Jung Hyun Yoon

Thyroid imaging reporting and data system for US features of nodules: a step in establishing better stratification of cancer risk.

PURPOSE To develop a practical thyroid imaging reporting and data system (TIRADS) with which to categorize thyroid nodules and stratify their malignant risk. MATERIALS AND METHODS The institutional review board approved this retrospective study, and the requirement to obtain informed consent for the review of images and records was waived. From May to December 2008, ultrasonographically (US)-guided fine-needle aspiration biopsy (FNAB) was performed in 3674 focal thyroid nodules in 3414 consecutive patients. The study included the 1658 thyroid nodules (≥1 cm in maximum diameter at US) in 1638 patients (1373 women, 265 men) for which pathologic diagnosis or follow-up findings were available. Univariate and multivariate analyses with generalized estimating equations were performed to investigate the relationship between suspicious US features and thyroid cancer. A score for each significant factor was assigned and multiplied by the β coefficient obtained for each significant factor from multivariate logistic regression analysis. Scores for each significant factor were then added, resulting in an equation that fitted the probability of malignancy in thyroid nodules. The authors evaluated the fitted probability by using a regression equation; the risk of malignancy was determined according to the number of suspicious US features. RESULTS The following US features showed a significant association with malignancy: solid component, hypoechogenicity, marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape. As the number of suspicious US features increased, the fitted probability and risk of malignancy also increased. Positive predictive values according to the number of suspicious US features were significantly different (P < .001). CONCLUSION Risk stratification of thyroid malignancy by using the number of suspicious US features allows for a practical and convenient TIRADS.

Diagnostic Performance of Gray-Scale US and Elastography in Solid Thyroid Nodules

PURPOSE To evaluate the diagnostic performance of gray-scale ultrasonography (US) and elastography in differentiating benign and malignant thyroid nodules. MATERIALS AND METHODS This was an institutional review board-approved retrospective study with waiver of informed consent. A total of 703 solid thyroid nodules in 676 patients (mean age, 49.7 years; range, 18-79 years) were included; there were 556 women (mean age, 49.5 years; range, 20-74 years) and 120 men (mean age, 50.7 years; range, 18-79 years). Nodules with marked hypoechogenicity, poorly defined margins, microcalcifications, and a taller-than-wide shape were classified as suspicious at grayscale US. Findings at elastography were classified according to the Rago criteria and the Asteria criteria. The diagnostic performances of gray-scale US and elastography were compared. For comparison between the diagnostic performances of gray-scale US and the combination of gray-scale US and elastography, three sets of criteria were assigned: criteria set 1, nodules with any suspicious grayscale US feature were assessed as suspicious; criteria set 2, Rago criteria were added as suspicious features to criteria set 1; and criteria set 3, Asteria criteria were added as suspicious features to criteria set 1. The diagnostic performances of gray-scale US, elastography with Rago criteria, and elastography with Asteria criteria, and odds ratios (ORs) with 95% confidence intervals for predicting thyroid malignancy were compared using generalized estimating equation analysis. RESULTS Of 703 nodules, 217 were malignant and 486 were benign. Sensitivity, negative predictive value (NPV), and OR of gray-scale US for the 703 nodules were 91.7%, 94.7%, and 22.1, respectively, and these values were higher than the 15.7% and 65.4% sensitivity, 71.7% and 79.1% NPV, and 3.7 and 2.6 ORs found for elastography with Rago and Asteria criteria, respectively. Specificity, positive predictive value, and accuracy for criteria set 1 were significantly higher than those for criteria sets 2 and 3 for most of the nodule subgroups that were considered. CONCLUSION Elastography alone, as well as the combination of elastography and gray-scale US, showed inferior performance in the differentiation of malignant and benign thyroid nodules compared with gray-scale US features; elastography was not a useful tool in recommending fine-needle aspiration biopsy.

