, EMBASE, and Web of Science databases were searched from 1st January 1970 to 1st March 2023. The studies were reviewed and the data was extracted by two separate reviewers. A Bayesian bivariate model was utilized to quantitatively synthesize the diagnostic accuracy and yield of the studies in R.

Results

A total of seven studies, involving indeterminate thyroid nodules undergoing SWE were included, and the overall malignancy rate was 34.1% (307/900). The summarized estimates of sensitivity and specificity were 0.792 (95% credible interval [CI], 0.727-0.850) and 0.845 (95% CI, 0.797-0.887), respectively. The summarized estimate for the diagnostic odds ratio (DOR) was 17.8 (95% CI, 14.0-22.6). Summarized receiver operating characteristic (SROC) plots indicated a trade-off between sensitivity and specificity, and the estimate of AUC was 0.866 (95% CI, 0.834-0.895). The summary estimates for positive and negative likelihood ratios were 4.67 (95% CI, 3.98-5.85) and 0.26 (95% CI, 0.23-0.28), respectively.

Conclusions

The overall accuracy of SWE remains satisfactory in indeterminate thyroid nodules. However, it should be noted that the available data are still extremely limited, and more studies or guidelines are required to provide further insights.

Emerging Role of Quantitative Ultrasound-Based Imaging Techniques for Characterizing Rotator Cuff Tears: A Scoping Review

Rotator cuff myosteatosis following cuff tears is very common and one of the most important prognostic factors in clinical management. Quantitative ultrasound-based imaging techniques (QUBIT) are frequently used along with magnetic resonance imaging (MRI) to evaluate rotator cuff fatty degeneration. However, the examination of rotator cuff tissue integrity by QUBIT is lacking a standardized imaging protocol and procedural methodologies. In this scoping review, we synthesized the current state of QUBIT against the reference imaging modalities in patients with rotator cuff tears. The literature search was extracted from 963 studies, with 22 studies included in the final review in accordance with the preferred reporting items for systematic reviews and meta-analyses extensions for scoping reviews. The selected studies included human participants and focused on measuring at least one prognostic or diagnostic factor using ultrasonography-based imaging with reference to MRI. The findings suggest both conventional B-mode ultrasound and shear wave elastography imaging were comparable to MRI-based imaging techniques for the evaluation of fatty infiltration and rotator cuff tear characterization. This review establishes guidelines for reporting shoulder-specific QUBIT aimed at developing a standardized imaging protocol. The objective was to enhance the diagnostic and prognostic capabilities of QUBIT in the clinical setting.

Diagnostic value of ACR TI-RADS combined with three-dimensional shear wave elastography in ACR TI-RADS 4 and 5 thyroid nodules

BACKGROUND

Three-dimensional shear wave elastography (3D-SWE) is a promising method in distinguishing benign and malignant thyroid nodules. By combining with conventional method, it may further improve the diagnostic value. The study aimed to assess the diagnostic value of American College of Radiology (ACR) thyroid imaging reporting and data system (TI-RADS) combined with 3D-SWE in ACR TI-RADS 4 and 5 thyroid nodules.

METHODS

All nodules were examined by conventional ultrasonography, ACR TI-RADS classification, and 3D-SWE examination. Conventional ultrasonography was used to observe the location, size, shape, margin, echogenicity, taller-than-wide sign, microcalcification, and blood flow of thyroid nodules, and then ACR TI-RADS classification was performed. The Young's modulus values (3D-C-Emax, 3D-C-Emean, and elastography standard deviation [3D-C-Esd]) were measured on the reconstructed coronal plane images. According to the receiver operating characteristic (ROC) curve, the best diagnostic efficiency among 3D-C-Emax, 3D-C-Emean, and 3D-C-Esd was selected and the cut-off threshold was calculated. According to the surgical pathology, they were divided into benign group and malignant group. And appropriate statistical methods such as t -test and Mann-Whitney U test were used to compare the difference between the two groups. On this basis, 3D-SWE combined with conventional ACR TI-RADS was reclassified as combined ACR TI-RADS to determine benign or malignant thyroid nodules.

