Use of color Doppler ultrasonography for the prediction of malignancy in follicular thyroid neoplasms: systematic review and meta-analysis

An attempt to reduce unnecessary surgical procedures... Can ultrasound characteristics help in differentiating adenoma vs carcinoma in follicular thyroid neoplasms?

INTRODUCTION AND OBJECTIVES

Thyroid nodules frequently require ultrasound and Fine Needle Aspiration Cytology (FNAC) evaluation. However, FNA cytology does not allow differentiation between follicular adenoma and carcinoma on Bethesda type IV lesions. This situation leads to many unnecessary surgical procedures because it is not possible to assure the benignity of the lesions, even when most of the specimens correspond to adenomas or even other benign lesions. The objective is this study is to establish if there are any US characteristics that would help us to predict the risk of malignancy of nodules with a pathological diagnosis of follicular neoplasm in order to achieve a more conservative management for non-suspicious nodules.

MATERIAL AND METHODS

We studied 61 nodules in 61 patients (51 women and 10 men) that underwent thyroid surgery and had histopathological results of either follicular adenoma or carcinoma. Different US characteristics of the nodules were analysed (composition, echogenicity, margin, calcification status, the presence of halo and overall observer suspicion of malignancy) and were correlated with the histopathological analysis.

RESULTS

We have found a statistically significant association between the presence of calcifications, ill-defined borders and overall observer suspicion or impression (defined by well-known suspicious for malignancy ultrasonographic features, such as calcification, poorly defined margin, and a markedly hypoechoic solid nodule; and benign ultrasonographic features, such as predominantly cystic echogenic composition and the presence of a perinodular hypoechogenic halo) with follicular carcinoma. However all those features have shown low sensitivities in the present study (30%, 30% and 50%, respectively). On the other hand, the absence of halo sign has shown a sensitivity of 100% and a negative predictive value (NPV) of 100% in our study.

CONCLUSIONS

The presence of calcifications, ill-defined borders and the overall impression or suspicion of malignancy associate with a higher risk for follicular carcinoma in Bethesda type IV thyroid nodules but their absence do not allow to predict benignity in these nodules. Inversely, when a halo sign lesion is observed, benign follicular neoplasm should be considered.

Performance of Contrast-Enhanced Ultrasound in Thyroid Nodules: Review of Current State and Future Perspectives

Ultrasound has been established as a baseline imaging technique for thyroid nodules. The main advantage of adding CEUS is the ability to assess the sequence and intensity of vascular perfusion and hemodynamics in the thyroid nodule, thus providing real-time characterization of nodule features, considered a valuable new approach in the determination of benign vs. malignant nodules. Original studies, reviews and six meta-analyses were included in this article. A total of 624 studies were retrieved, and 107 were included in the study. As recognized for thyroid nodule malignancy risk stratification by US, for acceptable accuracy in malignancy a combination of several CEUS parameters should be applied: hypo-enhancement, heterogeneous, peripheral irregular enhancement in combination with internal enhancement patterns, and slow wash-in and wash-out curve lower than in normal thyroid tissue. In contrast, homogeneous, intense enhancement with smooth rim enhancement and "fast-in and slow-out" are indicative of the benignity of the thyroid nodule. Even though overlapping features require standardization, with further research, CEUS may achieve reliable performance in detecting or excluding thyroid cancer. It can also play an operative role in guiding ablation procedures of benign and malignant thyroid nodules and metastatic lymph nodes, and providing accurate follow-up imaging to assess treatment efficacy.

Usefulness of Color Doppler Ultrasonography in the Risk Stratification of Thyroid Nodules

INTRODUCTION

Thyroid ultrasound (US) is crucial for clinical decision in the management of thyroid nodules. In this cross-sectional study, we aimed to test if the evaluation of thyroid nodules' vascularization could improve the risk stratification ability of the American College of Radiology (ACR) TI-RADS classification system.

METHODS

A total of 873 thyroid nodules undergoing fine-needle aspiration were classified according to ACR TI-RADS US classification. Three types of vascularization were identified: type 0, no vascular signals; type 1, peripheral vascular signals; type 2, peripheral and intralesional vascular signals. Cytology specimens were evaluated conforming to the Italian Reporting System for Thyroid Cytology, and TIR3b, TIR4, and TIR5 were defined as high risk for malignancy. Odds ratios (ORs) with 95% confidence intervals (CI) and the areas under the receiver operating characteristic curves (ROC-AUC) for high-risk cytology categories were calculated.

RESULTS

The 3 vascular patterns were differently distributed within the cytology categories: 52.4% of TIR1c, 15.9% of TIR2, 5.9% of TIR3a, 6.7% of TIR3b, 12.5% of TIR4, and 28.9% of TIR5 nodules had no vascular signals (p < 0.001). Nodule vascularity alone was not associated with a higher risk of malignant cytology (OR [95% CI] 0.75 [0.43-1.32], p = 0.32), without differences between peripheral (OR [95% CI] 0.65 [0.35-1.20]) and intranodular (OR [95% CI] 0.88 [0.48-1.62]) vascularization (p = 0.22). The ROC-AUC (95% CI) for the diagnosis of malignant cytology was similar when considering TI-RADS classification alone (0.736 [0.684-0.786]) and when considering TI-RADS classification plus the presence/absence of vascular signals (0.736 [0.683-0.789], p value for differences between the ROC-AUCs: 0.91). Among TR1, TR2, and TR3 TI-RADS classes, no nodules without vascular signals showed a malignant cytology, allowing the identification of nodules with benign cytology with 100% specificity within these US classes.

