TIRADS score is of limited clinical value for risk stratification of indeterminate cytological results

Correlation of ultrasound-based TIRADS and the Bethesda system for reporting of thyroid cytopathology: A study in a tertiary care centre

BACKGROUND

The age-standardised incidence rate of thyroid cancer in India is 1 in 416 in the general population. This increased incidence has mainly been attributed to improved detection methods for small thyroid lesions. Two such methods are the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TIRADS) and the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC).

AIMS AND OBJECTIVES

To study the correlation between ACR TIRADS and TBSRTC, and between each system and the final histopathological report.

MATERIALS AND METHODS

Thyroid cytopathology cases were retrieved for the period January 2019 to July 2022. For each case, the TIRADS score and Bethesda category were noted. Histopathology specimens were also traced.

RESULTS

The study comprised 1100 cases, with 955 female and 145 male patients (M:F = 1:6.59), and ages ranging between 7 and 85 years. The TIRADS scoring was available for 1036 cases. Histopathology was available for 231 cases. There was a significant correlation between TIRADS and TBSRTC, with a p-value of 0.000 and a substantial Kappa agreement of 0.688. Both TIRADS and TBSRTC also had significant correlations with the histopathology data, with a p-value of 0.000 for each. The sensitivity values for TBSRTC and TIRADS were 69.4% and 65.8%; specificity, 99.3% and 96.5%; positive predictive value (PPV), 98.3% and 91.8%; and negative predictive value (NPV) 84.7% and 84.4%, respectively. The risk of malignancy (ROM) was also calculated and was found to be high, especially for TBSRTC II, III, IV and V (11.3%, 20%, 61.5%, 97.4% respectively) and TIRADS 2 and 3 (10.3% and 29.6% respectively).

CONCLUSION

The TIRADS and TBSRTC systems of categorisation of thyroid lesions are concordant and could help improve the overall survival rate of patients with thyroid malignancies.

Diagnostic performance of ultrasound risk stratification systems on thyroid nodules cytologically classified as indeterminate: a systematic review and meta-analysis

PURPOSE

Ultrasound (US) risk stratification systems (RSSs) are increasingly being utilized for the optimal management of thyroid nodules, including those with indeterminate cytology. The goal of this study was to evaluate the category-based diagnostic performance of US RSSs in identifying malignancy in indeterminate nodules.

METHODS

This systematic review and meta-analysis was registered on PROSPERO (CRD42021266195). PubMed, EMBASE, and Web of Science were searched through December 1, 2022. Original articles reporting data on the performance of US RSSs for indeterminate nodules were included. The numbers of nodules classified as true negative, true positive, false negative, and false positive were extracted.

RESULTS

Thirty-three studies evaluating 7,225 indeterminate thyroid nodules were included. The diagnostic accuracy was quantitatively synthesized using a Bayesian bivariate model based on the integrated nested Laplace approximation in R. For the intermediate- to high-risk category, the sensitivity levels of the American College of Radiology, the American Thyroid Association, the European Thyroid Association, the Korean Thyroid Association/Korean Society of Thyroid Radiology, and Kwak et al. were found to be 0.80, 0.72, 0.76, 0.96, and 0.97, respectively. The corresponding specificity measurements were 0.36, 0.50, 0.49, 0.28, and 0.17. Furthermore, for the high-risk category, the sensitivity values were 0.40, 0.46, 0.55, 0.47, and 0.10, while the specificity levels were 0.91, 0.90, 0.71, 0.91, and 0.99, respectively.

CONCLUSION

The overall diagnostic performance of the US RSSs was moderate in the differentiation of indeterminate nodules.

Correlation of TIRADS and Bethesda Scoring Systems with Final Histopathology of Thyroid Nodules - An Institutional Experience

Fine needle aspiration cytology (FNAC) reduces the number of unnecessary thyroid surgeries for patients with benign nodules and appropriately triages patients with thyroid cancer to appropriate treatment. This was a observational study done on cases presenting with clinical suspicion of thyroid malignancy which underwent ultrasonography followed by FNAC of thyroid nodule. Ultrasonographic characterization of nodules was based on Thyroid Imaging Reporting and Data System (TIRADS) and cytology reporting was based on Bethesda system. All recruited patients underwent thyroidectomy. Pre-operative cytology and ultrasonography features were compared with final histopathology report. In our study, Bethesda system of cytology reporting for thyroid nodules had a better sensitivity, specificity and diagnostic accuracy than TIRADS system of ultrasound reporting. Bethesda system in FNAC had a larger area under the ROC curve (0.91) as compared to ultrasound TIRADS (0.70). Malignancy rate of TIRADS 5 nodules was 97.1% with significant p value (0.022). 100% of Bethesda VI lesions were malignant according to final histopathology report. Ultrasound TIRADS could pre-operatively predict malignancy in 63.6% of indeterminate thyroid nodules which were malignant according to post-operative histopathology. The overall concordance of ultrasound TIRADS, Bethesda system and histopathology was 69.8%. Higher TIRADS and Bethesda scoring among thyroid nodules was associated with increased risk of malignancy. US TIRADS is a good predictor of malignancy in indeterminate thyroid nodules.

Deep learning for the diagnosis of suspicious thyroid nodules based on multimodal ultrasound images

OBJECTIVES

This study aimed to differentially diagnose thyroid nodules (TNs) of Thyroid Imaging Reporting and Data System (TI-RADS) 3-5 categories using a deep learning (DL) model based on multimodal ultrasound (US) images and explore its auxiliary role for radiologists with varying degrees of experience.

METHODS

Preoperative multimodal US images of 1,138 TNs of TI-RADS 3-5 categories were randomly divided into a training set (n = 728), a validation set (n = 182), and a test set (n = 228) in a 4:1:1.25 ratio. Grayscale US (GSU), color Doppler flow imaging (CDFI), strain elastography (SE), and region of interest mask (Mask) images were acquired in both transverse and longitudinal sections, all of which were confirmed by pathology. In this study, fivefold cross-validation was used to evaluate the performance of the proposed DL model. The diagnostic performance of the mature DL model and radiologists in the test set was compared, and whether DL could assist radiologists in improving diagnostic performance was verified. Specificity, sensitivity, accuracy, positive predictive value, negative predictive value, and area under the receiver operating characteristics curves (AUC) were obtained.

RESULTS

The AUCs of DL in the differentiation of TNs were 0.858 based on (GSU + SE), 0.909 based on (GSU + CDFI), 0.906 based on (GSU + CDFI + SE), and 0.881 based (GSU + Mask), which were superior to that of 0.825-based single GSU (p = 0.014, p< 0.001, p< 0.001, and p = 0.002, respectively). The highest AUC of 0.928 was achieved by DL based on (G + C + E + M)US, the highest specificity of 89.5% was achieved by (G + C + E)US, and the highest accuracy of 86.2% and sensitivity of 86.9% were achieved by DL based on (G + C + M)US. With DL assistance, the AUC of junior radiologists increased from 0.720 to 0.796 (p< 0.001), which was slightly higher than that of senior radiologists without DL assistance (0.796 vs. 0.794, p > 0.05). Senior radiologists with DL assistance exhibited higher accuracy and comparable AUC than that of DL based on GSU (83.4% vs. 78.9%, p = 0.041; 0.822 vs. 0.825, p = 0.512). However, the AUC of DL based on multimodal US images was significantly higher than that based on visual diagnosis by radiologists (p< 0.05).

CONCLUSION

The DL models based on multimodal US images showed exceptional performance in the differential diagnosis of suspicious TNs, effectively increased the diagnostic efficacy of TN evaluations by junior radiologists, and provided an objective assessment for the clinical and surgical management phases that follow.

