The ultrasound risk stratification systems for thyroid nodule have been evaluated against papillary carcinoma. A meta-analysis

Performance of ACR-TIRADS in assessing thyroid nodules does not vary according to patient age

AIMS

A few studies have evaluated the performance of the American College of Radiology Thyroid Imaging Reporting And Data System (ACR-TIRADS) in pediatric and elderly patients and found differences between the latter two age groups and middle adulthood. Thus, the present study was undertaken to explore the possible variation of ACR-TIRADS performance across different ages of patients.

METHODS

A retrospective population undergoing thyroidectomy was selected to use histology as the reference standard. Ultrasound images were reviewed, and alignment of ACR-TIRADS with the corresponding histological diagnosis was made afterwards. Results of the age groups were compared. The ACR-TIRADS diagnostic performance was calculated considering the assessment of nodules across risk categories (i.e., from TR1 to TR5), rate of unnecessary FNAC (UN-FNAC), and rate of necessary but non-performed FNAC (NNP-FNAC).

RESULTS

Overall, 114 patients with a total of 220 nodules (46 carcinomas) were included. The rate of UN-FNAC was 66.3%, being 93.1% in TR3, 82.1% in TR4, and 31.4% in TR5. There were 15 NNP-FNACs. No significant difference was observed between age groups in terms of sample size, nodule, cancer, and FNAC. The nodule assessment according to ACR-TIRADS categories did not vary across ages. Sensitivity and specificity recorded in three age tertiles were not significantly different.

CONCLUSIONS

The present study shows that the performance of ACR-TIRADS is not significantly influenced by patient age.

The value of ACR, European, Korean, and ATA ultrasound risk stratification systems combined with RAS mutations for detecting thyroid carcinoma in cytologically indeterminate and suspicious for malignancy thyroid nodules

PURPOSE

The aim of this study was to evaluate the diagnostic value of four commonly utilized ultrasound (US) RSSs, namely, the American College of Radiology [ACR], European [EU], Korean [K] TI-RADSs and American Thyroid Association [ATA] US-based RSS criteria, in combination with activating point mutations of the RAS genes (NRAS, HRAS, and KRAS) for detection of thyroid carcinoma in cytologically indeterminate and suspicious for malignancy thyroid nodules.

METHODS

We retrospectively analyzed cytologically indeterminate and suspicious for malignancy thyroid nodules which underwent US, molecular testing and surgery between September 1, 2018, and December 31, 2023. Receiver operating characteristic (ROC) curves were generated, and the area under the curve (AUC, 95% confidence interval [CI]) was calculated.

RESULTS

A total of 100 cytologically indeterminate and 24 suspicious for malignancy thyroid nodules were analyzed. Compared to the four US-based RSSs alone, the diagnostic value of the four US-based RSSs combined with RAS mutations did not significantly improved (cytologically indeterminate, AUC [95% CI] 0.6 [0.5-0.7] and 0.6 [0.5-0.7], respectively, p = 0.70; cytologically suspicious for malignancy, AUC [95% CI] 0.7 [0.5-0.9] and 0.8 [0.6-0.9], respectively, p = 0.23).

CONCLUSIONS

The diagnostic value of the four main US-based RSSs (ACR, EU, K, and ATA) was not improved in conjunction with the evaluation of RAS mutations for preoperative risk stratification of cytologically indeterminate thyroid nodules.

CLINICAL RELEVANCE STATEMENT

In cytologically indeterminate nodules categorized according to US-based RSSs, isolated RAS positivity does not reliably distinguish between benignity and malignancy.

Combining Image Similarity and Predictive Artificial Intelligence Models to Decrease Subjectivity in Thyroid Nodule Diagnosis and Improve Malignancy Prediction

OBJECTIVES

To evaluate the efficacy of combining predictive artificial intelligence (AI) and image similarity model to risk stratify thyroid nodules, using retrospective external validation study.

METHODS

Two datasets were used to determine efficacy of the AI application. One was Stanford dataset ultrasound images of 192 nodules between April 2017 and May 2018 and the second was private practice consisting of 118 thyroid nodule images between January 2018 and December 2023. The nodules had definitive diagnosis by cytology or surgical pathology. The AI application was used to predict the diagnosis and American College of Radiology Thyroid Imaging and Data System (ACR TI-RADS) score.

RESULTS

In the Stanford dataset, the AI application predicted malignancies with sensitivity of 1.0 and specificity of 0.55. Positive predictive value (PPV) was 0.18 and negative predictive value (NPV) was 1.0. The Area Under the Curve - Receiver Operating Characteristic was 0.78. ACR TI-RADS based clinical recommendation had a polychoric correlation of 0.67. In the private dataset, the AI application predicted malignancies with sensitivity of 0.91 and specificity of 0.95. PPV was 0.8 and NPV was 0.98. The area under the curve - receiver operating characteristic was 0.93 and accuracy was 0.94. ACR TI-RADS based score had a polychoric correlation of 0.94.

CONCLUSION

The AI application showed good performance for sensitivity and NPV between the two datasets and demonstrated potential for 61.5% reduction in the need for fine needle aspiration and strong correlation to ACR TI-RADS. However, PPV was variable between the datasets possibly from variability in image selection and prevalence of malignancy. If implemented widely and consistently among various clinical settings, this could lead to decreased patient burden associated with an invasive procedure and possibly to decreased health care spending.

Application of microvascular ultrasound-assisted thyroid imaging report and data system in thyroid nodule risk stratification

OBJECTIVES

To establish superb microvascular imaging (SMI) based thyroid imaging reporting and data system (SMI TI-RADS) for risk stratification of malignancy in thyroid nodules.

METHODS

In total, 471 patients, comprising 643 thyroid nodules, who received conventional ultrasound (US), SMI, and a final diagnosis were extensively analyzed. A qualitative assessment of US features of the nodules was performed followed by univariable and multivariable logistic regression analyses, leading to the construction of the SMI TI-RADS, which was further verified using internal and external validation cohorts.

RESULTS

Among the stand-alone US, predictive factors were the shape and margins of the nodules, echogenicity and echogenic foci, vascularity, extrathyroidal extension, ring-SMI patterns, penetrating vascularity, flow-signal enlarged, and vascularity area ratio. SMI TI-RADS depicted an enhanced area under the receiver operating characteristic curve (AUC) of 0.94 (95% CI: 0.92, 0.96; p < 0.001 relative to other stratification systems), a 79% biopsy yield of malignancy (BYM, 189/240 nodules), and a 21% unnecessary biopsy rate (UBR, 51/240 nodules). In the verification cohorts, we demonstrated AUCs, malignancy biopsy yields, and unnecessary biopsy rates of 0.88 (95% CI: 0.83, 0.94), 79% (59/75 nodules), and 21% (16/75 nodules) for the internal cohort, respectively, and 0.91 (95% CI: 0.85, 0.96), 72% (31/43 nodules), and 28% (12/43 nodules) for the external cohort, respectively.

CONCLUSION

SMI TI-RADS was found to be superior in diagnostic sensitivity, specificity, and efficiency than existing TI-RADSs, showing better stratification of the malignancy risk, and thus decreasing the rate of unnecessary needle biopsy.

CRITICAL RELEVANCE STATEMENT

To develop an imaging and data system based on conventional US and SMI features for stratifying the malignancy risk in thyroid nodules.

KEY POINTS

SMI features could improve thyroid nodule risk stratification. SMI TI-RADS showed superior diagnostic efficiency and accuracy for biopsy guidance. SMI TI-RADS can provide better guidance for clinical diagnosis and treatment of thyroid nodules.

Multiparametric ultrasound evaluation of thyroid nodules

Thyroid nodules are common incidental findings. Most of them are benign, but many unnecessary fine-needle aspiration procedures, core biopsies, and even thyroidectomies or non-invasive treatments have been performed. To improve thyroid nodule characterization, the use of multiparametric ultrasound evaluation has been encouraged by most experts and several societies. In particular, US elastography for assessing tissue stiffness and CEUS for providing insight into vascularization contribute to improved characterization. Moreover, the application of AI, particularly machine learning and deep learning, enhances diagnostic accuracy. Furthermore, AI-based computer-aided diagnosis (CAD) systems, integrated into the diagnostic process, aid in risk stratification and minimize unnecessary interventions. Despite these advancements, challenges persist, including the need for standardized TIRADS, the role of US elastography in routine practice, and the integration of AI into clinical protocols. However, the integration of clinical information, laboratory information, and multiparametric ultrasound features remains crucial for minimizing unnecessary interventions and guiding appropriate treatments. In conclusion, ultrasound plays a pivotal role in thyroid nodule management. Open questions regarding TIRADS selection, consistent use of US elastography, and the role of AI-based techniques underscore the need for ongoing research. Nonetheless, a comprehensive approach combining clinical, laboratory, and ultrasound data is recommended to minimize unnecessary interventions and treatments.

NIFTP-adjusted risk estimation of Bethesda thyroid cytology categories should consider the indication for FNA according to TIRADS

BACKGROUND

Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was firstly described in 2016. Since NIFTP is thought a non-malignant tumor, the Bethesda system for thyroid cytology proposes two estimations of risk of malignancy of the diagnostic categories, one considering NIFTP as cancer and another one considering it as a benign neoplasm. The present study aimed to review NIFTPs in a single center, re-assess them across categories of three Thyroid Imaging Reporting and Data Systems (TIRADSs), and define the indication for biopsy according to the category-specific size cut-offs.

