The Thyroid Imaging Reporting and Data System (TIRADS) for ultrasound of the thyroid

PurposeTo develop a standardized system for analyzing and reporting thyroid ultrasound, or Thyroid Imaging Reporting and Data System (TIRADS), in order to improve the management of patients with thyroid nodules.Materials and methodsAn atlas of imaging features, a standardized vocabulary, a report template and TIRADS categories 0 to 6 were defined, based on the BI-RADS^® system used for mammography. The diagnostic efficacy of the system was tested by a retrospective review of 500 nodules (159 cancers and 341 benign nodules) and comparing US imaging features to histological findings.ResultsFive signs allow accurate detection of 90% of thyroid cancers. The score of a nodule can be easily defined by using an organigram. Sensitivity, specificity and odds-ratio of the score were respectively 95%, 68% and 40.ConclusionTIRADS is a quality assurance tool for thyroid ultrasound. It contains an image atlas, a standardized report and categories to evaluate thyroid nodules to easily assess the risk of individual nodules being cancers and facilitate patient management.     

Diagnostic Performance of the Modified Korean Thyroid Imaging Reporting and Data System for Thyroid Malignancy: A Multicenter Validation Study

ObjectiveTo evaluate the diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System (K-TIRADS), and compare it with the 2016 version of K-TIRADS using the Thyroid Imaging Network of Korea.Materials and MethodsBetween June and September 2015, 5708 thyroid nodules (≥ 1.0 cm) from 5081 consecutive patients who had undergone thyroid ultrasonography at 26 institutions were retrospectively evaluated. We used a biopsy size threshold of 2 cm for K-TIRADS 3 and 1 cm for K-TIRADS 4 (modified K-TIRADS 1) or 1.5 cm for K-TIRADS 4 (modified K-TIRADS 3). The modified K-TIRADS 2 subcategorized the K-TIRADS 4 into 4A and 4B, and the cutoff sizes for the biopsies were defined as 1 cm for K-TIRADS 4B and 1.5 cm for K-TIRADS 4A. The diagnostic performance and the rate of unnecessary biopsies of the modified K-TIRADS for detecting malignancy were compared with those of the 2016 K-TIRAD, which were stratified by nodule size (with a threshold of 2 cm).ResultsA total of 1111 malignant nodules and 4597 benign nodules were included. The sensitivity, specificity, and unnecessary biopsy rate of the benign nodules were 94.9%, 24.4%, and 60.9% for the 2016 K-TIRADS; 91.0%, 39.7%, and 48.6% for the modified K-TIRADS 1; 84.9%, 45.9%, and 43.5% for the modified K-TIRADS 2; and 76.1%, 50.2%, and 40.1% for the modified K-TIRADS 3. For small nodules (1–2 cm), the diagnostic sensitivity of the modified K-TIRADS decreased by 5.2–25.6% and the rate of unnecessary biopsies reduced by 19.2–32.8% compared with those of the 2016 K-TIRADS (p < 0.001). For large nodules (> 2 cm), the modified K-TIRADSs maintained a very high sensitivity for detecting malignancy (98%).ConclusionThe modified K-TIRADSs significantly reduced the rate of unnecessary biopsies for small (1–2 cm) nodules while maintaining a very high sensitivity for malignancy for large (> 2 cm) nodules.     

Retrospective Application of the 2015 American Thyroid Association Guidelines for Ultrasound Classification,Biopsy Indications,and Follow-up Imaging of Thyroid Nodules: Can Improved Reporting Decrease Testing?

IntroductionThyroid ultrasound has been widely used to determine which nodules need further investigation. The goal of this study is to determine if using an ultrasonographic features checklist based on 2015 American Thyroid Association (ATA) guidelines can improve reporting and decrease unnecessary further testing.MethodsIn this retrospective study, ultrasonographic images of all nodules biopsied at our institution in 2014 and 2015 were reviewed by radiologists blinded to fine needle aspiration (FNA) biopsy result using a checklist. The checklist was prepared based on 2015 ATA guidelines. The ultrasonographic characteristics of thyroid nodules were compared with the result of biopsy to determine positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity for predicting malignancy. Radiologists also made an overall recommendation on need for FNA.ResultsA total of 425 thyroid nodule ultrasound scans were reviewed by radiologists. Biopsy results of 31 nodules were malignant and 394 were non-malignant. Malignant nodules showed higher frequency of solid composition, hypoechoechogenicity, and cervical lymph node involvement compared to benign nodules. Solid nodule composition had the highest PPV (13%) and NPV (94.7%). Extra-thyroid extension had the highest specificity (90.1%). Lesion vascularity had the highest sensitivity (83.8%), followed by hypoechogenicity (65.6%). Overall, the checklist had a positive predictive value of 9%, negative predictive value of 97.5%, sensitivity of 96.8%, and specificity of 11.14%. Radiologists determined that 10% of the nodules were very low-risk and did not require FNA.ConclusionUsing a checklist based on 2015 ATA guideline thyroid nodule ultrasonographic features is a sensitive tool with high NPV to predict benign thyroid nodule, thereby preventing unnecessary FNAs.     