Optimization of the Management of Category III Thyroid Nodules Using Repeat FNA and TIRADS

The aim of the study was to examine the benefits of the joint use of repeat FNA (rFNA) and EU-TIRADS in category III nodules in relation to the kind of atypia: nuclear vs. architectural (denoted by AUS and FLUS respectively). The study included 127 AUS and 1739 FLUS nodules with a known category of EU-TIRADS. Repeat FNA was performed in 82 AUS and 934 FLUS nodules of which 57 and 515 were excised, respectively. AUS nodules had higher malignancy risk than FLUS nodules. EU-TIRADS showed higher accuracy for AUS nodules, the opposite to rFNA, that had higher accuracy for FLUS nodules. The combined criterion for AUS nodules (at least rFNA-V or EU-TIRADS-4) maximized sensitivity (92.3%) with acceptable specificity (70.0%); OR: 28.0. In the case of FLUS nodules, the combined criterion (rFNA-V or EU-TIRADS-5) maximized specificity (95.2%) with 57.7% sensitivity and a low percentage (13.9%) of positive nodules, OR: 27.0. In both types of nodules, the low risk category in EU-TIRADS and benign result of rFNA excluded cancer. Concluding, category III nodules with and without nuclear atypia differ in their risk of malignancy and, consequently, diagnostic criteria adopted for the evaluation of these nodules with rFNA and EU-TIRADS should be specific to AUS and FLUS nodules.

Machine Learning-Assisted Diagnostic System for Indeterminate Thyroid Nodules

To develop an ultrasound-based machine learning classifier to diagnose benignity within indeterminate thyroid nodules (ITNs) by fine-needle aspiration, 180 patients with 194 ITNs (Bethesda classes III, IV and V) undergoing surgery over a 5-y study period were analyzed. The data set was randomly divided into training and testing data sets with 155 and 39 ITNs, respectively. All nodules were evaluated by ultrasound using the American College of Radiology Thyroid Imaging Reporting and Data System by manually scoring composition, echogenicity, shape, margin and echogenic foci. Nodule size, participant age and patient sex were recorded. A support vector machine (SVM) model with a cost-sensitive approach was developed using the aforementioned eight parameters with surgical histopathology as the reference standard. Surgical pathology determined 90 (46.4%) ITNs were malignant and 104 (53.6%) were benign. The SVM model classified 14 nodules as benign in the testing data set, of which 13 were correct (sensitivity = 93.8%, specificity = 56.5%). Considering malignancy prevalence by Bethesda group, the negative predictive values of this model for Bethesda III and IV categories were 93.9% and 93. 8%, respectively. The high negative predictive value of the SVM ultrasound-based model suggests a pathway by which surgical excision of Bethesda III and IV ITNs classified as benign may be avoided.

Down-regulation of miR-7-5p and miR-548ar-5p predicts malignancy in indeterminate thyroid nodules negative for BRAF and RAS mutations

PURPOSE

The value of molecular markers in refining preoperative risk assessment of indeterminate thyroid nodules is being widely investigated. MicroRNAs (miRNA) are emerging as promising biomarkers for diagnostic and prognostic purposes. The aim of this study is to identify miRNAs specifically deregulated in mutation-negative indeterminate thyroid nodules.

METHODS

Ninety-eight nodules preoperatively diagnosed as TIR 3A or TIR 3B with available histological diagnosis of follicular adenoma (FA), noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP), and follicular variant papillary thyroid carcinoma (FV-PTC) have been retrospectively selected. Mutations in BRAF and RAS genes have been tested in all samples by real-time PCR; miRNAs were purified from cytology slides of 60 samples; expression analysis of 798 miRNAs was measured by the nCounter system.

RESULTS

Point mutations in BRAF and RAS genes were detected in 32 out of 98 nodules (32.7%), the majority of which in FV-PTCs. Differential expression of miRNA in wild-type nodules highlighted that two miRNAs, namely miR-7-5p and miR-548ar-5p, were downregulated in FV-PTCs compared to FAs. The combined expression of these miRNAs, tested by ROC analysis, showed an area under the curve of 0.79. Sensitivity and negative predictive value were high both in wild-type (93% and 92%, respectively) and in mutated nodules (94% and 85%, respectively).

CONCLUSION

The analysis of miR-7-5p and miR-548ar-5p expression in indeterminate thyroid nodules demonstrated a promising value in ruling out malignancy.

Subtype of atypia on cytology and risk of malignancy in pediatric thyroid nodules

BACKGROUND

Thyroid nodules with atypia of undetermined significance (AUS) are challenging to manage because of their intermediate risk of malignancy. Subclassification of atypia can refine malignancy risk in adult AUS nodules but has not been evaluated in children.

METHODS

This was a retrospective cohort study of pediatric patients (<19 years old) who underwent fine-needle aspiration (FNA) of a thyroid nodule with resulting AUS cytology. Atypia was subclassified as nuclear only, architectural only, nuclear and architectural, or oncocytic. The primary outcome was the association between atypia subtype and malignancy. A secondary outcome was the association of atypia subtype with repeat FNA cytology.

RESULTS

Sixty-eight AUS nodules in 61 patients were analyzed. The median age at FNA was 16.2 years (range, 9.8-18.9 years). Twenty-four nodules (35%) were malignant. Nuclear atypia only was present in 17 nodules (25%), architectural atypia only was present in 27 nodules (40%), nuclear and architectural atypia was present in 20 nodules (29%), and predominantly oncocytic features were present in 4 nodules (6%). The presence of nuclear atypia was associated with a significantly increased rate of malignancy (22 of 37 [59%] vs 2 of 31 [6.5%]; P < .001), whereas architectural atypia was not associated with malignancy (P = .8). Repeat FNA was performed in 42 of 68 nodules (62%). In nodules with initial nuclear and architectural atypia, benign repeat cytology had a high false-negative rate (3 of 6; 50%).

CONCLUSIONS

Pediatric AUS nodules with nuclear atypia have a high rate of malignancy, but architectural atypia is not associated with malignancy. In nodules with nuclear atypia, repeat FNA may inform clinical decisions regarding the need for resection. In the absence of suspicious clinical features, nodules without nuclear atypia might be considered for observation rather than resection or repeat FNA.

Evaluation of the efficacy of EU-TIRADS and ACR-TIRADS in risk stratification of pediatric patients with thyroid nodules

BACKGROUND

Pediatric thyroid nodules have a lower prevalence but a higher rate of malignancy (ROM) than those in adults. Ultrasound features suspected of malignancy lead to fine needle aspiration biopsy (FNAB) and subsequent cytological determination, upon which management is decided. Based on the characteristics of ultrasound, to standardize clinician decisions and avoid unnecessary FNAB, the European Thyroid Association and the American Radiology College have established guidelines for Thyroid Imaging, Reporting and Data System (EU-TIRADS and ACR-TIRADS) for ROM stratification of thyroid nodules. The aim of this study is to evaluate the diagnostic performance of ACR-TIRADS and EU-TIRADS in pediatric age.

MATERIALS AND METHODS

Subjects younger than 18 years of age with thyroid nodules greater than 0.5 cm observed in the 2000-2020 period were included.

RESULTS

Data from 200 subjects were collected. The overall ROM was 13%, rising to 26% if nodules with a diameter >1 cm were considered. Patients with a malignant nodule were more likely to have a higher EU-TIRADS score (p=0.03). Missed cancer diagnoses were 26.9%. Using the EU-TIRADS system, 40% of FNABs could have been avoided, while this scoring system would have resulted in FNAB being performed in 12% of cases where the assessment of ultrasound features would not recommend FNAB. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 73.1%, 57.1%, 73.1%, and 50%, respectively. Even considering the ACR-TIRADS, a higher score correlated with a higher ROM (p<0.001). This system missed 6 diagnoses of cancer (23.1%). Using the ACR-TIRADS system, 45.3% of FNABs could have been avoided, while FNAB should have been performed in 12% of cases where it was not recommended by ultrasound characteristics. Sensitivity, specificity, PPV and NPV were 76.9%, 50%, 76.9%, and 42.9%, respectively.

