Thyroid nodules with isolated macrocalcification: malignancy risk and diagnostic efficacy of fine-needle aspiration and core needle biopsy

Malignant risk of thyroid nodules with isolated macrocalcifications - A study based on surgery results

OBJECTIVE

To determine the malignancy risk of thyroid nodules with Isolated Macrocalcifications (IMC) based on surgical results and evaluate the postoperative risk of malignant nodules with IMC.

METHODS

A total of 46 thyroid nodules with IMC were enrolled from 3680 consecutive patients who underwent thyroidectomy between August 2018 and September 2023. The malignancy risk of IMC nodules, postoperative risk of malignant nodules, and whether the ultrasonic features of IMC (smooth, lobulated, or focal disruption of the anterior margin) were associated with malignancy were investigated. The nodules were further divided into three groups (group A, maximum diameter < 10 mm; group B, maximum diameter of 10‒14 mm and group C, maximum diameter ≥ 15 mm). Differences in malignancy and Lymph Node Metastasis (LNM) risks were also evaluated among the three groups.

RESULTS

The malignancy risk of the IMC nodules was 30.43% (14/46). Four patients developed LNM. Eight nodules were staged as T1aN0M0 and low-risk, whereas six nodules were staged as T1bN1aM0 and intermediate-risk. Focal disruption of the anterior margin of IMC was significantly associated with malignancy. Malignant and LNM risk showed no differences among nodules with different sizes.

CONCLUSIONS

IMC nodules with different sizes had a lower intermediate risk of malignancy and exhibited the same aggressive behavior. The cutoff value of these nodules for further Fine Needle Aspiration (FNA) warranted further investigation. Interruption of IMC was more often seen in malignant nodules, and more attention should be paid to these nodules.

The value of non-punctate echogenic foci in the ultrasonic diagnosis of thyroid nodules

PURPOSE

To evaluate the diagnostic value of different subtypes of non-punctate echogenic foci in thyroid malignancy.

METHODS

Retrospective research of 342 thyroid nodules with calcification was performed. The echogenic foci were divided into punctate echogenic foci (type I) and non-punctate echogenic foci (type II), and type II were further divided into four subtypes: macrocalcification (type IIa), continuous peripheral calcification (type IIb), discontinuous peripheral calcification (type IIc) and isolated calcification (type IId). Postoperative histopathological results were used as the gold standard to evaluate the correlation between non-punctate echogenic foci subtypes and thyroid malignancy.

RESULTS

The malignant risk of nodules with echogenic foci was type I (82.1%) > type IIa (66.2%) > type IIc (52.9%) > type IId (16.7%) > type IIb (13.9%), P < 0.001. Type I and type IIa echogenic foci were independent risk factors for thyroid cancer (OR = 16.593, 7.785). Solid, hypoechogenicity/marked hypoechogenicity and a single lesion in a unilateral thyroid lobe were independently associated with malignant thyroid nodules with macrocalcification(OR = 6.825, 40.042, 5.201). Irregular margins and uneven calcification thickness were independent factors for malignant thyroid nodules with peripheral calcification (OR = 5.676, 2.750).

CONCLUSION

Type IIa echogenic foci could independently predict thyroid malignancy. The diagnostic value of non-punctate echogenic foci depended on the differentiated combination of ultrasound characteristics. Type IIa nodules with solid composition, irregular margins, and a single lesion in a unilateral thyroid lobe implied a higher risk of malignancy; peripheral calcified nodules with irregular margins and uneven calcification thickness suggested an increased risk of malignancy.

Cancer rates and characteristics of thyroid nodules with macrocalcification

AIMS

The aim of this study was to determine the malignant potential of thyroid nodules with macrocalcifications and to evaluate the role of other sonographic findings in the diagnosis of malignancy in thyroid nodules besides macrocalcifications.

METHODS

The findings of 8250 patients who applied to our outpatient clinic and underwent thyroid ultrasonography(US) between 2008 and 2021 were retrospectively reviewed. We included a total of 296 patients with 296 macrocalcified nodules (macrocalcification group) and an age- and sex matched group of 300 patients (control group) with the cytopathologic and/or histopathologic data of fine-needle aspiration biopsy (FNAB) of thyroid nodules without calcification. Demographic characteristics of these patients, US characteristics of the nodules, and thyroid function tests were recorded. Cytopathological data of FNAB were classified according to BETHESDA.

RESULTS

The malignancy rate was 14.2% (42/296) in the macrocalcification group and 5.3% (16/300) in the control group (p < 0.001). There was no significant relationship between interrupted peripheral calcification and malignancy. Hypoechoic or markedly hypoechoic appearance, irregular border, solid structure, presence of accompanying pathological lymphadenopathy on sonographic examination and upper and middle zone localization were other sonographic features that increased the risk of malignancy of a nodule. The presence of autoimmunity was not found to be associated with the risk of malignancy. TSH and calcitonin levels of malignant nodules were higher than benign nodules. There was no significant difference between gender and malignancy. In the univariate analysis, it was found that the presence of macrocalcification increased the risk of malignancy 2.935 times. (OR:2.935, p < 0.001.95% CI for OR 1.611-5.349) In addition, being younger, being in the high TIRADS category, and being in the upper and middle zones were factors that increased the risk of malignancy. Gender, TSH level, nodule volume and structure were not associated with malignancy. However, after multivariate analysis, factors that significantly increased the risk of malignancy were younger age, higher TIRADS category, and nodule localization.

CONCLUSION

In our study, the malignancy rate was higher in the macrocalcification group than in the control group. However, no correlation was found after multivariate analysis. In the multivariate analysis, younger age, higher TIRADS category, and nodules located in the upper and middle zone were other factors associated with malignancy. There was no association between peripheral interrupted calcification and malignancy risk.

Biopsy strategies for intermediate and high suspicion thyroid nodules with macrocalcifications

OBJECTIVES

(1) To find strategies to improve diagnostic performance of ultrasound-guided biopsy of intermediate and high suspicion thyroid nodules with macrocalcifications. (2) To find malignancy rates of nodules with macrocalcification.

MATERIALS AND METHODS

From 2018 to 2022, fine-needle aspiration biopsy (FNAB) and core needle biopsy (CNB) were retrospectively evaluated. Macrocalcifications were categorized into three types: intra-nodular, rim and entirely calcified. Diagnostic performance was compared between biopsy modes (FNAB vs. CNB) and FNAB techniques (to-and-fro vs. whirling). Multivariate logistic regression was performed to determine features associated with performance of FNAB. Malignancy rates were calculated according to macrocalcification types.

RESULTS

A total of 114 procedures (87 FNAB and 27 CNB) in 89 nodules per 86 patients (mean age, 64 years; 76 women) were performed. Overall, CNB performed better than FNAB (unsatisfactory rate: 3.7% vs. 33.3%, p = .005). For macrocalcification thicker than 2 mm, whirling FNAB technique demonstrated a comparable unsatisfactory rate with statistical trends toward significance (to-and-fro: 69.2% vs. whirling: 27.8%, p = .055). The entirely calcified nodule was associated with poor performance of FNAB (adjusted odds ratio 4.46 [95% CI: 1.19-16.67], p = .027). Overall malignancy was 22.5%, higher in intra-nodular macrocalcification than rim and entirely calcified types (68.4% vs. 21.1% vs. 10.5%, p = .025).

CONCLUSION

For the entirely calcified type, CNB should be considered first to improve diagnosis. For other types, FNAB can be performed, and whirling technique may be an alternative technique in thicker macrocalcification. Malignancy in intermediate and high suspicion nodules with macrocalcification have non-negligible rates.

