Ultrasonography and fine-needle aspiration cytology of thyroid nodules: assessment of malignancy using the British Thyroid Association classification.

British Thyroid Association (BTA), American Thyroid Association (ATA), and American Association of Clinical Endocrinologists (AACE/ACE/AME) recommend for thyroid nodules an ultrasound (US)-based stratification of risk of malignancy. Aim of our study was to assess the diagnostic accuracy of US classification systems and their reliability for indication to fine-needle aspiration (FNA). Prospective study on 987 thyroid nodules consecutively referred for FNA. US images were independently reviewed by four experts for assignment of malignancy risk. Cytologically benign nodules had confirmation with a second FNA, whereas Bethesda class IV, V, and VI nodules were operated upon. Class III nodules had surgery or follow-up on the basis of clinical, immunocytochemical, and US features. BTA: Malignancy rate was 2.8% in benign, 10.0% in indeterminate, 51.3% in suspicion, and 80.9% in malignant US class. Sensitivity was 0.74, specificity was 0.92, and accuracy was 0.89. ATA: Malignancy rate was 0.0% in benign, 2.2% in very low suspicion, 3.0% in low suspicion, 5.8% in intermediate, and 55.0% in high suspicion US class. Sensitivity was 0.81, specificity was 0.87, and accuracy was 0.86. AACE/ACE/AME: Malignancy rate was 1.1% in low-risk, 4.4% in intermediate-risk, and 54.9% in high-risk US class. Sensitivity was 0.82, specificity was 0.87, and accuracy was 0.86. K correlation coefficient was 78.9%, 76.9%, and 82.0% for BTA, ATA, and AACE/ACE/AME classifications. Classification systems had elevated predictive value of malignancy in high-risk classes. ATA and AACE/ACE/AME systems were effective for ruling out indication to FNA in low-US-risk nodules. A similar diagnostic accuracy and a substantial interobserver agreement was provided by the three- and the five-category classifications.

Intrathyroidal ectopic thymus (IET), a benign lesion due to aberrant thymic migration during embryogenesis, is often discovered incidentally. We aimed to present the ultrasound (US) features, diagnostic methods, and follow-up of IET in children and adolescents. We searched our database of patients with a nodular thyroid lesion detected by US, between January 2007 and December 2019. In 30/255 (11.7%), IET was diagnosed. The study included 30 patients (20 males/10 females), mean age 5 years (0.1-12.2, median 5.6) with 34 lesions diagnosed by US as `incidentalomas.` None of the patients had palpable nodules. On US, IET appeared as a hypoechoic lesion, with multiple punctuate internal echoes. 29/34 of lesions had well-defined margins. The most common location of IET was in the middle part (27/34) of the left lobe (19/34). The mean longest diameter at diagnosis was 6.4 mm (2.5-21, median 4.5). Sonographic follow-up was available in 25 patients with 27 lesions. The mean time of observation was 2.7 years (0.3-7.5, median 2.1). While 13/27 cases showed decreased size or regression during follow-up, the other 13 increased in size, and there was no change in size in one. Pubertal progression was associated with both increment and decrease in size of IET. Fine needle aspiration (FNA) was performed in 5 patients and surgery in one. IET should be considered in the differential diagnosis of pediatric thyroid nodules as a cause of FNA and/or surgery. Regular US monitoring can be used safely in the follow-up of this lesion. We present one of the largest series in the literature with long-term follow-up and description of patients` pubertal status. IET prevalence was 11.7% among children and adolescents with a nodular thyroid lesion, higher than that stated in the literature.

ObjectiveTo 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 MethodsThe 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%).ResultsMacrocalcification 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.ConclusionMacrocalcification 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.