CONCLUSION

The present study confirms the correspondence of the EU-TIRADS and ACR-TIRADS categories with respect to malignancy but indicates not entirely satisfactory performance compared to FNAB alone. However, the use of the two TIRADS systems should be encouraged in multicentre studies to increase their performance and establish paediatric-specific points in the scoring criteria.

Comparative Study of ACR TI-RADS and ATA 2015 for Ultrasound Risk Stratification of Thyroid Nodules

OBJECTIVE

To study the adoption rate of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) scoring system over a 3-year period in a community setting and compare its performance with that of the American Thyroid Association 2015 (ATA 2015) ultrasound risk scoring system.

STUDY DESIGN

Case series with prospective data collection and retrospective chart review.

SETTING

Large community-based practice with multiple satellite offices and a dedicated thyroid ultrasound clinic.

METHODS

All patients referred to the thyroid clinic between January 2018 and December 2020 for ultrasound-guided fine-needle biopsy were assigned an ATA 2015 risk score in a prospective manner immediately prior to biopsy. ACR TI-RADS scores were recorded through retrospective chart review of the radiologist report. Performance of the 2 systems was compared with cytology as the gold standard.

RESULTS

A total of 949 nodules underwent biopsy, of which 236 had available data for both scoring systems. There was a 33.8% increase in adoption of the ACR TI-RADS over the 3-year study period. The ATA 2015 guidelines yielded sensitivity and specificity of 81.6% and 54.5%, respectively, as opposed to 73.7% and 27.0% for the ACR TI-RADS.

CONCLUSION

In our community, there has been a gradual increase in adoption of the ACR TI-RADS, although the ATA 2015 risk scoring system has performed better.

Ultrasonography and Fine-Needle Aspiration in Indeterminate Thyroid Nodules: A Systematic Review of Diagnostic Test Accuracy

OBJECTIVES/HYPOTHESIS

Sonographic risk criteria may assist in further prognostication of indeterminate thyroid nodules (ITNs). Our aim was to determine whether sonographic criteria could further delineate the post-test probability of malignancy in ITNs.

STUDY DESIGN

Meta-analysis of diagnostic test accuracy.

METHODS

A systematic review of Web of Science, MEDLINE, EMBASE, and CINAHL was performed from inception to April 15, 2021. Eligible studies included those which reported ultrasonographic evaluations with the American Thyroid Association (ATA) or the Thyroid Imaging Reporting and Data System (TIRADS) in adult patients with ITNs. ATA or TIRADS were scored as low (negative) or high (positive) malignancy risk using a previously validated binary classification. Primary outcomes included pooled sensitivity, specificity, likelihood ratios, and diagnostic odds ratio for all sonographic criteria. Studies were appraised using Quality Assessment of Diagnostic Accuracy Studies and the data were pooled using bivariate random-effects models.

RESULTS

Seventeen studies were included in the analysis. For Bethesda III, ATA had a specificity (0.90, 95% confidence interval (CI): 0.74-0.94), but a sensitivity of 0.52 (95% CI: 0.25-0.77). Conversely, K-TIRADS had the highest sensitivity (0.78, 95% CI: 0.62-0.89) with a specificity of 0.53 (95% CI: 0.31-0.74). Furthermore, American College of Radiology and EU TIRADS had specificities of 0.60 (95% CI: 0.36-0.80) and 0.81 (95% CI: 0.73-0.87) with sensitivities of 0.70 (95% CI: 0.37-0.90) and 0.38 (95% CI: 0.20-0.60), respectively. There were few studies with Bethesda IV nodules.

CONCLUSIONS

Though dependent on malignancy rates, Bethesda III nodules with low-suspicion TIRADS features may benefit from clinical observation, whereas nodules with high-suspicion ATA features may require molecular testing and/or surgery.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.

A Simplified Ultrasonographic Score for the Prediction of Cytologically Suspicious Thyroid Nodules

PURPOSE

 The major aim of ultrasound (US)-based risk stratification systems is to reduce unnecessary thyroid biopsies without losing the ability to recognize nodules with clinically significant malignancy. Each of the classic suspicious features of a thyroid nodule detected on US scan (hypoechoic pattern, microcalcifications, irregular margin, taller than wide shape, irregular vascularization) is significantly independently associated with the probability of malignancy, but none of them has good diagnostic accuracy. Thus, we evaluated the predictive value of a binary score simply based on the combination of these US features, regardless of the specific predictive value of each US feature, against the outcome of suspected malignancy at cytological diagnosis (TIR3 to TIR5 categories by SIAPEC-IAP [TIR+]).

MATERIALS AND METHODS

 1009 thyroid nodules from 1081 patients were considered. The US features of suspicion of all nodules were categorized in 5 binary scores (U1 to U5), each including from 1 to 5 of those features.

RESULTS

 U2 (at least 2 US suspicious features) was the most balanced predictor of TIR+ (PPV 0.48, NPV 0.93, LR+ 3.05 and LR- 0.24). Weighting the predictivity of the single features did not improve the estimate. Using U2 as the criterion to send nodules to FNAC would have reduced the number of biopsies by 60 % (604 patients) and the false negatives would have only accounted for 41 cases out of 237 TIR+ (17 %) with 39 cases of TIR3 and 2 cases of TIR4, including only 6 malignant nodules on histological examination. U2 performed much better than the ATA recommendations for detecting those nodules, resulting in TIR+ at cytology.

CONCLUSION

 This simple and reproducible sonographic score based on 2 US features of suspicion of malignancy has quite a good performance with respect to identifying thyroid lesions categorized by cytology as medium-high risk of malignancy and could allow us to reduce cytology costs for low-risk nodules.

Can Cytologic and Sonographic Features Help Prevent Overtreatment of Bethesda V Thyroid Nodules?

BACKGROUND

Although nearly half of thyroid nodules with Bethesda V cytology (suspicious for malignancy) may be benign or harbor low-grade neoplasms that can be sufficiently treated with lobectomy, many patients with Bethesda V cytology continue to be treated with total thyroidectomy. The objectives of this study were to establish whether cytomorphologic and ultrasonographic features can determine appropriate surgery for thyroid nodules with Bethesda V cytology and how often patients are overtreated with total instead of partial thyroidectomy.

METHODS

Utilizing a 10-y prospective database starting January 1, 2004, cytomorphologic and ultrasonographic features of thyroid nodules with Bethesda V cytology were reviewed. Overtreatment was defined as total thyroidectomy when histopathology revealed benign nodule, noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) or a unilateral < 4 cm low risk cancer.

RESULTS

Sixty-three patients were included in the study. Seventeen (27%) had benign, 14 (22%) NIFTP, and 32 (51%) malignant nodules. On cytology, nuclear pseudoinclusions, and on ultrasound, taller-than-wide configuration, were more common in malignant than benign or NIFTP nodules. Among 56 patients who underwent total thyroidectomy, 14 and 11 had a benign or NIFTP nodule, respectively, and 13 had a unilateral < 4 cm low risk cancer, suggesting that 68% (38/56) were overtreated.

CONCLUSIONS

Total thyroidectomy for Bethesda V thyroid nodules may result in overtreatment in more than half of the patients. Although certain cytomorphologic and ultarsonographic features may be helpful in determining appropriate surgery for Bethesda V thyroid nodules, additional characteristics are needed to reduce overtreatment of these nodules.

Diagnostic performance rates of the ACR-TIRADS and EU-TIRADS based on histopathological evidence

PURPOSE

In this study, we aimed to assess the effectiveness of malignancy stratification algorithms of the American College of Radiology (ACR) and European Thyroid Association (ETA) in the delineation of thyroid nodules using a database of nodules that were unequivocally diagnosed by means of histopathological examination and meticulously matched with the imaged nodules.