CONCLUSIONS

Color Doppler study of thyroid nodules does not improve the risk stratification ability of the ACR TI-RADS US classification system.

Multiparametric Ultrasound Evaluation of the Thyroid: Elastography as a Key Tool in the Risk Prediction of Undetermined Nodules (Bethesda III and IV)-Histopathological Correlation

The purpose of this study was to select thyroid nodules most at risk for malignancy among those cytologically undetermined by fine-needle aspiration biopsy (FNAB), using B-mode, color duplex Doppler and 2-D shear wave shear wave elastography (2-D-SWE). This was a prospective diagnostic accuracy study with 62 Bethesda III/IV nodules according to FNAB (atypia/follicular lesion of undetermined significance or follicular neoplasia/Hürthle cell neoplasm). Ultrasonography (US) data were compared with resection histologic results, revealing 35 of 62 benign nodules (56.4%) and 27 of 62 carcinomas (43.6%). Conventional US was uses to evaluate nodule echogenicity, dimensions, contours, presence of halo and microcalcifications. Doppler US was used to assess the vascularization (exclusively or predominantly peripheral or central) and mean resistance index of three nodule arteries. Elastography was used to evaluate the nodule elastographic pattern; mean nodule deformation index; deformation ratio between nodule and adjacent thyroid parenchyma; and mean deformation ratio between nodule and pre-thyroid musculature (MDR). Statistical analysis included χ², Fisher's exact, Student's t, Mann-Whitney tests and multivariable analysis by multiple logistic regression. Areas under the receiver operating characteristic curves (AUC-ROCs) were used for accuracy analysis. Fifty-eight participants (54.7 ± 14.0 y, 51 women) were studied. The parameters that were statistically significant to the univariate analysis were hypo-echogenicity, nodule diameter greater than width and all parameters analyzed from Doppler and elastography. Multivariate analysis revealed that the MDR (in kPa) was the best parameter for risk analysis of indeterminate nodules. Nodules with MDRs >1.53 exhibited a greater chance of malignancy (AUC-ROC = 0.98). We conclude that 2-D-SWE is able to select malignant nodules among those cytologically indeterminate, thus avoiding unnecessary surgery in these cytologic groups.

An attempt to reduce unnecessary surgical procedures... Can ultrasound characteristics help in differentiating adenoma vs carcinoma in follicular thyroid neoplasms?

INTRODUCTION AND OBJECTIVES

Thyroid nodules frequently require ultrasound and Fine Needle Aspiration Cytology (FNAC) evaluation. However, FNA cytology does not allow differentiation between follicular adenoma and carcinoma on Bethesda type IV lesions. This situation leads to many unnecessary surgical procedures because it is not possible to assure the benignity of the lesions, even when most of the specimens correspond to adenomas or even other benign lesions. The objective in this study is to establish if there are any US characteristics that would help us to predict the risk of malignancy of nodules with a pathological diagnosis of follicular neoplasm in order to achieve a more conservative management for non-suspicious nodules.

MATERIAL AND METHODS

We studied 61 nodules in 61 patients (51 women and 10 men) that underwent thyroid surgery and had histopathological results of either follicular adenoma or carcinoma. Different US characteristics of the nodules were analysed (composition, echogenicity, margin, calcification status, the presence of halo and overall observer suspicion of malignancy) and were correlated with the histopathological analysis.

RESULTS

We have found a statistically significant association between the presence of calcifications, ill-defined borders and overall observer suspicion or impression (defined by well-known suspicious for malignancy ultrasonographic features, such as calcification, poorly defined margin, and a markedly hypoechoic solid nodule; and benign ultrasonographic features, such as predominantly cystic echogenic composition and the presence of a perinodular hypoechogenic halo) with follicular carcinoma. However all those features have shown low sensitivities in the present study (30%, 30% and 50%, respectively). On the other hand, the absence of halo sign has shown a sensitivity of 100% and a negative predictive value (NPV) of 100% in our study.

CONCLUSIONS

The presence of calcifications, ill-defined borders and the overall impression or suspicion of malignancy are associated with a higher risk for follicular carcinoma in Bethesda type IV thyroid nodules but their absence does not allow to predict benignity in these nodules. Inversely, when a halo sign lesion is observed, benign follicular neoplasm should be considered.

Clinical applications of Doppler ultrasonography for thyroid disease: consensus statement by the Korean Society of Thyroid Radiology

Doppler ultrasonography (US) is widely used for the differential diagnosis of thyroid nodules, metastatic cervical lymph nodes in patients with thyroid cancer, and diffuse parenchymal disease, as well as for guidance in various US-guided procedures, including biopsy and ablation. However, controversies remain regarding the appropriate use and interpretation of Doppler US. Therefore, the Korean Society of Thyroid Radiology organized a taskforce to develop a consensus statement on the clinical use of Doppler US for thyroid disease. The review and recommendations in this article are based on a comprehensive analysis of the current literature and the consensus of experts.