Interobserver variability of ultrasound elastography: how it affects the diagnosis of breast lesions

OBJECTIVE The purpose of this article is to evaluate the interobserver variability of elastography on real-time ultrasound and how it influences the agreement of final assessment on ultrasound. SUBJECTS AND METHODS From April to May 2009, 65 breast lesions of 53 patients (mean age, 42.6 years; range, 18-72 years) who underwent ultrasound-guided core biopsy were included in this study. Ultrasound and elastography images of the lesion subjected to biopsy were obtained and prospectively analyzed by three radiologists with individual real-time image scanning prior to biopsy. Each radiologist recorded final ultrasound BI-RADS assessments using ultrasound and combined ultrasound and elastography and the fat-to-lesion ratio and elasticity score. The histopathologic results obtained from ultrasound-guided core biopsy or excision were used as the reference standard. Diagnostic performances and interobserver agreement were analyzed. RESULTS Of the 65 lesions, 43 (66.2%) were benign, and 22 (33.8%) were malignant. Specificity (20.2-33.3%), positive predictive value (38.7-45.1%), and accuracy (46.7-55.4%) were significantly improved in combined ultrasound and elastography (p < 0.001). Area under the curve (AUC) values for all three performers did not show significant differences in ultrasound (AUC, 0.959) and combined ultrasound and elastography (AUC, 0.957) (p = 0.92). Interobserver agreement was not improved with combined ultrasound and elastography (κ = 0.25) in comparison to ultrasound only (κ = 0.37). Interobserver agreement of real-time elastography was fair in both fat-to-lesion ratio (intraclass correlation coefficient score, 0.25) and elasticity score (κ = 0.28). Moderate agreement (κ = 0.46) was seen with static elastography. CONCLUSION Elastography improves the specificity, positive predictive value, and accuracy of ultrasound. However, significant interobserver variability exists, with real-time elastographic performance showing fair agreement.

The Diagnostic Accuracy of Ultrasound-Guided Fine-Needle Aspiration Biopsy and the Sonographic Differences Between Benign and Malignant Thyroid Nodules 3 cm or Larger

BACKGROUND Although fine-needle aspiration biopsy (FNAB) is considered the standard for preoperative evaluation of thyroid nodules, the value of this has been questioned for large thyroid nodules. Here, we evaluated the diagnostic accuracy of ultrasound-guided FNAB (US-FNAB) for thyroid nodules that were 3 cm or larger as well as the sonographic differences between benign and malignant nodules in this size group. MATERIALS AND METHODS There were 661 thyroid masses equal to or larger than 3 cm who underwent US-FNAB from February 2002 to December 2006 and were included in this study. The cytology and surgical pathology readings in these patients were reviewed along with the ultrasonography features, the last from the retrospective review by one radiologist. Histopathology was used to calculate accuracy parameters for the US-FNAB cytology readings. In addition, the likely diagnoses for patients with a benign cytology reading were ascertained. RESULTS Thyroid surgery was performed for 206 of the 661 nodules in the same number of patients (31.2%). All subjects who had inadequate, indeterminate, or suspicious for malignancy cytology readings had thyroid surgery. All of the patients who did not have thyroid surgery were considered likely to have benign disease because of their initial cytology reading and follow-up, and finally, 587 (88.8%) were benign and 74 (11.2%) were malignant. When considering malignant, suspicious for malignancy, and indeterminate cytology readings as positive and benign cytology as negative, the sensitivity was 96.7%, specificity 85.9%, positive predictive value 76.6%, negative predictive value 98.2%, and accuracy 89.4%. Ultrasonography features of malignancy were more prevalent in thyroid nodules that were malignant compared with those that were benign or considered likely to be benign (70.3% vs. 1.2%, p < 0.001), and ultrasonography features of a benign nodule were more prevalent in thyroid nodules that were benign or considered likely to be benign than those that were malignant (94.9% vs. 29.7%, p < 0.001). CONCLUSION In this study, US-FNAB appeared to be a relatively accurate method to evaluate thyroid nodules larger than 3 cm, with false-negative rates of about 2%. Much larger series would be required to determine its utility in this setting.