METHODS

A total of 165 patients having 251 thyroid nodules with histopathologically proven definitive diagnoses during a 5-year period were included in this study. All patients had preoperatively undergone ultrasonography (US) examination, and US characteristics of the thyroid nodules were retrospectively analyzed and assigned in compliance with the thyroid imaging reporting and data system categories recommended by the ACR (ACR-TIRADS) and ETA (EU-TIRADS). The diagnostic effectiveness in the delineation of thyroid nodules and unnecessary fine-needle aspiration (FNAB) rates were evaluated.

RESULTS

Overall, 189 nodules (75.30%) were diagnosed as benign, while 62 nodules (24.70%) were reported to be malignant based on histopathological assessment. Sensitivity and specificity rates were 71% and 75% for ACR-TIRADS and 73% and 80% for EU-TIRADS. The area under the curve values were 0.78 and 0.80 for ACR-TIRADS and EU-TIRADS, respectively. The unnecessary FNAB rates were 61% for ACR-TIRADS and 64% for EU-TIRADS as per the recommended criteria of each algorithm.

CONCLUSION

The diagnostic performance of both malignancy stratification systems was signified to be moderate and sufficient in a cohort of nodules with definite histopathological diagnosis. In light of our results, we demonstrated the strengths and weaknesses of the ACR- and EU-TIRADS for physicians who should be familiar with them for optimal management of thyroid nodules.

Overview of the Ultrasound Classification Systems in the Field of Thyroid Cytology

The increasing application of ultrasound (US) in recent years has led to a greater number of thyroid nodule diagnoses. Consequently, the number of fine needle aspirations performed to evaluate these lesions has increased. Although the majority of thyroid nodules are benign, identifying methods to define specific lesions and tailor risk of malignancy has become vital. Some of the tools employed to stratify thyroid nodule risk include clinical factors, thyroid US findings, and reporting systems for thyroid cytopathology. Establishing high concordance between US features and cytologic diagnoses might help reduce healthcare costs by diminishing unnecessary thyroid procedures and treatment. This review aims to review radiology US classification systems that influence the practice of thyroid cytology.

Less extensive surgery for low-risk papillary thyroid cancers post 2015 American Thyroid Association guidelines in an Australian tertiary centre

INTRODUCTION

The 2015 American Thyroid Association guidelines (ATA15) consider hemithyroidectomy (HT) a viable treatment option for low-risk papillary thyroid cancers (PTCs) between 1 and 4 cm. We aimed to examine the impact of ATA15 in a high-volume Australian endocrine surgery unit.

METHODS

A retrospective study of all patients undergoing thyroidectomy from January 2010 to December 2019.

INCLUSION CRITERIA

PTC histopathology, Bethesda V-VI, size 1-4 cm, and absence of clinical evidence of lymph node or distant metastases pre-operatively. Primary outcome was rate of HT before and after ATA15.

RESULTS

Of 5408 thyroidectomy patients, 339 (6.3%) met the inclusion criteria - 186 (54.9%) pre-ATA15 (2010-2015) and 153 (45.1%) post-ATA15 (2016-2019). The patient groups were similar; there were no significant differences between groups in age, sex, tumour size, proportion with Bethesda VI cytology, compressive symptoms, or thyrotoxicosis. Post-ATA15, there was a significant increase in HT rate from 5.4% to 19.6% (P = 0.0001). However, there was no corresponding increase in completion thyroidectomy (CT) rate (50.0% versus 27.6%, P = 0.2). The proportion managed with prophylactic central neck dissection (pCND) fell from 80.5% to 10.8% (P < 0.0001). Pre-ATA15, the only factor significantly associated with HT was Bethesda V. In contrast, post-ATA15, HT was more likely in patients with younger age, smaller tumours, and Bethesda V.

CONCLUSION

After the release of 2015 ATA guidelines, we observed a significant increase in HT rate and a significant decrease in pCND rate for low-risk PTCs in our specialised thyroid cancer unit. This reflects a growing clinician uptake of a more conservative approach as recommended by ATA15.

Deep Learning Based on ACR TI-RADS Can Improve the Differential Diagnosis of Thyroid Nodules

Objective

The purpose of this study was to improve the differentiation between malignant and benign thyroid nodules using deep learning (DL) in category 4 and 5 based on the Thyroid Imaging Reporting and Data System (TI-RADS, TR) from the American College of Radiology (ACR).

Design and Methods

From June 2, 2017 to April 23, 2019, 2082 thyroid ultrasound images from 1396 consecutive patients with confirmed pathology were retrospectively collected, of which 1289 nodules were category 4 (TR4) and 793 nodules were category 5 (TR5). Ninety percent of the B-mode ultrasound images were applied for training and validation, and the residual 10% and an independent external dataset for testing purpose by three different deep learning algorithms.

Results

In the independent test set, the DL algorithm of best performance got an AUC of 0.904, 0.845, 0.829 in TR4, TR5, and TR4&5, respectively. The sensitivity and specificity of the optimal model was 0.829, 0.831 on TR4, 0.846, 0.778 on TR5, 0.790, 0.779 on TR4&5, versus the radiologists of 0.686 (P=0.108), 0.766 (P=0.101), 0.677 (P=0.211), 0.750 (P=0.128), and 0.680 (P=0.023), 0.761 (P=0.530), respectively.

Conclusions

The study demonstrated that DL could improve the differentiation of malignant from benign thyroid nodules and had significant potential for clinical application on TR4 and TR5.

Sonographic Features Differentiating Follicular Thyroid Cancer from Follicular Adenoma-A Meta-Analysis

Simple Summary

The risk of thyroid malignancy assessment may include certain ultrasound features. The analysis is lacking for the differentiation of follicular thyroid adenomas and cancers (FTAs and FTCs). Our meta-analysis aimed to identify sonographic features suggesting malignancy in the case of follicular lesions, potentially differentiating FTA and FTC. Based on twenty studies describing sonographic features of 10,215 nodules, we found that the most crucial feature associated with an increased risk of FTC were tumor protrusion (odds ratios—OR = 10.19), microcalcifications or mixed type of calcifications: 6.09, irregular margins: 5.11, marked hypoechogenicity: 4.59, and irregular shape: 3.6.

Abstract

Certain ultrasound features are associated with an increased risk of thyroid malignancy. However, they were studied mainly in papillary thyroid cancers (PTCs); these results cannot be simply extrapolated for the differentiation of follicular thyroid adenomas and cancers (FTAs and FTCs). The aim of our study was to perform a meta-analysis to identify sonographic features suggesting malignancy in the case of follicular lesions, potentially differentiating FTA and FTC. We searched thirteen databases from January 2006 to December 2020 to find all relevant, full-text journal articles written in English. Analyses assessed the accuracy of malignancy detection in case of follicular lesions, potentially differentiating FTA and FTC included the odds ratio (OR), sensitivity, specificity, positive and negative predictive values. A random-effects model was used to summarize collected data. Twenty studies describing sonographic features of 10,215 nodules met the inclusion criteria. The highest overall ORs to increase the risk of malignancy were calculated for tumor protrusion (OR = 10.19; 95% confidence interval: 2.62–39.71), microcalcifications or mixed type of calcifications (coexisting micro and macrocalcifications): 6.09 (3.22–11.50), irregular margins: 5.11 (2.90–8.99), marked hypoechogenicity: 4.59 (3.23–6.54), and irregular shape: 3.6 (1.19–10.92). The most crucial feature associated with an increased risk of FTC is capsule protrusion, followed by the presence of calcifications, irrespectively of their type.

Focal Thyroid Incidentalomas on 18F-FDG PET/CT: A Systematic Review and Meta-Analysis on Prevalence, Risk of Malignancy and Inconclusive Fine Needle Aspiration

BACKGROUND

The rising demand for ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography (¹⁸F-FDG PET/CT) has led to an increase of thyroid incidentalomas. Current guidelines are restricted in giving options to tailor diagnostics and to suit the individual patient.