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

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Combined use of sonographic and elastosonographic parameters can improve the diagnostic accuracy in thyroid nodules at risk of malignancy at cytological examination

BACKGROUND

Thyroid nodules diagnosed as Thy3B at fine-needle aspiration biopsy have a relevant risk of malignancy (15-30%) and are usually addressed to surgery. However surgery will result unnecessary in most cases. The present study aims at evaluating the possible increase of diagnostic accuracy for predicting malignancy using novel sonographic and elastographic parameters.

METHODS

In fifty patients undergoing thyroidectomy because of a Thy3B thyroid nodule, sonographic and elastosonographic evaluation was carried out by single operator before surgery. Five sonographic parameters (echogenicity, irregular margins, microcalcifications, intra-nodule blood flow and its irregularity) and two elastosonographic parameters (intra-nodule stiffness and its extension to adjacent tissue) were considered. After obtaining histological diagnosis, diagnostic accuracy was calculated.

RESULTS

When the two procedures were analyzed separately, sensitivity, specificity, positive (PPV) and negative (NPV) predictive values were 100%, 85%, 63% and 100% for ultrasonography and 60%, 92.5%, 67%, 90% for elastrosonography, respectively. The newly introduced evaluation procedures increased sensitivity. When a combined sonographic and elastosonographic evaluation was introduced, diagnostic accuracy was significantly improved: when ≥4 out of the seven parameters indicated were present, the risk of malignancy was very high (sensitivity 100%, specificity 92.55%, PPV 77%, NPV 100%).

CONCLUSIONS

A novel combined sonographic and elastosonographic parameter evaluation improved diagnostic accuracy for identifying thyroid nodules suspicious of malignancy.

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.

Color Doppler ultrasonography diagnostic value in detection of malignant nodules in cysts with pathologically proven thyroid malignancy: a systematic review and meta-analysis

AIMS

Today, the color Doppler ultrasonography is used to further evaluate suspected malignant tumors. This study investigates the malignant thyroid nodules using color Doppler.

METHODS

After extracting true positive, false positive, false negative, and true negative among included studies, a quality was evaluated by the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio (with 95% confidence interval) were found using a random effect model. Summary receiver operating characteristic curves (SROC) were used to assess relationship between sensitivity and specificity. The area under the curve of the SROC was calculated to estimate the performance of color Doppler ultrasound to distinguish malignant thyroid nodules. Our registration code in PROSPERO is CRD42018111198.

RESULTS

Of 1125 articles, 288 articles were selected for the further investigation. After excluding irrelevant and poor articles, 20 studies were included for the meta-analysis. According to a random effect model, the pooled sensitivity and specificity of color Doppler ultrasound to distinguish malignant thyroid nodules were estimated as 0.74 (95% CI 0.62-0.83; [Formula: see text]) and 0.70 (95% CI 0.56-0.81; [Formula: see text]), respectively. The SROC curve consists of representing the paired results for sensitivity and specificity. According to SROC, AUC = 0.78 (95% CI 0.74-0.81) is between 0.75 and 0.92, so that color Doppler ultrasound has a good accuracy.

CONCLUSION

Color Doppler is a valuable non-invasive method for evaluating thyroid nodules, and it is a high-sensitivity diagnostic tool for assessing thyroid nodules. Resistive index > 0.75 and a pattern III or more in color Doppler predicts malignant with the confidence. Due to its precision, cost-efficiency, easy access, and non-invasive nature, color Doppler should be included in the standard clinical protocol for the decision-making period and the treatment evaluation.

Diagnostic accuracy of ultrasound characteristics in the identification of malignant thyroid nodules

Objective

This study was aimed at determining the diagnostic accuracy of the ultrasound characteristics in the identification of malignant thyroid nodules in patients attending the surgical clinic at a tertiary care hospital in Sri Lanka.

Results

This prospective validation study was conducted among 263 patients attending the surgical clinic at a tertiary care hospital, Sri Lanka. The ultrasound characteristics having statistically significant associations with thyroid malignancies were identified by employing a multivariable analysis. These ultrasound characteristics were compared with Fine Needle Aspiration Cytology results and indicators of diagnostic accuracy were computed. The study sample consisted of 33 malignant and 230 benign nodules. Internal vascularity, hypoechogenicity and microcalcification showed statistically significant positive associations with thyroid malignancy (p < 0.05). The highest positive likelihood ratio was observed for the presence of microcalcifications (10.4, 95% CI 4.6–23.7) with a specificity of 96.5% (95% CI 93.3–98.5%). Hypoechogenicity had a sensitivity of 66.7% (95% CI 48.2–82.0%) and a specificity of 74.8% (95% CI 68.6–80.3%). The presence of at least one positive ultrasound characteristic yielded the highest sensitivity (87.9%, 95% CI 71.8–96.6%), whereas, the presence of all three characteristics yielded a near perfect specificity (99.6%, 95% CI 97.6–99.9%). Hence, the presence of microcalcifications was found to be the single most useful criterion in predicting thyroid malignancy.