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

PURPOSEIn this study, we aimed to assess the effectiveness of malignancy stratification algorithms of the American College of Radiology (ACR) and European Thyroid Association (ETA) in the delineation of thyroid nodules using a database of nodules that were unequivocally diagnosed by means of histopathological examination and meticulously matched with the imaged nodules.METHODSA total of 165 patients having 251 thyroid nodules with histopathologically proven definitive diagnoses during a 5-year period were included in this study. All patients had preoperatively undergone ultrasonography (US) examination, and US characteristics of the thyroid nodules were retrospectively analyzed and assigned in compliance with the thyroid imaging reporting and data system categories recommended by the ACR (ACR-TIRADS) and ETA (EU-TIRADS). The diagnostic effectiveness in the delineation of thyroid nodules and unnecessary fine-needle aspiration (FNAB) rates were evaluated.RESULTSOverall, 189 nodules (75.30%) were diagnosed as benign, while 62 nodules (24.70%) were reported to be malignant based on histopathological assessment. Sensitivity and specificity rates were 71% and 75% for ACR-TIRADS and 73% and 80% for EU-TIRADS. The area under the curve values were 0.78 and 0.80 for ACR-TIRADS and EU-TIRADS, respectively. The unnecessary FNAB rates were 61% for ACR-TIRADS and 64% for EU-TIRADS as per the recommended criteria of each algorithm.CONCLUSIONThe diagnostic performance of both malignancy stratification systems was signified to be moderate and sufficient in a cohort of nodules with definite histopathological diagnosis. In light of our results, we demonstrated the strengths and weaknesses of the ACR- and EU-TIRADS for physicians who should be familiar with them for optimal management of thyroid nodules.

The number of detected thyroid nodules has been increasing in recent years with the widespread application of ultrasonography (US). The reported incidence varies from 20% to 68% in patients undergoing high-frequency US examination (1, 2). In case of a newly detected nodule, the primary concern is to discriminate benign ones, which constitute almost 90%, from malignant ones that require additional invasive procedures (3, 4). Fine-needle aspiration biopsy (FNAB) is the primary diagnostic tool due to its high sensitivity and specificity in distinguishing malignancy, yet it has several shortcomings, including inconclusive results and potential overdiagnosis (5).The particular nodular US features suggestive of malignancy are well known and thus US is employed for the indication of FNAB (6, 7). Nevertheless, none of those characteristics individually predicts the malignancy risk sufficiently (8, 9). Hence, various risk-stratification systems that consider a set of nodular US features have been established to predict the malignancy risk, mitigate superfluous FNABs, and enhance interobserver concordance. Among them, the Thyroid Imaging Reporting and Data System of the American College of Radiology (ACR-TIRADS) was set up in 2017 to classify all detected thyroid nodules according to its issued lexicon (10–12). Similarly, the European Thyroid Association TIRADS (EU-TIRADS) was developed to improve the sensitivity together with high negative predictive value (NPV) in characterization with a more straightforward scoring method (12, 13). Several studies have compared the effectiveness of these two risk-stratification systems (14–18), yet their performance in different thyroid nodules with various histopathologic results and subtypes still needs to be investigated.The objectives of our study were to appraise the diagnostic effectiveness of the ACR- and EU-TIRADS classification systems in nodular characterization and to analyze the rates of inappropriate FNABs according to the proposed criteria based on unequivocal histopathological results.     

Efficacy of Lauromacrogol Injection for Ablation of Benign Predominantly Cystic Thyroid Nodules and Related Factors: A Prospective Study

ObjectiveTo prospectively evaluate the efficacy of lauromacrogol injection for ablation (LIA) of benign predominantly cystic thyroid nodules and its related factors.Materials and MethodsA total of 142 benign predominantly cystic thyroid nodules (median volume, 12.5 mL; range, 0.4–156 mL) in 137 patients (male:female sex ratio, 36:101; mean age ± standard deviation [SD], 49 ± 13 years) were treated with LIA after being confirmed as benign via cytology. The volume reduction rate (VRR) of the nodules and cosmetic score were evaluated during follow-up at 1, 3, and 6 months after treatment and every 6 months thereafter. A VRR of ≥ 50% at the 12-month follow-up was considered to indicate effective treatment. The associations between the clinical factors and nodular ultrasound features, including the initial nodule volume, proportion of solid components, vascularity grade and ineffective treatment (VRR of < 50% at the 12-month follow-up), and regrowth were analyzed.ResultsAll patients completed follow-up for at least 12 months. The average ± SD follow-up period was 32 ± 11 months (range, 12–54 months). The effective treatment rate was 73.2% (104/142), while the regrowth rate was 12.0% (17/142) at the last follow-up. Grade 2–3 intranodular vascularity in the solid components of the nodules was the only independent factor associated with ineffective treatment, with an odds ratio (reference category, grade 0–1) of 3.054 (95% confidence interval, 1.148–8.127) (p = 0.025).ConclusionLIA is an effective treatment for predominantly cystic thyroid nodules. Grade 2–3 intranodular vascularity in the solid components of nodules is the only independent risk factor for ineffective LIA.     