RESULTS

Of the 112 thyroid nodules, 62 were malignant and 50 were benign. The optimal cut-off value of three-dimensional maximum Young's modulus in coronal plane (3D-C-Emax) was 51.5 kPa and the area under the curve (AUC) was 0.798. The AUC, sensitivity, specificity, and accuracy of conventional ACR TI-RADS were 0.828, 83.9%, 66.0%, and 75.9%, respectively. The AUC, sensitivity, specificity, and accuracy of combined ACR TI-RADS were 0.845, 90.3%, 66.0%, and 79.5%, respectively. The difference between the two AUC values was statistically significant.

CONCLUSIONS

Combined ACR TI-RADS has higher diagnostic efficiency than conventional ACR TI-RADS. The sensitivity and accuracy of combined ACR TI-RADS showed significant improvements. It can be used as an effective method in the diagnosis of thyroid nodules.

Preoperative evaluation of thyroid nodules - Diagnosis and management strategies

Thyroid cancer is the most common endocrine malignancy, with increasing incidence over the past few decades. Fine needle aspiration (FNA) biopsy is the gold standard for preoperative diagnosis of thyroid malignancies. Nevertheless, this method renders indeterminate results in up to 30% of the cases. Therefore, these patients are often referred to unnecessary surgery to establish the diagnosis. To improve the accuracy of preoperative diagnosis, several other ways, such as ultrasonography, elastography, immunohistochemical analysis, genetic testing, and core needle biopsy, have been developed and can be used either in association with or as an alternative to FNA. This review aims to evaluate all these diagnostic tools to determine the most appropriate way of managing thyroid nodules and subsequently improve the selection of cases referred to surgery.

Ultrasound imaging in thyroid nodule diagnosis, therapy, and follow-up: Current status and future trends

Ultrasound, the primary imaging modality in thyroid nodule management, suffers from drawbacks including: high inter- and intra-observer variability, limited field-of-view and limited functional imaging. Developments in ultrasound technologies are taking place to overcome these limitations, including three-dimensional-Doppler, -elastography, -nodule characteristics-extraction, and novel machine-learning algorithms. For thyroid ablative treatments and biopsies, perioperative use of three-dimensional ultrasound opens a new field of research. This review provides an overview of the current and future applications of ultrasound, and discusses the potential of new developments and trends that may improve the diagnosis, therapy, and follow-up of thyroid nodules.

Diagnostic Value of Different 3-D Shear Wave Elastography Sections in the Diagnosis of Thyroid Nodules

The aim of the study was to explore the value of 3-D shear wave elastography (SWE) in differentiating malignant from benign thyroid nodules. A total of 188 patients with 216 nodules who underwent conventional ultrasound, 2-D SWE and 3-D SWE were included in this study. All patients underwent surgical excision, and the pathological results were the gold standard. Receiver operating characteristic (ROC) curves of the American College of Radiology's Thyroid Imaging Reporting and Data System (ACR TI-RADS), 2-D SWE and 3-D SWE were plotted, and the areas under the curves (AUCs) were compared using a Z-test. There were 62 benign thyroid nodules and 154 malignant thyroid nodules in this study. Young's modulus (E_min, E_mean, E_max, E_sd) values of thyroid malignant nodules in different sections of 2-D SWE and 3-D SWE were significantly higher than those of thyroid benign nodules (p < 0.001). The AUC of E_max in 2-D SWE transverse sections was significantly lower than that in 3-D SWE transverse sections and 3-D SWE sagittal sections (0.768 vs. 0.831 and 0.844, p < 0.05). The AUC of 3-D S-E_max combined with ACR TI-RADS was 0.859; the specificity increased from 54.84% to 85.71%, and the diagnostic accuracy increased from 74.54% to 85.19%, compared with ACR TI-RADS. The difference was statistically significant (p < 0.05). Three-dimensional SWE combined with ACR TI-RADS for the diagnosis of thyroid nodules significantly improved the diagnostic ability of ACR TI-RADS, and was significantly better than 2-D SWE combined with ACR TI-RADS.

SuperSonic shear imaging for the differentiation between benign and malignant thyroid nodules: a meta-analysis

PURPOSE

To assess the diagnostic value of SuperSonic shear imaging (SSI) for the differentiation between benign and malignant thyroid nodules through meta-analysis.