Subcategorization of intermediate suspicion thyroid nodules based on suspicious ultrasonographic findings

PURPOSE

This study compared the malignancy risk of intermediate suspicion thyroid nodules according to the presence of suspicious ultrasonographic (US) findings.

METHODS

From January 2014 to December 2014, 299 consecutive intermediate suspicion thyroid nodules in 281 patients (mean age, 50.6±12.5 years) with final diagnoses were included in this study. Two radiologists retrospectively reviewed the US findings and subcategorized the intermediate suspicion category into nodules without suspicious findings and nodules with suspicious findings, including punctate echogenic foci, nonparallel orientation, or irregular margins. The malignancy rates were compared between the two subcategory groups.

RESULTS

Of the 299 intermediate suspicion thyroid nodules, 230 (76.9%) were subcategorized as nodules without suspicious findings and 69 (23.1%) as nodules with suspicious findings. The total malignancy rate was 33.4% (100/299) and the malignancy rate of nodules with suspicious findings was significantly higher than that of nodules without suspicious findings (47.8% vs. 29.1%, P=0.004). In nodules with suspicious findings, the most common suspicious finding was punctate echogenic foci (48/82, 58.5%) followed by nonparallel orientation (22/82, 26.8%) and irregular margins (12/82, 14.6%). Thirteen nodules had two suspicious findings simultaneously. A linearly increasing trend in the malignancy rate was observed according to the number of suspicious US findings (P for trend=0.001).

CONCLUSION

Intermediate suspicion thyroid nodules with suspicious findings showed a higher malignancy rate than those without suspicious findings. Further management guidelines for nodules with suspicious findings should differ from guidelines for nodules without suspicious findings, even in the same US category.

The clinical significance of the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) category 5 thyroid nodules: Not as risky as we think?

BACKGROUND

Although the prevalence of thyroid nodules is high, few prove to be malignant. Based on sonographic features, the American College of Radiology Thyroid Imaging Reporting and Data System categorizes malignancy risk of thyroid nodules with associated management recommendations for each category level. Malignancy rates among nodules with a highly suspicious Thyroid Imaging Reporting and Data System category 5 warrant examination in the context of additional risk stratification tools, including cytopathology and molecular testing.

METHODS

All patients who underwent fine-needle aspiration biopsy for Thyroid Imaging Reporting and Data System category 5 nodules from January 2018 to September 2021 in a large integrated academic health system were reviewed. Using the Bethesda System for Reporting Thyroid Cytopathology, categories V and VI were set as malignant. Molecular testing (ThyroSeq version 3; Rye Brook, NY) yielding ≥50% risk of malignancy was deemed positive and correlated with surgical pathology.

RESULTS

A total of 496 Thyroid Imaging Reporting and Data System category 5 nodules were identified. On fine-needle aspiration cytopathology, 61 (12.3%) were malignant. The breakdown included Bethesda System for Reporting Thyroid Cytopathology I, 15 (3%); II, 362 (73%); III, 52 (10.5%); IV, 5 (1%); V, 6 (1.3%); and VI, 55 (11.1%). Of Bethesda System for Reporting Thyroid Cytopathology III/IV nodules with molecular testing (n = 53), 24.5% yielded positive results. In total, 42 (8.5%) nodules underwent surgical resection, most of which were Bethesda System for Reporting Thyroid Cytopathology VI (n = 26, 61.9%). Of excised nodules, 33 (78.6%) nodules were malignant, 6 (14.3%) benign, and 3 (7.1%) noninvasive follicular thyroid neoplasm with papillary-like nuclear features. All Thyroid Imaging Reporting and Data System category 5 nodules with malignant cytology (Bethesda System for Reporting Thyroid Cytopathology V/VI) that underwent surgery were malignant on histopathology. On average, the total Thyroid Imaging Reporting and Data System points were higher in malignant nodules compared with benign (9.3 vs 7.3; P = .015). Moreover, benign nodules more frequently received Thyroid Imaging Reporting and Data System points when the radiologist was unable to determine composition or echogenicity (33% vs 3% among malignant nodules; P = .01).

CONCLUSION

Thyroid Imaging Reporting and Data System category 5 designation in thyroid nodules is associated with a lower risk of malignancy than previously reported. Benign and malignant nodules with Thyroid Imaging Reporting and Data System category 5 designation have discrepancies in certain Thyroid Imaging Reporting and Data System characteristics and individual points assigned, which may offer an opportunity for quality improvement and standardization measures in ultrasound reporting practices.

Incorporation of a machine learning pathological diagnosis algorithm into the thyroid ultrasound imaging data improves the diagnosis risk of malignant thyroid nodules

OBJECTIVE

This study aimed at establishing a new model to predict malignant thyroid nodules using machine learning algorithms.

METHODS

A retrospective study was performed on 274 patients with thyroid nodules who underwent fine-needle aspiration (FNA) cytology or surgery from October 2018 to 2020 in Xianyang Central Hospital. The least absolute shrinkage and selection operator (lasso) regression analysis and logistic analysis were applied to screen and identified variables. Six machine learning algorithms, including Decision Tree (DT), Extreme Gradient Boosting (XGBoost), Gradient Boosting Machine (GBM), Naive Bayes Classifier (NBC), Random Forest (RF), and Logistic Regression (LR), were employed and compared in constructing the predictive model, coupled with preoperative clinical characteristics and ultrasound features. Internal validation was performed by using 10-fold cross-validation. The performance of the model was measured by the area under the receiver operating characteristic curve (AUC), accuracy, precision, recall, F1 score, Shapley additive explanations (SHAP) plot, feature importance, and correlation of features. The best cutoff value for risk stratification was identified by probability density function (PDF) and clinical utility curve (CUC).

RESULTS

The malignant rate of thyroid nodules in the study cohort was 53.2%. The predictive models are constructed by age, margin, shape, echogenic foci, echogenicity, and lymph nodes. The XGBoost model was significantly superior to any one of the machine learning models, with an AUC value of 0.829. According to the PDF and CUC, we recommended that 51% probability be used as a threshold for determining the risk stratification of malignant nodules, where about 85.6% of patients with malignant nodules could be detected. Meanwhile, approximately 89.8% of unnecessary biopsy procedures would be saved. Finally, an online web risk calculator has been built to estimate the personal likelihood of malignant thyroid nodules based on the best-performing ML-ed model of XGBoost.

CONCLUSIONS

Combining clinical characteristics and features of ultrasound images, ML algorithms can achieve reliable prediction of malignant thyroid nodules. The online web risk calculator based on the XGBoost model can easily identify in real-time the probability of malignant thyroid nodules, which can assist clinicians to formulate individualized management strategies for patients.

Efficacy and safety of radiofrequency ablation for calcified benign thyroid nodules: results of over 5 years' follow-up

Purpose

To evaluate the efficacy and safety of radiofrequency ablation (RFA) for treating calcified benign thyroid nodules (CBTNs).

Methods

Fifty-two patients with 52 CBTNs who underwent RFA in our hospital were included in this retrospective study. According to the size of calcifications, CBTNs were divided into two groups: the punctate echogenic foci (PEF) group and macrocalcification group. Moreover, the macrocalcification group was further subdivided into two groups, the strong group and the weak group, based on their morphologic characteristics. After the RFA procedure, routine ultrasound (US) and clinical evaluation were performed at 1, 3, 6 and 12 months postoperatively and every 12 months thereafter.