Sonographic Features of the Follicular Variant of Papillary Thyroid Carcinoma

Objective. The purpose of this study was to evaluate the sonographic findings of the follicular variant of papillary thyroid carcinoma (FVPTC) and to assess the role of preoperative fine‐needle aspiration biopsy (FNAB). Methods. The sonographic findings of 27 thyroid nodules in 26 patients (2 male and 24 female; mean age, 45 years) with surgically proven FVPTC were reviewed retrospectively. Findings were categorized according to the echogenicity, margin, shape, and presence of microcalcifications. Malignant findings included marked hypoechogenicity, irregular or microlobulated margins, a taller‐than‐wide shape, and microcalcifications. Thyroid nodules with a single malignant finding as described above were classified as malignant. All patients underwent sonographically guided FNAB, and the sensitivity of the cytologic results was calculated. Results. Lesion sizes varied from 3 to 34 mm (mean, 15.2 mm), and lesions were most commonly solid (23 [85.2%]), hypoechoic (14 [51.9%]), and oval (17 [63%]) with well‐defined margins (14 [51.9%]) and no microcalcifications (23 [85.2%]). Eighteen lesions (66.7%) were correctly classified as malignant, whereas 9 (33.3%) were classified as benign on the basis of sonographic criteria. Twenty‐four samples were adequate for cytologic examination, and 3 were inadequate. Twenty‐one of 24 diagnostic cytologic results (87.5%) were suspicious for papillary carcinoma (5 of 21 [20.8%]) or malignant (16 of 21 [66.7%]), whereas 3 lesions (12.5%) had benign results. The sensitivity of FNAB was 77.8% (21 of 27). Conclusions. The follicular variant of papillary thyroid carcinoma tends to have relatively benign sonographic features, such as hypoechogenicity, well‐defined margins, an oval shape, and no microcalcifications, but most lesions were correctly classified as malignant by both sonography and FNAB. The possibility of FVPTC should be considered when thyroid nodules with a relatively benign sonographic appearance have suspicious or malignant FNAB results

Factors affecting inadequate sampling of ultrasound-guided fine-needle aspiration biopsy of thyroid nodules

Purpose  The aim of this study was to evaluate the overall ultrasonographic features and clinical factors that contribute to inadequate sampling in ultrasound‐guided fine‐needle aspiration biopsy (US‐FNAB) of thyroid nodules.

Malignancy Risk Stratification in Thyroid Nodules with Nondiagnostic Results at Cytologic Examination: Combination of Thyroid Imaging Reporting and Data System and the Bethesda System

PURPOSE To evaluate the malignancy risks of thyroid nodules with nondiagnostic results at ultrasonography (US)-guided fine-needle aspiration biopsy ( FNAB fine-needle aspiration biopsy ) and the criteria for selecting those for repeat US-guided FNAB fine-needle aspiration biopsy according to the thyroid imaging reporting and data system ( TIRADS thyroid imaging reporting and data system ). MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived. Five hundred forty-eight nondiagnostic nodules were included. US features of internal composition, echogenicity, margin, calcifications, shape, and vascularity were evaluated, and thyroid nodules were classified according to TIRADS thyroid imaging reporting and data system . TIRADS thyroid imaging reporting and data system category 3 included nodules without any suspicious features of solidity, hypoechogenicity or marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape. Categories 4a, 4b, 4c, and 5 included nodules with one, two, three or four, or five suspicious US features. The malignancy risk was calculated. RESULTS Of the 548 nodules, 40 (7.3%) were malignant and 508 (92.7%) were benign. The malignancy risks of categories 3 and 4a nodules were 0.8% and 1.8%, respectively, whereas the malignancy risks of categories 4b, 4c, and 5 nodules were 6.1%, 14.4%, and 31%. In the 294 nodules larger than 10 mm, the malignancy risks of categories 3, 4a, 4b, 4c, and 5 nodules were 0.9%, 1.3%, 0%, 15%, and 33%, respectively. In the 254 nodules measuring 10 mm or smaller, the malignancy risks of categories 3, 4a 4b, 4c, and 5 nodules were 0%, 2.7%, 14%, 14.3%, and 31%. CONCLUSION Nondiagnostic thyroid nodules without suspicious US features and those with one suspicious feature can be followed up with US, but nondiagnostic nodules with two or more suspicious features should undergo repeat US-guided FNAB fine-needle aspiration biopsy.

Effectiveness and limitations of core needle biopsy in the diagnosis of thyroid nodules: review of current literature.