Comparison of Thyroid Risk Categorization Systems and Fine-Needle Aspiration Recommendations in a Multi-Institutional Thyroid Ultrasound Registry

ObjectivesThe aim of this study was to compare how often fine-needle aspiration (FNA) would be recommended for nodules in unselected, low-risk adult patients referred for sonographic evaluation of thyroid nodules by ACR Thyroid Imaging Reporting and Data System (TI-RADS), the American Thyroid Association guidelines (ATA), Korean Thyroid Imaging Reporting and Data System (K-TIRADS), European Thyroid Imaging Reporting and Data System (EU-TIRADS), and Artificial Intelligence Thyroid Imaging Reporting and Data System (AI-TIRADS).MethodsSeven practices prospectively submitted thyroid ultrasound reports on adult patients to the ACR Thyroid Imaging Research Registry between October 2018 and March 2020. Data were collected about the sonographic features of each nodule using a structured reporting template with fields for the five ACR TI-RADS ultrasound categories plus maximum nodule size. The nodules were also retrospectively categorized according to criteria from ACR TI-RADS, the ATA, K-TIRADS, EU-TIRADS, and AI-TIRADS to compare FNA recommendation rates.ResultsFor 27,933 nodules in 12,208 patients, ACR TI-RADS recommended FNA for 8,128 nodules (29.1%, 95% confidence interval [CI] 0.286-0.296). The ATA guidelines, EU-TIRADS, K-TIRADS, and AI-TIRADS would have recommended FNA for 16,385 (58.7%, 95% CI 0.581-0.592), 10,854 (38.9%, 95% CI 0.383-0.394), 15,917 (57.0%, 95% CI 0.564-0.576), and 7,342 (26.3%, 95% CI 0.258-0.268) nodules, respectively. Recommendation for FNA on TR3 and TR4 nodules was lowest for ACR TI-RADS at 18% and 30%, respectively. ACR TI-RADS categorized more nodules as TR2, which does not require FNA. At the high suspicion level, the FNA rate was similar for all guidelines at 68.7% to 75.5%.ConclusionACR TI-RADS recommends 25% to 50% fewer biopsies compared with ATA, EU-TIRADS, and K-TIRADS because of differences in size thresholds and criteria for risk levels.     

Role of combined grey scale US and US tissue elastography in differentiating solid thyroid nodules

Background

Ultrasonographic (US) examination is an accurate method for detecting thyroid nodules, but its use in differentiating between benign and malignant thyroid nodules is relatively low. US elastography has been applied to study the hardness/elasticity of nodules to differentiate malignant from benign lesions thus deviating a significant group of patients from unnecessary FNAB.

Objectives

The aim of the study is to evaluate the validity of combined grey scale US and tissue elastography in differentiating benign form malignant solid thyroid nodules.

Methods

The study included 46 selected patients with solid thyroid nodules according to our inclusion and exclusion criteria. The patients underwent surgery for compressive symptoms or suspicion of malignancy on FNA cytology. US features and tissue elastography were scored according to the Rago criteria (1).

Results

On US elastography: all the 31 cases with a final diagnosis of benign nodule had a score of 1–3, while 14 of 15 (94.1%) with a final diagnosis of carcinoma had a score of 4–5, with a sensitivity of 93.3%, a specificity of 100% and an accuracy of 97.8%. Combined US and elastography reveals that hypoechogenicity/score 4–5 was most predictive of malignancy with sensitivity 80% and specificity 100%; and accuracy 93.4%.

Conclusions

US elastography seems to have great potential as a new tool for differentiating solid thyroid nodules and for recommending FNAC. Combined grey scale US features and US elastography added no significant value when compared with US elastography alone. Further prospective studies are needed.     