Results

The mean follow-up time was 68.98 ± 7.68 months (60–87 months), and the 5-year mean volume reduction rate (VRR) after RFA was 92.95%, with a complication rate of 0.6% (3/52). The mean initial volume of the macrocalcification group was significantly larger than that of the PEF group (9.94 ± 24.60 ml vs. 0.23 ± 0.22 ml, respectively; P = 0.011). Thus, their VRRs were not comparable between the two groups. However, baseline characteristics did not show statistically significant differences between the strong and weak macrocalcification subgroups. The VRRs of the strong subgroup were significantly lower than those of the weak subgroup at the 3-year, 4-year, and 5-year follow-ups.

Conclusion

RFA was effective and safe for treating CBTNs. Strong macrocalcification was related to the VRR of CBTNs after the RFA procedure.

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.

Comparison of Korean vs. American Thyroid Imaging Reporting and Data System in Malignancy Risk Assessment of Indeterminate Thyroid Nodules

BACKGROUND

The management of cytologically indeterminate thyroid nodules is challenging for clinicians. This study aimed to compare the diagnostic performance of the Korean Thyroid Imaging Reporting and Data Systems (K-TIRADS) with that of the American College of Radiology (ACR)-TIRADS for predicting the malignancy risk of indeterminate thyroid nodules.

METHODS

Thyroid nodules diagnosed by fine-needle aspiration (FNA) followed by surgery or core needle biopsy at a single referral hospital were enrolled.

RESULTS

Among 200 thyroid nodules, 78 (39.0%) nodules were classified as indeterminate by FNA (Bethesda category III, IV, and V), and 114 (57.0%) nodules were finally diagnosed as malignancy by surgery or core needle biopsy. The area under the curve (AUC) was higher for FNA than for either TIRADS system in all nodules, while all three methods showed similar AUCs for indeterminate nodules. However, for Bethesda category III nodules, applying K-TIRADS 5 significantly increased the risk of malignancy compared to a cytological examination alone (50.0% vs. 26.5%, P=0.028), whereas applying ACR-TIRADS did not lead to a change.

CONCLUSION

K-TIRADS and ACR-TIRADS showed similar diagnostic performance in assessing indeterminate thyroid nodules, and K-TIRADS had beneficial effects for malignancy prediction in Bethesda category III nodules.

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.

Comparison of the diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System for thyroid malignancy with three international guidelines

Purpose

This study compared the diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System (K-TIRADS) for thyroid malignancy with three international guidelines.

Methods

From June to September 2015, 5,708 thyroid nodules (≥1.0 cm) in 5,081 consecutive patients who underwent thyroid ultrasound (US) at 26 institutions were evaluated. The US features of the thyroid nodules were retrospectively reviewed and classified according to all four guidelines. In the modified K-TIRADS, the biopsy size threshold was changed to 2.0 cm for K-TIRADS 3 and 1.0 or 1.5 cm for K-TIRADS 4 (K-TIRADS_1.0cm and K-TIRADS_1.5cm, respectively). We compared the diagnostic performance and unnecessary fine-needle aspiration biopsy (FNAB) rates for thyroid malignancy between the modified K-TIRADS and three international guidelines.

Results

Of the 5,708 thyroid nodules, 4,597 (80.5%) were benign and 1,111 (19.5%) were malignant. The overall sensitivity was highest for the modified K-TIRADS_1.0cm (91.0%), followed by the European (EU)-TIRADS (84.6%), American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi (AACE/ACE/AME) (80.5%), American College of Radiology (ACR)-TIRADS (76.1%), and modified K-TIRADS_1.5cm (76.1%). For large nodules (>2.0 cm), the sensitivity increased to 98.0% in both the modified K-TIRADS_1.0cm and K-TIRADS_1.5cm. For small nodules (≤2.0 cm), the unnecessary FNAB rate was lowest with the modified K-TIRADS_1.5cm (17.6%), followed by the ACR-TIRADS (18.6%), AACE/ACE/AME (19.3%), EU-TIRADS (28.1%), and modified K-TIRADS_1.0cm (31.2%).

Conclusion

The modified K-TIRADS_1.5cm can reduce the unnecessary FNAB rate for small nodules (1.0-2.0 cm), while maintaining high sensitivity for detecting malignancies >2.0 cm.

Malignancy Risk Stratification of Thyroid Nodules with Macrocalcification and Rim Calcification Based on Ultrasound Patterns

Objective

To determine the association of macrocalcification and rim calcification with malignancy and to stratify the malignancy risk of thyroid nodules with macrocalcification and rim calcification based on ultrasound (US) patterns.

Materials and Methods

The study included a total of 3603 consecutive nodules (≥ 1 cm) with final diagnoses. The associations of macrocalcification and rim calcification with malignancy and malignancy risk of the nodules were assessed overall and in subgroups based on the US patterns of the nodules. The malignancy risk of the thyroid nodules was categorized as high (> 50%), intermediate (upper-intermediate: > 30%, ≤ 50%; lower-intermediate: > 10%, ≤ 30%), and low (≤ 10%).

Results

Macrocalcification was independently associated with malignancy in all nodules and solid hypoechoic (SH) nodules (p < 0.001). Rim calcification was not associated with malignancy in all nodules (p = 0.802); however, it was independently associated with malignancy in partially cystic or isoechoic and hyperechoic (PCIH) nodules (p = 0.010). The malignancy risks of nodules with macrocalcification were classified as upper-intermediate and high in SH nodules, and as low and lower-intermediate in PCIH nodules based on suspicious US features. The malignancy risks of nodules with rim calcification were stratified as low and lower-intermediate based on suspicious US features.

Conclusion

Macrocalcification increased the malignancy risk in all and SH nodules with or without suspicious US features, with low to high malignancy risks depending on the US patterns. Rim calcification increased the malignancy risk in PCIH nodules, with low and lower-intermediate malignancy risks based on suspicious US features. However, the role of rim calcification in risk stratification of thyroid nodules remains uncertain.

Somatic Mutation Profiling of Papillary Thyroid Carcinomas by Whole-exome Sequencing and Its Relationship with Clinical Characteristics

The incidence of papillary thyroid carcinomas (PTCs) has increased rapidly during the past several decades. Until now, the mechanisms underlying the tumorigenesis of PTCs have remained largely unknown. Next-generation-sequencing (NGS) provides new ways to investigate the molecular pathogenesis of PTCs. To characterize the somatic alterations associated with PTCs, we performed whole-exome sequencing (WES) of PTCs from 23 Chinese patients. This study revealed somatic mutations in genes with relevant functions for tumorigenesis, such as BRAF, BCR, CREB3L2, DNMT1, IRS2, MSH6, and TP53. We also identified novel somatic gene alterations which may be potentially involved in PTC progression. Gene set enrichment analysis revealed that the cellular response to hormone stimulus, epigenetic modifications, such as protein/histone methylation and protein alkylation, as well as MAPK, PI3K-AKT, and FoxO/mTOR signaling pathways, were significantly altered in the PTCs studied here. Moreover, Protein-Protein Interaction (PPI) network analysis of our mutated gene selection highlighted EP300, KRAS, PTEN, and TP53 as major core genes. The correlation between gene mutations and clinicopathologic features of the PTCs defined by conventional ultrasonography (US) and contrast-enhanced ultrasonography (CEUS) were assessed. These analyses established significant associations between subgroups of mutations and respectively taller-than-wide, calcified, and peak time iso- or hypo-enhanced and metastatic PTCs. In conclusion, our study supplements the genomic landscape of PTCs and identifies new actionable target candidates and clinicopathology-associated mutations. Extension of this study to larger cohorts will help define comprehensive genomic aberrations in PTCs and validate target candidates. These new targets may open methods of individualized treatments adapted to the clinicopathologic specifics of the patients.