Complementary Role of Elastography Using Carotid Artery Pulsation in the Ultrasonographic Assessment of Thyroid Nodules: A Prospective Study

Objective

The aim of this study was to evaluate the diagnostic performance of gray-scale ultrasonography (US), Doppler scan, and elastography using carotid artery pulsation in the diagnosis of thyroid nodules and to find a complementary role of elastography.

Materials and Methods

A total 197 thyroid nodules with 91 malignant and 106 benign pathologic results from 187 patients (41 males and 146 females; age range, 20-83 years; mean age, 49.4 years) were included in this prospective study. The gray-scale, Doppler US images, elastography with elasticity contrast index (ECI), and stiffness color were assessed. The diagnostic performances of each dataset were assessed in order to differentiate benign from malignant thyroid nodules.

Results

The optimal cut-off value of the ECI was 1.71. The area under receiver operating characteristic curve (Az value) was 0.821 for gray-scale US, 0.661 for the ECI, 0.592 for stiffness color, and 0.539 for Doppler US. The Az value for a combined assessment of gray-scale US and the ECI was higher than that for the gray-scale US alone; however, there was no statistical difference between the two (p = 0.219). The median ECI values of follicular thyroid carcinoma (FTC) and follicular variant of papillary thyroid carcinoma (FVPTC) were significantly lower than those of the other malignant lesions (p = 0.005). Meanwhile, the diffuse sclerosing variant of PTC and a metastatic nodule showed the two highest median values of the ECI.

Conclusion

For differentiating thyroid nodules, the diagnostic performances of the combination of gray-scale US and elastography with the ECI were similar to, but not superior, to those of gray-scale US alone. FVPTC and FTC have a significantly lower ECI value than those of the other malignant lesions.

Role of Superb Micro-Vascular Imaging in the Preoperative Evaluation of Thyroid Nodules: Comparison With Power Doppler Flow Imaging

OBJECTIVES

To evaluate whether Superb Micro-Vascular Imaging (SMI; Toshiba Medical Systems Corporation, Tochigi, Japan) is superior to power Doppler flow imaging (PDFI) in depicting thyroid nodular vascularity and to primarily explore the diagnostic performance of vascularity on SMI integrated with grayscale sonographic features for diagnosis of malignant thyroid nodules.

METHODS

Ninety-two resident patients with 113 nodules for surgery were included in the study. Thirty-four nodules were benign, and 79 nodules were malignant. Vascularity was classified as none, peripheral, mixed, and intranodular. Grayscale features, including calcifications, echogenicity, margins, shape, and internal components, were evaluated. The distribution of vascular patterns was compared between PDFI and SMI to determine the superior technique for diagnosing malignancy. A multivariate logistic regression analysis was used to evaluate the accuracy of SMI combined with grayscale sonography for thyroid malignancy.

RESULTS

The 92 patients had a male-to-female ratio of 12:11 and a median age of 42 years (range, 20-75 years). Intranodular vascularity on SMI had 91.2% specificity and 75.9% sensitivity, which were superior to PDFI, at 82.3% and 41.8%, respectively (P < .01). We attribute this finding to the fact that peripheral vessels of many nodules on PDFI were actually intense small penetrating vessels around the lesion on SMI. A taller-than-wide shape, microcalcifications, and SMI intranodular vascularity were independent risk factors for thyroid malignancy. The area under the receiver operating characteristic curve for the logistic regression model was 0.92, which was higher than that for a single suspicious sonographic feature (P < .05).

CONCLUSIONS

Intranodular vascularity on SMI is useful for determining thyroid carcinoma. Furthermore, a combination of SMI and grayscale features performs better than any single sonographic feature alone.

Systematic reviews of diagnostic tests in endocrinology: an audit of methods, reporting, and performance

BACKGROUND

Systematic reviews provide clinicians and policymakers estimates of diagnostic test accuracy and their usefulness in clinical practice. We identified all available systematic reviews of diagnosis in endocrinology, summarized the diagnostic accuracy of the tests included, and assessed the credibility and clinical usefulness of the methods and reporting.

METHODS

We searched Ovid MEDLINE, EMBASE, and Cochrane CENTRAL from inception to December 2015 for systematic reviews and meta-analyses reporting accuracy measures of diagnostic tests in endocrinology. Experienced reviewers independently screened for eligible studies and collected data. We summarized the results, methods, and reporting of the reviews. We performed subgroup analyses to categorize diagnostic tests as most useful based on their accuracy.

RESULTS

We identified 84 systematic reviews; half of the tests included were classified as helpful when positive, one-fourth as helpful when negative. Most authors adequately reported how studies were identified and selected and how their trustworthiness (risk of bias) was judged. Only one in three reviews, however, reported an overall judgment about trustworthiness and one in five reported using adequate meta-analytic methods. One in four reported contacting authors for further information and about half included only patients with diagnostic uncertainty.