METHODS

Online database searches were performed on PubMed, EMBASE, the Cochrane Library, and the Web of Science until 31 July 2021. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the quality of the included studies. Three measures of diagnostic test performance were used to examine the value of SSI, including the summary area under the receiver operating characteristic curve (AUROC), the summary diagnostic odds ratio (DOR), and the summary sensitivity and specificity. Heterogeneity was explored using meta-regression and subgroup analyses.

RESULTS

Finally, 21 studies with 3376 patients were included in this study. There were a total of 4296 thyroid nodules, in which 1806 malignant nodules and 2490 benign ones were involved. Thyroid nodules exhibited a malignancy rate of 42.0% (range 5.6-79.8%), 95.1% of which were of papillary variant. SSI showed a summary sensitivity of 74% [95% confidence interval (CI) 67-79%], specificity of 82% (95% CI 77-87%) and AUROC of 0.85 (95% CI 0.82-0.88) for the differentiation between benign and malignant thyroid nodules. The summary positive likelihood ratio (LR), negative LR, and DOR were 4.2 (95% CI 3.3-5.3), 0.32 (95% CI 0.26-0.40), and 13 (95% CI 9-18), respectively.

CONCLUSIONS

SSI showed high accuracy in the diagnostic differentiation between benign and malignant thyroid nodules and can be served as a noninvasive and important adjunct for thyroid nodule evaluation.

Transvaginal Shear Wave Elastography for Assessment of Endometrial and Subendometrial Pathologies: A Prospective Pilot Study

OBJECTIVE

To assess the role of shear wave elastography (SWE) in characterizing different endometrial and subendometrial pathologies.

METHODS

Seventy-three women with pathologically proven endometrial and subendometrial pathologies were enrolled in this prospective study and assessed with transvaginal SWE. The elasticity values (in kiloPascals), and the ratio of mean elasticity of the endometrial lesion to myometrial elasticity (E/M ratio) were compared in different pathologies.

RESULTS

There was a statistically significant difference (P <.001) in the mean, minimum, and maximum elasticity of the pathologies as well as the E/M ratio (P <.00001). In the analysis of the subgroups, the mean elasticity of endometrial polyp was statistically significantly lower than other subgroups (P <.01), while submucosal leiomyoma and focal adenomyoma had significantly higher values than other subgroups (P <.01). No statistically significant difference was noted in the mean elasticity of carcinoma and hyperplasia (P-.19).

CONCLUSION

SWE is a potential adjunct to ultrasound that provides an additional paradigm to characterize endometrial and subendometrial masses.

Diagnostic performance of C-TIRADS combined with SWE for the diagnosis of thyroid nodules

OBJECTIVE

To explore the value of the optimal parameters of shear wave elastography (SWE) to enhance the identification of benign and malignant thyroid nodules by C-TIRADS.

METHODS

The two-dimensional ultrasonography images and SWE images of 515 patients with a total of 586 thyroid nodules were retrospectively analyzed. The nodules were divided into the D ≤10 mm and D >10 mm groups according to size and were graded by C-TIRADS. With the pathological results as the gold standard, the receiver operating characteristic (ROC) curves were drawn, and the area under the curve (AUC) was calculated to compare the diagnostic performances of C-TIRADS, SWE, and the combination of the two on the benign and malignant thyroid nodules.

RESULTS

The ROC showed that the AUC of the maximum elastic modulus (0.875) was higher than that of the mean elastic modulus (0.798) and elasticity ratio (0.772), with an optimal cutoff point of 51 kPa, which was the optimal parameter to distinguish the malignant from the benign nodules (P < 0.001). In the D ≤10 mm group, the AUC of TIRADS combined with SWE (0.955) was elevated by 0.172 compared with the application of C-TIRADS alone (0.783), and the difference was statistically significant (P < 0.05). In the D >10 mm group, the AUC of TIRADS combined with SWE (0.904) was elevated by 0.076 compared with the application of C-TIRADS alone (0.828), and the difference was statistically significant (P < 0.05). Among all nodules, the application of C-TIRADS alone had a sensitivity of 88.14%, a specificity of 74.56%, and an accuracy of 85.50% in diagnosing benign and malignant thyroid nodules, while the sensitivity, specificity, and accuracy were 93.22%, 90.35%, and 92.66%, respectively, in combination with SWE.