Fine needle aspiration (FNA) is currently accepted as an easy, safe, and reliable tool for the diagnosis of thyroid nodules. Nonetheless, a proportion of FNA samples are categorized into non-diagnostic or indeterminate cytology, which frustrates both the clinician and patient. To overcome this limitation of FNA, core needle biopsy (CNB) of the thyroid has been proposed as an additional diagnostic method for more accurate and decisive diagnosis for thyroid nodules of concern. In this review, we focus on the effectiveness and limitations of CNB, and what factors should be considered when CNB is utilized in the diagnosis of thyroid nodules.

Comparison of the underestimation rate in cases with ductal carcinoma in situ at ultrasound-guided core biopsy: 14-gauge automated core-needle biopsy vs 8- or 11-gauge vacuum-assisted biopsy

OBJECTIVE The objective of this study was to compare the underestimation rate of invasive carcinoma in cases with ductal carcinoma in situ (DCIS) at percutaneous ultrasound-guided core biopsies of breast lesions between 14-gauge automated core-needle biopsy (ACNB) and 8- or 11-gauge vacuum-assisted biopsy (VAB), and to determine the relationship between the lesion type (mass or microcalcification on radiological findings) and the DCIS underestimation rate. METHODS We retrospectively reviewed imaging-guided biopsies of breast lesions performed from February 2003 to August 2008. 194 lesions were diagnosed as DCIS at ultrasound-guided core biopsy: 138 lesions in 132 patients by 14-gauge ACNB, and 56 lesions in 56 patients by 8- or 11-gauge VAB. The histological results of the core biopsy samples were correlated with surgical specimens. The clinical and radiological findings were also reviewed. The histological DCIS underestimation rates were compared between the two groups and were analysed for differences according to the clinical and radiological characteristics of the lesions. RESULTS The DCIS underestimation rate was 47.8% (66/138) for 14-gauge ACNB and 16.1% (9/56) for VAB (p<0.001). According to the lesion type on sonography, DCIS underestimation was 43.4% (63/145) in masses (47.6% using ACNB and 15.8% using VAB; p=0.012) and 24.5% (12/49) in microcalcifications (50.0% using ACNB and 16.2% using VAB; p=0.047). CONCLUSION The underestimation rate of invasive carcinoma in cases with DCIS at ultrasound-guided core biopsies was significantly higher for ACNB than for VAB. Furthermore, this difference does not change according to the lesion type on ultrasound. Therefore, ultrasound-guided VAB can be a useful method for the diagnosis of DCIS lesions presented as either mass or microcalcification.

Diagnostic role of conventional ultrasonography and shearwave elastography in asymptomatic patients with diffuse thyroid disease: initial experience with 57 patients.

Purpose Thyroid ultrasonography (US) is a useful diagnostic tool in the evaluation of diffuse thyroid disease (DTD), whereas shearwave elastography is a dynamic technique that can provide information about tissue hardness by using acoustic shearwaves remotely induced by a focused ultrasonic beam. This study aims at investigating the role of conventional US and shearwave elastography in the diagnosis of asymptomatic patients with DTD. Materials and Methods Fifty-seven patients who underwent both conventional US and shearwave elastography were included in this study. Interobserver variability of the three radiologists in assessment of underlying thyroid echogenicity on conventional US was analyzed. Diagnostic performances for diagnosing DTD on conventional US and shearwave elastography were calculated and compared. Results Fair agreement was observed in the identification of DTD with conventional US (kappa value=0.27). The area under the receiver operating characteristic curve (Az) were 0.52-0.585 on conventional US by three radiologists. The Az values when using the mean and maximum elasticity values as a diagnostic criteria for DTD were 0.619 and 0.59 on shearwave elastography. Patients with DTD showed higher mean [24.1±10 kilo-Pascals (kPa)] and maximum (36.4±13.3 kPa) elasticity values on shearwave elastography when compared to the normal group (23.4±10.8 kPa and 33.7±12.4 kPa, respectively), although without statistical significance (p=0.802 and p=0.452, respectively). Conclusion Conventional US did not show reliable interobserver agreement in the diagnosis of DTD. Although not statistically significant, shearwave elastography may provide additional information in the diagnosis of DTD. Therefore, larger prospective studies are needed to define the values of shearwave elastography for diagnosing DTD.