Papillary thyroid carcinoma (PTC) is the most common pathological type of thyroid cancer,accounting for 90%.Most cases of PTC are inert tumors,while a few are invasive.Cervical lymph node metastasis is one of the major manifestations of invasive PTC.Preoperative accurate prediction of cervical lymph node metastasis is of great significance for the selection of therapeutic regimen and the evaluation of prognosis.New ultrasound technology is a non-invasive,convenient,and radiation-free examination method,playing a key role in predicting the cervical lymph node metastasis of PTC.This paper reviews the research status and makes an outlook on new ultrasound technology in predicting cervical lymph node metastasis of PTC.

Objective To establish a nomogram for predicting the risk of cervical lymph node metastasis in differentiated thyroid carcinoma (DTC). Methods The patients with complete clinical data of DTC and cervical lymph node ultrasound and diagnosed based on pathological evidence from January 2019 to December 2021 were assigned into a training group (n=444) and a validation group (n=125).Lasso regression was performed to screen the data with differences between groups,and multivariate Logistic regression to establish a prediction model with the factors screened out by Lasso regression.C-index and calibration chart were employed to evaluate the prediction performance of the established model. Results The predictive factors for establishing the model were lymph node short diameter≥0.5 cm,long-to-short-axis ratio<2,disappearance of lymph node hilum,cystic transformation,hyperechogenicity,calcification,and abnormal blood flow (all P<0.001).The established model demonstrated a good discriminative ability,with the C index of 0.938 (95%CI=0.926-0.961) in the training group. Conclusion The nomogram established based on the ultrasound image features of cervical lymph nodes in DTC can accurately predict the risk of cervical lymph node metastasis in DTC.

Objective To evaluate extrathyroidal extension (ETE) in papillary thyroid microcarcinoma (PTMC) with three-dimensional tomographic ultrasound imaging (3D-TUI). Methods A total of 97 thyroid nodules of 79 patients with PTMC treated in PUMC Hospital from February 2016 to January 2018 were included in this study.Two ultrasound experts performed independent blinded assessment of the relationship between thyroid nodules and thyroid capsule by two-dimensional ultrasound (2D-US) and 3D-TUI.The results of 2D-US and 3D-TUI in evaluating ETE were compared with intraoperative findings and postoperative histological and pathological results. Results Among the 97 nodules,54 (55.7%) nodules had ETE.The diagnostic sensitivity (68.5% vs.37.0%;χ²=10.737,P=0.002),accuracy (74.5% vs.56.7%;χ²=6.686,P=0.015),and area under the receiver operating characteristic curve[0.761 (95%CI=0.677-0.845) vs.0.592 (95%CI=0.504-0.680);Z=3.500,P<0.001] of 3D-TUI were higher than those of 2D-US.However,3D-TUI and 2D-US showed no significant difference in the specificity (84.1% vs.81.4%;χ²=0.081,P=0.776),negative predictive value (67.9% vs.50.7%;χ²=3.645,P=0.066),or positive predictive value (84.1% vs.71.4%;χ²=1.663,P=0.240). Conclusion Compared with 2D-US,3D-TUI demonstrates increased diagnostic efficiency for ETE of PTMC.

Objective To investigate the influencing factors and establish a model predicting the performance of needle visualization in fine-needle aspiration (FNA) of thyroid nodules. Methods This study prospectively included 175 patients who underwent FNA of thyroid nodules in the Department of Ultrasound in China-Japan Friendship Hospital and compared the display of the needle tips in the examination of 199 thyroid nodules before and after the application of needle visualization.We recorded the location,the positional relationship with thyroid capsule,ultrasonic characteristics,and the distribution of the soft tissue strip structure at the puncture site of the nodules with unclear needle tips display before using needle visualization.Furthermore,according to the thyroid imaging reporting and data system proposed by the American College of Radiology,we graded the risk of the nodules.Lasso-Logistic regression was employed to screen out the factors influencing the performance of needle visualization and establish a nomogram for prediction. Results The needle tips were not clearly displayed in the examination of 135 (67.8%) and 53 (26.6%) nodules before and after the application of needle visualization,respectively,which showed a significant difference (P<0.001).Based on the positional relationship between the nodule and capsule,anteroposterior/transverse diameter (A/T) ratio,blood supply,and the distribution of subcutaneous strip structure at the puncture site,a nomogram was established to predict the probability of unclear display of the needle tips after application of needle visualization.The C-index of the prediction model was 0.75 (95%CI=0.67-0.84) and the area under the receiver operating characteristic curve was 0.72.The calibration curve confirmed the appreciable reliability of the prediction model,with the C-index of 0.70 in internal validation. Conclusions Needle visualization can improve the display of the needle tip in ultrasound-guided FNA of thyroid nodules.The nomogram established based on ultrasound features such as the positional relationship between the nodule and capsule,A/T ratio,blood supply,and the distribution of subcutaneous strip structure at the puncture site can predict whether needle visualization is suitable for the examination of nodules.