METHODS

The study period was from 2017 to 2023. The institutional database was searched for histologically proven NIFTPs with preoperative ultrasound images. NIFTPs were re-assessed according to the American College of Radiology (ACR), European (EU), and Korean (K) TIRADSs. The indication for biopsy was defined according to TIRADS category-specific size threshold.

RESULTS

Twenty NIFTPs from 19 patients were included. The median size of the NIFTPs was 23 mm. According to ultrasound, 80-85% of NIFTPs were at low-intermediate risk and 5-15% at high risk without significant difference among the tree TIRADSs (p = 0.91). The indication for FNA, according to three TIRADSs, was found in 52-58% of cases with no significant difference among systems (p = 0.96).

CONCLUSION

NIFTPs have heterogeneous presentation according to TIRADSs with very low indication rate for FNA.

Meaning of ACR-TIRADS recommendation in favor of follow-up rather than FNAC in thyroid nodules

Thyroid Imaging Reporting and Data Systems (TIRADSs) have been largely diffused for their high accuracy in risk stratification of thyroid nodules (TNs) and their selection for fine-needle aspiration cytology (FNAC). The most popular TIRADSs are ACR-, EU-, and K-TIRADS, with some discrepancies each other. One major difference is that ACR-TIRADS includes a recommendation in favor of follow-up in TNs having a major diameter insufficient to indicate FNAC. The present study aimed to explore prevalence and significance of this recommendation. EU- and K-TIRADS were used as comparator. A retrospective series of thyroidectomies was searched according to a pre-defined protocol. The study period was 2019-2023. Preoperative ultrasound images were reviewed by radiologists blinded of clinical data. Matching of TIRADS and histology was performed later. Histology was the gold standard. The study series included 39 TNs classified as category 3, 4, or 5 and assessed for follow-up according to ACR-TIRADS. The overall cancer frequency was 25.6%, being 13% in category 3, 20% in category 4, and 83.3% in category 5. The category assessment according to ACR-, EU-, and K-TIRADS was not significantly different. EU-TIRADS indicated FNAC in 10 TNs of which two cancers and eight benign lesions. K-TIRADS recommended FNAC in 32 TNs of which seven cancers and 25 benign lesions. TNs assessed for follow-up according to ACR-TIRADS are cancer in one-fourth of cases. EU- and, especially, K-TIRADS allow us to select for FNAC cancers, with the burden of non-negligible frequency of unnecessary FNACs.

Reappraising the role of thyroid scintigraphy in the era of TIRADS: A clinically-oriented viewpoint

Thyroid nodules (TNs) are a common entity, with the majority being benign. Therefore, employing an accurate rule-out strategy in clinical practice is essential. In the thyroid field, the current era is significantly marked by the worldwide diffusion of ultrasound (US)-based malignancy risk stratification systems of TN, usually reported as Thyroid Imaging Reporting And Data System (TIRADS). With the advent of US (and later TIRADS), the role of thyroid scintigraphy (TS) in clinical practice has gradually diminished. The authors of the present paper believe that the role of TS should be reappraised, also considering its essential role in detecting autonomously functioning thyroid nodules and its limited contribution to detecting thyroid cancers. Thus, this document aims to furnish endocrinologists, radiologists, surgeons, and nuclear medicine physicians with practical information to appropriately use TS.

Risk of TIRADS-based inappropriate FNAC in autonomous thyroid nodules is clinically negligible

Objective

Thyroid nodule (TN) is usually managed according to Thyroid Imaging And Reporting Data Systems (TIRADS) with the major aim to reduce as much as possible unnecessary fine-needle aspiration cytologies (UN-FNACs). Since the assessment of autonomously functioning thyroid nodule (AFTN) according to TIRADS is heterogeneous, that virtually benign entity may increase the rate of UN-FNAC. This study retrospectively analyzed the appropriateness of TIRADS-based FNAC indication in AFTNs, also looking at the impact of TSH and nodule size.

Methods

Cases diagnosed with AFTN on scintigraphy were searched. Patients who had undergone AFTN treatment, were on medications or supplementation that could affect thyroid function, or had multiple AFTNs were excluded. The AFTNs were assessed according to ACR-TIRADS.

Results

Forty-eight AFTNs were included of which 37.5% had FNAC indication according to TIRADS. The FNAC indication rate in the case of TSH lower than 0.4 mIU/L was significantly higher than in other cases (P = 0.0078). The most accurate TSH cut-off and AFTN size associated with UN-FNAC were ≤ 0.41 mIU/L and > 22 mm, respectively. The multivariate analysis showed that both TSH and nodule size were independent predictors of UN-FNAC with OR of 6.65 and 6.46, respectively. According to these data, the rate of FNAC indication dropped to 4.16%.

Conclusion

Inappropriate FNACs in AFTNs are primarily observed in patients with low TSH and large AFTN. Since these cases typically undergo scintigraphy, the risk of TIRADS-based UN-FNAC is clinically negligible. There is no need for integrating other imaging procedures into the TIRADS model.

Combining TSH measurement with TIRADS assessment to further improve the detection of thyroid cancers

BACKGROUND

Thyroid Imaging Reporting and Data Systems (TIRADSs) have demonstrated high performance in risk stratification of thyroid nodules (TNs). However, further improvements are needed in view of the ongoing project of an international TIRADS. Even if thyroid-stimulating hormone (TSH) measurement is traditionally used to assess the thyroid function, several papers have reported that higher TSH levels are associated with the presence of differentiated thyroid carcinoma (DTC). The present study aimed to investigate the role of TSH levels as improvement factor of American College of Radiology (ACR-), European Thyroid Association (EU-), and Korean Society (K-)TIRADS.

METHODS

Patients undergoing thyroidectomy were reviewed and TNs were re-assessed according to TIRADSs. Different TSH subgroups were attained. Histology was the reference standard. DTC risk of relapse was assessed according to American Thyroid Association guidelines.

RESULTS

The study series included 97 patients with 39.2% cancer prevalence. ACR-, EU-, and K-TIRADS indicated fine-needle aspiration cytology (FNAC) in 78.9%, 81.6%, and 92.1% of cases, respectively. All high-risk DTC had FNAC indication according to the three TIRADSs. The cancer rate was significantly lower in patients with TSH<0.4 mIU/L (P=0.04). The receiver operating characteristic (ROC) curve analysis showed that the best TSH cut-off to detect DTC patient was >1.3 mIU/L with Area Under the Curve (AUC)=0.70. Combining TSH data with TIRADS, the sensitivity of ACR-, EU-, and K-TIRADS increased to 92.1% 89.5%, and 94.7%, respectively. Conversely, the rate of unnecessary FNAC raised. At multivariate analysis, gender, TSH, and TIRADS were independent predictors of cancer.

CONCLUSIONS

Even if TIRADSs are strongly reliable to stratify the risk of malignancy of TNs, measuring TSH can further improve our sensitivity in detecting DTC.

Diagnostic Efficiency of ACR-TIRADS Score for Differentiating Benign and Malignant Thyroid Nodules of Various Pathological Types

BACKGROUND Thyroid nodule prevalence reaches 65% in the general population. Hence, appropriate ultrasonic examination is key in disease monitoring and management. We investigated the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) score for diagnosis of benign and malignant thyroid nodules and pathological types. MATERIAL AND METHODS A retrospective study was conducted. According to ultrasound images, ultrasonic characteristics of benign and malignant thyroid nodules and different pathological types were analyzed using ACR-TIRADS score, and diagnostic value was determined. AUCs were compared for tumor diagnosis and differentiation. RESULTS Overall, 1675 thyroid nodules from 1614 patients were included. AUC value of papillary thyroid carcinoma (PTC) diagnosed with ACR-TIRADS was highest (0.955 [95% CI=0.946-0.965]), while that of follicular thyroid carcinoma (FTC) was lowest (0.877 [95% CI=0.843-0.912]). FTC had the highest sensitivity (95.1%) and lowest specificity (64.8%). When the cut-off value was 5.5 points, accuracy of diagnosing PTC and anaplastic thyroid carcinoma (ATC) was highest, 80.5% and 78.7% respectively. Comparison of the multi-index prediction model constructed by multivariable logistic regression analysis and prediction model constructed by ACR-TIRADS score showed, when evaluating PTC and ATC, the multi-index model was better: AUCs of PTC were 0.966 vs 0.955, and AUCs of ATC were 0.982 vs 0.952, respectively, (P<0.05). CONCLUSIONS ACR-TIRADS score-based ultrasound examination of thyroid nodules aids diagnosis of benign and malignant thyroid nodules. TIRADS criteria favor diagnosis of PTC (and ATC) over FTC. ACR-TIRADS score can help clinicians diagnose thyroid nodules quickly and earlier, exhibits good clinical value, and can prevent missed diagnoses.

Prediction of classical versus non classical papillary thyroid carcinoma subtypes from cytology of nodules classified according to TIRADS

PURPOSE

Our purposes were: 1) to estimate the prediction performance (PP) of cytology in identifying papillary thyroid carcinoma (PTC) subtypes; 2) to explore how the PTC subtypes distribute among the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) categories.