A comparison of the fusion model of deep learning neural networks with human observation for lung nodule detection and classification

Objectives:To compare the diagnostic performance of a newly developed artificial intelligence (AI) algorithm derived from the fusion of convolution neural networks (CNN) versus human observers in the estimation of malignancy risk in pulmonary nodules.Methods:The study population consists of 158 nodules from 158 patients. All nodules (81 benign and 77 malignant) were determined to be malignant or benign by a radiologist based on pathologic assessment and/or follow-up imaging. Two radiologists and an AI platform analyzed the nodules based on the Lung-RADS classification. The two observers also noted the size, location, and morphologic features of the nodules. An intraclass correlation coefficient was calculated for both observers and the AI; ROC curve analysis was performed to determine diagnostic performances.Results:Nodule size, presence of spiculation, and presence of fat were significantly different between the malignant and benign nodules (p < 0.001, for all three). Eighteen (11.3%) nodules were not detected and analyzed by the AI. Observer 1, observer 2, and the AI had an AUC of 0.917 ± 0.023, 0.870 ± 0.033, and 0.790 ± 0.037 in the ROC analysis of malignity probability, respectively. The observers were in almost perfect agreement for localization, nodule size, and lung-RADS classification [κ (95% CI)=0.984 (0.961–1.000), 0.978 (0.970–0.984), and 0.924 (0.878–0.970), respectively].Conclusion:The performance of the fusion AI algorithm in estimating the risk of malignancy was slightly lower than the performance of the observers. Fusion AI algorithms might be applied in an assisting role, especially for inexperienced radiologists.Advances in knowledge:In this study, we proposed a fusion model using four state-of-art object detectors for lung nodule detection and discrimination. The use of fusion of deep learning neural networks might be used in a supportive role for radiologists when interpreting lung nodule discrimination.     

Diagnostic accuracy of fine-needle aspiration versus core-needle biopsy for the diagnosis of thyroid malignancy in a clinical cohort

Objectives

To retrospectively compare the accuracy of fine-needle aspiration (FNA) and core-needle biopsy (CNB) for the diagnosis of thyroid malignancy

Methods

We evaluated the results of FNA and CNB in 555 consecutive thyroid nodules with final diagnoses (malignancy 318, benign 237). All patients underwent FNA and CNB simultaneously for each nodule. We assessed the sensitivity, specificity and accuracy of FNA, CNB and FNA/CNB for the diagnosis of thyroid malignancy.

Results

The sensitivity of FNA, CNB and FNA/CNB for thyroid malignancy was 68.6%, 86.8% and 90.6%, specificity 100%, 99.2% and 99.2%, and accuracy 82.0%, 92.1% and 94.2%, respectively. The sensitivity and accuracy of CNB or FNA/CNB for thyroid malignancy were significantly higher than those of FNA (P?P?Conclusions Our clinical cohort data demonstrated that CNB was more accurate for the diagnosis of thyroid malignancy than FNA, and FNA/CNB was more accurate than CNB alone in small thyroid nodules. CNB will play a complementary role in optimal surgical decision-making and the management of thyroid nodules.

Key Points

? CNB was more accurate for the diagnosis of malignancy than FNA. ? Combined FNA/CNB was more accurate than CNB alone in small thyroid nodules. ? CNB should play at least a complementary role in managing thyroid nodules.     

Un intento de reducir intervenciones quirúrgicas innecesarias... ¿Pueden ayudar las características ecográficas a diferenciar el adenoma del carcinoma en las neoplasias tiroideas foliculares?

Introduction and objectivesThyroid nodules frequently require ultrasound and Fine Needle Aspiration Cytology (FNAC) evaluation. However, FNA cytology does not allow differentiation between follicular adenoma and carcinoma on Bethesda type IV lesions. This situation leads to many unnecessary surgical procedures because it is not possible to assure the benignity of the lesions, even when most of the specimens correspond to adenomas or even other benign lesions.The objective is this study is to establish if there are any US characteristics that would help us to predict the risk of malignancy of nodules with a pathological diagnosis of follicular neoplasm in order to achieve a more conservative management for non-suspicious nodules.Material and methodsWe studied 61 nodules in 61 patients (51 women and 10 men) that underwent thyroid surgery and had histopathological results of either follicular adenoma or carcinoma.Different US characteristics of the nodules were analysed (composition, echogenicity, margin, calcification status, the presence of halo and overall observer suspicion of malignancy) and were correlated with the histopathological analysis.ResultsWe have found a statistically significant association between the presence of calcifications, ill-defined borders and overall observer suspicion or impression (defined by well-known suspicious for malignancy ultrasonographic features, such as calcification, poorly defined margin, and a markedly hypoechoic solid nodule; and benign ultrasonographic features, such as predominantly cystic echogenic composition and the presence of a perinodular hypoechogenic halo) with follicular carcinoma. However all those features have shown low sensitivities in the present study (30%, 30% and 50%, respectively). On the other hand, the absence of halo sign has shown a sensitivity of 100% and a negative predictive value (NPV) of 100% in our study.ConclusionsThe presence of calcifications, ill-defined borders and the overall impression or suspicion of malignancy associate with a higher risk for follicular carcinoma in Bethesda type IV thyroid nodules but their absence do not allow to predict benignity in these nodules. Inversely, when a halo sign lesion is observed, benign follicular neoplasm should be considered.     

