Sonographic evaluation of cervical lymph nodes in papillary thyroid cancer

Nomograms based on preoperative multimodal ultrasound of papillary thyroid carcinoma for predicting central lymph node metastasis

OBJECTIVES

To establish a nomogram for predicting central lymph node metastasis (CLNM) based on the preoperative clinical and multimodal ultrasound (US) features of papillary thyroid carcinoma (PTC) and cervical LNs.

METHODS

Overall, 822 patients with PTC were included in this retrospective study. A thyroid tumor ultrasound model (TTUM) and thyroid tumor and cervical LN ultrasound model (TTCLNUM) were constructed as nomograms to predict the CLNM risk. Areas under the curve (AUCs) evaluated model performance. Calibration and decision curves were applied to assess the accuracy and clinical utility.

RESULTS

For the TTUM training and test sets, the AUCs were 0.786 and 0.789 and bias-corrected AUCs were 0.786 and 0.831, respectively. For the TTCLNUM training and test sets, the AUCs were 0.806 and 0.804 and bias-corrected AUCs were 0.807 and 0.827, respectively. Calibration and decision curves for the TTCLNUM nomogram exhibited higher accuracy and clinical practicability. The AUCs were 0.746 and 0.719 and specificities were 0.942 and 0.905 for the training and test sets, respectively, when the US tumor size was ≤ 8.45 mm, while the AUCs were 0.737 and 0.824 and sensitivity were 0.905 and 0.880, respectively, when the US tumor size was > 8.45 mm.

CONCLUSION

The TTCLNUM nomogram exhibited better predictive performance, especially for the CLNM risk of different PTC tumor sizes. Thus, it serves as a useful clinical tool to supply valuable information for active surveillance and treatment decisions.

KEY POINTS

• Our preoperative noninvasive and intuitive prediction method can improve the accuracy of central lymph node metastasis (CLNM) risk assessment and guide clinical treatment in line with current trends toward personalized treatments. • Preoperative clinical and multimodal ultrasound features of primary papillary thyroid carcinoma (PTC) tumors and cervical LNs were directly used to build an accurate and easy-to-use nomogram for predicting CLNM. • The thyroid tumor and cervical lymph node ultrasound model exhibited better performance for predicting the CLNM of different PTC tumor sizes. It may serve as a useful clinical tool to provide valuable information for active surveillance and treatment decisions.

Preoperative Evaluation of Central Lymph Nodes in Papillary Thyroid Carcinoma Using High-Resolution Ultrasound and Shear-Wave Elastography

ABSTRACT

The aim of this study was to discuss the diagnostic value of high-resolution ultrasound and virtual touch tissue imaging quantification (VTIQ) for distinguishing metastatic and benign central lymph nodes (CLNs) in patients with papillary thyroid carcinoma. This retrospective study involved 86 pathologically proven benign lymph nodes (LNs) and 118 metastatic LNs in patients with papillary thyroid carcinoma. We analyzed the sonographic features of CLNs (size, shape, distribution, hilum, echogenicity, cystic change, calcification, vascularity, shear-wave velocity [SWV]). The prevalence of sonographic features and the SWV was compared between metastatic and benign CLNs. The size, shape, margin, distribution, presence of hilum, echogenicity, calcification, and vascularity were significantly different between benign and metastatic CLNs (P < 0.05 for all). The mean maximum SWV for malignant CLNs was 3.139 ± 0.408 m/s, whereas that of benign CLNs was 2.418 ± 0.369 m/s (P < 0.05). The cutoff point of the SWV for differentiating benign and malignant LNs was 2.675 m/s. Logistic regression analysis showed that round or irregular shape, aggregation or fusion, calcification, and VTIQ value greater than 2.675 m/s of CLNs were independent risk factors for malignancy, with an odds ratio of 5.77, 3.05, 3.23, and 62.85, respectively. High-resolution ultrasound and VTIQ can provide valuable information for distinguishing metastatic from benign CLNs.

Imaging of Cervical Lymph Nodes in Thyroid Cancer: Ultrasound and Computed Tomography

Sonographic evaluation of cervical lymph nodes in patients with thyroid malignancy is important both for preoperative staging and for post-treatment surveillance, and contrast-enhanced computed tomography plays a complementary role. Knowledge of anatomy and surgical approaches, combined with an understanding of the various imaging features that distinguish malignant from benign lymph nodes, allows for accurate staging, thereby enabling complete surgical initial resection.

Correlation between sonographic features and pathological findings of cervical lymph node metastasis of differentiated thyroid carcinoma

Background

The aim of this study is to evaluate the relationship between the sonographic features and pathological findings of cervical lymph node metastasis of differentiated thyroid carcinoma (DTC).