METHODS

Nodules were included if both the histology with the PTC subtype report and the cytology report with the possible PTC subtype were available. The PP was calculated by making the proportion of True positives/False positives+false negatives.

RESULTS

309 cytologically "suspicious for malignancy" and "malignant" thyroid nodules with PTC histology were evaluated. ACR TI-RADS categorization for classical PTC was significantly different from non-classical PTC (p-value 0.02). For the whole cohort the PP of cytologically classical cases was 0.74, while that of cytologically non classical cases was 0.41. ACR TI-RADS categorization was not significantly different for aggressive vs non-aggressive PTC subtypes (p-value 0.1). When considering only aggressive or non-aggressive PTC subtypes, the PP of cytologically classical cases was respectively 0.86 and 0.87, while that of cytologically non classical cases was respectively 0.27 and 0.22. The PP of cytologically classical cases was 0.73 and 0.79, respectively for macroPTCs and microPTCs, while that of cytologically non classical cases was 0.55 and 0.33, respectively for macroPTCs and microPTCs.

CONCLUSION

Cytology examination reliably performed in predicting classical PTC versus non classical PTC subtypes. ACR TI-RADS categorization was significantly different among classical PTC versus non classical PTC subtypes.

Value of repeated US-guided fine-needle aspiration (US-FNAB) in the follow-up of benign thyroid nodules: a real-life study based on the MoCyThy (Modena's Cytology of the Thyroid) DATABASE with a revision of the literature

PURPOSE

The utility of repeating ultrasound-guided fine-needle aspiration (US-FNAB) in the follow-up of benign (THY2) thyroid nodules is still debated. The aim of this study was to retrospectively investigate the diagnostic value of re-biopsy of thyroid nodules following an initially benign result.

METHODS

We retrospectively analyzed US-FNABs performed at the Unit of Endocrinology of Modena from 2006 to 2009. The firstly benign cytological result was compared with the cytological results of subsequent US-FNABs (2nd and/or 3rd) executed on the same nodule.

RESULTS

Among 10449 US-FNABs, 6270 (60%) received a THY2 cytological categorization. Of them, 278 (4.43%) underwent a subsequent US-FNAB: 86.7% maintained the same cytology, 32 (11.5%) changed to THY3 (indeterminate) and 5 (1.8%) to THY4 (suspicious of malignancy). Among the 24 nodules addressed to surgery, 9 (37%) were histologically malignant, with an overall miss rate of 3.2%. Male patients had higher risk of discordant results at subsequent US-FNAB (p = 0.005, OR:3.59, 95%CI:1.453-7.769) while dimensional increase above 5 mm was predictive of concordant benign cytology (p = 0.036, OR:0.249, 95%CI:0.068-0.915). Age, suspicious US characteristics, and distance between US-FNABs resulted not predictive.

CONCLUSIONS

Re-biopsy of benign nodules confirmed the benign nature in most cases. In case of discordant cytology, relocation in indeterminate category was the most common. The histological diagnosis of cancer occurred in one quarter of nodules surgically removed, with a low overall clinically significant miss rate. Thus, a small percentage of false negatives exists; males and subjects with US suspicious nodules should be carefully followed-up, considering case by case re-biopsy possibility.

Improving the TIR3B oncological stratification: try to bridge the gap through a comprehensive presurgical algorithm

PURPOSE

Indeterminate cytology still puzzles clinicians, due to its wide range of oncological risks. According to the Italian SIAPEC-IAP classification, TIR3B cytology holds up to 30% of thyroid cancer, which justifies the surgical indication, even if more than half of cases do not result in a positive histology. The study aim is to identify potential clinical, ultrasound or cytological features able to improve the surgical indication.

METHODS

Retrospective analysis. A consecutive series of TIR3B nodules referred to the Endocrine Unit of Careggi Hospital from 1st May 2014 to 31st December 2021 was considered for the exploratory analysis (Phase 1). Thereafter, a smaller confirmatory sample of consecutive TIR3B diagnosed and referred to surgery from 1st January 2022 to 31st June 2022 was considered to verify the algorithm (Phase 2). The main clinical, ultrasound and cytological features have been collected. A comprehensive stepwise logistic regression was applied to build a prediction algorithm. The histological results represented the final outcome.

RESULTS

Of 599 TIR3B nodules referred to surgery, 451 cases were included in the exploratory analysis. A final score > 14.5 corresponded to an OR = 4.98 (95% CI 3.24-7.65, p < 0.0001) and showed a PPV and NPV of 57% and 79%, respectively. The Phase 2 analysis on a confirmatory sample of 58 TIR3B cytology confirmed that a threshold of 14.5 points has a comparable PPV and NPV of 53% and 80%, respectively.

CONCLUSIONS

A predictive algorithm which considers the main clinical, US and cytological features can significantly improve the oncological stratification of TIR3B cytology.

Thyroid ultrasound and its ancillary techniques

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

The American Thyroid Association risk classification of papillary thyroid cancer according to presurgery cytology

OBJECTIVE

To compare the American Thyroid Association (ATA) risk staging of histologically proven papillary thyroid cancer (PTC) in patients who received a presurgery cytologic result of either indeterminate thyroid nodules (ITNs, Bethesda III/IV) or suspicious for malignancy/malignant (TIR 4/5, Bethesda V/VI).

METHODS

Clinical, ultrasonographic, cytological data from patients with histologically diagnosed PTC were retrospectively collected.

RESULTS

Patients were stratified according to the preoperative fine-needle aspiration cytology into 2 groups: 51 ITNs (TIR3A/3B) and 118 suspicious/malignant (TIR 4/5). Male/female ratio, age, and presurgery TSH level were similar between the 2 groups. At ultrasound, TIR 4/5 nodules were significantly more frequently hypoechoic (P = .037), with irregular margins (P = .041), and with microcalcifications (P = .020) and were more frequently classified as high-risk according to the European Thyroid Imaging and Reporting Data System (EU-TIRADS; P = .021). At histology, the follicular PTC subtype was significantly more prevalent among ITNs while classical PTC subtype was more frequent in TIR 4/5 group (P = .002). In TIR 4/5 group, a higher rate of focal vascular invasion (P < .001) and neck lymph node metastasis (P = .028) was observed. Intermediate-risk category according to ATA was significantly more frequent in TIR 4/5 group while low-risk category was more frequently found among ITNs (P = .021), with a higher number of patients receiving radioiodine in TIR 4/5 group (P = .002). At multivariate logistic regression, having a TIR 4/5 cytology was associated with a significant risk of having a higher ATA risk classification as compared to ITN (OR 4.6 [95% CI 1.523-14.007], P = .007), independently from presurgery findings (nodule size at ultrasound, sex, age, and EU-TIRADS score).

CONCLUSIONS

Papillary thyroid cancers recorded among ITNs are likely less aggressive and are generally assessed as at lower risk according to ATA classification.

Molecular imaging and related therapeutic options for medullary thyroid carcinoma: state of the art and future opportunities

Due to its rarity and non-specific clinical presentation, accurate diagnosis, and optimal therapeutic strategy of medullary thyroid carcinoma (MTC) remain challenging. Molecular imaging provides valuable tools for early disease detection, monitoring treatment response, and guiding personalized therapies. By enabling the visualization of molecular and cellular processes, these techniques contribute to a deeper understanding of disease mechanisms and the development of more effective clinical interventions. Different nuclear imaging techniques have been studied for assessing MTC, and among them, PET/CT utilizing multiple radiotracers has emerged as the most effective imaging method in clinical practice. This review aims to provide a comprehensive summary of the current use of advanced molecular imaging modalities, with a particular focus on PET/CT, for the management of patients with MTC. It aims to guide physicians towards a rationale for the use of molecular imaging also including theranostic approaches and novel therapeutical opportunities. Overall, we emphasize the evolving role of nuclear medicine in MTC. The integration of diagnostics and therapeutics by in vivo molecular imaging represents a major opportunity to personalize treatment for individual patients, with targeted radionuclide therapy being one representative example.

Risk stratification of papillary thyroid cancers using multidimensional machine learning

BACKGROUND

Papillary thyroid cancer (PTC) is one of the most common endocrine malignancies with different risk levels. However, preoperative risk assessment of PTC is still a challenge in the worldwide. Here, the authors first report a Preoperative Risk Assessment Classifier for PTC (PRAC-PTC) by multidimensional features including clinical indicators, immune indices, genetic feature, and proteomics.

MATERIALS AND METHODS

The 558 patients collected from June 2013 to November 2020 were allocated to three groups: the discovery set [274 patients, 274 formalin-fixed paraffin-embedded (FFPE)], the retrospective test set (166 patients, 166 FFPE), and the prospective test set (118 patients, 118 fine-needle aspiration). Proteomic profiling was conducted by FFPE and fine-needle aspiration tissues from the patients. Preoperative clinical information and blood immunological indices were collected. The BRAFV600E mutation were detected by the amplification refractory mutation system.