CONCLUSION

The diagnostic performance of SWE in combination with TIRADS was better than that of SWE or C-TIRADS alone. Here, SWE enhanced the diagnostic performance of C-TIRADS for the benign and malignant thyroid nodules, most significantly for nodules with D ≤10 mm.

Ultrasound elastography

Physicians have used palpation as a diagnostic examination to understand the elastic properties of pathology for a long time since they realized that tissue stiffness is closely related to its biological characteristics. US elastography provided new diagnostic information about elasticity comparing with the morphological feathers of traditional US, and thus expanded the scope of the application in clinic. US elastography is now widely used in the field of diagnosis and differential diagnosis of abnormality, evaluating the degree of fibrosis and assessment of treatment response for a range of diseases. The World Federation of Ultrasound Medicine and Biology divided elastographic techniques into strain elastography (SE), transient elastography and acoustic radiation force impulse (ARFI). The ARFI techniques can be further classified into point shear wave elastography (SWE), 2D SWE, and 3D SWE techniques. The SE measures the strain, while the shear wave-based techniques (including TE and ARFI techniques) measure the speed of shear waves in tissues. In this review, we discuss the various techniques separately based on their basic principles, clinical applications in various organs, and advantages and limitations and which might be most appropriate given that the majority of doctors have access to only one kind of machine.

Predicting malignancy in thyroid nodules with benign cytology results: The role of Conventional Ultrasound, Shear Wave Elastography and BRAF V600E

BACKGROUND: Ultrasound-guided fine-needle aspiration (US-FNA) is the most accurate method for preoperative diagnosis of thyroid nodules, but how to deal with false negative results. OBJECTIVE: This study aimed to find preoperative diagnosis methods including Conventional Ultrasound (CUS), Shear Wave Elastography (SWE) and BRAF V600E testing to differentiate false negative nodules. METHODS: Forty-nine nodules in 49 patients with benign FNA results and pathological diagnoses were included. CUS and SWE features were evaluated. BRAF V600E analysis was performed after FNA. Diagnostic performances of three methods were analyzed in predicting malignancy in benign FNA results. RESULTS: Twenty-seven of 49 nodules were malignant, and 22 nodules were benign. Hypoechogenicity, taller-than-wider, irregular boundary, microcalcification, SWE max, SWE mean and BRAF V600E mutation were risk factors for malignancy. All 7 malignant nodules with BRAF V600E mutations and 18 of 20 malignant nodules without BRAF V600E mutations have two or more suspicious CUS features. Six of 7 malignant nodules with BRAF V600E mutations and 16 of 20 malignant nodules without BRAF V600E mutations had SWE mean value greater than the cut-off value. CONCLUSIONS: CUS, SWE and BRAF V600E were diagnostic tools for malignancy in FNA benign nodules. Further clinical decisions should be considered for nodules with 2 or more suspicious CUS features and SWE parameters greater than cut-off values whether BRAF V600E is mutational or not.

A Computer-Aided Diagnosis System and Thyroid Imaging Reporting and Data System for Dual Validation of Ultrasound-Guided Fine-Needle Aspiration of Indeterminate Thyroid Nodules

Purpose

The fully automatic AI-Sonic computer-aided design (CAD) system was employed for the detection and diagnosis of benign and malignant thyroid nodules. The aim of this study was to investigate the efficiency of the AI-Sonic CAD system with the use of a deep learning algorithm to improve the diagnostic accuracy of ultrasound-guided fine-needle aspiration (FNA).

Methods

A total of 138 thyroid nodules were collected from 124 patients and diagnosed by an expert, a novice, and the Thyroid Imaging Reporting and Data System (TI-RADS). Diagnostic efficiency and feasibility were compared among the expert, novice, and CAD system. The application of the CAD system to enhance the diagnostic efficiency of novices was assessed. Moreover, with the experience of the expert as the gold standard, the values of features detected by the CAD system were also analyzed. The efficiency of FNA was compared among the expert, novice, and CAD system to determine whether the CAD system is helpful for the management of FNA.

Result

In total, 56 malignant and 82 benign thyroid nodules were collected from the 124 patients (mean age, 46.4 ± 12.1 years; range, 12–70 years). The diagnostic area under the curve of the CAD system, expert, and novice were 0.919, 0.891, and 0.877, respectively (p < 0.05). In regard to feature detection, there was no significant differences in the margin and composition between the benign and malignant nodules (p > 0.05), while echogenicity and the existence of echogenic foci were of great significance (p < 0.05). For the recommendation of FNA, the results showed that the CAD system had better performance than the expert and novice (p < 0.05).