Objectives:To compare diagnostic performance of British Thyroid Association (BTA), American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) and Artificial Intelligence TIRADS (AI-TIRADS) for thyroid nodule malignancy. To determine comparative unnecessary fine needle aspiration (FNA) rates.Methods:218 thyroid nodules with definitive histology obtained during 2017 were included. Ultrasound images were reviewed retrospectively in consensus by two subspecialist radiologists, blinded to histopathology, and nodules assigned a BTA, ACR-TIRADS and AI-TIRADS grade. Nodule laterality and size were recorded to allow accurate histopathological correlation and determine which nodules met criteria for FNA.Results:77 (35.3%) nodules were malignant. Deeming ultrasound Grade 4–5 as test-positive and 1–2 as test-negative, sensitivity and specificity for BTA was 98.28 and 42.55%, for ACR-TIRADS: 95.24 and 40.57% and for AI-TIRADS: 93.44 and 45.71%. FNA was indicated in 101 (71.6%), 67 (47.5%) and 65 (46.1%) benign nodules utilising BTA, ACR-TIRADS and AI-TIRADS respectively. The unnecessary FNA rate was significantly higher with BTA (46.3%) compared to ACR-TIRADS (30.7%) and AI-TIRADS (29.8%) p < 0.001.Conclusion:BTA, ACR-TIRADS and AI-TIRADS had similar diagnostic performance for predicting thyroid nodule malignancy with sensitivity >93% for all systems when considering ultrasound Grade 4–5 as malignant and Grade 1–2 as benign. ACR-TIRADS and AI-TIRADS both had a significantly lower rate of recommended FNA in benign nodules compared to BTA.Advances in knowledge:BTA, ACR-TIRADS and AI-TIRADS have comparable diagnostic performance with high sensitivity but relatively low specificity for predicting thyroid nodule malignancy in this cohort using histology as gold-standard. Using Grade 1–2 as benign and 4–5 as malignant there were more false negatives with TIRADS but this improved when taking other features into account while BTA had a significantly higher rate of unnecessary FNA.

Background: Fine needle aspiration (FNA) cytology is a key investigation of thyroid nodules. There are several reports of FNA accuracy, which ranges from 75.0% to 94.8%, while false negative rates are 5.8% to 21.5%. In Thailand, there is no available data of FNA accuracy according to the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The present study reported single-institute data of FNA accuracy, that could be used in thyroid nodule management. Objective: To determine the diagnostic accuracy of FNA cytology results of thyroid nodules collected in Thammasat University (TU) Hospital. Materials and Methods: The present study was a retrospective study collected cytologic results of all thyroid nodules that subsequently had definitive histopathologic diagnoses. The data were gathered from clinics at TU Hospital that performed thyroid nodule FNA between May 2011 and November 2014. The FNA cytology results were classified according to TBSRTC. Each cytopathologic result was compared with its postoperative tissue histopathology. The malignancy rate, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated. Results: The present study included 197 thyroid nodule FNA cytology results. The sensitivity and specificity were 77.8% and 65.4%, respectively. The calculated PPV was found to be 47.7%, and the NPV was 87.9%. The accuracy of these results was 69.0%. The malignancy rate of the unsatisfactory group was 6.25%, benign group 8.05%, atypia of undetermined significance or follicular lesion of unknown significance 22.22%, follicular neoplasm/suspicious for follicular neoplasm 14.20%, suspicious for malignancy 73.68%, and malignant 100%. Conclusion: The FNA cytology in TU Hospital has comparable sensitivity to the other studies. Interestingly, the malignancy rate in the follicular neoplasm category is lower than that of the other institutes because of a high false positive rate in this category. This causes lower specificity and accuracy, which may cause a higher rate of unnecessary operations. Keywords: FNA; Thyroid nodule; Diagnostic accuracy

The risk of malignancy in thyroid nodules correlates with the presence of ultrasonographic features. In adults, ultrasound risk-classification systems have been proposed to indicate the need for further invasive diagnosis. Furthermore, elastography has been shown to support differential diagnosis of thyroid nodules. The purpose of our study was to assess the application of the American Thyroid Association (ATA), British Thyroid Association (BTA) ultrasound risk-classification systems and strain elastography in the management of thyroid nodules in children and adolescents from one center. Seventeen nodules with Bethesda III, IV, V and VI were selected from 165 focal lesions in children. All patients underwent ultrasonography and elastography followed by fine needle aspiration biopsy. Ultrasonographic features according to the ATA and BTA stratification systems were assessed retrospectively. The strain ratio in the group of thyroid nodules diagnosed as malignant was significantly higher than in benign nodules (6.07 vs. 3.09, p = 0.036). According to the ATA guidelines, 100% of malignant nodules were classified as high suspicion and 73% of benign nodules were assessed as low suspicion. Using the BTA U-score classification, 80% of malignant nodules were classified as cancerous (U5) and 20% as suspicious for malignancy (U4). Among benign nodules, 82% were classified as indeterminate or equivocal (U3) and 9% as benign (U2). Our results suggest that application of the ATA or BTA stratification system and elastography may be a suitable method for assessing the level of suspected malignancy in thyroid nodules in children and help make a clinical decision about the need for further invasive diagnosis of thyroid nodules in children.