Objective To evaluate the performance of micro-flow imaging(MFI)in the differential diagnosis of benign and malignant thyroid nodules. Methods Totally 50 patients with thyroid nodules examined by conventional ultrasound,MFI,and contrast-enhanced ultrasound and confirmed by histological or cytological pathology in the First Medical Center of Chinese PLA General Hospital from May to December in 2020 were enrolled in the study.The clinical data and ultrasound images were retrospectively analyzed.A binary logistic regression model was established to evaluate the performance of the model in predicting benign and malignant thyroid nodules. Results Logistic regression showed that composition and “S-W-C” sign were independent risk factors for predicting malignant thyroid nodule.The sensitivity,specificity,and Youden index of the logistic regression model were 73.33%,80.00%,and 0.53,respectively,and the area under receiver operating characteristic curve was 0.799(95%CI=0.662-0.899). Conclusion MFI facilitates the differential diagnosis of benign and malignant thyroid nodules and has the potential to be applied in the future.

Objective To explore the roles of conventional ultrasound and contrast-enhanced ultrasound in distinguishing between benign and malignant thyroid nodules with calcification. Methods A total of 102 solid thyroid nodules with calcification in 76 patients were evaluated by conventional ultrasound alone and conventional ultrasound combined with contrast-enhanced ultrasound.The features obtained through conventional ultrasound alone and that combined with contrast-enhanced ultrasound were scored,and the diagnostic performance of the two methods was analyzed based on the final pathological results. Results The distribution of microcalcification(P<0.0001),aspect ratio>1(P=0.039),unclear boundary(P=0.027),ring enhancement around nodules(P=0.000),and the degree(P=0.000)and uniformity(P=0.001)of enhancement for the non-calcified part were statistically different between benign and malignant nodules.Compared with conventional ultrasound alone,conventional ultrasound combined with contrast-enhanced ultrasound significantly improved the area under the curve(0.841 vs.0.701,P<0.001)and specificity(97.06% vs. 44.12%,P=0.007),without significant change in sensitivity(67.55% vs. 73.53%,P=0.727). Conclusions The combination with contrast-enhanced ultrasound can improve the performance of conventional ultrasound in the differential diagnosis of benign and malignant thyroid solid nodules with calcification.Eight malignant signs include solid,hypoechoic,microcalcification,aspect ratio,and blurred edges detected by conventional ultrasound,and non-circular enhancement around nodules,low enhancement and non-uniform enhancement of solid parts detected by contrast-enhanced ultrasound.A solid thyroid nodule with calcification presenting five or more malignant signs highly suggests malignancy.

Objective To establish an artificial intelligence model based on B-mode thyroid ultrasound images to predict central compartment lymph node metastasis(CLNM)in patients with papillary thyroid carcinoma(PTC). Methods We retrieved the clinical manifestations and ultrasound images of the tumors in 309 patients with surgical histologically confirmed PTC and treated in the First Medical Center of PLA General Hospital from January to December in 2018.The datasets were split into the training set and the test set.We established a deep learning-based computer-aided model for the diagnosis of CLNM in patients with PTC and then evaluated the diagnosis performance of this model with the test set. Result The accuracy,sensitivity,specificity,and area under receiver operating characteristic curve of our model for predicting CLNM were 80%,76%,83%,and 0.794,respectively. Conclusion Deep learning-based radiomics can be applied in predicting CLNM in patients with PTC and provide a basis for therapeutic regimen selection in clinical practice.