CONCLUSION

Up to half of the diagnostic endocrine tests in which the likelihood ratio was calculated or provided are likely to be helpful in practice when positive as are one-quarter when negative. Most diagnostic systematic reviews in endocrine lack methodological rigor, protection against bias, and offer limited credibility. Substantial efforts, therefore, seem necessary to improve the quality of diagnostic systematic reviews in endocrinology.

Korean Thyroid Imaging Reporting and Data System features of follicular thyroid adenoma and carcinoma: a single-center study

PURPOSE

This study aimed to assess the diagnostic efficacy of Korean Thyroid Imaging Reporting and Data System (K-TIRADS) features for distinguishing follicular thyroid adenoma (FTA) from follicular thyroid carcinoma (FTC).

METHODS

From January 2013 to July 2016, 46 follicular neoplasms in 45 patients who underwent preoperative thyroid ultrasonography (US) and thyroid surgery were included. The US features of each thyroid nodule were retrospectively evaluated by a single radiologist using a picture archiving and communication system. The diagnostic indices of K-TIRADS for follicular neoplasms were calculated according to whether K-TIRADS category 4 lesions were excluded or classified as benign or malignant.

RESULTS

Of the 46 follicular neoplasms (mean size, 3.1±1.6 cm), 37 were FTAs (mean size, 3.1±1.7 cm) and nine were FTCs (mean size, 3.0±1.5 cm). A statistically significant difference was found between FTAs and FTCs regarding the margin (P=0.035), while no significant differences were observed in the composition, echogenicity, shape, orientation, calcification, or vascularity of the lesions (P<0.05). The FTAs belonged to K-TIRADS categories 3 (n=22) and 4 (n=15), while the FTCs belonged to K-TIRADS categories 3 (n=4), 4 (n=4), and 5 (n=1). However, there was no statistically significant difference in the distribution of K-TIRADS categories between FTAs and FTCs (P=0.184).

CONCLUSION

K-TIRADS features were not helpful for distinguishing FTA from FTC, although follicular neoplasms showed a high prevalence of K-TIRADS categories 3 and 4.

Likelihood of malignancy in thyroid nodules according to a proposed Thyroid Imaging Reporting and Data System (TI-RADS) classification merging suspicious and benign ultrasound features

Objective

The aim of this study was to describe the ultrasound features of benign and malignant thyroid nodules and evaluate the likelihood of malignancy associated with each feature according to the Bethesda System for Reporting Thyroid Cytopathology and histopathology. With this analysis, we propose a new TI-RADS classification system.

Materials and methods

The likelihood of malignancy from ultrasound features were assessed in 1413 thyroid nodules according to the Bethesda System for Reporting Thyroid Cytopathology and histopathological findings. A score was established by attributing different weights to each ultrasound feature evaluated.

Results

Features positively associated with malignancy in bivariate analysis received a score weight of +1. We attributed a weight of +2 to features which were independently associated with malignancy in a multivariate analysis and +3 for those associated with the highest odds ratio for malignancy (> 10.0). Hence, hypoechogenicity (graded as mild, moderate or marked, according to a comparison with the overlying strap muscle), microcalcification and irregular/microlobulated margin received the highest weights in our scoring system. Features that were negatively associated with malignancy received weights of -2 or -1. In the proposed system a cutoff score of 2 (sensitivity 97.4% and specificity 51.6%) was adopted as a transition between probably benign (TI-RADS 3) and TI-RADS 4a nodules. Overall, the frequency of malignancy in thyroid nodules according to the categories was 1.0% for TI-RADS 3, 7.8% for TI-RADS 4a, 35.3% for TI-RADS 4b, and 84.7% for TI-RADS 5.

Conclusion

A newly proposed TI-RADS classification adequately assessed the likelihood of malignancy in thyroid nodules.

Most Thyroid Cancers Detected by Sonography Lack Intranodular Vascularity on Color Doppler Imaging: Review of the Literature and Sonographic-Pathologic Correlations for 698 Thyroid Neoplasms

OBJECTIVES

This study investigated the controversy of whether hypervascularity on color Doppler sonography correlates with thyroid malignancy by reviewing the literature and sonographic-pathologic correlation.

METHODS

Over a 20-year period, 698 thyroid nodules had color Doppler and histopathologic data. Intranodular vascularity was graded 0 to 3+, and histopathologic findings were recorded.

RESULTS

The data were collected from 698 patients (557 women and 141 men) with a mean age of 48 years (range, 16-87 years). Of the 698 neoplasms, 425 were malignant (mean size, 1.7 cm; range, 0.4-9 cm; 150 ≤1 cm), and 273 were benign. The carcinomas included 391 papillary, 12 Hürthle cell, 9 medullary, 6 follicular, 5 poorly differentiated, and 2 anaplastic. The grading of intranodular vascularity was 0 in 63.3%, 1+ in 12.9%, 2+ in 6.6%, and 3+ in 17.4%. Among thyroid carcinomas, follicular carcinoma and the encapsulated subtype of the follicular variant of papillary carcinoma had significantly higher intranodular vascularity than the rest (P < .0001). Benign neoplasms included 226 follicular adenoma/adenomatoid nodules (mean size, 3.2 cm; range, 1.2-8.0 cm), 42 Hürthle cell adenoma/adenomatoid nodules (mean size, 2.6 cm; range, 0.8-5.5 cm), and 5 hyalinizing trabecular adenomas (mean size, 2.4 cm; range, 0.6-6.0 cm; 4 ≤1 cm). The grading of intranodular vascularity was 0 in 6.9%, 1+ in 12.1%, 2+ in 2.6%, and 3+ in 78.4%. Intranodular hypervascularity was associated with adenoma/adenomatoid thyroid nodules, whereas a lack of vascularity was related to thyroid carcinomas (P < .0001).