Diagnostic value of 2017 ACR Thyroid Imaging Reporting and Data System (TI-RADS) combined with fine needle aspiration biopsy in thyroid nodules

OBJECTIVE

To evaluate diagnostic value of Thyroid Imaging Reporting and Data System published by American College of Radiology (ACR TI-RADS) in 2017, ultrasound-guided fine-needle aspiration (US-FNA), and the combination of both methods in differentiation between benign and malignant thyroid nodules.

METHODS

The data of US-FNA and ACR TI-RADS are collected from 159 patients underwent thyroid surgery in our hospital, which include a total of 178 thyroid nodules. A Bethesda System for Reporting Thyroid Cytopathology category of ≥IV and an ACR TI-RADS category ≥4 are regarded as diagnosis standards for malignancy in US-FNA and ACR TI-RADS, respectively. The pathological results after surgery are considered as the gold standard. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the ACR TI-RADS, US-FNA and the combination of both methods for the differential diagnosis of thyroid nodules are calculated, respectively.

RESULTS

The sensitivity, specificity and accuracy of ACR TI-RADS are 85.4%, 37.5%and 72.5%, respectively. The sensitivity, specificity and accuracy of US-FNA are 70.0%, 100%and 78.1%, respectively. After combining these two methods, the sensitivity, specificity and accuracy increase to 99.23%, 37.50%and 82.58%, respectively. The sensitivity of ACR TI-RADS is higher than that of US-FAN, and the sensitivity of combining these two methods is also higher than that of using ACR TI-RADS and US-FNA alone.

CONCLUSION

The established ACR TI-RADS can help in selecting the target during nodule puncture, while the combination of ACR TI-RADS and US-FAN can further improve diagnostic ability for detecting malignant thyroid nodules.

Atypia of undetermined significance/follicular lesions of undetermined significance: What radiologists need to know

Atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS) refers to an intermediate histologic category of thyroid nodules in The Bethesda System for Reporting Thyroid Cytopathology. Although the risk of malignancy in this category was originally cited as 5-15%, recent literature has suggested higher rates of related malignancy ranging from 38% to 55%. Malignant nodules warrant surgery with total thyroidectomy or thyroid lobectomy, whereas benign nodules can be observed or followed with serial ultrasounds (US) based on their imaging characteristics. The management of nodules with a cytopathologic diagnosis of AUS/FLUS can be difficult because theses nodules lie between the extremes of benign and malignant. The management options for such nodules include observation, repeat fine-needle aspiration, and surgery. The use of molecular genetics, the identification of suspicious US characteristics, and the recognition of additional clinical factors are all important in the development of an appropriate, tailored management approach. Institutional factors also play a crucial role.

Molecular Aspects and Prognostic Significance of Microcalcifications in Human Pathology: A Narrative Review

The presence of calcium deposits in human lesions is largely used as imaging biomarkers of human diseases such as breast cancer. Indeed, the presence of micro- or macrocalcifications is frequently associated with the development of both benign and malignant lesions. Nevertheless, the molecular mechanisms involved in the formation of these calcium deposits, as well as the prognostic significance of their presence in human tissues, have not been completely elucidated. Therefore, a better characterization of the biological process related to the formation of calcifications in different tissues and organs, as well as the understanding of the prognostic significance of the presence of these calcium deposits into human tissues could significantly improve the management of patients characterized by microcalcifications associated lesions. Starting from these considerations, this narrative review highlights the most recent histopathological and molecular data concerning the formation of calcifications in breast, thyroid, lung, and ovarian diseases. Evidence reported here could deeply change the current point of view concerning the role of ectopic calcifications in the progression of human diseases and also in the patients' management. In fact, the presence of calcifications can suggest an unfavorable prognosis due to dysregulation of normal tissues homeostasis.

Thyroid Nodules with Isolated Macrocalcifications: Malignancy Risk of Isolated Macrocalcifications and Postoperative Risk Stratification of Malignant Tumors Manifesting as Isolated Macrocalcifications

Objective

To determine the malignancy risk of isolated macrocalcifications (a calcified nodule with complete posterior acoustic shadowing) detected on ultrasonography (US) and to evaluate the postoperative American Thyroid Association (ATA) risk stratification of malignant tumors manifesting as isolated macrocalcifications.

Materials and Methods

A total of 3852 thyroid nodules (≥ 1 cm) of 3061 consecutive patients who had undergone biopsy between January 2011 and June 2018 were included in this study. We assessed the prevalence, malignancy rate, and size distribution of isolated macrocalcifications and evaluated the histopathologic features and postoperative ATA risk stratification of malignant tumors manifesting as isolated macrocalcifications.

Results

Isolated macrocalcifications were found in 38 (1.2%) of the 3061 patients. Final diagnosis was established in 30 (78.9%) nodules; seven malignant tumors were diagnosed as papillary thyroid carcinomas (PTCs). The malignancy rate of the isolated macrocalcifications was 23.3% in the 30 nodules with final diagnoses and 18.4% in all nodules. Among the six surgically-treated malignant tumors, five (83.3%) had an extrathyroidal extension (ETE) (minor ETE 1, gross ETE 4), and two (33.3%) had macroscopic lymph node metastasis. Four (66.7%) malignant tumors were categorized as high-risk tumors, one as an intermediate-risk tumor, and one as a low-risk tumor using the ATA risk stratification. Histopathologically, out of the six malignant tumors, ossifications were noted in four (66.7%) and predominant calcifications in two (33.3%).

Conclusion

The US pattern of isolated macrocalcifications (≥ 1 cm) showed an intermediate malignancy risk (at least 18.4%). All malignant tumors were PTCs, and most showed an aggressive behavior and a high or intermediate postoperative ATA risk.

Diagnostic Efficacy and Safety of Core Needle Biopsy as a First-Line Diagnostic Method for Thyroid Nodules: A Prospective Cohort Study

Background: The diagnostic role of ultrasonography (US)-guided core needle biopsy (CNB) as a first-line diagnostic method for thyroid nodules remains controversial. This study was performed to determine the diagnostic efficacy and safety of CNB as a first-line diagnostic method for thyroid nodules. Methods: From February 2016 to January 2018, CNB was prospectively performed by an experienced radiologist in all consecutive patients with thyroid nodules indicated for fine-needle aspiration (FNA). Three patients refused this protocol. Finally, 212 consecutive patients with 248 thyroid nodules were enrolled in this prospective study. Combined CNB/FNA was selectively performed in 43 patients. The diagnostic efficacy of CNB was evaluated by the rate of inconclusive results (nondiagnostic or indeterminate results), and its feasibility was estimated by calculating the successful biopsy rate and by measuring the procedure time from the time of the initial skin puncture to the last withdrawal of the biopsy needle from the skin. The safety of the procedure was evaluated by the major and minor complication rates. A US evaluation was performed before and after manual self-compression to assess for hemorrhage at the biopsy site, and delayed complications were assessed 5-7 days after the biopsy. Any hemorrhage that did not require hospitalization was classified as a minor complication. Results: CNB was performed once (n = 125, 50.4%), twice (n = 122, 49.2%), or three times (n = 1, 0.4%) per nodule. The diagnostic results of CNB were as follows: nondiagnostic (0.8%), benign (63.3%), indeterminate (10.1%), follicular neoplasm (3.2%), suspected malignancy (2.4%), and malignancy (20.1%); the rate of inconclusive results was 10.9%. The successful biopsy rate of CNB was 100%, and the median procedure time was 102 seconds (interquartile range 51-181 seconds). There were no major or delayed complications. There were 6 cases (2.8%) of minor complications, which included 2 cases (0.9%) with symptomatic hematomas and 4 cases (1.9%) with asymptomatic small hematomas. Conclusion: The findings confirm that CNB is effective in reducing the rate of inconclusive results and it is safe. CNB may be used as an alternative first-line diagnostic method for thyroid nodules by an experienced operator.