Conclusions

Precise diagnosis and recommendation of FNA are continuing hot topics for thyroid nodules. The CAD system based on deep learning had better accuracy and feasibility for the diagnosis of thyroid nodules, and was useful to avoid unnecessary FNA. The CAD system is potentially an effective auxiliary approach for diagnosis and asymptomatic screening, especially in developing areas.

Evaluation of thyroid nodules by shear wave elastography: a review of current knowledge

PURPOSE

Shear wave elastography (SWE), as a tool for diagnosing thyroid malignancy, has gathered considerable attention during the past decade. Diverging results exist regarding the diagnostic performance of thyroid SWE.

METHODS

A comprehensive literature review of thyroid SWE was conducted using the terms "Thyroid" and "shear wave elastography" in PubMed.

RESULTS

The majority of studies found SWE promising for differentiating malignant and benign thyroid nodules on a group level, whereas results are less convincing on the individual level due to huge overlap in elasticity indices. Further, there is lack of consensus on the optimum outcome reflecting nodule elasticity and the cut-off point predicting thyroid malignancy. While heterogeneity between studies hinders a clinically meaningful meta-analysis, the results are discussed in a clinical perspective with regard to applicability in clinical practice as well as methodological advantages and pitfalls of this technology.

CONCLUSION

Technological as well as biological hindrances seem to exist for SWE to be clinically reliable in assessing benign and malignant thyroid nodules. Structural heterogeneity of thyroid nodules in combination with operator-dependent factors such as pre-compression and selection of scanning plane are likely explanations for these findings. Standardization and consensus on the SWE acquisition process applied in future studies are needed for SWE to be considered a clinically reliable diagnostic tool for detection of thyroid cancer.

Comparison of ACR TI-RADS, Kwak TI-RADS, ATA guidelines and KTA/KSThR guidelines in combination with SWE in the diagnosis of thyroid nodules

OBJECTIVE

To compare the diagnostic efficacy of ACR TI-RADS, Kwak TI-RADS, ATA guidelines and KTA/KSThR guidelines in combination with shear wave elastography (SWE) for thyroid nodules.

METHODS

The retrospective study included 566 thyroid nodules with maximum diameter≥5 mm which confirmed by FNA cytology or/and surgical pathology. The sensitivity, specificity, accuracy, Youden index of diagnosis of thyroid nodules by ACR TI-RADS, Kwak TI-RADS, ATA guidelines, KTA/KSThR guidelines and SWE were calculated. The ROC curve was drawn to determine the cut-off values of the four ultrasound classification systems and SWE Emax. The diagnostic efficacy of the four ultrasound classification systems in combination with SWE were calculated and compared with those of pre-combination.

RESULTS

The ROC curves indicated that the cut-off value of ACR TI-RADS, Kwak TI-RADS, ATA guidelines, KTA/KSThR guidelines and Emax of SWE was TR5, 4c, high-suspicion, high-suspicion, and 41.7 kPa, respectively, and the area under the ROC curve (AUC) was 0.907(0.879-0.934), 0904(0.876-0.932), 0.894(0.863-0.924), 0.888(0.856-0.919), 0.886(0.859-0.913), respectively. After combination with SWE, the the sensitivities of the four ultrasound classification systems for the diagnosis of nodules were improved, and the differences were statistically significant (all P≤0.001); the specificities were decreased, but the differences were not statistically significant (all P > 0.05); the accuracies were improved, but only the difference of ACR TI-RADS was statistically significant (x2 = 4.45, P = 0.035); the differences in the AUCs were not significant (all P > 0.05).

CONCLUSIONS

The four ultrasound classification systems and SWE all had high performance in the diagnosis of thyroid nodules. The four classification systems in combination with SWE were all beneficial to the differential diagnosis of nodules, and ACR TI-RADS in combination with SWE was more effective, especially for TR3 and TR4 nodules.