Objective To investigate the clinical value of core-needle biopsy(CNB)for low-risk papillary thyroid microcarcinoma(PTMC)after radiofrequency ablation(RFA). Methods A total of 190 patients(including 142 females and 48 males,20-74 years old)with unifocal low-risk PTMCs[mean volume of(106.29±96.15)mm³]treated by RFA from June 2016 to September 2018 were evaluated in this study.During the RFA procedure,enlarged ablation was performed.Patients were followed up 1,3,6,12 months after RFA and every 6 months thereafter.The volume of ablation area and the volume reduction ratio(VRR)were calculated.To evaluate the ablation performance,CNB was performed to the central zone,the peripheral zone,and surrounding thyroid parenchyma 3 or 6 months after RFA. Results The mean follow-up time was(30.04±12.41)months.The mean volume of tumor significantly decreased from(106.29±96.15)mm³ to(1.47±8.00)mm³.Two ablated tumors were diagnosed to have residue by CNB and underwent additional RFA.No recurrence,metastatic lymph nodes,or distal metastasis were found during the follow-up.All the patients were tolerable to RFA and CNB procedure. Conclusion CNB can be used to evaluate the ablation performance after RFA for low-risk PTMC.

Objective To establish a prediction model for the short-term efficacy of percutaneous ultrasound-guided radiofrequency ablation(RFA)in the treatment of papillary thyroid microcarcinoma(PTMC). Methods We retrospectively analyzed the preoperative and follow-up data of 159 patients with PTMC who underwent percutaneous ultrasound-guided RFA treatment in the Department of Ultrasound,the First Medical Center of Chinese PLA General Hospital from January to December in 2018.The association with 12-month tumor status(end event)was evaluated by multivariate logistic regression model.A nomogram was built to predict the risk of tumors which did not disappear completely within 12 months after RFA. Results We found that gender(P=0.017),age(P=0.047),and calcification(P=0.049)were the strongest predictors for establishing the model.The tumor maximum diameter and RFA energy were the secondary relevant factors for establishing the model.The constructed model showed good performance in both training cohort(AUC=0.762)and validation cohort(AUC=0.740). Conclusion A quantitative model was established for predicting the tumor status within one year after treatment of PTMC by RFA,which can accurately predict the short-term efficacy of RFA and provide a clinical basis for explaining the recovery results of patients.

Objective To compare the health-related quality of life(HRQoL)of patients with papillary thyroid microcarcinoma(PTMC)treated by different modalities. Methods The PTMC patients after treatment who came to our department for follow-up from October to December in 2019 were enrolled and assigned into three groups according to treatment modalities:radiofrequency ablation(RFA)group(n=80), hemithyroidectomy(HT)group(n=34), and total thyroidectomy(TT)group(n=35).All patients completed three scales:short form 36-item health survey(SF-36), thyroid cancer-specific health-related quality of life questionnaire(THYCA-QoL), and fear of progression questionnaire-short form(FoP-Q-SF).Multivariate linear regression analysis was employed to adjust for confounders and the quality of life scores were compared among the three treatment modalities. Results In the SF-36, physical component summary(PCS)(P=0.006, P=0.033)and role-physical(RP)(P=0.003, P=0.001)scores of patients in the RFA and HT groups were significantly higher than those in the TT group, whereas PCS(P=1.000)and RP(P=1.000)showed no significant difference between the RFA group and the HT group.In addition, the mental component summary(MCS)score in RFA group was higher than that in TT group(P=0.034).The THYCA-QoL demonstrated that the patients in TT group complained more about scar than the patients in HT(P=0.003)and RFA(P<0.001)groups, and the patients in the RFA group complained less about weight gain than those in the HT(P=0.028)and TT(P<0.001)groups.In the FoP-Q-SF, the scores of the quality of life of patients concerned about disease progression had no significant difference among the three groups(P> 0.05).Conclusion Compared with traditional open surgery, ultrasound-guided RFA has unique advantages in improving patients’ quality of life and can be used as an alternative to open surgery for PTMC.

Objective To explore the value of trans-lymphatic contrast-enhanced ultrasound(CEUS)in the diagnosis of cervical lymph node metastasis of thyroid cancer. Methods The patients with suspected thyroid cancer underwent conventional ultrasound and trans-lymphatic CEUS examinations before the biopsy.The differences in ultrasound and CEUS characteristics of cervical lymph nodes between the metastatic group and the non-metastatic group were compared,and pathological results were regarded as the golden standard. Results Twenty patients had thyroid cancer,including 12 cases with lymph node metastasis and 8 cases without metastasis.The diagnostic sensitivity(91.7% vs. 75.0%)and accuracy(90.0% vs.80.0%)of trans-lymphatic CEUS were higher than those of conventional ultrasound.The normal lymph nodes presented homogeneous enhancement,while the metastatic lymph nodes showed heterogeneous or non-enhancement during the trans-lymphatic CEUS examination.Conclusion As a new modality of ultrasound,trans-lymphatic CEUS contributes to the diagnosis of cervical lymph node metastasis of thyroid cancer and supplements the deficiencies of conventional ultrasound.