The Diagnostic Role of Computed Tomography for ACR TI-RADS 4-5 Thyroid Nodules With Coarse Calcifications

Objectives: Coarse calcifications are prone to cause echo attenuation during ultrasonography (US) and hence affect the classification of benign and malignant nodules. This study aimed to investigate the diagnostic role of computed tomography (CT) for differentiating the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) 4–5 nodules with coarse calcifications.

Methods: CT data of 216 ACR TI-RADS 4–5 nodules with coarse calcifications confirmed by surgery and pathology in 207 patients were analyzed retrospectively. Halo sign, artifacts, and CT values (i.e., Hounsfield unit) of the nodules were determined by two radiologists. Univariate analysis and binary logistic regression were used to determine the relationship of halo sign, artifact, and CT value with benign nodules. A predictive model for benign nodules with coarse calcifications was then constructed. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of halo sign, artifact, CT value, and logistic regression model.

Results: Of the 216 ACR TI-RADS 4–5 nodules with coarse calcifications, 170 were benign and 46 were malignant. There were 92 benign and 7 malignant nodules with halo sign (χ² = 22.067, P < 0.001), and 79 benign and 10 malignant nodules with artifacts (χ² = 9.140, P < 0.001). The CT values of benign and malignant nodules were 791 (543–1,025) Hu and 486 (406–670) Hu, respectively (Z = −5.394, P < 0.001). Binary logistic regression demonstrated that the halo sign, artifact, and CT value were independent predictors for benign nodules with coarse calcifications. The area under the ROC curve (AUC) of halo sign, artifact, CT value and regression model for predicting benign nodules with coarse calcifications were 0.776, 0.711, 0.784, and 0.850, respectively, and the optimal threshold of CT value was 627.5 Hu.

Conclusion: Halo sign, artifact, and CT value > 627.5 Hu were helpful for identifying ACR TI-RADS 4–5 thyroid benign nodules with coarse calcifications. The diagnostic performance of the logistic regression model was higher than that of any single indicator. Accurate identification of these indicators could identify benign nodules and reduce unnecessary surgical trauma.

Hounsfield Unit Values in ACR TI-RADS 4-5 Thyroid Nodules with Coarse Calcifications: An Important Imaging Feature Helpful for Diagnosis

Purpose

The purpose of this study is to investigate the diagnostic role of Hounsfield unit (HU) values on noncontrast computed tomography (CT) for differentiating benignity from malignancy in the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) 4-5 nodules with coarse calcifications.

Patients and Methods

CT images of 216 ACR TI-RADS 4-5 nodules with coarse calcifications from 207 patients who underwent surgery in our hospital between 2017 and 2019 were retrospectively reviewed. The average HU values (AHUVs) and maximum HU values (MHUVs) of the nodules were measured on noncontrast CT. The distribution of AHUVs and MHUVs in benign and malignant nodules with coarse calcifications was analyzed using the Mann-Whitney test. Receiver operating characteristic (ROC) curves were used to identify the best cut-off values. Diagnostic performances were assessed according to the area under the ROC curve (AUC), sensitivity and specificity.

Results

Of the 216 ACR TI-RADS 4-5 nodules with coarse calcifications, 170 were benign and 46 were malignant. The AHUVs of benign and malignant nodules were 791 HU [interquartile range (IQR), 543-1025 HU] and 486 HU (IQR, 406-670 HU), respectively (P < 0.001). The MHUVs of benign and malignant nodules were 1084 HU (IQR, 717-1477 HU) and 677 HU (IQR, 441-986 HU), respectively (P < 0.001). The AUCs for AHUVs and MHUVs for predicting benign nodules with coarse calcifications were 0.759 and 0.732, and the cut-off values were 627.5 HU and 806.0 HU, with sensitivities of 67.6% and 68.8% and specificities of 73.9% and 67.4%, respectively. The sensitivity and specificity of the combination were 68.8% and 76.1%.

Conclusion

AHUVs and MHUVs were helpful in differentiating benignity from malignancy in ACR TI-RADS 4-5 nodules with coarse calcifications. This may provide an important basis for reducing misdiagnosis and unnecessary aspiration or surgical trauma.

2019 Practice guidelines for thyroid core needle biopsy: a report of the Clinical Practice Guidelines Development Committee of the Korean Thyroid Association

Ultrasound-guided core needle biopsy (CNB) has been increasingly used for the pre-operative diagnosis of thyroid nodules. Since the Korean Society of the Thyroid Radiology published the ‘Consensus Statement and Recommendations for Thyroid CNB’ in 2017 and the Korean Endocrine Pathology Thyroid CNB Study Group published ‘Pathology Reporting of Thyroid Core Needle Biopsy’ in 2015, advances have occurred rapidly not only in the management guidelines for thyroid nodules but also in the diagnostic terminology and classification schemes. The Clinical Practice Guidelines Development Committee of the Korean Thyroid Association (KTA) reviewed publications on thyroid CNB from 1995 to September 2019 and updated the recommendations and statements for the diagnosis and management of thyroid nodules using CNB. Recommendations for the resolution of clinical controversies regarding the use of CNB were based on expert opinion. These practical guidelines include recommendations and statements regarding indications for CNB, patient preparation, CNB technique, biopsy-related complications, biopsy specimen preparation and processing, and pathology interpretation and reporting of thyroid CNB.

Thyroid Radiology Practice: Diagnosis and Interventional Treatment of Patients with Thyroid Nodules

갑상선 영상의학 진료란 갑상선 질환 환자를 영상의학적 방법을 활용하여 질병 진단과 중재적 치료를 하는 의료 행위로 정의될 수 있으며 주요 진료 대상은 갑상선 결절 질환 환자들이다. 갑상선 결절의 진단은 일차적으로 초음파 영상진단과 생검에 의해서 이루어지고 결절의 치료는 비수술적 중재적 치료와 갑상선절제술이다. 갑상선 낭종 혹은 낭성우세 양성 결절에서는 에탄올절제술이 일차적 치료법이고 고주파절제술은 고형 혹은 고형우세 양성 결절과 갑상선 재발암 치료에 적용되고 있다. 갑상선 영상의학 진료는 갑상선 결절 질환 환자의 진단 및 비수술적 치료의 대부분을 담당하는 중요한 임상적 역할을 가지고 있으며, 적절한 환자 진료를 위해서는 표준적 진료 지침에 근거하여 진료가 수행되어야 한다. 환자에게 최적의 갑상선 영상의학 진료를 제공하기 위해서는 영상의학과 외래에서 환자를 진료하는 것이 바람직하며 외래 중심의 갑상선 영상의학 진료를 확대하도록 함께 노력해야 할 시점이다.

CT features of thyroid nodules with isolated macrocalcifications detected by ultrasonography

Purpose

A thyroid nodule with an isolated macrocalcification is visualized as a calcified nodule with complete posterior shadowing on ultrasonography (US). This study aimed to determine the computed tomography (CT) features of isolated macrocalcifications detected using US.

Methods

This study included 20 patients who had thyroid nodules with isolated macroalcifications and underwent neck CT or chest CT. The patients were enrolled from a sample of 82 patients with isolated macrocalcifications detected by US drawn from 7,142 consecutive patients who underwent thyroid biopsy at two institutions. We evaluated the CT features of nodules with isolated macrocalcifications and categorized them as central or rim calcifications. We assessed the nodule size and the frequency of nondiagnostic fine-needle aspiration (FNA) results and malignant tumors according to the CT features of isolated macrocalcifications.