Methods

A total of 49 patients who had thyroid surgery and lateral or central cervical lymph node dissection from October to December 2019 in our hospital were selected. All the lymph nodes included in the dissection were examined by intraoperative ultrasound and were divided into 5 groups according to the sonographic characteristics (A: overall hyperechoic group; B: hypoechoic with punctate hyperechoic group; C: mass hyperechoic group; D: cystic degeneration group; E: hypoechoic group without punctate hyperecho). All samples were sent to the Pathology Department according to the area of origin and classified and numbered for comparative analysis of the microscopic pathology and the sonogram.

Results

A total of 120 suspicious metastatic lymph nodes were finally screened out by intraoperative ultrasound. The sonographic signs of these suspicious metastatic lymph nodes in the lateral and central regions of the neck were significantly different from the normal lymph nodes. Besides, the indicators including sensitivity, specificity, accuracy, positive predictive value and negative predictive value of intraoperative ultrasound for detecting lateral and central lymph nodes were 89.04% vs. 82.98%, 93.83% vs. 80.00%, 90.97% vs. 81.10%, 92.86% vs. 70.91%, and 90.48% vs. 88.89%, respectively. The pathological features of metastatic lymph nodes were shown as follows: group A, diffuse distribution of follicular structure; group C, focal distribution of follicular structure; group B and E, atypical follicular epithelial cells with or without papillary structure. Necrosis and liquefaction were observed in group D.

Conclusions

The relationship between sonographic features and follicular structure of metastatic lymph nodes are firmly related. A correct understanding of these features is practical to improve the diagnostic rate of conventional ultrasonography and reduce the incidences of misdiagnosis.

Correlations of neck ultrasound and pathology in cervical lymph node of papillary thyroid carcinoma

Background: High-resolution sonography is becoming a method of choice for the detection and diagnosis of cervical lymph node metastasis in patients with papillary thyroid carcinoma (PTC). The purpose of this study is to assess the diagnostic accuracy of neck ultrasound (US) in the detection of lymph node metastases from PTC.Methods: Data for all patients with papillary thyroid cancers and preoperative neck US were reviewed retrospectively. The diagnostic accuracy of US was determined according to whether histologically confirmed cancer was present in surgical cervical lymph node specimens.Results: A total of 206 patients (149 central and 57 central and lateral lymph nodes dissection) were included. Their mean age was 56 years (14-88 years). Central and lateral lymph nodes were involved in 68% (n = 141 patients; 141/206) and 60% (n = 34 patients; 34/57) of cases, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of US in predicting papillary thyroid carcinoma (PTC) metastasis in the central neck were 69%, 71%, 84% and 51% respectively, and in the lateral neck were 85%, 65%, 78% and 75% respectively.Conclusions: Preoperative neck US is a valuable tool in the detection of cervical lymph node metastases from papillary thyroid cancer and can provide reliable information to assist in surgical management.

Prevalence, Risk Factors And Location Of Skip Metastasis In Papillary Thyroid Carcinoma: A Systematic Review And Meta-Analysis

Background

Skip metastasis is a special type in cervical lymph node metastasis (LNM) of patients diagnosed with papillary thyroid carcinoma (PTC) which induced poor prognosis. There are few studies about skip metastasis and conclusions remained uncertain. Therefore, this study aims to explore the frequency and to investigate risk factors of skip metastasis in PTC.

Methods

Through searching the keyword by PubMed and Embase databases which articles published up to 1^st August 2018 about skip metastasis in papillary thyroid carcinoma, we extract data in order to assure whether those materials meet the criteria.

Results

The prevalence of skip metastasis is 12.02% in light of our meta-analysis of 18 studies with 2165 patients. The upper pole location (RR = 3.35, 95% CI =1.65-6.79, P = 0.0008) and tumors size ≤1 cm (RR = 2.65, 95% CI =1.50-4.70, P = 0.0008) are significantly associated with skip metastasis, whereas lymphovascular invasion (RR = 0.33, 95% CI =0.15-0.75, P = 0.0083) exists lower rate of skip metastasis. Multifocality, gender, age, bilaterality, thyroiditis and Extrathyroidal extension (ETE) are insignificantly associated with skip metastasis. Level II and level III are the most frequently affected areas.

Conclusion

The lateral compartment should be carefully examined especially for those PTC patients who present primary tumors in the upper lobe with a primary tumor size ≤10 mm which could be detected with skip metastasis.

Percutaneous Laser Ablation of Unifocal Papillary Thyroid Microcarcinoma: Utility of Conventional Ultrasound and Contrast-Enhanced Ultrasound in Assessing Local Therapeutic Response

PURPOSE

To investigate the use of conventional ultrasound and contrast-enhanced ultrasound (CEUS) in assessing local therapeutic response of percutaneous laser ablation (PLA) for papillary thyroid microcarcinoma (PTMC).