OBJECTIVES

We aimed at exploring the extent of potential overdiagnostics by performing a systematic review and meta-analysis of the literature on the prevalence, the risk of malignancy (ROM) and the risk of inconclusive FNAC (ROIF) of focal thyroid incidentalomas (FTI) on ¹⁸F-FDG PET/CT.

DATA SOURCES

A literature search in MEDLINE, Embase and Web of Science was performed to identify relevant studies.

STUDY SELECTION

Studies providing information on the prevalence and/or ROM of FTI on ¹⁸F-FDG PET/CT in patients with no prior history of thyroid disease were selected by two authors independently. Sixty-one studies met the inclusion criteria.

DATA ANALYSIS

A random effects meta-analysis on prevalence, ROM and ROIF with 95% confidence intervals (CIs) was performed. Heterogeneity and publication bias were tested. Risk of bias was assessed using the quality assessment of diagnostic accuracy studies (QUADAS-2) tool.

DATA SYNTHESIS

Fifty studies were suitable for prevalence analysis. In total, 12,943 FTI were identified in 640,616 patients. The pooled prevalence was 2.22% (95% CI = 1.90% - 2.54%, I² = 99%). 5151 FTI had cyto- or histopathology results available. The pooled ROM was 30.8% (95% CI = 28.1% - 33.4%, I² = 57%). 1308 (83%) of malignant nodules were papillary thyroid carcinoma (PTC). The pooled ROIF was 20.8% (95% CI = 13.7% - 27.9%, I² = 92%).

LIMITATIONS

The main limitations were the low to moderate methodological quality of the studies and the moderate to high heterogeneity of the results.

CONCLUSION

FTI are a common finding on ¹⁸F-FDG PET/CTs. Nodules are malignant in approximately one third of the cases, with the majority being PTC. Cytology results are non-diagnostic or indeterminate in one fifth of FNACs. These findings reveal the potential risk of overdiagnostics of FTI and emphasize that the workup of FTI should be performed within the context of the patient's disease and that guidelines should adopt this patient tailored approach.

Incorporation of a Machine Learning Algorithm With Object Detection Within the Thyroid Imaging Reporting and Data System Improves the Diagnosis of Genetic Risk

Background

The role of next generation sequencing (NGS) for identifying high risk mutations in thyroid nodules following fine needle aspiration (FNA) biopsy continues to grow. However, ultrasound diagnosis even using the American College of Radiology's Thyroid Imaging Reporting and Data System (TI-RADS) has limited ability to stratify genetic risk. The purpose of this study was to incorporate an artificial intelligence (AI) algorithm of thyroid ultrasound with object detection within the TI-RADS scoring system to improve prediction of genetic risk in these nodules.

Methods

Two hundred fifty-two nodules from 249 patients that underwent ultrasound imaging and ultrasound-guided FNA with NGS with or without resection were retrospectively selected for this study. A machine learning program (Google AutoML) was employed for both automated nodule identification and risk stratification. Two hundred one nodules were used for model training and 51 reserved for testing. Three blinded radiologists scored the images of the test set nodules using TI-RADS and assigned each nodule as high or low risk based on the presence of highly suspicious imaging features on TI-RADS (very hypoechoic, taller-than-wide, extra-thyroidal extension, punctate echogenic foci). Subsequently, the TI-RADS classification was modified to incorporate AI for T4 nodules while treating T1-3 as low risk and T5 as high risk. All diagnostic predictions were compared to the presence of a high-risk mutation and pathology when available.

Results

The AI algorithm correctly located all nodules in the test dataset (100% object detection). The model predicted the malignancy risk with a sensitivity of 73.9%, specificity of 70.8%, positive predictive value (PPV) of 70.8%, negative predictive value (NPV) of 73.9% and accuracy of 72.4% during the testing. The radiologists performed with a sensitivity of 52.1 ± 4.4%, specificity of 65.2 ± 6.4%, PPV of 59.1 ± 3.5%, NPV of 58.7 ± 1.8%, and accuracy of 58.8 ± 2.5% when using TI-RADS and sensitivity of 53.6 ± 17.6% (p=0.87), specificity of 83.3 ± 7.2% (p=0.06), PPV of 75.7 ± 8.5% (p=0.13), NPV of 66.0 ± 8.8% (p=0.31), and accuracy of 68.7 ± 7.4% (p=0.21) when using AI-modified TI-RADS.

Conclusions

Incorporation of AI into TI-RADS improved radiologist performance and showed better malignancy risk prediction than AI alone when classifying thyroid nodules. Employing AI in existing thyroid nodule classification systems may help more accurately identifying high-risk nodules.

Usability of EU-TIRADS in the Diagnostics of Hürthle Cell Thyroid Nodules with Equivocal Cytology

The aim of this study was to compare the diagnostic effectiveness of EU-TIRADS in two groups of nodules with equivocal cytology (categories III-V of Bethesda system), with and without Hürthle cells (HC and non-HC). The study included 162 HC and 378 non-HC nodules with determined histopathological diagnosis (17.9% and 15.6% cancers). In both groups calculated and expected risk of malignancy (RoM) for high, intermediate and benign risk categories of EU-TIRADS were concordant. RoM for low risk category was higher than expected in both groups, but especially in HC (HC: 13.9%, non-HC: 7.0%, expected: 2-4%). The majority of cancers in HC of that category were follicular thyroid carcinomas (FTC) and Hürthle cell thyroid carcinoma (HTC) (60.0% vs. non-HC: 16.7%). The diagnostic efficacy of EU-TIRADS was lower in HC (the area under the receiver operating characteristics curve (AUC): 0.621, sensitivity (SEN): 44.8%, specificity (SPC): 78.9% for high risk threshold) than in non-HC (AUC: 0.711, SEN: 61.0%, SPC: 77.7%). AUC was the highest for category V (AUC > 0.8, both groups) and the lowest for category IV (inefficient, both group). If intermediate risk category was interpreted as an indication for surgery, 25% of cancers from category III and 21.4% from category IV would not be treated in the HC group (0.0% and 7.4% from non-HC group, respectively). EU-TIRADS does not aid making clinical decisions in patients with cytologically equivocal HC nodules, particularly those classified into category IV of Bethesda System for Reporting Thyroid Cytopathology (BSRTC).

DNA FISH Diagnostic Assay on Cytological Samples of Thyroid Follicular Neoplasms

Simple Summary

Cytopathology cannot distinguish benign from malignant follicular lesions in 20–30% of cases. These indeterminate cases includes the so-called follicular neoplasms (FNs) according to The Bethesda System for Reporting Thyroid Cytopathology. Frozen samples from 66 classic follicular adenomas (cFAs) and carcinomas (cFTCs) studied by array-comparative genomic hybridization identified three specific alterations of cFTCs (losses of 1p36.33-35.1 and 22q13.2-13.31, and gain of whole chromosome X) confirmed by fluorescent in situ hybridization (FISH) in a second independent series of 60 touch preparations from frozen samples of cFAs and cFTCs. In a third independent set of 27 cases of already stained pre-operative fine-needle aspiration cytology samples diagnosed as FNs and histologically verified, FISH analysis using these three markers identified half of cFTCs. Specificity of our assay for identifying cFTCs is higher than 98% which might be comparable with BRAF^600E testing in cases of suspicion of classic papillary thyroid carcinomas.