Results

CT scans showed central calcifications in 18 (90.0%) and rim calcifications in two (10.0%) of the 20 nodules with isolated macrocalcifications. Among the 18 nodules with central isolated macrocalcifications, complete compact calcification was found in six nodules and partial coarse calcification in 12 nodules. In 18 nodules with central isolated macrocalcifications, the nondiagnostic FNA rate and frequency of malignant tumors were not significantly different between complete and partial central calcifications (P=0.620 and P=0.999, respectively). Malignant tumors were only found in nodules with central isolated macrocalcifications.

Conclusion

The majority of nodules with isolated macrocalcifications showed central calcifications on CT. Thyroid nodules with isolated macrocalcifications detected by US should not be classified as having a type of rim or peripheral calcification.

Core needle biopsy in the management of thyroid nodules with an indeterminate fine-needle aspiration report

Ultrasonography (US)-guided fine-needle aspiration biopsy (FNAB) cytology is widely used but is limited due to its pathologically indeterminate results in diagnosing thyroid nodules. Recently, US-guided core-needle biopsy (CNB) was introduced as an effective and safe technique for diagnosing indeterminate thyroid nodules. Using CNB, information about architectural histologic structure such as nodule capsule or more immunochemical staining can be obtained which lead to a more accurate diagnosis. Up to 98% of indeterminate thyroid lesions can be classified as malignant or benign when CNB is used for follow-up analysis. Other evidences revealed the effectiveness of CNB in reducing inconclusive results and improving the diagnostic performance of thyroid nodules initially diagnosed as AUS/FLUS by FNAB. In this review, we investigate how to deal with indeterminate thyroid nodules diagnosed by FNAB and determine how CNB has a role in diagnosing these indeterminate thyroid nodules.

Piezoelectric needle sensor reveals mechanical heterogeneity in human thyroid tissue lesions

Palpable thyroid lesions are common, and although mostly benign, lethal malignant nodules do occur and may be difficult to differentiate. Here, we introduce the use of a piezoelectric system called Smart-touch fine needle (or STFN) mounted directly onto conventional biopsy needles, to evaluate abnormal tissues, through quantitative real-time measurements of variations in tissue stiffness as the needle penetrates tissue. Using well-characterized biomaterials of known stiffness and explanted animal tissue models, we first established experimental protocols for STFN measures on biological tissues, as well as optimized device design for high signal-to-noise ratio. Freshly excised patient thyroids with varying fibrotic and malignant potential revealed discrete variations in STFN based tissue stiffness/stiffness heterogeneity and correlated well with final histopathology. Our piezoelectric needle sensor reveals mechanical heterogeneity in thyroid tissue lesions and provides a foundation for the design of hand-held tools for the rapid, mechano-profiling of malignant lesions in vivo while performing fine needle aspiration (FNA).

A case of mixed-pattern calcifications in multinodular goiter associated with a benign diagnosis

•

Calcified nodules in a goiter are often found when performing an ultrasound of the neck.

•

Analysis of different calcification patterns could contribute to discriminating between nodules.

•

Mixed pattern calcifications is not so frequent and not interpreted.

•

We believe that a better radiologic evaluation setting of thyroid nodules needs to be performed.

Background

Calcified nodules are often found in a goiter when performing an ultrasound of the neck. An analysis of different calcification patterns could contribute to discriminating between nodules with a lower malignancy risk and those with a higher malignancy risk. In certain cases, the results of a simple cytological analysis of a nodule are not specific enough to be completely trusted.

Case presentation

We present the case of a goiter with a mixed calcification pattern, including a type of calcification that is strongly associated with a malignant diagnosis, for which a completely benign diagnosis was determined.

Conclusion

We believe that further studies examining a combination of ultrasound (US) and computed tomography (CT) scan presentations of thyroid nodules need to be performed.

Using Artificial Intelligence to Revise ACR TI-RADS Risk Stratification of Thyroid Nodules: Diagnostic Accuracy and Utility

Background Risk stratification systems for thyroid nodules are often complicated and affected by low specificity. Continual improvement of these systems is necessary to reduce the number of unnecessary thyroid biopsies. Purpose To use artificial intelligence (AI) to optimize the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS). Materials and Methods A total of 1425 biopsy-proven thyroid nodules from 1264 consecutive patients (1026 women; mean age, 52.9 years [range, 18-93 years]) were evaluated retrospectively. Expert readers assigned points based on five ACR TI-RADS categories (composition, echogenicity, shape, margin, echogenic foci), and a genetic AI algorithm was applied to a training set (1325 nodules). Point and pathologic data were used to create an optimized scoring system (hereafter, AI TI-RADS). Performance of the systems was compared by using a test set of the final 100 nodules with interpretations from the expert reader, eight nonexpert readers, and an expert panel. Initial performance of AI TI-RADS was calculated by using a test for differences between binomial proportions. Additional comparisons across readers were conducted by using bootstrapping; diagnostic performance was assessed by using area under the receiver operating curve. Results AI TI-RADS assigned new point values for eight ACR TI-RADS features. Six features were assigned zero points, which simplified categorization. By using expert reader data, the diagnostic performance of ACR TI-RADS and AI TI-RADS was area under the receiver operating curve of 0.91 and 0.93, respectively. For the same expert, specificity of AI TI-RADS (65%, 55 of 85) was higher (P < .001) than that of ACR TI-RADS (47%, 40 of 85). For the eight nonexpert radiologists, mean specificity for AI TI-RADS (55%) was also higher (P < .001) than that of ACR TI-RADS (48%). An interactive AI TI-RADS calculator can be viewed at http://deckard.duhs.duke.edu/∼ai-ti-rads . Conclusion An artificial intelligence-optimized Thyroid Imaging Reporting and Data System (TI-RADS) validates the American College of Radiology TI-RADS while slightly improving specificity and maintaining sensitivity. Additionally, it simplifies feature assignments, which may improve ease of use. © RSNA, 2019 Online supplemental material is available for this article.

Echogenic foci in thyroid nodules: diagnostic performance with combination of TIRADS and echogenic foci

BACKGROUND

The malignancy risks of various echogenic foci in thyroid nodules are not consistent. The association between malignancy and echogenic foci and various Thyroid Imaging Reporting and Data System (TIRADS) in thyroid nodules has not been evaluated. We evaluated the malignancy probability and diagnostic performance of thyroid nodules with various echogenic foci and in combination with TIRADS.

METHODS

This retrospective study was approved by Institutional Review Board. The data were retrospectively collected from January 2013 to December 2014. In total, 954 patients (mean age, 50.8 years; range, 13-86 years) with 1112 nodules were included. Using χ2 test, we determined the prevalence of benign and malignant nodules among those with and without echogenic foci; we associated each of 6 echogenic foci types with benign and malignant nodules. Diagnostic performance was compared between the 6 types alone and in combination with various TIRADS.

RESULTS

Among 1112 nodules, 390 nodules (35.1%) were found to have echogenic foci, and 722 nodules (64.9%) were not. Among nodules with echogenic foci, 254 nodules (65.1%) were malignant. The punctate echogenic foci with comet-tail artifact showed malignancy rate of 77.8% in solid and predominantly solid nodules. Our study demonstrated relatively low PPV (33.3-56.4%) in nodules with large echogenic foci without shadowing, macrocalcification, and peripheral curvilinear or eggshell echogenic foci with or without shadowing. However, when combined with high suspicion category of TIRADS, PPV increased to 50.0-90.9%.