RESULTS

The authors developed a machine learning model of 17 variables based on the multidimensional features of 274 PTC patients from a retrospective cohort. The PRAC-PTC achieved areas under the curve (AUC) of 0.925 in the discovery set and was validated externally by blinded analyses in a retrospective cohort of 166 PTC patients (0.787 AUC) and a prospective cohort of 118 PTC patients (0.799 AUC) from two independent clinical centres. Meanwhile, the preoperative predictive risk effectiveness of clinicians was improved with the assistance of PRAC-PTC, and the accuracies reached at 84.4% (95% CI: 82.9-84.4) and 83.5% (95% CI: 82.2-84.2) in the retrospective and prospective test sets, respectively.

CONCLUSION

This study demonstrated that the PRAC-PTC that integrating clinical data, gene mutation information, immune indices, high-throughput proteomics and machine learning technology in multicentre retrospective and prospective clinical cohorts can effectively stratify the preoperative risk of PTC and may decrease unnecessary surgery or overtreatment.

Thyroid metastasis from renal cell carcinoma presenting as a solid mass with rapid enlargement

Summary

Thyroid metastases from nonthyroidal malignancies (NTMs) represent a diagnostic challenge, often displaying heterogeneous clinical manifestations. These metastases are rare but significant, accounting for approximately 2% of thyroid malignancies. Distinguishing them from primary thyroid malignancies is challenging due to the lack of specific ultrasound features, and the ultrasound-based risk stratification systems offer limited utility in such cases. Fine needle aspiration cytology is crucial for definitive diagnosis, yet it may not always provide accurate results. In this case report, we describe a unique instance of thyroid metastases originating from renal cell carcinoma, emphasizing the complexities in diagnosis and the importance of considering oncological conditions when assessing thyroid masses. Awareness of thyroid metastasis from NTMs, particularly in cases of diffuse thyroid hypoechogenicity and hypothyroidism, is essential for clinicians in their diagnostic approach.

Learning points

Thyroid metastases from nonthyroidal malignancies are diagnostic challenges due to their heterogeneous clinical presentations, often mimicking primary thyroid malignancies. Thyroid metastases from nonthyroidal malignancies are relatively rare, but they still account for approximately 2% of thyroid malignancies. It is fundamental to consider oncological conditions when assessing thyroid masses, especially in cases of diffuse thyroid hypoechogenicity, hypothyroidism, and history of other tumors. Thyroid presentation is quite similar to that of autoimmune hypothyroidism, endocrinologists must be aware of the possibility of thyroid hypofunction due to the massive invasion of the parenchyma.

Laser Ablation for Benign and Malignant Thyroid Nodules - A Mini-Literature Review

BACKGROUND

Thyroid nodules are a common disease in endocrine clinical practice. They are often benign, asymptomatic, and do not require any treatment. But, in a non-negligible proportion, they can cause local symptoms of compression or esthetic concerns. In the last two decades, the advent of laser ablation (LA) has become a valid alternative to surgery for these nodules. Moreover, LA has also been successfully used to treat small thyroid cancers and neck recurrence.

OBJECTIVE

This study aims to review and summarize the published literature regarding LA in the treatment of benign and malignant thyroid nodules.

METHODS

A comprehensive literature search on PubMed from 2000 to 2023 was carried out. The search terms included: thyroid, nodules, laser, cancer, lymph node metastasis, and autonomously functioning nodules. The most relevant investigations in the field were selected.

RESULTS

In the last two decades, a very remarkable number of papers consistently demonstrated that LA is able to durably shrink benign nodules on average by about 50%; better results are obtained in spongiform nodules with a volume less than 15 ml; 500 J/ml of tissue should be administered. LA may be a valid option to treat autonomously functioning nodules and papillary thyroid cancers especially if they are <10 mm, and with neck recurrence in patients already submitted to surgery. LA has also been demonstrated to be cost-effective compared to surgical treatment both in benign and malignant lesions, with similar outcomes.

CONCLUSION

Evidence demonstrated that LA is a valid alternative to surgery in benign and malignant thyroid lesions, but also to obtain a successful treatment, a careful selection of the lesion is mandatory.

Appropriate and mindful measurement of serum calcitonin in patients with thyroid nodules. A white paper

Medullary thyroid carcinoma (MTC) is an infrequent thyroid malignancy that is often diagnosed at advanced stage with consequent poor prognosis. Thus, the earlier the diagnosis of MTC, the better the prognosis. Unfortunately, the preoperative detection of MTC remains challenging in clinical practice. In fact, while ultrasound and fine-needle aspiration cytology have suboptimal performance in this context, measuring serum calcitonin (Ctn), fully recognized as the most reliable test to detect MTC, is not universally accepted as routine test in all patients with thyroid nodule(s). The authors of this paper reappraise critically the matter of Ctn measurement in view of the recent advancements in the literature to point out the essential information to be known, and then to prepare an easy-to-use guide for clinicians to appropriately consider the measurement of serum Ctn during clinical practice.

Should we reconsider high-risk features in thyroid ultrasonography?

OBJECTIVE

Round shape is generally considered to reduce the risk of malignancy according to recent guidelines. On the contrary, according to some reports, spherically shaped thyroid nodules are associated with a higher risk of malignancy. Thus, we aimed to evaluate the malignancy risk of solid round isoechoic nodules detected at thyroid ultrasonography and compare it with that of solid ovoid isoechoic nodules.

METHODS

Between 2017 and 2022, solitary solid round isoechoic nodules with diameters ³10 and £25 mm at thyroid ultrasonography were retrospectively selected and enrolled in the study. Age, size, nodule volume, serum thyrotropin levels, thyroid antibody levels, and cytopathological and histopathological results were recorded.

RESULTS

A total of 457 solitary solid isoechoechoic nodules from 457 patients (262 females and 195 males; median age, 59 [31-70] years) were selected, of which 203 were solid round isoechoic nodules, and 254 were solid ovoid isoechoic nodules. A total of 54 surgical operations were performed on 457 nodules, and 31 of them resulted in malignancy. From the 31 malignant results, 25 originated from solid round isoechoic nodules and the remaining 6 originated from solid ovoid isoechoic nodules (p<0.025).

CONCLUSION

We found that round nodules have higher malignancy rates than ovoid nodules. We think that ultrasonographic risk stratification systems used to target the most suitable nodules for the necessary biopsies can be dynamically updated, and sphericity can be added as a parameter in patient-based decision-making.

A Reappraisal of Suspicious Sonographic Features of Thyroid Nodules: Shape Is Not an Independent Predictor of Malignancy

CONTEXT

For the correct clinical application of the sonographic risk-stratification systems, the definition of independent risk features that are foundational to each system is crucial.

OBJECTIVE

The aim of this study was to identify the gray-scale sonographic features independently associated with malignancy, and to compare different definitions.

METHODS

This prospective, diagnostic accuracy study took place in a single thyroid nodule referral center. All patients consecutively referred to our center for fine-needle aspiration cytology of a thyroid nodule between November 1, 2015 and March 30, 2020, were enrolled before cytology. Each nodule was examined by 2 experienced clinicians to record the sonographic features on a rating form. Histologic (when available) or cytologic diagnosis was used as the reference standard. For each single sonographic feature and definition, the sensitivity, specificity, positive and negative predictive values, and diagnostic odds ratios (DOR) were calculated. The significant predictors were then included in a multivariable regression model.

RESULTS

The final study cohort consisted of 903 nodules in 852 patients. A total of 76 nodules (8.4%) were malignant. Six features were independent predictors of malignancy: suspicious lymph node (DOR 16.23), extrathyroidal extension (DOR 6.60), irregular or infiltrative margins (DOR 7.13), marked hypoechogenicity (DOR 3.16), solid composition (DOR 3.61), and punctate hyperechoic foci (including microcalcifications and indeterminate foci; DOI 2.69). Taller-than-wide shape was not confirmed as an independent predictor.

CONCLUSION

We identified the key suspicious features of thyroid nodules and provided a simplified definition of some debated ones. Malignancy rate increases with number of features.

Diagnostic tests for medullary thyroid carcinoma: an umbrella review

PURPOSE

To summarize the more robust evidence about the performance of tools useful for diagnosis of medullary thyroid carcinoma (MTC) such as calcitonin (Ctn) and other circulating markers, ultrasound (US), fine-needle aspiration (FNA), and other imaging procedures.

METHODS

This systematic review of systematic reviews was carried out according to a predefined protocol. A search string was created. An electronical comprehensive search of literature was performed on December 2022. Quality assessment of eligible systematic reviews was performed and main findings were described.

RESULTS

Twenty-three systematic reviews were included and several findings were achieved. Ctn is the most reliable diagnostic marker of MTC with no evidence of improvement with stimulation test. CEA doubling time is more reliable than Ctn in identifying MTC with poorer prognosis. US sensitivity is suboptimal in MTC and only just over half of cases are at high risk according to Thyroid Imaging And Reporting Data Systems. Cytology can correctly detect MTC in just over half of cases and measuring Ctn in washout fluid from FNA is necessary. PET/CT is useful for detecting recurrent MTC.

CONCLUSIONS

Future guidelines of both thyroid nodule management and MTC diagnosis should consider these evidence-based data.

Predictors and a prediction model for positive fine needle aspiration biopsy in C-TIRADS 4 thyroid nodules

Objectives

To screen out the predictors and establish a prediction model of positive fine needle aspiration biopsy (FNAB) in the Chinese Guidelines for Malignant Risk Stratification of Thyroid Nodule Ultrasound (C-TIRADS) 4 thyroid nodules, and this nomogram can help clinicians evaluate the risk of positive FNAB and determine if FNAB is necessary.