CONCLUSIONS

Most sonographically detected thyroid cancers lack intranodular vascularity, and most hypervascular thyroid nodules are adenoma/adenomatoid nodules, the encapsulated subtype of the follicular variant of papillary carcinoma, or follicular carcinomas.

A Novel Microvascular Flow Technique: Initial Results in Thyroids

To evaluate the flow imaging capabilities of a new prototype ultrasound (US) image processing technique (superb micro-vascular imaging [SMI]; Toshiba Medical Systems, Tokyo, Japan) for depiction of microvascular flow in normal thyroid tissue and thyroid nodules compared with standard color and power Doppler US imaging.Ten healthy volunteers and 22 patients, with a total of 25 thyroid nodules, scheduled for US-guided fine needle aspiration were enrolled in this prospective study. Subjects underwent US examination consisting of grayscale, color and power Doppler imaging (CDI and PDI) followed by color and monochrome SMI and pulsed Doppler. SMI is a novel, microvascular flow imaging mode implemented on the Aplio 500 US system (Toshiba). SMI uses advanced clutter suppression to extract flow signals from large to small vessels and depicts this information at high frame rates as a color overlay image or as a monochrome map of flow. Two radiologists independently scored still images and digital clips for overall flow detection, vessel branching details and noise on a visual-analog scale of 1 (worst) to 10 (best).For the volunteers SMI visualized microvasculature with significantly lower velocity than CDI and PDI (P < 0.012). In all thyroid nodules, SMI demonstrated microvascular flow with significantly higher image scores and provided better depiction of the vessel branching details compared with CDI and PDI (P < 0.0001). Clutter noise was significantly higher in monochrome SMI mode than in the other modes, including color SMI (P < 0.001).The novel SMI mode consistently improved the depiction of thyroid microvascular flow compared with standard CDI and PDI.

Primary follicular thyroid carcinoma metastasis to the kidney and widespread dissemination: A case report

Distant metastases are more common in follicular thyroid carcinoma (FC) than in papillary thyroid carcinoma. However, FC metastasis to the kidney with eggshell calcification, as observed in the present case, is rare. The current report presents a case of a 67-year-old woman exhibiting a solitary tumor in the mid pole of the left kidney. Radical nephrectomy was performed, as the tumor was diagnosed as a primary renal carcinoma using contrast-enhanced computed tomography. Once the tumor was confirmed to be FC, total thyroidectomy was performed. Following administration of an oral therapeutic dose of 100 mCi ¹³¹I, functional imaging demonstrated the presence of multifocal metastases in the chest and abdomen. Euthyrox^® was prescribed orally to aid normal thyroid function. Follow-up 6 months later using radionuclide imaging demonstrated the disappearance of the multifocal metastases in the chest and abdomen. The distant metastasis of FC may represent the initial symptom of the primary lesion, which was neglected. Ultrasound is an effective method to examine nodules located on the thyroid.

Ultrasonography Diagnosis and Imaging-Based Management of Thyroid Nodules: Revised Korean Society of Thyroid Radiology Consensus Statement and Recommendations

The rate of detection of thyroid nodules and carcinomas has increased with the widespread use of ultrasonography (US), which is the mainstay for the detection and risk stratification of thyroid nodules as well as for providing guidance for their biopsy and nonsurgical treatment. The Korean Society of Thyroid Radiology (KSThR) published their first recommendations for the US-based diagnosis and management of thyroid nodules in 2011. These recommendations have been used as the standard guidelines for the past several years in Korea. Lately, the application of US has been further emphasized for the personalized management of patients with thyroid nodules. The Task Force on Thyroid Nodules of the KSThR has revised the recommendations for the ultrasound diagnosis and imaging-based management of thyroid nodules. The review and recommendations in this report have been based on a comprehensive analysis of the current literature and the consensus of experts.

Thyroid Imaging Reporting and Data System Risk Stratification of Thyroid Nodules: Categorization Based on Solidity and Echogenicity

BACKGROUND

Although ultrasonography (US) has an essential role in assessing the malignancy risk of thyroid nodules, a malignancy risk-stratification system has not been established. The purpose of this study was to develop a clinically feasible US risk-stratification system--the Thyroid Imaging Reporting and Data System (TIRADS)--primarily based on the solidity and echogenicity of thyroid nodules.

METHODS

From January 2010 to May 2011, a total of consecutive 2000 thyroid nodules (≥ 1 cm) with final diagnoses were enrolled from the database of low and high cancer volume institutions (1000 nodules from each institution). For the development of TIRADS, the type and predictive value of US predictors in the groups categorized by solidity and echogenicity were analyzed, and the US predictors were integrated and categorized according to the malignancy risk.

