Seon Hyeong Choi

Interobserver and intraobserver variations in ultrasound assessment of thyroid nodules

BACKGROUND Thyroid ultrasound (US) is used as the first diagnostic tool to assess the management of the disease. In spite of its importance, US is a very subjective method and highly dependent on the skill of the performer. There have been few reports evaluating thyroid US performance and even fewer reports of observer variability in US assessment. Therefore, we evaluated inter- and intraobserver variations in US assessment of thyroid nodules and diagnosis among four radiologists and estimated its diagnostic accuracy. METHODS A total of 204 thyroid nodules in 144 patients were reviewed. There were 89 benign and 115 malignant cases. Four radiologists with more than 5 years of experience independently reviewed US images twice at 6-week intervals. Echogenicity, composition, margin, shape, calcification, vascularity, and final assessment were evaluated. Inter- and intraobserver variations were determined with Cohens kappa statistics, and accuracy was calculated. RESULTS For interobserver variations, echogenicity showed slight agreement (kappa = 0.34); composition, margin, calcification, and final assessment had fair agreement (kappa = 0.59, 0.42, 0.58, and 0.54, respectively); shape and vascularity showed substantial agreement (kappa = 0.61 and 0.64, respectively). For intraobserver variability, almost all showed substantial agreement (kappa > 0.61). Overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the four radiologists were 88.2%, 78.7%, 76.2%, 89.6%, and 82.8%, respectively. CONCLUSIONS Experienced radiologists showed more than a moderate degree of agreement in US assessment of thyroid nodules, and their final assessments were highly accurate.

Extrathyroid Extension of Well-Differentiated Papillary Thyroid Microcarcinoma on US

BACKGROUND Extrathyroidal extension is an important factor to determine the extent of thyroid surgery. The aim of the present study was to evaluate the usefulness of high-resolution ultrasound (US) for predicting the extrathyroidal extension of papillary thyroid microcarcinoma (PTMC). METHODS This study included a total of 221 PTMCs in 181 patients. PTMC was defined as thyroid papillary carcinoma equal or less than 1 cm in size. The US findings, such as contact and disruption of thyroid capsule, were evaluated to predict the extrathyroidal extension of thyroid carcinoma. We calculated the diagnostic accuracy and odds ratio for each US finding. RESULTS Of the 221 PTMCs, extrathyroidal extension was present in 89 (40.3%) based on pathologic results. The mean size was not significantly different between PTMCs with and without extrathyroidal extension (p = 0.527). When the degree of contact was high, extrathyroidal extension of the thyroid cancer was high (p < 0.0001). Considering the odds ratio, Az value, and positive predictive value of each US finding, more than 25% contact with the adjacent capsule is the most accurate measurement for predicting extrathyroidal extension. CONCLUSIONS This study suggests that the presence and degree of contact between a PTMC and the adjacent capsule as found on preoperative US can provide an useful predictive information about an extrathyroidal extension.

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.

The Role of Ultrasound in Thyroid Nodules with a Cytology Reading of Suspicious for Papillary Thyroid Carcinoma

BACKGROUND Irrespective of ultrasound (US) features, surgery is usually recommended for patients who have a fine-needle aspiration biopsy (FNAB) read as suspicious for papillary carcinoma (PTC). The aim of the present study was to evaluate the role of US in the management of thyroid nodules with a FNAB reading suspicious for PTC. METHODS Between August 2002 and May 2006, 303 patients who had thyroid nodules with a FNAB reading suspicious for PTC underwent surgery. The sonographic findings in the patients were classified as suspicious for malignancy or probably benign based on the US reading. The US readings and final pathological diagnoses of thyroid nodules were analyzed in these patients. RESULTS The malignancy rate was 84.2% in patients with a FNAB specimen suspicious for PTC. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the US were 96.4%, 74.5%, 92.7%, 94.9%, and 80.9%, respectively, in nodules read as suspicious for PTC on FNAB. Whereas 243 (96.4%) lesions were found to be malignant at surgery, in the 252 lesions that had ultrasound findings suspicious for malignancy, only 13 (25.5%) lesions were malignant out of the 51 that had US readings of probably benign (p < 0.05). CONCLUSIONS The probability of malignancy is much lower in thyroid nodules with benign US findings even if the FNAB is read as suspicious for PTC. Therefore, US may be useful in planning the extent of surgery in patients with a FNAB reading of suspicious for PTC. As thyroid malignancy occurs in approximately 26% of patients with cytology readings suspicious for PTC and benign-appearing US, the US reading alone is not sufficient to determine the need for surgery. The US and FNAB are complementary to each other and should be useful when providing informed consent before thyroid surgery.

Practice guideline for the performance of breast ultrasound elastography

Ultrasound (US) elastography is a valuable imaging technique for tissue characterization. Two main types of elastography, strain and shear-wave, are commonly used to image breast tissue. The use of elastography is expected to increase, particularly with the increased use of US for breast screening. Recently, the US elastographic features of breast masses have been incorporated into the 2nd edition of the Breast Imaging Reporting and Data System (BI-RADS) US lexicon as associated findings. This review suggests practical guidelines for breast US elastography in consensus with the Korean Breast Elastography Study Group, which was formed in August 2013 to perform a multicenter prospective study on the use of elastography for US breast screening. This article is focused on the role of elastography in combination with B-mode US for the evaluation of breast masses. Practical tips for adequate data acquisition and the interpretation of elastography results are also presented.

Surgical strategies for non-functioning pancreatic neuroendocrine tumours.

The purpose of this study was to identify management strategies for non‐functioning pancreatic neuroendocrine tumours (NF‐PNETs) by analysis of surgical outcomes at a single institution.

