Differentiated Thyroid Cancer after Thyroidectomy.

The widespread use of neck US and other imaging modalities has contributed to a phenomenon of increased detection of differentiated thyroid cancer (DTC). Most of these cancers remain indolent, without requiring surgical intervention. Nonetheless, a subset of patients who require surgical treatment experience subsequent disease recurrence. This most commonly occurs in the cervical lymph nodes and thyroid bed, followed by distant metastasis to the lungs and bones. Because imaging is an integral part of postoperative surveillance, radiologists play a central role in the detection of recurrent tumors and in guiding treatment in these patients. US is the primary imaging modality used for postoperative evaluation. Other modalities such as CT, MRI, radioactive iodine imaging, and PET/CT aid in the accurate diagnosis and characterization of recurrent disease. Therefore, radiologists must have a thorough understanding of the utility of these imaging techniques and the imaging characteristics of recurrent DTC when interpreting these multimodality studies. The interpretation of imaging findings should also be correlated with the clinical status of patients and their biochemical markers to minimize interpretative errors. The authors present a broad overview of the postoperative evaluation of DTC, including its initial primary management, staging, and prognostication; clinical risk stratification for recurrent disease; postoperative surveillance with imaging and evaluation of biochemical markers; and management of recurrent DTC. Published under a CC BY 4.0 license. Supplemental material is available for this article.

Clinical, ultrasound and anatomopathological concordance of thyroid nodules in Kinshasa: a cross-sectional study.

BACKGROUND: The European Thyroid Association Thyroid Imaging Data and Reporting Systems (EU-TIRADS) is widely used in the risk stratification of thyroid nodule malignancy. However, data on the subject in Sub-Saharan Africa are limited. The objective of this study is to evaluate the clinical, sonographic and histopathological concordance of thyroid nodules in the diagnosis of thyroid cancer. METHODS: This was an analytical cross-sectional study that examined the clinical, ultrasound and pathological data of 61 patients from 4 hospitals in the city province of Kinshasa over a period of 24 months, from June 01, 2020 to May 31, 2022. RESULTS: Of the 61 patients, their mean age was 47.38 ± 8.8 years. The mean clinical score of the patients was 3.4 ± 0.84 with the extremes ranging from 1 to 5. The majority of the patients were classified as having an intermediate risk, ie 85.2% of the cases. It was noted that 41% of the nodules had a high risk according to the EU-TIRADS score and 8.2% of the nodules were malignant after histopathological analysis. The ROC curves reported at the diagnosis of malignancy show an area under the curve of 0.709 with 95% CI (0.486-0.931), a Youden index of 0.769 for the clinical score, and an area under the curve of 0.830 with 95% CI (0.605-0.995), a Youden index of 0.772 for the EU-TIRADS score. CONCLUSION: In a low-income country, a well-performed thyroid ultrasound and the well-applied clinical score could be an important tool in the selection of thyroid nodules suspected of malignancy and requiring histopathological examination to avoid excessive acts in the patient.

Risk of malignancy in thyroid nodules with increased 11C-Choline uptake detected incidentally on PET/CT: A diagnostic accuracy study.

PURPOSE: The purpose was to evaluate the pathological nature of focal thyroid uptake seen in 11C-Choline PET/CT performed for prostate cancer. MATERIAL AND METHODS: The study was IRB-approved. All 11C-Choline PET/CT exam reports for studies performed between January 01, 2018, and July 30, 2021, in male patients with prostate cancer in our institution were retrospectively reviewed. Exams with "focal thyroid uptake" on their final report were selected. Patients with surgery or ablation in the thyroid prior to the PET/CT, proven parathyroid adenomas or absent thyroid ultrasound were excluded. Repeated PET/CT exams of same patient were excluded. PET images were analyzed visually and semi-quantitatively by measuring the maximum standardized uptake value (SUVmax) of the focal thyroid uptake. Available thyroid ultrasound images, cytology and pathology reports were reviewed. Statistical analyses were performed. RESULTS: Out of 10,047 sequential 11C-Choline PET/CT studies, 318 reports included "focal thyroid uptake." About 128 of these studies were repeat exams and were excluded. Additional 87 patients were excluded, because the uptake was determined to be adjacent, rather than confined to the thyroid gland. Out of the remaining 103 patients, 74 patients had focal thyroid uptake and concurrent thyroid sonographic evaluation. Out of the 74 focal uptakes evaluated with ultrasound, 21 were presumed benign thyroid nodules based on the ultrasound and 53 had further evaluation with biopsy. Sixty three nodules were benign (21 presumed benign on ultrasound and 42 cytology or surgical pathology-proven), 9 nodules were malignant and 2 remained indeterminate. There was no significant difference between the SUVs of the benign and malignant groups (P > .3). CONCLUSION: In this retrospective study of patients with prostate cancer who underwent 11C-Choline PET/CT, we identified a group of patients who underwent thyroid ultrasound for incidental finding of focal 11C-Choline thyroid uptake. Incidence of malignancy in this group was 12%. Therefore, further investigation with ultrasound and possibly ultrasound-guided biopsy may be warranted when a choline avid thyroid nodule is found incidentally on choline PET.

Echotexture of recurrent laryngeal nerves: the depiction of recurrent laryngeal nerves at high-frequency ultrasound during radical thyroidectomy.