Methods

We retrospectively analyzed data from 547 patients who had C-TIRADS 4 thyroid nodules and underwent fine-needle aspiration biopsy (FNAB) at the Second Affiliated Hospital of Chongqing Medical University between November 30, 2021 and September 5, 2022. Patients who met our inclusion criteria were divided into two groups based on positive or negative FNAB results. We compared their ultrasound (US) features, BRAF V600E status, thyroid function, and other general characteristics using univariate and multivariate logistic regression analyses to identify independent predictors. These predictors were then used to construct a nomogram. The calibration plot, area under the curve (AUC), and decision curve analysis were employed to evaluate the calibration, discrimination, and clinical utility of the prediction model.

Results

Out of 547 patients, 39.3% (215/547) had a positive result on fine-needle aspiration biopsy (FNAB), while 60.7% (332/547) had a negative result. Univariate logistic regression analysis revealed no significant differences in TPOAb, TgAb, TSH, Tg, nodule location, sex, or solid status between the two groups (P>0.05). However, age, nodule size, internal or surrounding blood flow signal, microcalcifications, aspect ratio, morphology, and low echo showed significant differences (P<0.05). Multivariate logistic regression analysis was conducted to explore the correlation between potential independent predictors. The results showed that only age (OR=0.444, 95% Cl=0.296~0.666, P<0.001), low echo (OR=3.549, 95% Cl=2.319~5.432, P<0.001), microcalcifications (OR=2.531, 95% Cl=1.661~3.856, P<0.001), aspect ratio (OR=3.032, 95% Cl=1.819~5.052, P<0.001), and morphology (OR=2.437, 95% Cl=1.586~3.745, P<0.001) were independent predictors for a positive FNAB. These variables were used to construct a prediction nomogram. An ROC curve analysis was performed to assess the accuracy of the nomogram, and AUC=0.793, which indicated good discrimination and decision curve analysis demonstrated clinical significance within a threshold range of 14% to 91%.

Conclusion

In conclusion, 5 independent predictors of positive FNAB, including age (≤45 years old), low echo (yes), microcalcifications (yes), aspect ratio (>1) and morphology (irregular), were identified. A nomogram was established based on the above 5 predictors, and the nomogram can be used as a complementary basis to help clinicians make decisions on FNAB of C-TI-RADS 4 thyroid nodules.

The pre-thyroidectomy surgeon's checklist. Recommendations of the AFC>E (Association francophone de chirurgie endocrinienne), with the SFE (Société française d'endocrinologie) and the SFMN (Société française de médecine nucléaire)

During the patient interview, signs of compression or invasion are sought out: dyspnea, dysphagia, dysphonia. The circumstances of discovery of the thyroid pathology are indicated. The surgeon must be closely acquainted with the EU-TIRADS and Bethesda classifications so as to be able to evaluate and explain to the patient the risk of malignancy. He must also be able to interpret a cervical ultrasound in view of proposing a procedure adapted to the pathology. Cervicothoracic CT-scan (or MRI) must be prescribed in the event of suspected plunging nodule or clinical/echography signs: non-palpable lower pole of the thyroid behind the clavicle, dyspnea, dysphagia, collateral circulation. The surgeon goes on to investigate possible relationships with adjacent organs, to evaluate extension toward the aortic arch and the positions (anterior, posterior or mixed) of the goiter, the objective being to determine the most adapted approach: classical cervicotomy, manubriotomy or sternotomy. Even in the event of a tumoral pathology, PET-FDG is not one of the imagery exams carried out systematically. Only in case of TSH < 0.5μU/mL should thyroid scintigraphy be proposed. Prior to any thyroid surgery, serum TSH levels, calcitoninemia and calcemia must be measured.

Evaluation of the Performance of ACR TI-RADS Also Considering Those Nodules with No Indication of FNAC: A Single-Center Experience

BACKGROUND

Several US risk stratification score systems (RSSs) have been developed to standardize a thyroid nodule risk of malignancy. It is still a matter of debate which RSS is the most reliable. The purpose of this study is to evaluate: (1) the concordance between the American College of Radiology TI-RADS (ACR TI-RADS) and fine needle aspiration cytology (FNAC), (2) the cancer rate in the ACR TI-RADS categories, (3) the characteristics of nodules evaluated by FNAC even if not formally indicated according to ACR TI-RADS ('not indicated FNACs").

METHODS

From January 2021 to September 2022, patients attending the Endocrinology Unit of the CTO Hospital of Rome for evaluation of thyroid nodules were included.

RESULTS

830 nodules had negative cytology, belonging to TIR2 and TIR1C. One hundred and thirteen nodules were determined to be suspicious for or consistent with malignancy belonging to TIR3B/TIR4/TIR5. Of this last group, 94% were classified as TR4/TR5 nodules. In total, 87/113 underwent surgery. Among these, 73 had histologically proven cancer, 14 turned out to be benign. "Not indicated FNACs" was 623. Among these, 42 cancers were present.

CONCLUSIONS

This study confirmed the diagnostic power of ACR TI-RADS. In addition, these data suggest revising the ACR TI-RADS indication to FNAC, especially for TR4.

[Clinical Application of the 2021 Korean Thyroid Imaging Reporting and Data System (K-TIRADS)]

In patients with thyroid nodules, ultrasonography (US) has been established as a primary diagnostic imaging method and is essential for treatment decision. The Korean Thyroid Imaging Reporting and Data System (K-TIRADS) is a pattern-based, US malignancy risk stratification system that can easily diagnose nodules during real-time ultrasound examinations. The 2021 K-TIRADS clarified the US criteria for nodule classification and revised the size thresholds for nodule biopsy, thereby reducing unnecessary biopsies for benign nodules while maintaining the appropriate sensitivity to detect malignant tumors in patients without feature of high risk thyroid cancer. Thyroid radiology practice has an important clinical role in the diagnosis and non-surgical treatment of patients with thyroid nodules, and should be performed according to standard practice guidelines for proper and effective clinical care.

Suboptimal accuracy of ultrasound and ultrasound-based risk stratification systems in detecting medullary thyroid carcinoma should not be overlooked. Findings from a systematic review with meta-analysis

OBJECTIVE

Ultrasound (US) is the pivotal procedure during the diagnostic work-up of thyroid nodule and several US-based risk stratification systems (RSSs) have been recently developed. Since the performance of RSSs in detecting medullary thyroid carcinoma (MTC) has been rarely investigated, the present systematic review aimed to achieve high evidence about (1) how MTC is classified according to RSSs; (2) if RSSs correctly classify MTC at high risk/suspicion, and (3) if MTC is classified as suspicious at US when RSSs are not used.

DESIGN

The review was performed according to MOOSE. The online search was performed by specific algorithm on January 2022. A random-effects model was used for statistical analysis.

RESULTS

Twenty-five papers were initially included and their risk of bias was generally low. According to ATA system, 65% of MTCs was assessed at high suspicion and 25% at intermediate suspicion. Considering all RSSs, a 54.8% of MTCs was put in a high-risk/suspicion category. Pooling data from studies without data of RSS the prevalence of ultrasonographically suspicious MTCs was 60%.

CONCLUSIONS

As conclusion, MTC presentation according to RSSs is partially known and it is classified in a high-risk/suspicion category of RSSs in just over a half of cases. This advises for further studies, ideally supported by international societies, to better define the US presentation of MTC.

Diagnostic performance of six ultrasound-based risk stratification systems in thyroid follicular neoplasm: A retrospective multi-center study

This study aimed to compare the diagnostic performances of six commonly used ultrasound-based risk stratification systems for distinguishing follicular thyroid adenoma (FTA) from follicular thyroid carcinoma (FTC), including the American Thyroid Association Sonographic Pattern System (ATASPS), ultrasound classification systems proposed by American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinology (AACE/ACE/AME), Korean thyroid imaging reporting and data system (K-TIRADS), European Thyroid Association for the imaging reporting and data system (EU-TIRADS), American College of Radiology for the imaging reporting and data system (ACR-TIRADS), and 2020 Chinese Guidelines for Ultrasound Malignancy Risk Stratification of Thyroid Nodules (C-TIRADS). A total of 225 FTA or FTC patients were retrospectively analyzed, involving 251 thyroid nodules diagnosed by postoperative pathological examinations in three centers from January 2013 to October 2021. The diagnostic performances of six ultrasound-based risk stratification systems for distinguishing FTA from FTC were assessed by plotting the receiver operating characteristic (ROC) curves and compared at different cut-off values. A total of 205 (81.67%) cases of FTA and 46 (18.33%) cases of FTC were involved in the present study. Compared with those of FTA, FTC presented more typical ultrasound features of solid component, hypoechoic, irregular margin and sonographic halo (all P<0.001). There were no significant differences in ultrasound features of calcification, shape and comet-tail artifacts between cases of FTA and FTC. There was a significant difference in the category of thyroid nodules assessed by the six ultrasound-based risk stratification systems (P<0.001). The areas under the curve (AUCs) of ATASPS, AACE/ACE/AME, K-TIRADS, EU-TIRADS, ACR-TIRADS and C-TIRADS in distinguishing FTA from FTC were 0.645, 0.729, 0.766, 0.635, 0.783 and 0.798, respectively. Our study demonstrated that all the six ultrasound-based risk stratification systems present potential in the differential diagnosis of FTA and FTC. Specifically, C-TIRADS exerts the best diagnostic performance among the Chinese patients. ATASPS possesses a high sensitivity, while K-TIRADS possesses a high specificity in distinguishing FTA from FTC.