RESULTS

The suspicious US features of microcalcification, taller than wide shape, and spiculated/microlobulated margin were independently predictive of malignancy in the solid or hypoechoic nodule group (p < 0.001, respectively). Meanwhile, only microcalcification was independently predictive of malignancy in the partially cystic nodule group (p = 0.006), and microcalcification and spiculated/microlobulated margin were independently predictive of malignancy in the iso- and hyperechoic nodule group (p = 0.002 and p = 0.015, respectively). Although the presence of any suspicious US features had a high malignancy risk in the group of solid hypoechoic nodules, it had an intermediate malignancy risk in the group of partially cystic or iso- and hyperechoic nodules. The malignancy risk of thyroid nodules was stratified into five TIRADS categories by integrating the type and predictive values of US predictors based on solidity and echogenicity.

CONCLUSION

The malignancy risk of thyroid nodules can be stratified by TIRADS according to US patterns by combining solidity, echogenicity, and suspicious US features. The proposed risk-stratification system based on solidity and echogenicity will be useful for risk stratification and management decision of thyroid nodules.

Diagnostic role of ultrasound and elastosonography in nodular goiter

Among several ultrasound patterns, thyroid nodule hypoechogenicity, spot microcalcifications, and an absent halo sign are used for predicting increased risk of thyroid malignancy. The predictive value of ultrasound, however, increases at the expense of its sensitivity, and malignancy is predicted with high specificity only when multiple ultrasound features are simultaneously present. Ultrasound features are important in determining the strength of the indication for carrying out fine needle aspiration. To this end, a system for standardization of ultrasound features (Thyroid Imaging Reporting and Data System) aids in establishing risk of malignancy. Ultrasound elastosonography is a technique that assesses hardness as an indicator of malignancy risk. It has been carried out in selected studies of patients with thyroid nodules, and has been shown to have a high predictive value for malignancy, which is also maintained in cytologically indeterminate and non-diagnostic nodules. Although conventional ultrasound maintains its pivotal role in defining which nodules are candidates for ultrasound elastosonography characterization, the latter seems to have considerable potential in the diagnosis, or exclusion, of thyroid cancer. This especially concerns thyroid nodules with indeterminate cytology at fine-needle aspiration.

Follicular thyroid carcinoma with predominantly cystic formation presenting initially with multiple distant metastases

Primary malignancies presenting with multiple distant metastases include lung cancer, gastrointestinal malignancy, breast cancer, and prostatic cancer. Multiple distant metastases from follicular thyroid carcinoma (FTC) are uncommon. Cystic formation in FTC is an atypical finding in ultrasonography. The cystic formation of a thyroid nodule is usually considered a benign sonographic finding. We report the case of a 78-year-old man who presented with multiple distant metastases from an FTC with a predominantly cystic formation.

RAS mutations in thyroid FNA specimens are highly predictive of predominantly low-risk follicular-pattern cancers

INTRODUCTION

RAS mutations are common in thyroid tumors and confer a high risk of cancer when detected in fine-needle aspiration (FNA) specimens. Specific characteristics of RAS-positive thyroid cancers are not well described.

METHODS

From April 2007 to April 2009, 921 consecutive patients undergoing FNA were evaluated prospectively with a panel of molecular markers. Ultrasonographic, cytological, histological, and surgical outcomes were retrospectively assessed.

RESULTS

Sixty-eight aspirates from 66 patients were positive for RAS mutations including 63 cytologically indeterminate (93%), 3 malignant (4%), and 2 benign (3%) specimens. Cancer was histologically confirmed in 52 of 63 aspirates (83%) including the following: 46 papillary thyroid cancers, 4 follicular thyroid cancers, 1 medullary cancer, and 1 anaplastic cancer. All 46 RAS-positive papillary thyroid cancers, including 1 metastatic cancer, had follicular variant histology papillary thyroid cancer; only 11 tumors demonstrated vascular/capsular invasion and 4 had infiltrative growth. Of 48 patients with differentiated thyroid cancer, lymph node metastasis was uncommon and bilateral cancer was present in 48%. Only 33% of malignant nodules were suspicious by preoperative ultrasonography. At a mean follow-up of 22 months, 31 of 35 differentiated thyroid cancer patients (89%) have no evidence of recurrence, 4 patients (9%) have detectable thyroglobulin, 1 patient has bone metastases, and both patients with medullary and anaplastic cancer have died.

CONCLUSION

Most RAS-positive thyroid cancers have indeterminate cytology, lack suspicious ultrasound features, and are histologically low-grade follicular variant histology papillary thyroid cancer. Lymph node and distant metastases are uncommon but bilateral disease is frequent. Total thyroidectomy should be considered for initial surgical management of most patients with RAS-positive FNA results. The role of prophylactic lymphadenectomy remains unclear.