Abstract

Although fine-needle aspiration cytology (FNAC) is helpful in determining whether thyroid nodules are benign or malignant, this distinction remains a cytological challenge in follicular neoplasms. Identification of genomic alterations in cytological specimens with direct and routine techniques would therefore have great clinical value. A series of 153 cases consisting of 72 and 81 histopathologically confirmed classic follicular adenomas (cFAs) and classic follicular thyroid carcinomas (cFTCs), respectively, was studied by means of different molecular techniques in three different cohorts of patients (pts). In the first cohort (training set) of 66 pts, three specific alterations characterized by array comparative genomic hybridization (aCGH) were exclusively found in half of cFTCs. These structural abnormalities corresponded to losses of 1p36.33-35.1 and 22q13.2-13.31, and gain of whole chromosome X. The second independent cohort (validation set) of 60 pts confirmed these data on touch preparations of frozen follicular neoplasms by triple DNA fluorescent in situ hybridization using selected commercially available probes. The third cohort, consisting of 27 archived cytological samples from an equal number of pts that had been obtained for preoperative FNAC and morphologically classified as and histologically verified to be follicular neoplasms, confirmed our previous findings and showed the feasibility of the DNA FISH (DNA fluorescent in situ hybridization) assay. All together, these data suggest that our triple DNA FISH diagnostic assay may detect 50% of cFTCs with a specificity higher than 98% and be useful as a low-cost adjunct to cytomorphology to help further classify follicular neoplasms on already routinely stained cytological specimens.

Contemporary Thyroid Nodule Evaluation and Management

CONTEXT

Approximately 60% of adults harbor 1 or more thyroid nodules. The possibility of cancer is the overriding concern, but only about 5% prove to be malignant. The widespread use of diagnostic imaging and improved access to health care favor the discovery of small, subclinical nodules and small papillary cancers. Overdiagnosis and overtreatment is associated with potentially excessive costs and nonnegligible morbidity for patients.

EVIDENCE ACQUISITION

We conducted a PubMed search for the recent English-language articles dealing with thyroid nodule management.

EVIDENCE SYNTHESIS

The initial assessment includes an evaluation of clinical risk factors and sonographic examination of the neck. Sonographic risk-stratification systems (e.g., Thyroid Imaging Reporting and Data Systems) can be used to estimate the risk of malignancy and the need for biopsy based on nodule features and size. When cytology findings are indeterminate, molecular analysis of the aspirate may obviate the need for diagnostic surgery. Many nodules will not require biopsy. These nodules and those that are cytologically benign can be managed with long-term follow-up alone. If malignancy is suspected, options include surgery (increasingly less extensive), active surveillance or, in selected cases, minimally invasive techniques.

CONCLUSION

Thyroid nodule evaluation is no longer a 1-size-fits-all proposition. For most nodules, the likelihood of malignancy can be confidently estimated without resorting to cytology or molecular testing, and low-frequency surveillance is sufficient for most patients. When there are multiple options for diagnosis and/or treatment, they should be discussed with patients as frankly as possible to identify an approach that best meets their needs.

A retrospective study of reducing unnecessary thyroid biopsy for American College of Radiology Thyroid Imaging Reporting and Data Systems 4 assessment through applying shear wave elastography

Objective The purpose of the study is to quantitatively assess shear-wave elastography (SWE) value in American College of Radiology Thyroid Imaging Reporting and Data Systems (ACR TI-RADS) 4. Materials and methods One hundred and fifty-two ACR TI-RADS 4 thyroid nodules undergoing SWE were included in the study. The mean (EMean), minimum (EMin) and maximum (EMax) of SWE elasticity were measured. Results The areas under the receiver operating characteristic (ROC) curves for SWE EMean, EMin and EMax in detecting benign and malignant nodules were 0.95, 0.83 and 0.84, respectively. Cut-off value of EMean ≤ 23.30 kPa is able to downgrade the lesion category to ACR TI-RADS 3 and cut-off value of EMean ≥ 52.14 kPa is able to upgrade the lesion category to ACR TI-RADS 5. Conclusions The EMean of SWE will probably identify nodules that have a high potential for benignity in ACR TI-RADS 4. It may help identify and select benign nodules while reducing unnecessary biopsy of benign thyroid nodules.

Diagnostic Value of Six Thyroid Imaging Reporting and Data Systems (TIRADS) in Cytologically Equivocal Thyroid Nodules

The aim was to compare the usefulness of selected thyroid sonographic risk-stratification systems in the diagnostics of nodules with indeterminate/suspicious cytology or unequivocal cytology in a population with a history of iodine deficiency. The diagnostic efficacy of ACR-TIRADS (the American College of Radiology Thyroid Imaging Reporting and Data Systems), EU-TIRADS (European Thyroid Association TIRADS), Korean-TIRADS, Kwak-TIRADS, AACE/ACE-AME-guidelines (American Association of Clinical Endocrinologists/ American College of Endocrinology-Associazione Medici Endocrinologi guidelines) and ATA-guidelines (American Thyroid Association guidelines) was evaluated in 1000 nodules with determined histopathological diagnosis: 329 FLUS/AUS (10.6% cancers), 167 SFN/SHT (11.6% cancers), 44 SM (77.3% cancers), 298 BL (benign lesions), 162 MN (malignant neoplasms). The percentage of PTC (papillary thyroid carcinoma) among cancers was higher in Bethesda MN (86.4%) and SM (suspicion of malignancy) nodules (91.2%) than in FLUS/AUS (57.1%, p < 0.005) and SFN/SHT (suspicion of follicular neoplasm/ suspicion of Hürthle cell tumor) nodules (36.8%, p < 0.001). TIRADS efficacy was higher for MN (AUC: 0.827-0.874) and SM nodules (AUC: 0.775-0.851) than for FLUS/AUS (AUC: 0.655-0.701) or SFN/SHT nodules (AUC: 0.593-0.621). FLUS/AUS (follicular lesion of undetermined significance/ atypia of undetermined significance) nodules assigned to a high risk TIRADS category had malignancy risk of 25%. In the SFN/SHT subgroup none TIRADS category changed nodule's malignancy risk. EU-TIRADS and AACE/ACE-AME-guidelines would allow diagnosing the highest number of PTC, FTC (follicular thyroid carcinoma), HTC (Hürthle cell carcinoma), MTC (medullary thyroid carcinoma). The highest OR value was for Kwak-TIRADS (12.6) and Korean-TIRADS (12.0). Conclusions: TIRADS efficacy depends on the incidence of PTC among cancers. All evaluated TIRADS facilitate the selection of FLUS/AUS nodules for the surgical treatment but these systems are not efficient in the management of SFN/SHT nodules.

Feasibility of Thyroid Imaging Reporting and Data System Classification in Predicting Thyroid Malignancy

In this study, we aimed to evaluate the diagnostic value of thyroid imaging reporting and data system (TIRADS) in the estimation of malignancy and assess the concordance between TIRADS and the histopathology results of the postoperative specimens. Consecutive ultrasound imaging records of patients with multinodular goiter from January 2010 to December 2017 who underwent surgery were retrospectively reviewed. The risk of malignancy of each TIRADS category was determined, and correlation with pathology was assessed. The patients with malignant cytology findings (Bethesda 6) who were categorized TIRADS 6 were excluded from the study. The positive and negative predictive values, sensitivity, specificity, and accuracy of the TIRADS classification were calculated on a 2 x 2 table with their own formulas. A total of 1457 patients were evaluated, and 1122 of these were included in the study. The risk of malignancy for nodules evaluated as TIRADS 2 was 0.6 per cent, TIRADS 3 was 13.1 per cent, TIRADS 4a was 20 per cent, TIRADS 4b was 61.1 per cent, TIRADS 4c was 85.7 per cent, and TIRADS 5 was 93.3 per cent. The positive predictive value of TIRADS classification was found to be 43.4 per cent, negative predictive value was found to be 90.7 per cent, sensitivity was found to be 78 per cent, specificity was found to be 68.4 per cent, and accuracy was found to be 70.7 per cent for our institution. The TIRADS classification based on suspicious ultrasound findings is reliable in predicting thyroid malignancy and can be routinely used in daily practice.