Aggressive variants of follicular cell-derived thyroid carcinoma: an overview

PURPOSE

The incidence of thyroid carcinoma has increased globally in the past years. Papillary thyroid carcinoma (PTC) is the most frequent neoplasm of the thyroid gland comprehending the 90% of the thyroid carcinoma and has an indolent clinical behaviour. However, some variants of follicular cell-derived thyroid carcinoma, including variants of classic of PTC, have been identified that show a more aggressive biological behaviour. An accurate diagnosis of these entities is crucial for planning a more aggressive treatment and improving patients' prognosis of patients. The aim of this review is to present the main clinical, histological, and molecular features of aggressive variants of follicular cell-derived thyroid carcinoma, and to provide useful histological parameters for determining the most suitable therapeutic strategy for patients affected by these forms.

RESULTS

Variants of classic PTC such as the diffuse sclerosing variant (DSV), the tall cell variant (TCV), the columnar cell variant (CCV), the solid/trabecular variant (STV) and the hobnail variant (HV), and other variants of follicular cell-derived thyroid carcinoma, such as poorly differentiated thyroid carcinoma (PDTC), and anaplastic thyroid carcinoma (ATC), are associated with aggressive behaviour.

CONCLUSIONS

The correct identification and diagnosis of aggressive variants of follicular cell-derived thyroid carcinoma is important, as they allow the clinician to adopt the most refined therapeutic strategies in order to the survival of the patients.

Diagnostic accuracy of ultrasonographic features in detecting thyroid cancer in the transition age: a meta-analysis

Context

Significant uncertainty exists about the diagnostic accuracy of ultrasonographic (US) features used to predict the risk of thyroid cancer in the pediatric population. Moreover, there are no specific indications for thyroid nodule evaluation in patients during the transition age.

Objective

The meta-analysis aimed to address the following question: which thyroid nodule US features have the highest accuracy in predicting malignancy in the transition age.

Methods

We performed a meta-analysis of observational/cohort/diagnostic accuracy studies dealing with thyroid nodule sonography, reporting US features, and using histology as a reference standard for the diagnosis of malignancy and histology or cytology for the diagnosis of benignity in the transition age (mean/median age 12-21 years).

Results

The inclusion criteria were met by 14 studies, published between 2005 and 2020, including 1306 thyroid nodules (mean size 17.9 mm) from 1168 subjects. The frequency of thyroid cancer was 36.6%. The US features with the highest diagnostic odds ratio (DOR) for malignancy were the presence of suspicious lymph nodes (DOR: 56.0 (95% CI: 26.0-119.0)), a 'taller than wide' shape of the nodule (6.0 (95% CI: 2.0-16.0)), the presence of microcalcifications (13.0 (95% CI: 6.0-29.0)) and irregular margins (9.0 (95% CI: 5.0-17.0)). Heterogeneity among the studies was substantial.

Conclusions

Following the diagnosis of a thyroid nodule in the transition age, a thorough US examination of the neck is warranted. The detection of suspicious lymph nodes and/or thyroid nodules with a 'taller than wide' shape, microcalcifications, and irregular margins is associated with the highest risk of malignancy in the selection of nodules candidates for biopsy.

Improvement in thyroid ultrasound report quality with radiologists' adherence to 2015 ATA or 2017 TIRADS: a population study

Objectives

There has been slow adoption of thyroid ultrasound guidelines with adherence rates as low as 30% and no population-based studies investigating adherence to guideline-based malignancy risk assessment. We therefore evaluated the impact of adherence to the 2015 ATA guidelines or 2017 ACR-TIRADS guidelines on the quality of thyroid ultrasound reports in our healthcare region.

Methods

We reviewed 899 thyroid ultrasound reports of patients who received fine-needle aspiration biopsy and were diagnosed with Bethesda III or IV nodules or thyroid cancer. Ultrasounds were reported by radiology group 1, group 2, or other groups, and were divided into pre-2018 (before guideline adherence) or 2018 onwards. Reports were given a utility score (0-6) based on how many relevant nodule characteristics were included.

Results

Group 1 had a pre-2018 utility score of 3.62 and 39.4% classification reporting rate, improving to 5.77 and 97.0% among 2018-onwards reports. Group 2 had a pre-2018 score of 2.8 and reporting rate of 11.5%, improving to 5.58 and 93.3%. Other radiology groups had a pre-2018 score of 2.49 and reporting rate of 32.2%, improving to 3.28 and 61.8%. Groups 1 and 2 had significantly higher utility scores and reporting rates in their 2018-onward reports when compared to other groups' 2018-onward reports, pre-2018 group 1 reports, and pre-2018 group 2 reports.

Conclusions

Dedicated adherence to published thyroid ultrasound reporting guidelines can lead to improvements in report quality. This will reduce diagnostic ambiguity and improve clinician's decision-making, leading to overall reductions in unnecessary FNA biopsy and diagnostic surgery.

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

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

Performance of current ultrasound-based malignancy risk stratification systems for thyroid nodules in patients with follicular neoplasms

OBJECTIVES

To investigate the ability of the currently used ultrasound-based malignancy risk stratification systems for thyroid neoplasms (ATA, AACE/ACE/AME, K-TIRADS, EU-TIRADS, ACR-TIRADS and C-TIRADS) in distinguishing follicular thyroid carcinoma (FTC) from follicular thyroid adenoma (FTA). Additionally, we evaluated the ability of these systems in correctly determining the indication for biopsy.

METHODS

Three hundred twenty-nine follicular neoplasms with definitive postoperative histopathology were included. The nodules were categorized according to each of six stratification systems, based on ultrasound findings. We dichotomized nodules into the positive predictive group of FTC (high and intermediate risk) and negative group of FTC based on the classification results. Missed biopsy was defined as neoplasms that were diagnosed as FTCs but for which biopsy was not indicated based on lesion classification. Unnecessary biopsy was defined as neoplasms that were diagnosed as FTAs but for whom biopsy was considered indicated based on classification. The diagnostic performance and missed and unnecessary biopsy rates were evaluated for each stratification system.

RESULTS

The area under the curve of each system for distinguishing follicular neoplasms was < 0.700 (range, 0.511-0.611). The missed biopsy rates were 9.0-22.4%. The missed biopsy rates for lesions ≤ 4 cm and lesions sized 2-4 cm were 16.2-35.1% and 0-20.0%, respectively. Unnecessary biopsy rates were 65.3-93.1%. In ≤ 4 cm group, the unnecessary biopsy rates were 62.2-89.7%.

CONCLUSION

The malignancy risk stratification systems can select appropriate nodules for biopsy in follicular neoplasms, while they have limitations in distinguishing follicular neoplasms and reducing unnecessary biopsy. Specific stratification systems and recommendations should be established for follicular neoplasms.

KEY POINTS

• Current ultrasound-based malignancy risk stratification systems of thyroid nodules had low efficiency in the characterization of follicular neoplasms. • The adopted stratification systems showed acceptable performance for selecting FTC for biopsy but unsatisfactory performance for reducing unnecessary biopsy.

The Future of Thyroid Nodule Risk Stratification

Clinical evidence supports the association of ultrasound features with benign or malignant thyroid nodules and serves as the basis for sonographic stratification of thyroid nodules, according to an estimated thyroid cancer risk. Contemporary guidelines recommend management strategies according to thyroid cancer risk, thyroid nodule size, and the clinical scenario. Yet, reproducible and accurate thyroid nodule risk stratification requires expertise, time, and understanding of the weight different ultrasound features have on thyroid cancer risk. The application of artificial intelligence to overcome these limitations is promising and has the potential to improve the care of patients with thyroid nodules.

Dynamic follow-up of the effects of programmed death 1 inhibitor treatment on thyroid function and sonographic features in patients with hepatocellular carcinoma

Objective

Programmed cell death protein-1 (PD-1) inhibitors are widely used for the treatment of hepatocellular carcinoma (HCC). Thyroid dysfunction is common in patients treated with this therapy, although the dynamic changes in thyroid function and sonographic features remain unclear.

Methods

We analyzed 38 patients with HCC who received anti-PD-1 therapy at our hospital. Demographic, clinical, laboratory, and ultrasound data were extracted from electronic medical records. The grading of thyroid nodules was based on the American College of Radiology Thyroid Imaging Reporting and Data System classification. Statistical analyses were performed using GraphPad Prism 5.0.

Results

Fifteen patients (40%) had hypothyroidism, among which six had hypothyroidism at baseline, three had overt hypothyroidism, and six had subclinical hypothyroidism after anti-PD1 therapy. The proportion of patients with euthyroid function and thyroid antibody positivity was significantly lower than that of patients with thyroid dysfunction (10% vs 39%, P < 0.05). Nine patients (24%) had irregular echo patterns on sonographic imaging, six of whom had irregular echo patterns present during the treatment, but only one had them persist until the end of treatment. At baseline, the classification of most thyroid nodules was grade 3, with a significant increase in grade 4A and 4B classifications during treatment, though most nodules remained grade 3 at the end of treatment. There were no significant differences in survival rates between the euthyroid and thyroid dysfunction groups.