Validation of intra- and interobserver reproducibility of shearwave elastography: Phantom study

PURPOSE To assess intra- and interobserver reproducibility of quantitative ultrasound (US) elastography for breast masses using shearwave elastography (SWE). MATERIALS AND METHODS The US elastography phantom was used. This training phantom contained 12 masses with dimensions from 6 to 11mm and varying B-mode (hypo- iso- and hyperechoic) characteristics and viscoelastic properties varying from about 50 to 250kPa. Four attending radiologists participated as operators and used Supersonic Imaging 15-4 MHz array to acquire images. In each session, B-mode US features were assessed once and US elastography values were assessed twice in a consecutive and distinct manner. A total of three identical sessions of data acquisition were performed at 2-week intervals. For categorical variables such as BI-RADS features of mass on B-mode image and qualitative SWE features, kappa (k) values were calculated by the generalized linear mixed model. For continuous variables, kPa, and ratio, intraclass correlation coefficients (ICCs) were calculated. RESULTS Interobserver agreement for SWE image similarity was moderate (k=0.57). With respect to quantitative SWE values, intraobserver ICCs were 0.65, 0.77, 0.92, and 0.91 for maximum elasticity; 0.70, 0.83, 0.94, and 0.94 for mean elasticity; and 0.67, 0.83, 0.92, and 0.92 for elasticity ratio for operators 1, 2, 3, and 4, respectively. Interobserver reproducibility showed good agreement with ICC values of 0.77 for maximum elasticity, 0.82 for mean elasticity, and 0.79 for elasticity ratio. CONCLUSION Quantitative US elastography for breast masses was highly reproducible with good agreement across operators. With respect to intraobserver reproducibility, ICC values varied but three out of four operators showed good agreement.

Power Doppler sonography: evaluation of solid breast lesions and correlation with lymph node metastasis

OBJECTIVE The purpose of this study was to assess the role of power Doppler US in differentiating benign from malignant solid breast masses when used in conjunction with grayscale sonography (US) and the relationship with axillary lymph node metastasis. SUBJECTS AND METHODS Grayscale US of 353 solid lesions was categorized using the US BI-RADS final assessment system prospectively. On power Doppler US, the presence of identified or penetrating vessels within the mass was evaluated, respectively. Diagnostic accuracy was calculated at grayscale US with and without power Doppler US. Among malignant cases, tumor vascularity was correlated with lymph node involvement. RESULTS When the size of the masses was controlled, the identified or penetrating vessels were significantly more frequent in malignant lesions (P<.05). By using the identified and penetrating vessels in the mass as one of the diagnostic criteria for malignancy, the diagnostic accuracy was improved. In 54 infiltrating ductal carcinomas, although lymph node involvement was more frequently seen in the group having identified or penetrating vessels (40 and 35.3%) than in the avascular group (16.7 and 27%), it was not statistically significant (P>.05). CONCLUSION We suggest that identified or penetrating vessels within the mass on power Doppler US can be one of the malignant criteria.

Expression patterns of stromal MMP-2 and tumoural MMP-2 and -9 are significant prognostic factors in invasive ductal carcinoma of the breast.

Matrix metalloproteinases (MMPs) are matrix‐degrading enzymes that play a pivotal role in aggressive behaviours, such as rapid tumour growth, invasion, and metastasis, of several types of solid tumours. In particular, stromal MMP‐2 plays important roles in the progression of malignant tumours, but most clinical studies have focused on tumoural MMP‐2 and ‐9 expression, and not stromal MMP‐2 expression. One hundred and seventy‐seven cases diagnosed as invasive ductal carcinoma of the breast between 2000 and 2005 were included in this study. Expressions of tumoural MMP‐2 and ‐9 and stromal MMP‐2 were analysed by immunostaining on a tissue microarray. Subsequently, the associations between those results and various clinicopathological parameters were evaluated. Stromal MMP‐2 expression correlated significantly with clinicopathological parameters such as advanced T category, larger tumour size, high histological grade, tumour necrosis, ER‐ and PR‐negative, and HER‐2‐positive (all p < 0.05). In univariate and multivariate analyses, overall survival was linked with stromal MMP‐2 expression as well as dual expression of stromal MMP‐2 and tumoural MMP‐2 and ‐9 (all p < 0.05). Stromal MMP‐2 expression may play a crucial role in predicting aggressive clinical behaviour in breast cancer patients.

Ultrasound and Clinicopathological Characteristics of Triple Receptor-Negative Breast Cancers

Purpose Triple receptor-negative (TRN) breast cancer is associated with high risk of recurrence and poor prognosis. The present study assessed the clinicopathologic characteristics and ultrasound (US) features of TRN breast cancers. Methods Pathological and biological data were reviewed for 558 breast cancer patients treated at Kangbuk Samsung Hospital, between January 2003 and December 2009. The patients were separated into TRN breast cancer and non-TRN breast cancer groups, based on the results of immunohistochemical prognostic panels. Clinical and pathologic features were compared for the two groups. US features, including shape, orientation, margins, boundaries, echo patterns, posterior acoustic features, surrounding tissues, and microcalcifications, were determined for 41 TRN patients and 189 non-TRN controls (ER+/PR+/HER2-). Results Of 558 cases, 58 (10.4%) had the TRN phenotype. Four hundred and thirty-four cases (77.8%) were invasive ductal carcinomas. TRN cancer was significantly associated with specific characteristics of tumor size, nuclear grade, histologic grade, venous invasion, and lymphatic invasion. With respect to US features, TRN cancers were more likely to have an oval shape, a circumscribed margin, and marked hypoechogenicity. Conclusion Tumor characteristics were different between TRN and non-TRN breast cancers, although US cannot differentiate the subtype of breast cancers TRN cancer tend to show somewhat different US morphology.