Background: Single-center trials have demonstrated an acceptable level of inter-observer agreement in the evaluation of the ultrasound (US) features of thyroid nodules, but limited data are available about the consistency in the assessment of US findings among different thyroid centers. Aim of the study: to assess the inter-observer agreement between different thyroid centers and among different specialists in the evaluation of the main US features of thyroid nodules. Materials and methods A blinded retrospective analysis of 100 electronically-recorded US images was conducted in three large-volume thyroid centers by seven qualified thyroid imaging experts, two radiologist and five endocrinologists. The following US features were evaluated: composition (solid, predominantly solid, predominantly cystic, and cystic); echogenicity (hyperechoic, isoechoic, mildly and deeply hypoechoic); margins (well-defined, ill-defined, microlobulated, and spiculated); calcifications (absent, microscopic, macroscopic, eggshell); hyperechoic foci of uncertain significance; comet-tail artifacts; vascularity (no vascular signals, perinodular and/or slight intranodular flow, and marked intranodular flow). Thyroid nodules were also classified according to four major US classification systems: AACE/ACE/AME, EU-TIRADS, ATA and ACR. The inter-observer agreement was calculated using cross-tabulation expressed in Cohen's Kappa. Kappa values were evaluated, according to Landis and Koch, as follows: 0-0.20 poor, 0.21-0.40 fair, 0.41-0.60 moderate, 0.61-0.80 substantial, and 0.81-1.0 almost perfect agreement. A sub-analysis assessed how many times and how many operators evaluated as suspicious for malignancy the US features of each nodule. Results: The inter-observer agreement resulted in a K-correlation coefficient of 34.5%, 44.0%, 42.3% and 38.8% for the ATA, AACE/ACE/AME, ACR, and EU-TIRADS classification systems, respectively. The interobserver agreement for the main thyroid nodule US findings resulted as follows: composition 53.2%; echogenicity 46.9%; margins 33.2%; comet-tail 10.6%, microcalcifications 46.8%; macrocalcifications 37.7%; eggshell calcifications 64.9%; intranodular vascularity 45.9%. Conclusion: The level of agreement among different thyroid centers in the description of suspicious US features in thyroid nodules ranged from fair to moderate, with the lowest level of consistency for the characteristics of margins and the presence of comet-tails. A similar range of variability was demonstrated also for the four US classification systems. An universally accepted lexicon of thyroid US features and a dedicated training in thyroid US findings definition are needed to improve the inter-observer agreement and the predictive value of US classification systems in real world practice.

Ring-Enhancement on CEUS: Is it Useful in the Differential Diagnosis of Solid Thyroid Nodules?

Objective. To determine the role of imaging-cytology correlation in reducing false negative results of fine-needle aspiration (FNA) at thyroid nodules. Methods. This retrospective study included 667 nodules 1 cm or larger in 649 patients diagnosed as benign at initial cytologic evaluation and that underwent follow-up ultrasound (US) or FNA following a radiologist's opinion on concordance between imaging and cytologic results. We compared the risk of malignancy of nodules classified into subgroups according to the initial US features and imaging-cytology correlation. Results. Among included nodules, 11 nodules were proven to be malignant (1.6%) in follow-up FNA or surgery. The malignancy rate was higher in nodules with suspicious US features (11.4%) than in nodules without suspicious US features (0.5%, P < 0.001). When a thyroid nodule had discordant US findings on image review after having benign FNA results, malignancy rate increased to 23.3%, significantly higher than that of nodules with suspicious US features (P < 0.001). However, no significant difference was found in the risk of malignancy between the nodules without suspicious US features (0.5%) and imaging-cytology concordant nodules (0.6%, P = 0.438). Conclusions. Repeat FNA can be effectively limited to patients with cytologically benign thyroid nodules showing discordance in imaging-cytology correlation after initial biopsy, which reduces unnecessary repeat aspirations.