Conclusion

Anti-PD-1 therapy-induced thyroid dysfunction was accompanied by changes in thyroid function, antibodies, and ultrasonography. Therefore, in patients receiving anti-PD-1 therapy, close, dynamic monitoring of thyroid function, antibodies, and ultrasonographic characteristics is necessary.

Radiomics analysis improves 18FDG PET/CT-based risk stratification of cytologically indeterminate thyroid nodules

PURPOSE

As ~25% of cytologically indeterminate thyroid nodules harbour malignancy, diagnostic lobectomy is still performed in many cases. ¹⁸FDG PET/CT rules out malignancy in visually negative nodules; however, none of the currently available interpretation criteria differentiates malignant from benign ¹⁸FDG-avid nodules. We evaluated the ability of PET metrics and radiomics features (RFs) to predict final diagnosis of ¹⁸FDG-avid cytologically indeterminate thyroid nodules.

METHODS

Seventy-eight patients were retrospectively included. After volumetric segmentation of each thyroid lesion, 4 PET metrics and 107 RFs were extracted. A logistic regression was performed including thyroid stimulating hormone, PET metrics, and RFs to assess their predictive performance. A linear combination of the resulting parameters generated a radiomics score (RS) that was matched with cytology classes (Bethesda III and IV) and compared with final diagnosis.

RESULTS

Two RFs (shape_Sphericity and glcm_Autocorrelation) differentiated malignant from benign lesions. A predictive model integrating RS and cytology classes effectively stratified the risk of malignancy. The prevalence of thyroid cancer increased from 5 to 37% and 79% in accordance with the number (score 0, 1 or 2, respectively) of positive biomarkers.

CONCLUSIONS

Our multiparametric model may be useful for reducing the number of diagnostic lobectomies with advantages in terms of costs and quality of life for patients.

Prognostic factors in patients with persistent/recurrent differentiated thyroid carcinoma after comprehensive treatment

Objective: To investigate the prognostic factors of patients with persistent/recurrent differentiated thyroid carcinoma (DTC) especially with external invasive persistent recurrent DTC after comprehensive treatment. Methods: The clinical data of 525 patients with persistent/recurrent DTC who underwent surgical treatment from August 2011 to June 2021 in the Department of Head and Neck Surgery of Jiangsu Cancer Hospital were retrospectively analyzed. The prognostic factors affecting overall survival (OS) and relapse-free survival (RFS) of persistent/recurrent DTC, especially external invasive persistent/recurrent DTC were analyzed. Results: Among 525 patients, 318 patients underwent thyroidectomy, 359 patients underwent central lymph node dissection, and 409 patients underwent lateral cervical lymph node dissection. Among 493 followed-up patients, 5-year OS and RFS were 95.10% and 89.60%, 8-year OS and RFS were 91.80% and 81.30%. Cox regression analysis showed that in patients with persistent/recurrent DTC after comprehensive treatment, age ≥55 years at reoperation after recurrence, male gender and distant metastasis were independent risk factors of OS (all P<0.05); while the simultaneous invasion of thyroid and lymph nodes, multiple organ invasion and the number of previous operations ≥2 were independent risk factors of RFS (all P<0.05). In patients with external invasive persistent/recurrent DTC after comprehensive treatment, age ≥55 years at reoperation after recurrence and male gender were independent risk factors of OS (both P<0.05); while multiple organ invasion and the number of previous operations ≥2 were independent risk factors of RFS (both P<0.05). Conclusions: Male patients aged 55 years old and above, with distant metastasis have a higher risk of poorer prognosis in persistent/recurrent DTC; while patients with simultaneous external invasion of thyroid and lymph nodes, multiple organ invasion and the number of previous operations ≥2 are more likely to relapse. For external invasive persistent/recurrent DTC, male patients aged 55 years old and above have a higher risk of poorer prognosis; while patients with multiple organ invasion and the number of previous operations ≥2 are more likely to have recurrence.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Exploring the Performance of Ultrasound Risk Stratification Systems in Thyroid Nodules of Pediatric Patients

Neck ultrasound (nUS) is the cornerstone of clinical management of thyroid nodules in pediatric patients, as well as adults. The current study was carried out to explore and compare the diagnostic performance of the main US-based risk stratification systems (RSSs) (i.e., the American College of Radiology (ACR), European (EU), Korean (K) TI-RADSs and ATA US RSS criteria) for detecting malignant thyroid lesions in pediatric patients. We conducted a retrospective analysis of consecutive children and adolescents who received a diagnosis of thyroid nodule. We included subjects with age <19 years having thyroid nodules with benign cytology/histology or final histological diagnosis. We excluded subjects with (a) a previous malignancy, (b) a history of radiation exposure, (c) cancer genetic susceptibility syndromes, (d) lymph nodes suspicious for metastases of thyroid cancer at nUS, (e) a family history of thyroid cancer, or (f) cytologically indeterminate nodules without histology and nodules with inadequate cytology. We included 41 nodules in 36 patients with median age 15 years (11-17 years). Of the 41 thyroid nodules, 29 (70.7%) were benign and 12 (29.3%) were malignant. For both ACR TI-RADS and EU-TIRADS, we found a sensitivity of 41.7%. Instead, for both K-TIRADS and ATA US RSS, we found a sensitivity of 50%. The missed malignancy rate for ACR-TIRADS and EU-TIRADS was 58.3%, while that for K-TIRADS and ATA US RSS was 50%. The unnecessary FNA prevalence for ACR TI-RADS and EU-TIRADS was 58.3%, while that for K-TIRADS and ATA US RSS was 76%. Our findings suggest that the four US-based RSSs (i.e., ACR-TIRADS, EU-TIRADS, K-TIRADS, and ATA US RSS) have suboptimal performance in managing pediatric patients with thyroid nodules, with one-half of cancers without indication for FNA according to their recommendations.

Validation of Four Thyroid Ultrasound Risk Stratification Systems in Patients with Hashimoto's Thyroiditis; Impact of Changes in the Threshold for Nodule's Shape Criterion

Simple Summary

Thyroid Imaging Reporting and Data Systems (TIRADS) optimize the selection of thyroid nodules for cytological examination. There is a question: is the effectiveness of these systems affected by morphological changes to thyroid parenchyma that are visible in the course of Hashimoto’s thyroiditis (HT)? This question is very important because of the increased risk of malignancy in thyroid nodules in patients with HT. We investigated widely accepted ultrasound malignancy risk features with a special consideration of the suspected nodule’s shape in patients with and without HT. We also validated EU-TIRADS, K-TIRADS, ACR-TIRADS, and ATA guidelines in both groups and evaluated the impact of changes in the threshold for nodule’s shape criterion on the diagnostic value of these TIRADS. The presence of Hashimoto’s thyroiditis did not exert any significant adverse implications for the efficiency of examined TIRADS. The impact of changes in the threshold for nodule’s shape criterion was the highest for EU-TIRADS.

Abstract

The aim of the study was to validate thyroid US malignancy features, especially the nodule’s shape, and selected Thyroid Imaging Reporting and Data Systems (EU-TIRADS; K-TIRADS; ACR-TIRADS, ATA guidelines) in patients with or without Hashimoto’s thyroiditis (HT and non-HT groups). The study included 1188 nodules (HT: 358, non-HT: 830) with known final diagnoses. We found that the strongest indications of nodule’s malignancy were microcalcifications (OR: 22.7) in HT group and irregular margins (OR:13.8) in non-HT group. Solid echostructure and macrocalcifications were ineffective in patients with HT. The highest accuracy of nodule’s shape criterion was noted on transverse section, with the cut-off value of anteroposterior to transverse dimension ratio (AP/T) close to 1.15 in both groups. When round nodules were regarded as suspicious in patients with HT (the cut-off value of AP/T set to ≥1), it led to a three-fold increase in sensitivity of this feature, with a disproportionally lower decrease in specificity and similar accuracy. Such a modification was effective also for cancers other than PTC. The diagnostic effectiveness of analyzed TIRADS in patients with HT and without HT was similar. Changes in the threshold for AP/T ratio influenced the number of nodules classified into the category of the highest risk, especially in the case of EU-TIRADS.

Facing Thyroid Nodules in Paediatric Patients Previously Treated with Radiotherapy for Non-Thyroidal Cancers: Are Adult Ultrasound Risk Stratification Systems Reliable?

Simple Summary

The risk of thyroid nodules harbouring cancer has been evaluated, in adults, using specific ultrasound criteria. However, it is unclear whether such evaluation can be translated in paediatric patients. In this study, we tested the effectiveness of three known risk evaluation systems in children with thyroid nodules and with a history of radiation exposure. We found that these systems are reliable in confirming or ruling out cancer in most cases, except when evaluating very small nodules (<1 cm). For these reasons, these risk criteria should be adopted to account for the reduced size of malignant lesions when evaluating paediatric subjects.