CONCLUSION

Combination with TIRADS with different types of echogenic foci offer better stratification of the malignancy risk.

Value of differential diagnosis of contrast-enhanced ultrasound in benign and malignant thyroid nodules with microcalcification

Value of differential diagnosis of contrast-enhanced ultrasound in benign and malignant thyroid nodules with microcalcification was explored. A total of 184 patients with thyroid nodules with microcalcification, treated in People's Hospital of Shanxi Province from April 2015 to March 2017, were selected as research subjects. Contrast-enhanced ultrasound was used for imaging examination of the thyroid nodules. Three regions of interest were drawn at the positions with the strongest ultrasound imaging, for which the time-intensity curve (TIC), time to peak (Tp), peak intensity (Peak), area under curve (AUC) and mean transit time (MTT) were obtained separately. The features of contrast-enhanced ultrasound for malignant thyroid nodules were manifested as irregular focus edge, unclear boundary, low fiber reinforcement of the whole focus, uneven distribution of images and blood perfusion defect inside the focus, especially severe blood perfusion defect in the nodule center. The TIC showed a slow ascending and slow descending trend in general. The TIC features and the features of contrast-enhanced ultrasound for malignant thyroid nodules were prominently different from those for benign thyroid nodules. Compared with those in the surrounding normal tissues of thyroid gland, the Peak was remarkably shorter, and the AUC was notably smaller in the center and edge of malignant thyroid nodules (P<0.05); and the nodule center had obviously shorter Peak and smaller AUC than the nodule edge (P<0.05). Furthermore, in comparison with those of malignant thyroid nodules, the Peak was extended and AUC was enlarged markedly in the center and edge of benign thyroid nodules (P<0.05). In conclusion, the contrast-enhanced ultrasound can preferably compare the lesions of benign and malignant thyroid nodules with microcalcification, which possesses certain value in the differential diagnosis of benign and malignant thyroid nodules.

A Single-Center Retrospective Validation Study of the American College of Radiology Thyroid Imaging Reporting and Data System

OBJECTIVE

This study aimed to evaluate a new risk stratification system, the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS), published in 2017.

MATERIALS AND METHODS

From January 2015 to December 2016, 1033 thyroid nodules in 1013 patients who had undergone sonography and thyroid surgery or fine-needle aspiration (FNA) in our hospital were included. The sonographic features were described in a standard manner and analyzed according to the white paper of the ACR TI-RADS Committee. Nodules were assigned points for each feature, and the points were totaled to determine the final TI-RADS levels.

RESULTS

Of the 1033 nodules, 725 were benign and 308 were malignant proven by operation or FNA. The malignant risk was associated with the composition, echogenicity, shape, margins, and echogenic foci of the nodules (P < 0.001). The calculated risk of malignancy was higher in nodules with macrocalcifications than those with peripheral calcifications, which is different from the ACR TI-RADS. The calculated malignancy rates of nodules with TR5, TR4, TR3, and TR2 were 67.1%, 13.0%, 1.1%, and 0%, respectively, which showed a higher malignant risk than the suggested threshold of TR5 in the ACR TI-RADS. Six nodules with TR4 recommended for no follow-up and 55 nodules with TR5 recommended for follow-up were malignant with cervical lymph node metastasis.

CONCLUSIONS

The ACR TI-RADS provides effective malignancy risk stratification for thyroid nodules and was useful for the decision for FNA. However, the points assigned for echogenic foci, the set of the TI-RADS risk thresholds, and FNA thresholds may need more consideration and prospective validation.

Core needle biopsy of thyroid nodules: outcomes and safety from a large single-center single-operator study

Background There currently remains a debate over the use of core needle biopsy (CNB) or fine needle aspiration (FNA) for diagnosis of thyroid nodules. The major drawbacks of previous CNB studies include heterogeneity of the study population, variable techniques, devices, and operator experience affecting the outcome of the procedure. Purpose To assess the diagnostic performance and safety of CNB of thyroid nodules performed by a single experienced operator in consecutive patients. Material and Methods From January 2012 to December 2012, 538 thyroid nodules that underwent CNB were retrospectively evaluated. All CNB procedures were performed by a single operator with 18 years of experience. The histopathology of the surgical specimens was considered as the standard reference for malignancy. A final diagnosis of benignity was made by surgery, one benign lesion on FNA and/or CNB with no change on follow-up examinations (>1 year) or benign lesion on ≥2 FNA and/or CNB. The diagnostic performance, incidence of technical failure, unnecessary surgery, and complication were evaluated. Results The diagnostic accuracy, sensitivity, and specificity of CNB for malignancy were 92.0%, 85.3%, and 100%, respectively. The non-diagnostic result rate of CNB was 4.8% (26/538) and the inconclusive result rate was 24.3% (131/538). The incidence of technical failure was 0.6% (3/541) and unnecessary surgery was 0.6%. The complication rate was 0.2%, without life-threatening complications. The sensitivity, specificity, and accuracy were 85.3% (156/183), 100.0% (154/154), and 92.0% (310/337), respectively. Conclusion CNB shows a high diagnostic performance for detection of thyroid malignancy and follicular neoplasm, with low rates of technical failure and complications.

Malignancy risk of initially benign thyroid nodules: validation with various Thyroid Imaging Reporting and Data System guidelines

OBJECTIVE

Some authors have found little or no diagnostic benefit from repeated biopsy of benign thyroid nodules. However, to our knowledge, integration of Thyroid Imaging Reporting and Data System (TIRADS) guidelines with one biopsy for sufficient benign thyroid nodule diagnosis has not been previously described. We investigated malignancy rate and probability by using various malignancy stratification systems in initially biopsy-proven benign nodules and sought to determine their clinical relevance in management of benign thyroid nodules.

METHODS

This retrospective study collected 6762 thyroid nodules from 6493 consecutive patients who underwent biopsy between January 2013 and December 2013. The initial biopsy with ≥1 year of follow-up was used as the gold standard for benign diagnosis. For our study purpose, we analyzed 2747 (57.0%, 2747 of 4822, 532 women, 2111 men; 229 malignant and 2518 benign) thyroid nodules diagnosed by initial biopsy with 28.2 ± 9.1 (range, 12-41) months of follow-up. We calculated the malignancy probability of thyroid nodules by using various malignancy risk stratification systems.

RESULTS

The overall calculated thyroid malignancy rate was 8.3% (229 of 2747). Initially biopsy-proven benign nodules exhibited a ≤3.0% malignancy probability when assessed as "low suspicion" by Korean-TIRADS (K-TIRADS), "low suspicion" by the ATA guideline, and "very probably benign" by the French TIRADS guideline and gave a score of ≤3 by the web-based TIRADS.

CONCLUSION

When initially biopsy-proven benign nodules exhibit a "low suspicion" US pattern and low malignancy probability, as stratified by various TIRADS guidelines, imaging surveillance instead of second biopsy is warranted.

KEY POINTS

• One biopsy is sufficient for initially biopsy-proven benign nodules. • Repetitive biopsy is necessary for imaging-pathology mismatched nodules. • Scoring risk stratification permits personalized management.

Validation of Three Scoring Risk-Stratification Models for Thyroid Nodules

BACKGROUND

To minimize potential harm from overuse of fine-needle aspiration, Thyroid Imaging Reporting and Data Systems (TIRADSs) were developed for thyroid nodule risk stratification. The purpose of this study was to perform validation of three scoring risk-stratification models for thyroid nodules using ultrasonography features, a web-based malignancy risk-stratification system, and a model developed by the Korean Society of Thyroid Radiology and the American College of Radiology.