Imaging-Detected Incidental Thyroid Nodules that Undergo Surgery: A Single-Center Experience Over 1 Year

BACKGROUND AND PURPOSE:Incidental thyroid nodules are commonly seen on imaging, and their work-up can ultimately lead to surgery. We describe characteristics and pathology results of imaging-detected incidental thyroid nodules that underwent surgery.MATERIALS AND METHODS:A retrospective review was performed of 303 patients who underwent thyroid surgery over a 1-year period to identify patients who presented with incidental thyroid nodules on imaging. Medical records were reviewed for the types of imaging studies that led to detection, nodule characteristics, and surgical pathology.RESULTS:Of 303 patients, 208 patients (69%) had surgery for thyroid nodules. Forty-seven of 208 patients (23%) had incidental thyroid nodules detected on imaging. The most common technique leading to detection was CT (47%). All patients underwent biopsy before surgery. The cytology results were nondiagnostic (6%), benign (4%), atypia of undetermined significance or follicular neoplasm of undetermined significance (23%), follicular neoplasm or suspicious for follicular neoplasm (19%), suspicious for malignancy (17%), and diagnostic of malignancy (30%). Surgical pathology was benign in 24 of 47 (51%) cases of incidental thyroid nodules. In the 23 incidental cancers, the most common histologic type was papillary (87%), the mean size was 1.4 cm, and nodal metastases were present in 7 of 23 cases (30%). No incidental cancers on imaging had distant metastases.CONCLUSIONS:Imaging-detected incidental thyroid nodules led to nearly one-fourth of surgeries for thyroid nodules, and almost half were initially detected on CT. Despite indeterminate or suspicious cytology results that lead to surgery, more than half were benign on final pathology. Guidelines for work-up of incidental thyroid nodules detected on CT could help reduce unnecessary investigations and surgery.

Incidental thyroid nodules (ITNs) are commonly encountered on imaging studies, being seen in 50% of ultrasonographic studies and 16%–18% of CT and MR imaging studies that include the thyroid gland.^1–3 While ITNs are associated with a low rate of malignancy, and subclinical thyroid cancers have an excellent prognosis,^2–6 ITNs pose a management dilemma for radiologists and other clinicians whose concern for missing malignancies may lead to further evaluation for small nonspecific thyroid nodules.The reporting practice of ITNs seen on imaging is highly variable among radiologists.⁷ Radiologists must exercise their judgment when reporting and issuing recommendations regarding incidental thyroid nodules. The reporting of ITN on imaging can lead to further investigation, such as follow-up sonography examinations, fine needle aspiration biopsy (FNAB), or, in some cases, diagnostic thyroid lobectomy or thyroidectomy.^8,9 Of patients who undergo FNAB, 22%–51% proceed to surgery.^10–12 These surgical patients represent an important group to study because they have higher costs and morbidity associated with the work-up of their ITNs. Thus, it is important to consider the costs and benefits of work-up in patients with ITN who fall into this surgical group.A substantial number of patients who undergo surgery do not have cancer.¹⁰ When the preoperative cytology result from FNAB is malignant, the sensitivity of cytology is high (99%).¹³ However, it is recommended that patients with cytology of “follicular neoplasm,” “suspicion for follicular neoplasm,” and “suspicion for malignancy” also proceed to surgery. With these other categories, the false-positive rate of cytology can be as high as 44%.¹³ In addition, thyroid surgery can result in such complications as recurrent laryngeal nerve injury, hypoparathyroidism, and bleeding. Therefore, radiologists should understand the downstream sequelae of a clinical pathway that begins with an imaging-detected ITN and ends with surgery.The purpose of this study was to describe characteristics and pathology results of ITNs that undergo surgery. We hypothesize that imaging-detected ITN comprise a substantial proportion of surgeries for thyroid nodules, and that many thyroid nodules are in the end benign on final surgical pathology.     

Combined 99mTc-methoxyisobutylisonitrile scintigraphy and fine-needle aspiration cytology offers an accurate and potentially cost-effective investigative strategy for the assessment of solitary or dominant thyroid nodules

Purpose

Fine-needle aspiration (FNA) has revolutionised the care of patients with thyroid nodules and is the initial investigation of choice. However, as a result of nondiagnostic (Thy1) and nonneoplastic (Thy2) specimens, it remains an imperfect sole solution with a range of sensitivities and a high inadequate ratio. Therefore the British Thyroid Association (BTA) guidelines recommend a second FNA immediately for Thy1 specimens and 3–6 months later for Thy2 specimens. Patients must be followed up to exclude malignancy. In this study we assessed the performance of MIBI scintigraphy for diagnosing thyroid malignancy and the cost-effectiveness of a combined FNA/MIBI investigative strategy for the management of thyroid nodules.

Methods

The diagnostic performance of MIBI scintigraphy was calculated from a retrospective review of local data combined with a meta-analysis of the published literature. Decision tree analysis was used to calculate the cost-effectiveness of a combined FNA/MIBI investigative strategy compared to the BTA guidelines.