Abstract

Thyroid nodule ultrasound-based risk stratification systems (US-RSSs) have been successfully used in adults to predict the likelihood of malignancies. However, their applicability to the paediatric population is unclear, especially in children with a history of radiation exposure, who are at a higher cancer risk. We tested the efficacy of three US-RSSs in this setting by retrospectively applying three classification systems (ACR-TIRADS, ATA and EU-TIRADS) to all paediatric patients referred for thyroid nodules and with a radiation exposure history. We compared the results with a reference standard (pathology or 36-month follow-up); sensitivity, specificity, positive and negative predictive values (PPV and NPV) and accuracy were calculated. A total of 52 patients were included; fourteen of them (27%) had papillary thyroid cancer (PTC) at the final histology. No significant differences across the US-RSSs were detected; specificity (range 95–97%) and NPV (range 88–93%) were particularly elevated. However, ACR-TIRADS, ATA and EU-TIRADS did not indicate the need for a biopsy in six (42.8%), seven (50%) and eight (57%) cases of PTC; in five cases, this lack of indication was due to a small (<1 cm) nodule size. In conclusion, US-RSSs show a high NPV and specificity in paediatric patients, whereas the cytology indication could be improved by reconsidering the dimensional criterion.

Development and Validation of an Ultrasonic Diagnostic Model for Differentiating Follicular Thyroid Carcinoma from Follicular Adenoma

Background

High-resolution ultrasound is the first choice for the diagnosis of thyroid nodules, but it is still difficult to distinguish between follicular thyroid carcinoma (FTC) and follicular adenoma (FA). Our research aimed to develop and validate an ultrasonic diagnostic model for differentiating FTC from FA.

Methods

This study retrospectively analyzed 196 patients who were diagnosed as FTC (n=83) and FA (n=113). LASSO regression analysis was used to screen clinical and ultrasonic features. Multivariate logistic regression analysis was used to establish the ultrasonic diagnostic model of FTC. Nomogram was used for the visualization of diagnostic models. C-index, ROC, and calibration curves analysis were used to evaluate the accuracy of the diagnostic model. Decision curve analysis (DCA) was used to evaluate the net benefits of the ultrasonic diagnostic model for FTC diagnosis under different threshold probabilities. The bootstrap method was used to verify the ultrasonic diagnostic model.

Results

After Lasso regression analysis, 10 clinical and ultrasonic features were used to construct the ultrasonic diagnostic model of FTC. The C-index and AUC of the model were 0.868 and 0.860, respectively. DCA showed that the ultrasonic model had good clinical application value. The C-index in the validation group was 0.818, which was close to the C-index in the model.

Conclusion

Ultrasonic diagnostic model constructed with 10 clinical and ultrasonic features can better distinguish FTC from FA.

The dilemma of 18F-FDG PET/CT thyroid incidentaloma: what we should expect from FNA. A systematic review and meta-analysis

PURPOSE

¹⁸F-FDG thyroid incidentaloma (TI) occurs in ~2% of PET/CT examinations with a cancer prevalence of up to 35-40%. Guidelines recommend fine-needle aspiration cytology (FNA) if a focal ¹⁸F-FDG TI corresponds to a sonographic nodule >1 cm. The aim of this systematic review and meta-analysis was to provide evidence-based data on the diagnostic distribution of ¹⁸F-FDG TIs in the six Bethesda systems for reporting thyroid cytopathology (BETHESDA) subcategories.

METHODS

Original studies reporting ¹⁸F-FDG TIs and cytologically classified according to BETHESDA were included. Six separate meta-analyses were performed to obtain the pooled prevalence (95% confidence interval, 95% CI) of ¹⁸F-FDG TIs in the six BETHESDA subcategories.

RESULTS

Fifteen studies were finally included. Nine studies were from Asian/Eastern and six from Western countries. FNA data according to BETHESDA was available in 2304 cases. The pooled prevalence of ¹⁸F-FDG TIs according to BETHESDA was BETHESDA I 10% (6-14), BETHESDA II 45% (37-53), BETHESDA III 8% (3-13), BETHESDA IV 8% (5-12), BETHESDA V 6% (4-9), BETHESDA VI 19% (13-25). A significantly different prevalence was found in the BETHESDA IV between Asian/Eastern (2%) and Western (19%) studies.

CONCLUSION

Two-thirds of focal ¹⁸F-FDG TIs undergoing FNA have either malignant (BETHESDA VI) or benign (BETHESDA II) cytology while a minority will have indeterminate (BETHESDA III or IV) FNA results. Significant differences between Asian/Eastern and Western studies are also present in the prevalence of indeterminate FNA results.

Diagnostic value of thyroid micronodules with high b-value diffusion weighted imaging: Comparative study with high-resolution ultrasound

PURPOSE

This study aims to compare the diagnostic performance of two imaging methods for thyroid nodules ≤1.0 cm and reduce unnecessary overdiagnosis.

METHODS

A retrospective study was conducted on 80 patients with pathologically confirmed solitary thyroid micronodules underwent both high-resolution ultrasound (HRUS) and High b-value (2000 s/mm²) diffusion weighted imaging (DWI). Intra- and interobserver agreement (Intraclass correlation coefficient) was followed by Kruskal-Wallis test to detect whether the quantitative apparent diffusion coefficient (ADC) and thyroid nodule subgroups were related. Cohen's kappa analysis was applied to assess the interobserver consistency of DWI and HRUS characteristics. The receiver operating characteristic curves were adopted for evaluating the diagnostic performance of thyroid malignancy. The sensitivity, specificity, and accuracy of the two imaging methods were compared using the McNemar's test and Kappa test.

RESULTS

A total of 80 patients were included, consisting of 43 malignant and 37 benign micronodules. The sensitivity, specificity and accuracy of DWI combined with rADC (ADCmin to ADCn ratio) for the diagnosis of thyroid micronodules were 83.7%, 89.2% and 86.3%, respectively. The area under the curve (AUC) was 0.91 (95% confidence interval [CI]: 0.84-0.97). The sensitivity, specificity and accuracy of HRUS diagnosis were 100%, 62.16% and 82.5%, respectively.

CONCLUSION

High b-value DWI is superior to HRUS for evaluating the diagnostic performance of solid thyroid micronodules. DWI and its ADC quantitative analysis could be added to the evaluation of thyroid micronodules to improve the specificity of diagnosis, reduce overdiagnosis and avoid unnecessary biopsies or surgeries.

Cancer prevalence in the subcategories of the indeterminate class III (AUS/FLUS) of the Bethesda system for thyroid cytology: a meta-analysis

PURPOSE

The indeterminate cytologic report represents a major challenge in the field of thyroid nodule. The indeterminate class III of the Bethesda classification system (i.e., AUS/FLUS) includes a heterogeneous group of subcategories characterized by doubtful nuclear and/or architectural atypia. The study aim was to  conduct a systematic review and meta-analysis to evaluate the rate of malignancy in each subcategory of Bethesda III.

METHODS

PubMed, CENTRAL, and Scopus databases were searched until April 2020. Original articles reporting data on the subcategories of Bethesda III were included. The histological diagnosis was the reference standard to classify true/false negative and true/false positive cases.

RESULTS

The pooled cancer prevalence in each subcategory of Bethesda III was estimated using a random-effects model. Twenty-three papers with 4241 nodules were included. Overall, 1163 (27.4%) were malignant. The cancer rate observed in the subcategories ranged from 15%, in "Hürthle cell aspirates with low risk pattern", to 44%, in "Focal cytologic atypia".

CONCLUSIONS

The overall cancer rate found in the Bethesda III ranged more largely than that originally estimated (10-30%) and varied among any scenarios. These evidence-based data represent a reference for the clinical management of these patients.

The Value of Relative Size in the Ultrasound Diagnosis of Follicular Thyroid Neoplasm

Purpose

Ultrasonography as the first choice for thyroid nodules is still difficult to distinguish between solid follicular thyroid neoplasm (FTN) and solid nodular goiter (NG). We tried to investigate the value of relative size (M/S, M: the maximum diameter of target nodule, S: the maximum diameter of the largest of the remaining nodules) that may help to differentiate FTN from NG.

Methods

T test and chi-square test were used to retrospectively analyze the differences of the clinical and ultrasonographic characteristics between FTN and NG in 422 cases in our hospital. T test was used to analyze the difference of M/S value in the two kinds of nodules. ROC was used to evaluate the accuracy of M/S value in distinguishing the two.

Results

There were statistically significant differences in age, echogenicity, calcification, peripheral halo and blood supply between the two. The M/S value is not only significantly different in the two kinds of nodules but also can be used as a quantitative indicator to guide ultrasound diagnosis. ROC analysis showed that the cutoff point and AUC of M/S value were 1.94 and 0.709, respectively.

Conclusion

In the ultrasound diagnosis of multiple thyroid nodules, the M/S value can better distinguish FTN and NG. We need to be aware of FTN when the M/S value of the nodule is greater than 2.

Korean Thyroid Imaging Reporting and Data System: Current Status, Challenges, and Future Perspectives

The Korean Thyroid Imaging Reporting and Data System (K-TIRADS) is an ultrasound-based risk stratification system for thyroid nodules that has been widely applied for the diagnosis and management of thyroid nodules since 2016. This review article provides an overview of the use of the K-TIRADS compared with other risk stratification systems. Moreover, this review describes the challenges in the clinical application of the K-TIRADS, as well as future development directions toward the personalized management of patients with thyroid nodules.