Radiological–pathological correlation of the British Thyroid Association ultrasound classification of thyroid nodules: a real-world validation study

Objective:To explore the diagnostic efficacy of ultrasound-guided fine needle aspiration cytology（US-FNAC） for thyroid nodules ≥1 cm, and the effect of Hashimoto's thyroiditis（HT） on it. Methods:The clinical data of 1027 cases of thyroid nodules ≥ 1 cm were retrospectively analyzed. Two-dimensional ultrasound, US-FNAC and BRAFV600E gene testing were performed. The postoperative pathological results were used as the criterion. The two dimensional ultrasound examination, clinical characteristics, follow-up results, and BRAFV600E were used to diagnosis for unoperated patients. The diagnostic efficiency of US-FNAC in HT（+） group and HT（-） group was compared, and the factors affecting the diagnostic efficiency were analyzed. Results:Of the 1027 nodules, the cytological results were nondiagnostic/unsatisfactory in 73 nodules（7.1%）, benign in 282（27.5%）, atypia of undetermined significance/follicular lesion of undetermined significance in 230（22.4%）, follicular neoplasm/suspicious for a follicular neoplasm in 20（1.9%）, suspicious for malignancy in 120（11.7%）, and malignant in 302（29.4%）. 515 cases underwent surgery. Among them, 495 were malignant and 20 were benign. 512 cases continued to be followed up without surgery, and the BRAFV600E of them were wild type. Combined with the two dimensional ultrasound examination, clinical features, and follow-up results, they were judged to be benign. The accuracy, sensitivity, specificity, positive predictive value, negative predictive value, false positive rate and the false negative rate the of US-FNAC were 98.7%, 98.4%, 99.3%, 99.5%, 97.5%, 0.7% and 1.6%, respectively. The accuracy, sensitivity and negative predictive value of the HT（+） group were 95.5%, 95.4% and 82.8%, respectively, which were lower than that of HT（-） group （99.5%, 99.4%, 99.2% ）（P=0.001, 0.018, P<0.001）. The false negative rate of the HT（+） group was 4.6%, higher than 0.6% of the HT（-） group（P=0.018）, and HT was an risk factor for increased FNR（OR=7.596, 95%CI: 1.452-39.740）. Conclusion:US-FNAC is an effective method for the diagnosis of thyroid nodules and it has high sensitivity and specificity in ≥ 1 cm nodules. However, the combination of HT reduces the diagnostic accuracy and HT is a risk factor for increased false negative rate.

We aimed to compare the malignancy risk stratification of histologically proven thyroid nodules using the 2015 American Thyroid Association (ATA) Management Guidelines, 2014 British Thyroid Association (BTA) Guidelines for the Management of Thyroid Cancer and the Thyroid Imaging Reporting and Data System (TIRADS). Thyroid nodules measuring > 1 cm resected over 5.5 years were retrospectively studied. Demographic information as well as cytology and histopathology results were collected. Static ultrasonography (US) images and radiologists' reports of each resected nodules were reviewed and classified based on the above risk classification systems. A total of 167 thyroid nodules from 150 patients were examined. More malignant nodules were solid (78.4% vs. 62.5%; p = 0.049) or hypoechoic (70.6% vs. 28.6%; p < 0.001), and had irregular margins (35.3% vs. 8.0%; p < 0.001), taller-than-wide morphology (9.8% vs. 2.7%; p = 0.031), microcalcifications (33.3% vs. 8.0%; p < 0.001), disrupted rim calcifications (9.8% vs. 0.9%; p = 0.012) or associated abnormal cervical lymphadenopathy (13.7% vs. 0.9%; p = 0.001) compared with benign nodules. The guidelines' diagnostic performance was: ATA - sensitivity 98.0%, specificity 17.3%, positive predictive value (PPV) 35.0%, negative predictive value (NPV) 95.0%; BTA - sensitivity 90%, specificity 50.9%, PPV 45.5%, NPV 91.8%; and TIRADS - sensitivity 94.0%, specificity 28.2%, PPV 37.3%%, NPV 91.2%. Sonographic patterns outlined by the three guidelines displayed high sensitivity and NPV. Although isolated suspicious US features cannot predict malignancy risk, they should be considered when risk stratifying nodules that do not fit into particular sonographic patterns based on current guidelines.