Results

From 712 patients, the sensitivity, specificity, PPV and NPV of MIBI scintigraphy for the diagnosis of malignancy were 96 %, 46 %, 34 % and 97 %, respectively. MIBI-based strategies were more accurate and associated with lower cost per patient (£1,855/€2,125 vs. £2,445/€2,801) and lower cost per cancer diagnosed (£1,902/€2,179 vs. £2,469/€2,828) with negligible change in life expectancy.

Conclusion

Due to its high NPV, MIBI scintigraphy can usefully exclude malignancy for Thy1 and Thy2 lesions. Its low specificity means MIBI scintigraphy cannot be recommended as a first-line investigation, but as a second-line investigation MIBI scintigraphy may lead to a lower rate of unnecessary thyroidectomies. Combined FNA/MIBI strategies are potentially cost-effective in the management of solitary or dominant thyroid nodules.     

Utilidad de la ecografía en la evaluación de los nódulos tiroideos

ObjectiveTo evaluate the diagnostic capacity of ultrasonography (US) for differentiating between malignant and benign thyroid nodules and its usefulness in obviating unnecessary invasive procedures.Patients and methodsFrom January 2012 through December 2014, a total of 321 fine-needle aspiration biopsy (FNAB) procedures were done in 302 patients selected according to the criteria recommended by the American Association of Clinical Endocrinology guidelines and the American Thyroid Association guidelines. We analyzed the following characteristics on US: location, size, morphology, contour, consistency, echostructure, echogenicity, calcifications, and vascularization. We used univariate and multivariate analyses to investigate the relationship between the US findings and thyroid cancer.ResultsThe prevalence of malignancy in our study population was 5.92%. The US findings that were significantly associated with a greater probability of malignancy were microcalcifications, central vascularization, and hypoechogenicity. The US findings that were associated with a lower risk of malignancy were areas of colloid degeneration and nodule heterogeneity.ConclusionOur results suggest that decisions about whether to perform FNAB should be based on the presence of suspicious US findings found with our statistic model rather than on the size of the nodule. Thus, unnecessary FNAB procedures on nodules without suspicious US characteristics can be avoided.     

First-Line Use of Core Needle Biopsy for High-Yield Preliminary Diagnosis of Thyroid Nodules

BACKGROUND AND PURPOSE:Although core needle biopsy was introduced as a diagnostic alternative to fine-needle aspiration, the utility and safety of core needle biopsy for thyroid nodules in a large population has yet to be studied comprehensively. We evaluate core needle biopsy yields on a large-scale basis to investigate its potential in the preliminary diagnosis of thyroid nodules.MATERIALS AND METHODS:Between March 2005 and December 2013, 2448 initially detected thyroid nodules from 2120 consecutive patients who underwent core needle biopsy were retrospectively evaluated. Of these, 72 thyroid nodules from 63 patients were excluded due to prior fine-needle aspiration attempts. The inconclusive and conclusive result rates, diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and unnecessary surgery rate of core needle biopsy were evaluated.RESULTS:With core needle biopsy as the first-line method, the inconclusive result rate was 11.9% (283/2376) and the conclusive result rate was 88.1% (2093/2376). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of core needle biopsy for the diagnosis of malignancy were 96.7% (1160/1200), 89.7% (347/387), 100% (813/813), 100% (347/347), and 95.3% (813/853), respectively. There were no major complications and 12 minor complications.CONCLUSIONS:We have demonstrated that first-line use of core needle biopsy may well improve diagnostic accuracy in thyroid nodules, reducing inconclusive or false-negative results and unnecessary operations. Such benefits underscore the promising role of core needle biopsy in managing thyroid nodules and optimizing related surgical decision-making.

Although ultrasonography (US)-guided fine-needle aspiration (FNA) is a safe, accurate, and cost-effective method for diagnosing malignancy in thyroid nodules, there are limitations.^1,2 A major drawback is the frequency of inconclusive results (ie, indeterminate or inadequate results), accounting for 25%–30% of FNA results.^2,3 In such instances, even repeat FNA attempts may still be nondiagnostic (9.9%–47.8% incidence).^4–6 Nodules with inconclusive FNA results are commonly referred for diagnostic surgery at reported rates of 22.2%–94.7%.^7–9 Although several studies suggest that biomarkers (molecular or genetic) and clinical or sonography parameters may serve to support FNA outcomes,^10–12 surgical confirmation is often still required.^1,2,12Core needle biopsy (CNB) was introduced as a diagnostic alternative to FNA or tissue diagnosis. It is well-tolerated and safe and associated with a low incidence of complications.^{3,4,6,13–16} However, its role has remained second-line, largely serving as a supplement in patients with inconclusive FNA results. However, a number of studies have reported that a diagnosis was established via CNB in up to 98% of nodules with indeterminate FNA results; and by performing CNB and repeat FNA in combination, 97% of nodules with prior inadequate FNA yields are eventually diagnosed.^{4–6,14–16} Most interesting, there have been few studies to date on the use of CNB as a first-line examination for the diagnosis of thyroid nodules.^17–19 Consequently, the utility and safety of CNB for thyroid nodules in a large population have not yet been studied comprehensively.This study was conducted on the premise that highly diagnostic yields are achievable via CNB, without undue or major complications. We therefore evaluated CNB yields on a large-scale basis to investigate its full potential in the preliminary diagnosis of thyroid nodules.     