METHODS

Sixty-four patients with 64 PTMCs who were referred to our hospital from November 2013 to July 2016 were treated with PLA. The extent of ablation was assessed by CEUS at 10-20 min and 7 days after PLA. The size and volume of the ablation zone were evaluated on conventional ultrasound at 1 h, 1, 3, 6 and 12 months, and every half-year thereafter, and recurrences were also recorded. Ultrasound-guided fine needle aspiration biopsy (FNAB) of the ablated area was performed at 1, 6 and 12 months after PLA.

RESULTS

Two incomplete ablations were detected by CEUS, and a second ablation was performed. The mean largest diameter and volume of the ablated area on CEUS at 10-20 min and 7 days after PLA were significantly larger than those of pre-treatment on conventional ultrasound (p < 0.05, for both). At the last follow-up, the mean largest diameter was reduced from 4.6 ± 1.5 to 0.6 ± 1.3 mm (p < 0.0.5), and the average volume was 41.0 ± 40.4 mm³, which decreased to 1.8 ± 6.7 mm³ (p < 0.0.5). A cervical metastatic lymph node was detected on ultrasound and confirmed by ultrasound-guided FNAB at 30 months after PLA.

CONCLUSIONS

CEUS could play a crucial role in assessing the completeness of PLA for treating PTMC, and conventional ultrasound can not only guide the FNAB process but also is important in the follow-up of PTMC after PLA.

Diagnostic accuracy of ultrasonographic features for lymph node metastasis in papillary thyroid microcarcinoma: a single-center retrospective study

Background

Whether sonography is an appropriate imaging modality for cervical lymph nodes in patients with papillary thyroid microcarcinoma (PTMC) remains unclear. Hence, this study aimed to evaluate the diagnostic value of ultrasonography (US) features for lymph node metastasis in PTMC.

Methods

Seven hundred twelve patients with PTMC who underwent conventional ultrasonography examinations of the cervical lymph nodes were included. All included cases underwent total thyroidectomy plus prophylactic central lymph node dissection. The included lymph nodes were marked superficially, and the corresponding lymph nodes were completely removed and sent for pathological examination. The US features of lymph nodes with and without metastasis were compared, and the odds ratios of the suspicious US features were determined with univariate and multivariate analyses.

Results

Round shape, loss of an echogenic fatty hilum, cystic change, calcification, and abnormal vascularity were significantly more common in metastatic than nonmetastatic lymph nodes, whereas the boundary and echo did not significantly differ. Multivariate logistic regression analysis showed that round shape, loss of echogenic fatty hilum, cystic change, calcification, and abnormal vascularity were independent predictive factors for the assessment of metastatic lymph nodes. Round shape had the highest sensitivity of all variables, while loss of an echogenic fatty hilum had the highest specificity and accuracy. The area under the receiver operating characteristic curve, which was calculated to verify the relationship between the various US features and metastatic lymph nodes, was 0.793.

Conclusions

Our study found that the US features of round shape, cystic change, calcification, loss of echogenic fatty hilum, and abnormal vascularity were useful sonographic criteria for differentiating between cervical lymph nodes with and without metastasis.

The relevance of preoperative ultrasound cervical mapping in patients with thyroid cancer

BACKGROUND

Cervical lymph node involvement in thyroid cancer is associated with locoregional recurrence and decreased disease-free survival. Preoperative lymph node mapping helps in planning surgery for neck dissection and improves patient outcomes. We sought to perform a qualitative and quantitative analysis of ultrasound mapping for thyroid cancer and evaluate the clinical importance of this exam in terms of identifying the group of patients who would benefit most from subsequent surgical dissection.

METHODS

We retrospectively reviewed the cases of 263 patients who underwent thyroid surgery between 2009 and 2013. We calculated the positive predictive values (PPVs) of ultrasound mapping of both the lateral and central compartments together and the lateral or central compartment individually. A quantitative analysis was performed by comparing the number of positive lymph nodes at ultrasound imaging with histopathologic evaluation.

RESULTS

A total of 136 cases of thyroid cancer in 120 patients met the inclusion criteria for ultrasound mapping analysis. The PPVs (and 95% confidence intervals) were 83.82 (0.76-0.89) for the lateral and central compartments, 85.39% (0.76-0.91) for the lateral compartment, and 80.48% (0.7-0.87) for the central compartment. When comparing the positive lymph nodes at ultrasound imaging with histopathologic evaluation, the result was χ(2) = 10.33 (p = 0.006).