To compare the accuracy of two widely used thyroid imaging, reporting and data systems (TI-RADS), namely ACR TI-RADS and Kwak TI-RADS, in the differential diagnosis of benign and malignant thyroid nodules. We reviewed the data of 350 thyroid nodules with definite diagnoses by surgical histopathology (n=144, 41.14%) or fine needle aspiration (FNA) cytopathology (n=206, 58.86%). The nodules were graded using ACR TI-RADS and Kwak TI-RADS based on the ultrasound images, and the diagnostic accuracy of these two systems was evaluated by the area under the receiveroperating characteristic curve (AUC). The AUCs of ACR TI-RADS and Kwak TI-RADS were both 0.879. For a differential diagnosis of the thyroid nodules, ACR TI-RADS had a diagnostic sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, Youden's index and accuracy of 77.3%, 89.1%, 83.0%, 85.1%, 7.101, 0.255, 27.848, 0.664 and 0.843, respectively, with an optimal threshold of TR5, as compared with 84.8%, 84.0%, 78.3%, 89.0%, 5.283, 0.181, 29.265, 0.688 and 0.843, respectively, of Kwak TI-RADS, which had an optimal threshold of 4c. Both ACR TI-RADS and Kwak TI-RADS have good performance for differential diagnosis of thyroid nodules, but ACR TI-RADS has a higher specificity and a lower sensitivity compared with Kwak TI-RADS.

Thyroid nodules are a common finding in clinical practice. Although ultrasonography is an accepted method for evaluating these nodules, Fine Needle Aspiration (FNA) is the procedure of choice for assessing the risk of malignancy. This study aims to determine the association between sonographic features of thyroid nodules based on Thyroid Imaging Reporting and Data System classification and the cytology results. In this prospective cohort study, 147 patients from Tehran Medical Imaging Center who had thyroid nodules underwent ultrasonography-guided FNA, and their sonographic features were recorded. The pathologic findings were also obtained according to the Bethesda system. Finally, the association between sonographic features and cytological results was analyzed. Eighteen (12.3%) nodules were malignant, and 129 nodules (87.7%) were benign. The association of TIRADS categories with the risk of malignancy is as follows: TIRADS 1 (n=0, 0%), TIRADS 2 (n=10, 16.9%), TIRADS 3 (n=6, 10.5%), TIRADS 4 (n=2, 16.7%), and TIRADS 5 (n=0, 0%). The bloody lamellae of thyroid nodules were significantly correlated with the risk of malignancy (P&lt;0.05). However, there was no statistically significant association between the risk of malignancy and gender (P=0.47), calcification (P=0.9), firmness (P=0.19), halo sign (P=0.95), location of nodules (P=0.35), and nodules' echogenicity (P=0.058). Although there are trusted classifications such as TIRADS for categorizing thyroid nodules, there is still uncertainty in utilizing them, especially in the management of nodules classified as TIRADS 2, in which various sonographic features are shared between benign and malignant nodules.

Ultrasound (US) is the most important imaging in the preoperative diagnosis of medullary thyroid carcinoma (MTC). MTC are easy to be misdiagnosed due to lacking typical malignant US features. This study investigated US features, clinical characteristics, prognosis, and detection methods, aimed to explore the association between US features and biological behavior, and improve early diagnosis of MTC. A total of 189 MTC patients were enrolled in the study. Based on US features, 29 MTC were categorized as "indeterminate" (i-MTC) and 160 MTC were categorized as "malignant" (m-MTC) according to Thyroid Imaging, Reporting and Data System published by America College of Radiology (ACR TI-RADS). We compared US features, clinical characteristics and prognosis between both groups. We analyzed cytological categories of fine needle aspiration (FNA) within each i-MTC and m-MTC group according to the 2017 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). We assessed the positive rate of FNA, frozen pathological examination, and preoperative serum calcitonin (Ctn) level in i-MTC and m-MTC groups. Preoperative US features were significantly different in shape, margin, composition, echogenicity, and calcifications between i-MTC and m-MTC (p < 0.05). I-MTC showed a hypoechoic solid or solid-cystic nodule lacking malignant US features. While m-MTC was presented as a solid nodule with obviously malignant US features. There were significant differences in lymph node dissection, extent of tumor, lymph node metastasis, and TNM stage and prognosis between i-MTC and m-MTC (p < 0.05). Compared to m-MTC, i-MTC underwent central neck dissection more frequently rather than lateral neck dissection at the time of the initial operation; i-MTC had less extrathyroidal invasion and lymph node metastasis, earlier stage, higher rate of biochemical cure, and lower rate of structural persistence/recurrence (p < 0.05). The 2017 TBSRTC of i-MTC and m-MTC was significantly different (p < 0.05). Preoperative serum Ctn level had a higher diagnostic sensitivity for both i-MTC and m-MTC when comparing to FNA and frozen pathological examination (p < 0.05). US features were associated with biological characteristics and prognosis of MTC. I-MTC lack malignant US features, preformed less aggressiveness, and better prognosis. TBSRTC according to FNA combined with serum Ctn were helpful for the detection of i-MTC.