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

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.     

Modified Core Biopsy Technique to Increase Diagnostic Yields for Well-Circumscribed Indeterminate Thyroid Nodules: A Retrospective Analysis

BACKGROUND AND PURPOSE:The results of conventional core biopsy for some thyroid nodules with indeterminate cytology have still remained indeterminate. The aim of this study was to evaluate whether the ultrasonography-guided core needle biopsy technique containing the nodule, capsular portion, and surrounding parenchyma was more effective than a conventional method in enhancing diagnostic yield for circumscribed solid thyroid nodules without malignant sonographic features.MATERIALS AND METHODS:This retrospective comparative study evaluated 26 thyroid nodules in 26 consecutive patients between 2006 and 2010. They were biopsied by using a conventional method, and 61 nodules from 60 patients were biopsied by using a modified ultrasonography-guided core needle biopsy technique in 2013. The patients enrolled in this study presented with circumscribed solid thyroid nodules without malignant sonographic features, classified as nondiagnostic or atypia/follicular lesions of undetermined significance at previous cytology. The ultrasonography-guided core needle biopsy results of the 2 groups were compared.RESULTS:The rate of inconclusive ultrasonography-guided core needle biopsy results was 34.6% (9/26) in the conventional group and 11.4% (7/61) in the modified technique group (P = .018). There was no significant difference in the mean size of the nodules between the 2 groups (P = .134). The malignancy rate was 33% (3/9) for the conventional group and 52% (27/52) for the modified technique group (P = .473). The most common malignant pathology was a follicular variant of papillary thyroid carcinoma and follicular adenoma was the most common benign lesion.CONCLUSIONS:For circumscribed solid nodules without malignant sonographic features with indeterminate cytology, the ultrasonography-guided core needle biopsy technique containing the nodule, capsular portion, and surrounding parenchyma is more effective in diagnostic yield compared with a conventional method that biopsies the intranodular portion.

Despite the lack of definite malignant sonographic features, solid thyroid nodules showing nondiagnostic or atypia or follicular lesions of undetermined significance (AUS/FLUS) in fine-needle aspiration (FNA) readings by using the Bethesda System for Reporting Thyroid Cytopathology have raised concerns about the diagnosis of malignancy.^1–4 The management of nodules with nondiagnostic lesions or AUS/FLUS has been a matter of debate.^2,3 Several studies have suggested that sonography-guided core needle biopsy (US-CNB) helps decrease the frequency of inconclusive diagnostic results and improves the rate of accurate diagnoses.^5–9US-CNB is safe and well-tolerated, yields a low incidence of complications, and serves as an alternative to FNA for obtaining tissues for diagnosis.^7,10 However, its results have remained indeterminate for up to 36% of the nodules whose cytology is insufficient to differentiate nodular hyperplasia from follicular neoplasm, even after US-CNB.⁵ On ultrasonography (US), circumscribed solid nodules without malignant features are frequently confirmed histologically as nodular hyperplasia, a follicular neoplasm (follicular/Hürthle adenoma or carcinoma), a follicular variant of papillary thyroid carcinoma (PTC), or a classic type of PTC.^11–14The preoperative diagnosis of PTC would usually be sufficient with FNA because nuclear features are the key to diagnosis.⁴ “Follicular neoplasm” is defined as an encapsulated lesion whose growth pattern (microfollicular, macrofollicular, trabecular, or another growth pattern) is distinct from that of the surrounding thyroid parenchyma. Nodular hyperplasia is one of the most common pathologies in benign thyroid disease and is characterized by a densely cellular follicular proliferation that lacks a capsule on histology.^4,15,16 Because nodular hyperplasia may sometimes be considered normal thyroid tissue after core needle biopsy diagnosis, the presence of a capsule and normal parenchyma in the thyroid nodule can be meaningful for the differentiation of a follicular neoplasm from nodular hyperplasia. Nodules with circumscribed solid features only identified on US are diagnosed as indeterminate because they have neither malignant nor benign features.¹⁷ Moreover, indeterminate FNA of these lesions may lead to an unnecessary diagnostic operation. Thus, circumscribed solid thyroid nodules not associated with other malignant features require the use of CNB techniques under US guidance other than a conventional method that biopsies the internal portion of the thyroid nodule. One recent study suggested that the use of a CNB technique that biopsied the capsule of the thyroid nodule and the surrounding parenchyma was useful for the diagnosis of cytologically indeterminate nodules.¹⁸ However, the authors did not compare the results of the conventional method with those of the modified method or focus on the diagnosis of problematic nodules by using a conventional CNB method. We evaluated whether the modified CNB technique was more effective in the diagnostic yield of circumscribed solid nodules without malignant sonographic features with indeterminate cytology compared with a conventional method. Therefore, we compared the inconclusive rate (nondiagnostic or AUS/FLUS rate) and malignant rate of CNB results between the conventional and the modified technique groups.     