CONCLUSION

This single-institution study indicated that preoperative ultrasound mapping is an accurate imaging procedure for predicting lymphatic spread in differentiated and medullary thyroid cancer. Ultrasound mapping can be used as an efficient tool for surgical planning and prognosis determination, as well as for identifying the group of patients who would benefit most from subsequent surgical intervention.

Twinkling artifact on color Doppler ultrasound: an advantage or a pitfall?

The twinkling artifact (TA) or color comet-tail artifact is characterized by a rapidly changing mixture of red and blue color Doppler signals. Even though many diseases and clinical conditions have been shown to produce this artifact, its source is not clearly understood yet. The TA may provide additional information to gray-scale ultrasound findings in several clinical situations. However, there may be pitfalls to keep in mind. We must first be aware of the TA to benefit from the advantages and avoid the pitfalls. In this review, we aim to give practicing radiologists an overview of the mechanisms and clinical applications of the TA by illustrating sample cases we have encountered.

Sonographic features of primary tumor as independent predictive factors for lymph node metastasis in papillary thyroid carcinoma

PURPOSE

The aim of this research was to find the sonographic features of primary tumor as independent predictive factors for lymph node metastasis in papillary thyroid carcinoma.

METHODS/PATIENTS

To facilitate the research, 514 patients with papillary thyroid carcinoma were divided into solitary and multifocal groups. In solitary group, thyroid lesions were divided into several subgroups by size, border, margin, echogenicity, echohomogeneity, calcification, vascularization, location, stiffness and Hashimoto's thyroiditis (HT) conditions. Then, univariable and multivariable analyses were performed to find the sonographic features of primary tumor as independent predictive factors for lymph node metastasis in papillary thyroid carcinoma.

RESULTS

A significant difference of lymph node metastasis rate was found between multifocal and solitary groups (P < 0.05). In univariable analysis, size, vascularization and coexistence of HT were found to be statistically significant factors (P = 0.004, 0.118, 0.016). Multivariable analysis revealed that lymph node metastasis rate was mainly associated with size [odds ratio (OR) = 1.690, 95 % confidence interval (CI) 1.157-2.469] and coexistence of HT (OR = 0.441, 95 % CI 0.219-0.888).

CONCLUSION

Preoperative sonographic features of primary tumor including the number, size and coexistence of HT were independent predictive factors for the state of cervical lymph node metastasis in patients with papillary thyroid carcinoma.

Preoperative localization of neck recurrences from thyroid cancer: charcoal tattooing under ultrasound guidance

BACKGROUND

Reoperation for thyroid cancer recurrence is a surgical challenge in previously dissected necks, and there is a need for a reliable procedure for surgeon guidance. In this study, the usefulness of preoperative charcoal tattooing for surgical guidance was evaluated.

METHODS

From July 2007 to May 2010, 53 patients (40 females; Mage=44 years, range 19-76 years) were prospectively included for preoperative localization of neck recurrences from differentiated (n=46) or medullary thyroid cancer (n=7). Preoperative cytological assessment was performed for at least one lesion in each patient. Ultrasound (US) imaging was performed with high-frequency probes (8-14 Mhz). Micronized peat charcoal (0.5-3 mL) was injected under US guidance using a 25 gauge needle, 0-15 days preoperatively.

RESULTS

A total of 106 lesions were selected for charcoal tattooing. Of these, 101 had been tattooed, and 102 were removed (85 metastases, 17 benign on pathology). The tolerance of charcoal injection was good in all but three patients. A mean volume of 1 mL of charcoal was injected with a mean of two targets per patient. Charcoal labeling facilitated intraoperative detection in 56 "difficult" lesions (i.e., small size, dense fibrosis, anatomical pitfalls), and charcoal trace facilitated intraoperative guidance in 17 lesions. Feasibility and usefulness rates were 83% and 70.7% respectively.

CONCLUSION

These findings suggest that charcoal tattooing under US guidance is an easy to implement, safe, and useful procedure for surgeon guidance in neck reoperation for thyroid cancer.

Ultrasonography of various thyroid diseases in children and adolescents: a pictorial essay

Thyroid imaging is indicated to evaluate congenital hypothyroidism during newborn screening or in cases of a palpable thyroid mass in children and adolescents. This pictorial essay reviews the ultrasonography (US) of thyroid diseases in children and adolescents, including normal thyroid gland development, imaging features of congenital thyroid disorders (dysgenesis, [aplasia, ectopy, hypoplasia], dyshormonogenesis, transient hypothyroidism, thyroglossal duct cyst), diffuse thyroid disease (Grave's disease, Hashimoto's thyroiditis, and suppurative thyroiditis), and thyroid nodules. The primary imaging modalities for evaluating thyroid diseases are US and radionuclide scintigraphy. Additionally, US can be used to guide aspiration of detected nodules.