METHODS

Using ultrasonography images, radiologists assessed thyroid nodules according to the following criteria: internal content, echogenicity of the solid portion, shape, margin, and calcifications. A total of 954 patients (Mage = 50.8 years; range 13-86 years) with 1112 nodules were evaluated at the authors' institute from January 2013 to December 2014. The discrimination ability of the three models was assessed by estimating the area under the receiver operating characteristic curve. Additionally, Hosmer-Lemeshow goodness-of-fit statistics (calibration ability) were used to evaluate the agreement between the observed and expected number of nodules that were benign or malignant.

RESULTS

Thyroid malignancy was present in 37.2% (414/1112) of nodules. According to the 14-point web-based scoring risk-stratification system, malignancy risk ranged from 4.5% to 100.0% and was positively associated with an increase in risk scores. The areas under the receiver operating characteristic curve of the validation set were 0.884 in the web-based model, 0.891 in the Korean Society of Thyroid Radiology model, and 0.875 in the American College of Radiology model. The Hosmer-Lemeshow goodness-of-fit test indicated that the web-based scoring system showed the best-calibrated result, with a p-value of 0.078.

CONCLUSION

The three scoring risk-stratification models using the ultrasonography features of thyroid nodules to stratify malignancy risk showed acceptable predictive accuracy and similar areas under the curve. The web-based scoring system demonstrated the strongest agreement in calibration ability analysis. The easily accessible automated web-based scoring risk-stratification system may overcome the complexity of the various Thyroid Imaging Reporting and Data System guidelines and provide simplified guidance on personalized and optimal management in real practice.

Detection of Malignancy Among Suspicious Thyroid Nodules <1 cm on Ultrasound with Various Thyroid Image Reporting and Data Systems

BACKGROUND

In patients undergoing active surveillance of papillary thyroid microcarcinoma, definitive therapy-usually preceded by a definitive diagnostic procedure-is not recommended until evidence of disease progression is obtained, as stated in the American Thyroid Association guidelines. This is because the deferring of definitive diagnosis and therapy until disease progression has no impact on the disease-specific survival. This study evaluated the malignancy rate and probability of thyroid nodules, which was further stratified based on the size cutoff value of 1 cm, with suspicious findings on ultrasonography (US), by using various malignant stratification systems.

METHODS

The data were retrospectively collected between January 2003 and June 2003 from nine university hospitals that had previously participated in the Korean Society of Thyroid Radiology multicenter study on the ultrasonographic differentiation between benign and malignant thyroid nodules. In total, 829 thyroid nodules from 711 patients (620 women, 91 men; M_age = 48.7 years; range 6-98 years; 351 malignant and 478 benign nodules) were included. The probability for malignancy of thyroid nodules was calculated, which was further stratified by size, by using four different types of malignant risk-stratification systems. The factors that could differentiate benign from malignant nodules were assessed using the chi-square test.

RESULTS

In the suspicious thyroid nodules <1 cm on US, the malignancy probability ranged from 77.4% to 82.8%; the lowest rate was found in the Korean Society of Thyroid Radiology multicenter study, whereas the highest rate was noted in the Web-based system. Thus, the probability of benign nodules among suspicious thyroid nodules <1 cm on US was 17.2-22.6%.

CONCLUSION

A biopsy should be considered before active surveillance to exclude benign nodules with suspicious US features, and could thus prevent unnecessary active surveillance and patient anxiety.

European Thyroid Association Guidelines for Ultrasound Malignancy Risk Stratification of Thyroid Nodules in Adults: The EU-TIRADS

Thyroid ultrasound (US) is a key examination for the management of thyroid nodules. Thyroid US is easily accessible, noninvasive, and cost-effective, and is a mandatory step in the workup of thyroid nodules. The main disadvantage of the method is that it is operator dependent. Thyroid US assessment of the risk of malignancy is crucial in patients with nodules, in order to select those who should have a fine needle aspiration (FNA) biopsy performed. Due to the pivotal role of thyroid US in the management of patients with nodules, the European Thyroid Association convened a panel of international experts to set up European guidelines on US risk stratification of thyroid nodules. Based on a review of the literature and on the American Association of Clinical Endocrinologists, American Thyroid Association, and Korean guidelines, the panel created the novel European Thyroid Imaging and Reporting Data System, called EU-TIRADS. This comprises a thyroid US lexicon; a standardized report; definitions of benign and low-, intermediate-, and high-risk nodules, with the estimated risks of malignancy in each category; and indications for FNA. Illustrated by numerous US images, the EU-TIRADS aims to serve physicians in their clinical practice, to enhance the interobserver reproducibility of descriptions, and to simplify communication of the results.

ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee

classification that is widely used in breast imaging, their authors chose to apply the acronym TI-RADS, for Thyroid Imaging, Reporting and Data System. In 2012, the ACR convened committees to (1) provide recommendations for reporting incidental thyroid nodules, (2) develop a set of standard terms (lexicon) for ultrasound reporting, and (3) propose a TI-RADS on the basis of the lexicon. The committees published the results of the first two efforts in 2015. In this article, the authors present the ACR TI-RADS Committee's recommendations, which provide guidance regarding management of thyroid nodules on the basis of their ultrasound appearance. The authors also describe the committee's future directions.

Core Needle Biopsy of the Thyroid: 2016 Consensus Statement and Recommendations from Korean Society of Thyroid Radiology

Core needle biopsy (CNB) has been suggested as a complementary diagnostic method to fine-needle aspiration in patients with thyroid nodules. Many recent CNB studies have suggested a more advanced role for CNB, but there are still no guidelines on its use. Therefore, the Task Force Committee of the Korean Society of Thyroid Radiology has developed the present consensus statement and recommendations for the role of CNB in the diagnosis of thyroid nodules. These recommendations are based on evidence from the current literature and expert consensus.

A Multicenter Prospective Validation Study for the Korean Thyroid Imaging Reporting and Data System in Patients with Thyroid Nodules

OBJECTIVE

To validate a new risk stratification system for thyroid nodules, the Korean Thyroid Imaging Reporting and Data System (K-TIRADS), using a prospective design.

MATERIALS AND METHODS

From June 2013 to May 2015, 902 thyroid nodules were enrolled from four institutions. The type and predictive value of ultrasonography (US) predictors were analyzed according to the combination of the solidity and echogenicity of nodules; in addition, we determined malignancy risk and diagnostic performance for each category of K-TIRADS, and compared the efficacy of fine-needle aspiration (FNA) with a three-tier risk categorization system published in 2011.

RESULTS

The malignancy risk was significantly higher in solid hypoechoic nodules, as compared to partially cystic or isohyperechoic nodules (each p < 0.001). The presence of any suspicious US features had a significantly higher malignancy risk (73.4%) in solid hypoechoic nodules than in partially cystic or isohyperechoic nodules (4.3-38.5%; p < 0.001). The calculated malignancy risk in K-TIRADS categories 5, 4, 3, and 2 nodules were 73.4, 19.0, 3.5, and 0.0%, respectively; and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for malignancy were 95.5, 58.6, 44.5, 96.9, and 69.5%, respectively, in K-TIRADS categories 4 and 5. The efficacy of FNA for detecting malignancy based on K-TIRADS was increased from 18.6% (101/544) to 22.5% (101/449), as compared with the three-tier risk categorization system (p < 0.001).

CONCLUSION

The proposed new risk stratification system based on solidity and echogenicity was useful for risk stratification of thyroid nodules and the decision for FNA. The malignancy risk of K-TIRADS was in agreement with the findings of a previous retrospective study.

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

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