Thyroid incidentaloma detected by time-resolved magnetic resonance angiography at 3T: prevalence and clinical significance

OBJECTIVE

To determine the prevalence of thyroid incidentalomas detected by time-resolved magnetic resonance angiography (TRMRA) and to evaluate their clinical significance by using an ultrasonographic (US) and cytologic correlation.

MATERIALS AND METHODS

We retrospectively reviewed 2010 consecutive TRMRA examinations performed at our institution between August 2006 and April 2010. The TRMRA findings of thyroid incidentalomas were analyzed according to location, size, as well as vascularity, and were correlated with the US findings and cytologic results. Each nodule was classified as suspiciously malignant, indeterminate or probably benign according to the US criteria recommended by the Korean Society of Thyroid Radiology.

RESULTS

A total of 102 incidentalomas were detected in 90 of 2010 patients (5%). TRMRA showed homogenous hypervascularity in 48 (47%), inhomogeneous hypervascularity in 46 (45%), and hypovascularity in 8 (8%) thyroid nodules. At follow-up study, out of 26 patients with 30 incidentalomas on TRMRA, 27 nodules were identified on US. Of the 27 nodules, 24 (89%) nodule were classified as indeterminate, two (7%) as probably benign, and one (4%) as suspiciously malignant. Among the 16 nodules with available cytopathologic results, 14 (82%) were benign, one (6%) was indeterminate, and one (6%) was malignant.

CONCLUSION

Thyroid incidentalomas are found in 5% of TRMRA examinations. Although their presence does not necessarily indicate malignancy, nonspecific findings of detected incidentalomas on TRMRA require further evaluation by US.

Thyroid ultrasonography. Part 2: nodules

This article reviews common ultrasonographic patterns identified in both benign and malignant thyroid nodules. Categorizing nodules into benign and malignant patterns may be helpful to decide if ultrasound-guided fine-needle aspiration (FNA) should be performed. In addition, the FNA biopsy guidelines issued by major organizations are reviewed.

Follicular adenoma and carcinoma of the thyroid gland

Follicular neoplasms of the thyroid gland include benign follicular adenoma and follicular carcinoma. Currently, a follicular carcinoma cannot be distinguished from a follicular adenoma based on cytologic, sonographic, or clinical features alone. The pathogenesis of follicular carcinoma may be related to iodine deficiency and various oncogene and/or microRNA activation. Advances in molecular testing for genetic mutations may soon allow for preoperative differentiation of follicular carcinoma from follicular adenoma. Until then, a patient with a follicular neoplasm should undergo a diagnostic thyroid lobectomy and isthmusectomy, which is definitive treatment for a benign follicular adenoma or a minimally invasive follicular cancer. Additional therapy is necessary for invasive follicular carcinoma including completion thyroidectomy, postoperative radioactive iodine ablation, whole body scanning, and thyrotropin suppressive doses of thyroid hormone. Less than 10% of patients with follicular carcinoma will have lymph node metastases, and a compartment-oriented neck dissection is reserved for patients with macroscopic disease. Regular follow-up includes history and physical examination, cervical ultrasound and serum TSH, and thyroglobulin and antithyroglobulin antibody levels. Other imaging studies are reserved for patients with an elevated serum thyroglobulin level and a negative cervical ultrasound. Systemic metastases most commonly involve the lung and bone and less commonly the brain, liver, and skin. Microscopic metastases are treated with high doses of radioactive iodine. Isolated macroscopic metastases can be resected with an improvement in survival. The overall ten-year survival for patients with minimally invasive follicular carcinoma is 98% compared with 80% in patients with invasive follicular carcinoma.

Real-time elastosonography: useful tool for refining the presurgical diagnosis in thyroid nodules with indeterminate or nondiagnostic cytology

BACKGROUND

Indeterminate and nondiagnostic patterns represent the main limitation of fine-needle aspiration (FNA) cytology of thyroid nodules, clinical and echographic features being poorly predictive of malignancy. The newly developed real-time ultrasound elastography (USE) has been previously applied to differentiate malignant from benign lesions. The aim of this study was to get further insights into the role of USE in the presurgical diagnosis of nodules with indeterminate or nondiagnostic cytology.

PATIENTS

The study included 176 patients who had one (n=138) or multiple (n=38) nodules with indeterminate or nondiagnostic cytology on FNA, for whom histology was available after thyroidectomy. A total of 195 nodules (142 indeterminate, 53 nondiagnostic) were submitted to USE, and elasticity was scored as 1 (high), 2 (intermediate), or 3 (low).

RESULTS

In indeterminate lesions, the score 1, describing high elasticity, was strongly predictive of benignity, being found in 102 of 111 benign nodules and in only one of 31 carcinomas (P<0.0001). By combining the scores 2 and 3, USE had a sensitivity of 96.8% and a specificity of 91.8%. In nodules with nondiagnostic cytology, score 1 was found in 39 of 45 benign nodules and in only one of eight carcinomas (P<0.0001). By combining the scores 2 and 3, USE had a sensitivity of 87.5% and a specificity of 86.7%.

CONCLUSIONS

USE may represent an important tool for the diagnosis of thyroid cancer in nodules with indeterminate or nondiagnostic cytology and may prove useful in selecting patients who are candidates for surgery.