Assessment of perinodular stiffness in differentiating malignant from benign thyroid nodules

OBJECTIVE

We evaluated the diagnostic accuracy of perinodular stiffness, four risk stratification systems (RSSs) (KWAK-TIRADS, ACR-TIRADS, EU-TIRADS, and C-TIRADS), and the combination of perinodular stiffness and the four RSSs in differentiating malignant from benign thyroid nodules (TNs).

METHODS

A total of 788 TNs in 726 patients were examined with conventional ultrasound (US) examination and sound touch elastography (STE). All TNs were classified by each of the four RSSs. The stiffness inside (E) the TNs was measured by STE. The stiffness of the 2.0-mm perinodular region (Eshell) was measured with the Shell measurement function of STE. The diagnostic performances of four RSSs, the E values, and the Eshell values were evaluated. All TNs were further divided into subgroups based on size (≤ 10 mm group and > 10 mm group).

RESULTS

Ninety-six TNs were classified as benign and 692 as malignant. Among the single-method approaches, ACR-TIRADS showed the highest AUC (0.77) for differentiating malignant from benign TNs for all TNs included. Eshell showed the highest AUC (0.75) in differentiating malignant from benign TNs for TNs with sizes ≤ 10 mm, and there were no significant differences in AUC among all single methods for diagnosis of TNs with sizes > 10 mm (P > 0.05). The combination of C-TIRADS and Eshell/E yielded the highest AUC for all TNs (0.83) and for TNs with size ≤ 10 mm (0.85) compared with other combinations.

CONCLUSIONS

Eshell/E combined with conventional US improves the diagnostic accuracy in TNs and may reduce unnecessary fine-needle aspiration.

Three-Dimensional Multi-Frequency Shear Wave Absolute Vibro-Elastography (3D S-WAVE) With a Matrix Array Transducer: Implementation and Preliminary In Vivo Study of the Liver

Magnetic resonance elastography (MRE) is commonly regarded as the imaging-based gold-standard for liver fibrosis staging, comparable to biopsy. While ultrasound-based elastography methods for liver fibrosis staging have been developed, they are confined to a 1D or a 2D region of interest and to a limited depth. 3D Shear Wave Absolute Vibro-Elastography (S-WAVE) is a steady-state, external excitation, volumetric elastography technique that is similar to MRE, but has the additional advantage of multi-frequency excitation. We present a novel ultrasound matrix array implementation of S-WAVE that takes advantage of 3D imaging. We use a matrix array transducer to sample axial multi-frequency steady-state tissue motion over a volume, using a Color Power Angiography sequence. Tissue motion with the frequency components {40,50,60} and {45,55,65} Hz are acquired over a (90° lateral) × (40° elevational) × (16 cm depth) sector with an acquisition time of 12 seconds. We compute the elasticity map in 3D using local spatial frequency estimation. We characterize this new approach in tissue phantoms against measurements obtained with transient elastography and MRE. Six healthy volunteers and eight patients with chronic liver disease were imaged. Their MRE and S-WAVE volumes were aligned using T1 to B-mode registration for direct comparison in common regions of interest. S-WAVE and MRE results are correlated with R² = 0.92, while MRE and TE results are correlated with R² = 0.71. Our findings show that S-WAVE with matrix array has the potential to deliver a similar assessment of liver fibrosis as MRE in a more accessible, inexpensive way, to a broader set of patients.

British Thyroid Association 2014 classification ultrasound scoring of thyroid nodules in predicting malignancy: Diagnostic performance and inter-observer agreement

Objectives

To assess the inter-observer agreement amongst five observers of differing levels of expertise in applying the British Thyroid Association (2014) guidelines for ultrasound scoring of thyroid nodules (BTA-U score) in the management of thyroid cancer, and to assess the U-score diagnostic performance in predicting malignancy.

Method

A total of 73 consecutive patients were included over a two-year period (July 2012 to July 2014), after referral to a tertiary head and neck oncology centre for ultrasound plus fine needle aspiration and cytology. Our five observers retrospectively and independently reviewed static ultrasound images on PACS and scored the thyroid nodules according to BTA-U classification. The observers were blinded to each other's scoring, cytology and histology results. Either the Kappa-statistic or intra-class correlation was used to assess the level of inter-observer agreement, plus agreement between the radiological and cytological diagnoses. The diagnostic performance of U-scoring for predicting final histological diagnosis was assessed with sensitivity, specificity, positive and negative predictive values.