What Is the Ideal Core Number for Ultrasonography-Guided Thyroid Biopsy of Cytologically Inconclusive Nodules?

BACKGROUND AND PURPOSE:Core needle biopsy of the thyroid under ultrasonographic guidance provides a larger tissue sample and may facilitate a more precise histologic diagnosis, reducing the need for repetitive fine-needle aspiration or a diagnostic operation. However, there is no consensus regarding the ideal number of specimens to be obtained for ultrasonography-guided core needle biopsy. The aim of this study was to decide the ideal core number for ultrasonography-guided core needle biopsy of cytologically inconclusive nodules.MATERIALS AND METHODS:Sixty consecutive biopsies were performed in 60 thyroid nodules with Bethesda Category I or III cytology. Three biopsy cores were obtained for each thyroid nodule. The first biopsy specimens were taken from the nodule, while the second and third specimens obtained included the nodular tissue, nodular capsule, and surrounding parenchyma. Diagnostic ability was evaluated according to the following: protocol A, first specimen; protocol B, first and second specimens; and protocol C, all specimens. The McNemar test was used for statistical analysis.RESULTS:Of the 60 nodules, diagnostic ability was achieved in 41 nodules (68%) with protocol A, in 56 nodules (93%) with protocol B, and in 58 nodules (97%) with protocol C. The diagnostic ability of protocols B and C was significantly higher than that of protocol A (all P values < .001). However, the diagnostic ability of protocol B was not significantly different from that of protocol C.CONCLUSIONS:Ultrasonography-guided core needle biopsy for cytologically inconclusive thyroid nodules should obtain at least 2 core specimens with intranodular and capsule targets.

Ultrasonography (US)-guided fine-needle aspiration (FNA) is considered the criterion standard for the evaluation of thyroid nodules due to its simplicity, safety, cost-effectiveness, and diagnostic accuracy. However, a major limitation of FNA is the nondiagnostic and indeterminate cytology results that comprise approximately 10%–33.6% and 15%–42% of all FNA samples,^1–4 respectively. The Bethesda System for Reporting Thyroid Cytopathology recommended repeat FNA for any nodule with initially nondiagnostic or indeterminate cytology results.⁵ However, repeat FNA does not seem to be a satisfactory solution because approximately 17%–47% of nodules with initially nondiagnostic cytology^6–9 and 38.5%–43% of nodules with initially indeterminate cytology^10,11 will be rediagnosed with inconclusive results.Core needle biopsy (CNB) of the thyroid gland under US guidance provides a larger tissue sample and may facilitate a more precise histologic diagnosis, reducing the need for repetitive FNA or a diagnostic operation.^11–18 In addition, US-guided CNB for thyroid nodules by using a modern spring-activated biopsy needle has been reported to be a safe and well-tolerated procedure.^19–23 However, to the best of our knowledge, there is no consensus regarding the ideal number of core specimens to be obtained for US-guided thyroid CNB.The purpose of this study was to compare the diagnostic ability based on biopsy core numbers and to decide the ideal core number for US-guided thyroid biopsy of cytologically inconclusive nodules.     

The Role of Tc-99 m-MIBI Scan in the Assessment of the Cystic Thyroid Nodule

PurposeA non-surgical therapeutic option requires assurance that a cystic thyroid nodule with non-diagnostic cytology is benign. This work was undertaken to determine whether Tc-99 m-MIBI scan (MIBI) findings can guide the best therapeutic option with confidence.Material and MethodsWe studied 81 cystic non-functioning thyroid nodules with non-diagnostic fine-needle aspiration biopsy (FNAB) report classified according to ATA 2015 ultrasonography (US) patterns for suspicion of malignancy. All had a MIBI to assess metabolic activity within the nodule as well as histopathological diagnosis. Diagnostic value analysis of MIBI as compared to the US pattern was determined.ResultsNone of the 11 patients with US pattern of benign showed positive MIBI, and all had a histopathological report of benign. Diagnostic value of MIBI on US pattern of very low suspicion showed sensitivity, specificity, PPV, and NPV of 100%, 78.9%, 42.9%, and 100%, respectively.ConclusionOur data shows that the only approach to a safe non-surgical treatment option in a cystic nodule with non-diagnostic FNAB is when no metabolic activity is seen on MIBI.