Objective To explore the association between contrast-enhanced ultrasound and risk of tumor recurrence in papillary thyroid carcinoma(PTC). Methods A total of 287 PTCs in 287 patients who underwent surgery,conventional ultrasound,and contrast-enhanced ultrasound(CEUS)were enrolled in this study.According to 2015 American Thyroid Association(ATA)Modified Initial Risk Stratification System,the patients were categorized into three groups:low risk,intermediate risk,and high risk.The CEUS patterns of PTCs were compared between different risk stratifications. Results Hypo-enhancement was presented in 57.6% of ATA low-risk PTCs,iso-enhancement in 62.3% of ATA intermediate-risk PTCs,and hyper-enhancement in 48.2% of ATA high-risk PTCs(P<0.0001).The risk stratifications and enhanced intensity in PTC showcased a positive correlation(Spearman’s rho of 0.442,P<0.0001)and a linear trend(χ ² value of 55.921,P<0.0001).Higher enhancement intensity corresponded to higher risk stratification.Ordinal logistic regression analysis indicated that PTCs with hyper-enhancement and iso-enhancement presented higher risks than those with hypo-enhancement after age and gender were adjusted,and theOR values were 17.5(8.4-36.2)and 3.4(2.0-5.8),respectively. Conclusions CEUS patterns correlate intimately with the recurrence risk in PTC.Hyper-enhancement PTCs tend to present high risks,while hypo-enhancement PTCs tend to present low risks of recurrence.

Objective To evaluate the diagnostic value of contrast-enhanced ultrasound(CEUS)in thyroid extrathyroidal extension(ETE)of papillary thyroid carcinoma(PTC).Methods Totally 172 PTC patients(184 thyroid nodules)were examined by conventional ultrasound(US)and CEUS before operation.Sonographic features of thyroid nodules and the relationship between nodules and thyroid capsule were retrospectively evaluated.The diagnostic efficacy of these two methods for ETE was compared,and the effect of nodule enhancement level on the diagnosis of ETE was analyzed.Results The sensitivity,specificity,and accuracy of CEUS were 78.9%,89.4% and 84.2% in diagnosing ETE,while those of US were 60.0%,86.2%,and 73.4%,respectively.Among them,the sensitivity(P=0.000)and accuracy(P=0.009)of CEUS in diagnosing ETE were significantly higher than those of US,but there was no statistically significant difference in specificity(P=0.375).The area under the receiver operator characteristic curve of CEUS(0.84)was significantly larger than that of US(0.73)(Z=2.24,P=0.01).The diagnostic value of CEUS in ETE was related to the enhancement level of nodules.The sensitivity,specificity,and accuracy of CEUS in the diagnosis of ETE were highest in hypo-enhanced nodules,followed by hyper-enhanced nodules and the iso-enhanced nodules.Conclusion CEUS has higher performance than US in detecting ETC of PTC.

Objective To establish a predictive model for central compartment lymph node metastasis (CLNM) in patients with papillary thyroid carcinoma (PTC).Methods We retrospectively evaluated patients with histologically confirmed PTC treated in Chinese PLA General Hospital between January 2018 and January 2019.Totally 855 patients undergoing thyroidectomy with central lymph node dissection were enrolled in this study (577 in the training cohort and 278 in the validation cohort).The clinical manifestations of the patients and the ultrasound features of the tumors were recorded.To predict the probability of CLNM,we developed the clinical-ultrasound model with significant factors selected by the stepwise logistic regression.The Akaike Information Criterion (AIC) was use to select the optimal model,and the area under the curve (AUC) and the calibration curves were used to evaluate the performance of the prediction model.Results Multivariate analysis showed that sex (P<0.001),age 45-55 years (P=0.004) or ≥55 years (P=0.003),tumor size 1-2 cm (P<0.001) or >2 cm (P=0.008),multifocality (P=0.029),microcalcification (P=0.019),diffused distribution of microcalcifications (P=0.001),and vascularity levels 2-3 (P=0.002) were effective for CLNM prediction.The model based on the clinical and ultrasound features showed good performance in both training cohort with AUC of 0.78 (95%CI:0.74-0.82) and validation cohort with AUC of 0.70 (95%CI:0.67-0.76).Conclusions A quantitative model of CLNM in PTC patients was established based on the risk factors.According to the model,central lymph node dissection is recommended for PTC patients with high scores.