Developing a tool that could reliably refute total thyroidectomy for solitary Bethesda IV thyroid nodules

PURPOSE

To assess the reliability of a simple, accessible, cost-effective rule-out tool, for use in triaging patients with Bethesda IV nodules to appropriate surgery.

METHODS

The diagnostic tool was assembled by combining the negativity for suspicious ultrasound features (irregular margins, microcalcification, and a taller-than-wide orientation), and mutational marker negativity (BRAF and NRAS). The tool, (US^-/mutation^-), was tested on 167 patients with solitary Bethesda IV nodules. The primary outcome was its negative predictive value (NPV) for lesions requiring total thyroidectomy (TT). The impact of mutational marker negativity, as part of the tool, was evaluated by comparing the NPV of (US^-/mutation^-) to that of (US^-/mutation⁺).

RESULTS

10 out of 167 lesions were positive for a mutational marker. These underwent TT, and only 2/10 (20%) were benign, on final histology. In 6/8 malignant lesions, TT was concordant with current clinical guidelines. 157 patients comprised the negative study cohort, for both mutational markers and suspicious US features. These underwent thyroid lobectomy, and 17 cases resulted in malignancy, only 8 of which required completion thyroidectomy. Accordingly, the NPV of (US^-/mutation^-) for malignancy was 89% (140/157), and 95% (149/157) for malignancy requiring TT. However, the NPV of (US^-/mutation⁺) was 20% for malignancy, and 40% for malignancy requiring TT. These differences were statistically significant (89% vs. 20%; p < 0.0001, and 95% vs. 40%; p < 0.0001).

CONCLUSION

US^-/mutation^- is a reliable rule-out tool, with sufficient diagnostic accuracy to spare patients, with Bethesda IV nodules, an overly radical TT.

TI-RADS Diagnostic Performance: Which Algorithm is Superior and How Elastography and 4D Vascularity Improve the Malignancy Risk Assessment

Given the increased prevalence of thyroid nodules in the general population (~50%), the real challenge resides in correctly recognizing the suspicious ones. This study proposes to compare four important Thyroid Imaging and Reporting Data Systems (TI-RADS) and evaluate the contribution of elastography and 4D Color Doppler assessment of vascularity in estimating the risk of malignancy. In the study, 133 nodules with histopathological examination were included. Of these, 35 (26.31%) proved to be malignant. All nodules were classified using the four selected systems and our proposed improved score. The American College of Radiology (ACR) and EU TI-RADS had good sensitivity (94.28%, 97.14%) and NPV (93.33%, 95.83%), but fairly poor specificity (31.81%, 23.46%) and PPV (35.48%, 31.19%), with an accuracy of 42.8% and 45.8%, respectively. Horvath TI-RADS had better accuracy of 66.9% and somewhat improved specificity (62.24%), but poorer sensitivity (80%). Russ’ French TI-RADS includes elastography in the risk assessment strategy. This classification proved superior in all aspects (Se: 91.42%, Sp:82.65%, NPV:96.42%, PPV:65.30%, and Acc of 84.96%). The mean strain ratio (SR) value for malignant lesions was 5.56, while the mean SR value for benign ones was significantly lower, 2.54 (p < 0.05). It also correlated well with the response variable: histopathological result (p < 0.001). Although, adding 4D vascularity to the French score generated a similar calculated accuracy and from a statistical point of view, the parameter itself proved beneficial for predicting the malignancy risk (p < 0.001) and may add important knowledge in uncertain situations. Advanced ultrasound techniques definitely improved the risk estimation and should be used more extensively.

Thyroid FNA: Is cytopathologist review of ultrasound features useful?

Cytopathologist review of thyroid ultrasound (US) has been proposed to be useful in diagnosis and patient triage. This review explores the implications for practicing cytopathologists of integrating US review into the thyroid fine-needle aspiration diagnosis. At present, there is no agreed-upon system for combining cytologic and US features and communicating those results as a single report. If cytologists are performing tasks that require expertise in US interpretation, then they should know and be fully conversant with US interpretation. Whether cytologists performing aspirations require expertise in US interpretation is not clear. Regardless, cytologists should avoid using US results to alter their cytologic interpretations unless they clearly communicate that this is what they are doing. An evidence-based integrated reporting system that would allow cytologists to clearly explain to other physicians exactly how they reached their interpretation might provide value beyond current standard practice.

The Usefulness of the Thyroid Imaging Reporting and Data System in Determining Thyroid Malignancy

OBJECTIVES/HYPOTHESIS

To determine the effect of a modified Thyroid Imaging and Reporting Data System (TIRADS) in predicting malignancy in surgically treated nodules.

STUDY DESIGN

Retrospective review.

METHODS

This study was carried out at a tertiary care center from July 2016 to July 2017. Patients were included if they had a thyroid nodule that had an ultrasound assessment with subsequent fine-needle aspiration biopsy (FNAB) as well as surgical resection. Patients were excluded if they had previous head and neck surgery. Patients were stratified into those who had a formal modified TIRADS report by the radiologist versus those who had an ultrasound report without TIRADS reporting. FNAB results were reported as per Bethesda Thyroid Cytology Criteria, and the final pathology report was nominalized as malignant or benign.

RESULTS

One hundred twenty-four consecutive patients who met the inclusion criteria listed above were included within the study. Thirty one patients (25%) had a modified TIRADS report from the radiologist, whereas 93 patients (75%) did not. There was no statistical significance between the two groups in terms of: gender (P = .24), age (P = .77), FNAB results (P = .95), final surgical pathology (P = .90), or incidental findings of malignancy (P = .09). Comparative analysis showed no statistically significant difference between the two groups in terms of the concordance of FNAB and a final pathological diagnosis of malignancy (P = .91).

CONCLUSIONS

Despite the known diagnostic utility of the TIRADS in relation to FNAB results and its widespread use, this study shows that the overall detection of malignancy is not statistically different in those who received a modified TIRADS report.

LEVEL OF EVIDENCE

3 Laryngoscope, 130: 2087-2091, 2020.

Thyroid follicular microcarcinoma

Differentiated thyroid cancers are the most common malignancies arising in thyroid gland. Papillary thyroid cancer presents a very favorable prognosis, while follicular type is slightly more aggressive, mainly for its attitude to hematogenous spreading with distant metastases. Papillary microcarcinoma (10 mm or less) has an excellent prognosis, largely demonstrated, and its management is changed in the last few years, reducing surgical procedure, role of radio iodine ablation (RAI) and TSH suppression. But no effective data are available for follicular thyroid microcarcinoma (mFTC); very few reports and studies are present in literature about mFTC, mainly for its low incidence. Aim of this paper is to review current literature to reach, in absence of evidence, some suggestion in managing mFTC.

Interobserver agreement and efficacy of consensus reading in Kwak-, EU-, and ACR-thyroid imaging recording and data systems and ATA guidelines for the ultrasound risk stratification of thyroid nodules

PURPOSE

To investigate the interobserver agreement (IA) and the impact of consensus reading using four risk stratification systems for thyroid nodules (TN).

METHODS

Four experienced specialists independently rated US images of 80 TN according to the Kwak-TIRADS, EU-TIRADS, ACR TI-RADS, and ATA Guidelines. The cases were randomly extracted from a prospectively acquired database (n > 1500 TN). The observers were blinded to clinical data. This study was divided into two sessions (S1 and S2) with 40 image sets each. After every session, a consensus reading was carried out (C1, C2). Subsequently, the effect of C1 was tested in S2 with 40 new cases followed by C2. Fleiss' kappa (κ) was calculated for S1 and S2 to estimate the IA and learning curves. The results of C1 and C2 were used as reference for diagnostic accuracy calculations.