Results

A Kappa-value of 0.73 (95% CI: 0.68-0.77) confirmed substantial inter-observer agreement amongst the five observers. All 17 histology confirmed malignant nodules were correctly classified as potentially malignant by all observers. The sensitivity and negative predictive value of BTA-U score in detecting and predicting malignancy were 100%, whereas the specificity and positive predictive values were 34% and 32%, respectively.

Conclusions

There is good inter-observer agreement in using the BTA-U score amongst different observers at differing levels of expertise. Adhering to BTA-U scoring can potentially achieve 100% sensitivity in selecting malignant nodules for sampling.

Comparisons and Combined Application of Two-Dimensional and Three-Dimensional Real-time Shear Wave Elastography in Diagnosis of Thyroid Nodules

Purpose Two-dimensional and three-dimensional real-time shear wave elastography (2D+3D SWE) represents a new technology for the quantification of tissue elasticity. This study investigated whether they could be performed to differentiate between benign and malignant thyroid nodules.

Methods Conventional B-mode ultrasound, 2D and 3D SWE were performed in 96 patients with 97 thyroid nodules with pathology results.

Results All the elastography values of 2D&3D SWE in malignant thyroid nodules were higher than those in benign nodules. These two elastography methods alone could not improve diagnostic value comparing to B-mode ultrasound significantly. However, B-mode US + 2D SWE (TI-RADS ≥ 4c or S-Emean ≥ 23.75 kPa, suspicious), B-mode US + 3D SWE (TI-RADS ≥ 4c or 3D-T-Emean ≥ 20.75 kPa, suspicious), B-mode US + 2D + 3D SWE (TI-RADS ≥ 4c or S-Emean ≥ 23.75 kPa or 3D-T-Emean ≥ 20.75 kPa, suspicious) had higher sensitivity and accuracy values than those of 3 methods alone but lower specificity values. Among them, B-mode ultrasound + 2D SWE had the highest sensitivity, NPV, accuracy and Youden's index (0.881, 0.788, 0.804 and 0.57).

Conclusions 2D SWE or 3D SWE alone could not improve the diagnostic value of differentiating malignant from benign thyroid nodules comparing to conventional B-mode ultrasound. But combination methods could improve the diagnostic value, especially B-mode US + 2D SWE.

Accuracy of the European Thyroid Imaging Reporting and Data System (EU-TIRADS) in the valuation of thyroid nodule malignancy in reference to the post-surgery histological results

Purpose

To assess the clinical usefulness of the European Thyroid Imaging and Reporting Data System (EU-TIRADS) in the valuation of thyroid nodules malignancy in reference to post-surgery histological results.

Material and methods

Pre-operative ultrasound was performed in consecutive patients admitted for thyroid surgery between June 2017 and January 2018. Thyroid nodules were classified according to EU-TIRADS to five groups: 1-5. At least one fine-needle aspiration biopsy (FNAB)/patient (dominant or suspected nodule) was performed in an outpatient clinic. The final diagnosis was based on the histological result. The percentage of cancers in each EU-TIRADS group was evaluated. Finally, sensitivity, specificity, accuracy, as well as positive and negative predictive values for malignancy were assessed.

Results

Fifty-two patients with a total of 140 thyroid nodules (median: 3 nodules/thyroid [minimum-maximum: 1-6]) were enrolled in the study. Thyroid cancer was diagnosed in 0% (0/6) in EU-TIRADS 2; 0% (0/92) in EU-TIRADS 3; 5.9% (2/34) in EU-TIRADS 4, and 75% (6/8) in EU-TIRADS 5. In nodules assessed as EU-TIRADS ≥ 4 sensitivity, specificity, positive and negative predictive values for malignancy were, respectively: 75% (CI 95%: 40.7-93.5), 94.1% (CI 95%: 86.0-98.5), 75% (CI 95%: 40.7-93.5), and 94.1% (CI 95%: 86.0-98.5).

Conclusions

EU-TIRADS is a valuable and simple tool for assessment of the risk of malignancy of thyroid nodules and demonstrates a high ultrasound correlation with histological post-surgery results. FNAB should be performed in all nodules assessed as EU-TIRADS ≥ 4, due to higher risk of malignancy.

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.