RESULTS

IA significantly increased (p < 0.01) after C1 with κ values of 0.375 (0.615), 0.411 (0.596), 0.321 (0.569), and 0.410 (0.583) for the Kwak-TIRADS, EU-TIRADS, ACR TI-RADS, and ATA Guidelines in S1 (S2), respectively. ROC analysis (C1 + C2) revealed similar areas under the curve (AUC) for the Kwak-TIRADS, EU-TIRADS, ACR TI-RADS, and ATA Guidelines (0.635, 0.675, 0.694, and 0.654, respectively, n.s.). AUC did not increase from C1 (0.677 ± 0.010) to C2 (0.632 ± 0.052, n.s.). ATA Guidelines were not applicable in five cases.

CONCLUSIONS

IA and diagnostic accuracy were very similar for the four investigated risk stratification systems. Consensus reading sessions significantly improved the IA but did not affect the diagnostic accuracy.

Evaluation of surgical risk and prognosis between thyroid nodules of size <1 and ≥1 cm

Background

The objective of this study was to evaluate the surgical risk and prognosis between thyroid nodules of size <1 and ≥1 cm and to explore whether it is reasonable generally to ignore the diagnosis and treatment of thyroid nodules and thyroid carcinoma <1 cm in wide areas of China.

Methods

A retrospective observational study included all first-time thyroid surgery patients between January 2005 and December 2016 of the First Affiliated Hospital of Harbin Medical University. All patients were divided into two groups (group A: <1 cm, group B: ≥1 cm) according to the maximum diameter of the nodules and demographics, surgery procedure, pathology, postoperative complications, morbidity, and mortality were analyzed.

Results

A total of 6,317 patients were reviewed and 3,424 (54.20%) of them were malignant; 2,128 patients in group A and 4,189 in group B. Patients in group A had better pathological diagnosis, inferior extent of lymph node metastasis, less surgical complexity, fewer postoperative complications, and longer disease-free survival (DFS).

Conclusions

Thyroid operations were safer and involved fewer postoperative complications when thyroid nodules were <1 cm and patients who were diagnosed with malignant thyroid disease had superior prognoses. Underdeveloped regions of China should diagnose and treat thyroid nodules <1 cm early.

ACR TI-RADS and ATA US scores are helpful for the management of thyroid nodules with indeterminate cytology

BACKGROUND

Cytologically indeterminate thyroid nodules currently present a challenge for clinical decision-making. The main aim of our study was to determine whether the classifications, American College of Radiology (ACR) TI-RADS and 2015 American Thyroid Association (ATA) guidelines, in association with The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), could be used to stratify the malignancy risk of indeterminate thyroid nodules and guide their clinical management.

METHODS

The institutional review board approved this retrospective study of a cohort of 140 thyroid nodules in 139 patients who were referred to ultrasound-guided fine-needle aspiration cytology (FNAC) from January 2012 to June 2016 with indeterminate cytological results (44 Bethesda III, 52 Bethesda IV and 44 Bethesda V) and in whom pre-FNAC thyroid US images and histological results after surgery were available. Each included nodule was classified by one radiologist blinded to the cytological and histological diagnoses according to the ACR TIRADS scores and the US patterns as recommended in the 2015 ATA guidelines. The risk of malignancy was estimated for Bethesda, TI-RADS scores, ATA US patterns and their combination.

RESULTS

Of the 140 indeterminate thyroid nodules examined, 74 (52.9%) were histologically benign. A different rate of malignancy (p < 0.001) among Bethesda III, IV and V was observed. The rate of malignancy increased according to the US suspicion categories (p < 0.001) in both US classifications (TI-RADS and ATA). Thyroid nodules classified as Bethesda III and the lowest risk US categories (very low, low and intermediate suspicion by ATA and 2, 3 and 4a by TI-RADS) displayed a sensitivity of 95.3% for both classifications and a negative predictive value of 94.3 and 94.1%, respectively. The highest risk US categories (high suspicion by ATA and 4b,4c and 5 by TI-RADS) were significantly associated with cancer (odds ratios [ORs] 14.7 and 9.8, respectively).

CONCLUSIONS

Ultrasound classifications, ACR TI-RADS and ATA guidelines, may help guide the management of indeterminate thyroid nodules, suggesting a conservative approach to nodules with low-risk US suspicion and Bethesda III, while molecular testing and surgery should be considered for nodules with high-risk US suspicion and Bethesda IV or V.

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP): a review for clinicians

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is an encapsulated or clearly delimited, noninvasive neoplasm with a follicular growth pattern and nuclear features of papillary thyroid carcinoma (PTC). It is considered a 'pre-malignant' lesion of the RAS-like group. Ultrasonography (US), cytology and molecular tests are useful to suspect thyroid nodules that correspond to NIFTP but there is wide overlap of the results with the encapsulated follicular variant of PTC (E-FVPTC). In these nodules that possibly or likely correspond to NIFTP, if surgery is indicated, lobectomy is favored over total thyroidectomy. The diagnosis of NIFTP is made after complete resection of the lesion by observing well-defined criteria. In the case of patients who received the diagnosis of FVPTC and whose pathology report does not show findings of malignancy (lymph node metastasis, extrathyroidal invasion, vascular/capsular invasion), if the tumor was encapsulated or well delimited, the slides can be revised by an experienced pathologist to determine whether the diagnostic criteria of NIFTP are met, but special attention must be paid to the adequate representativeness of the capsule and tumor. Since NIFTP is not 'malignant', tumor staging is not necessary and patients are not submitted to thyroid cancer protocols or guidelines. We believe that patients with NIFTP without associated malignancy and without nodules detected by US of the remnant lobe (if submitted to lobectomy) can be managed like those with follicular adenoma.

Extending expressed RNA genomics from surgical decision making for cytologically indeterminate thyroid nodules to targeting therapies for metastatic thyroid cancer

The Afirma Genomic Sequencing Classifier (GSC) is a rule‐out test for malignancy/noninvasive follicular thyroid neoplasms with papillary‐like nuclear features among patients with Bethesda category III/IV nodules, whereas the complimentary Xpression Atlas provides genomic insights from a curated panel of 511 genes among GSC suspicious and Bethesda category V/VI nodules. Together, they facilitate personalized treatment decisions based on genomic insights derived from the transcriptome of the biopsied target and extend the diagnostic and therapeutic reach of cytopathologists and fine‐needle aspiration biopsy sample collection.

Multispectral Optoacoustic Tomography of Benign and Malignant Thyroid Disorders: A Pilot Study

This study aimed at evaluating hybrid multispectral optoacoustic tomography/ultrasound for imaging of thyroid disorders, including Graves' disease and thyroid nodules. Methods: The functional biomarkers and tissue parameters deoxygenated hemoglobin, oxygenated hemoglobin, total hemoglobin, saturation of hemoglobin, fat content, and water content were analyzed in thyroid lobes affected by Graves' disease (n = 6), thyroid lobes with healthy tissue (n = 8), benign thyroid nodules (n = 13), and malignant thyroid nodules (n = 3). Results: In Graves' disease, significantly higher deoxygenated hemoglobin (3.18 ± 0.52 vs. 2.13 ± 0.62; P = 0.0055) and total hemoglobin (8.34 ± 0.88 vs. 6.59 ± 1.16; P = 0.0084) and significantly lower fat content (0.64 ± 0.37 vs. 1.69 ± 1.25; P = 0.0293) were found than in healthy controls. Malignant thyroid nodules showed significantly lower saturation of hemoglobin (55.4% ± 2.6% vs. 60.8% ± 7.2%; P = 0.0393) and lower fat content (0.62 ± 0.19 vs. 1.46 ± 0.87; P = 0.1295) than benign nodules. Conclusion: This pilot study showed the applicability and the potential of hybrid multispectral optoacoustic tomography/ultrasound to semiquantitatively provide tissue characterization and functional parameters in thyroid disorders for improved noninvasive diagnostics of thyroid diseases.