Introduction: To investigate the ultrasound characteristics of recurrent laryngeal nerves (RLNs) during radical surgery for thyroid cancer and to enhance the understanding of RLN ultrasound features. Methods: From October 2021 to December 2022, a prospective study was conducted involving 24 patients scheduled for bilateral thyroid surgery. Near the conclusion of the surgery, intraoperative ultrasonography of the RLN within the tracheoesophageal groove was performed using a 15-7 MHz transducer. The thickness and width of the RLN were measured during the procedure. Results: The internal architecture of the RLN was observed to consist of multiple hypoechoic, parallel, but discontinuous linear hyperechoic areas separated by bands. In the normal RLN group, the diameter of the RLN was relatively consistent, with thickness ranging from 2.20 to 2.71 mm (mean: 2.48 ± 0.14 mm) and width from 1.25 to 1.70 mm (mean: 1.45 ± 0.11 mm). Both weight and the body mass index (BMI) showed a statistically significant correlation with RLN thickness (Weight: r=0.544, P=0.001; BMI: r=0.605, P=0.001). The BMI also showed a statistically significant correlation with the RLN width (r=0.377, P=0.033). In the RLN invasion group, the width of invaded RLNs ranged from 1.9 to 2.3 mm (mean: 2.10 ± 0.11 mm), while the width of non-invaded RLNs ranged from 2.6 to 3.2 mm (mean: 2.93 ± 0.20 mm). Conclusions: Ultrasound effectively reveals the structural features of the RLN and enhances sonographers' understanding of RLN characteristics.

Risk Stratification of Thyroid Nodules Diagnosed as Bethesda Category III by Ultrasound, Size, and Cytology.

OBJECTIVE: This study aimed to evaluate the performance of an integrated risk stratification system (RSS) based on ultrasound (US) RSSs, nodule size, and cytology subcategory for diagnosing malignancy in thyroid nodules initially identified as Bethesda category III on fine-needle aspiration. MATERIALS AND METHODS: This retrospective study was conducted at two institutions and included consecutive patients with Bethesda category III nodules, and final diagnoses confirmed by repeat biopsy or surgery. A total of 320 Bethesda category III nodules (≥1 cm) from 309 patients (223 female and 86 male; mean age, 50.9 ± 12.0 years) were included. The malignancy risk of Bethesda category III nodules and predictors of malignancy were assessed according to US RSSs, nodule size, and cytology subcategory. The diagnostic performances of US-size cytology (USC) RSS and US RSS alone for malignancy were compared. RESULTS: The intermediate or high suspicion US category independently increased the malignancy risk in all US RSSs (P ≤ 0.001). Large nodule size (≥3 cm) independently increased the malignancy risk of low- or intermediate suspicion US category nodules. Additionally, the atypia of undetermined significance cytology subcategory independently increased the malignancy risk of low suspicion US category nodules in most US RSSs. The area under the receiver operating characteristic curve of the USC RSSs was greater than that of the US RSSs alone (P < 0.048). Malignancy was not found in the very low risk category of USC RSS. CONCLUSION: The diagnostic performance of USC RSS for malignancy was superior to that of US RSS alone in Bethesda category III nodules. Malignancy can be ruled out in the very low-risk category of USC RSS.

Hybrid Somatostatin Receptor PET/MRI of the Head and Neck.

Hybrid PET/MRI has the potential to transform neuro-oncologic imaging, particularly in diagnosis and treatment planning of somatostatin receptor-expressing tumors of the head and neck. Hybrid PET/MRI combines high-resolution MRI with functional information from PET, providing precise anatomic information and overcoming difficulties in localization inherent to PET alone. There is a range of tumors in the head and neck that overexpress somatostatin receptors and are therefore amenable to evaluation with somatostatin receptor PET/MRI. These include meningiomas, paragangliomas, olfactory neuroblastomas, pituitary neuroendocrine tumors, middle ear neuroendocrine tumors, and medullary thyroid carcinomas. The combination of PET and MRI is superior to either modality alone and can address several unique diagnostic challenges associated with these lesions. The authors discuss the superior capabilities of somatostatin receptor PET/MRI, including improved lesion localization, more sensitive demonstration of disease extent, enhanced surveillance, optimized radiation therapy planning, and accurate prediction of response to somatostatin analog therapy. Although there are only a few dedicated PET/MRI units available in clinical practice, commercial software is now available that can automatically fuse PET/CT data with recently acquired MRI data, increasing the availability of this approach. Radiologists should be aware of the advantages of somatostatin receptor PET/MRI in evaluation of head and neck tumors as well as the potential pitfalls of this approach so that they can accurately advise clinicians and better interpret these studies. ©RSNA, 2024 See the invited commentary by Shatzkes and Strauss in this issue.

Single-center external validation and reconstruction of multiple predictive models for skip lateral lymph node metastasis in papillary thyroid carcinoma.

Objective: The unique metastatic pattern of skip lateral lymph node metastasis (SLLNM) in PTC patients may lead to missed diagnosis of lateral cervical metastatic lymph nodes. Therefore, many different SLLNM prediction models were constructed. In this study, partially eligible models (Hu 2020, Wang 2020, and Zhao 2023 nomograms) were selected for external validation, and then new variables were incorporated for model reconstruction to extend clinical applicability. Methods: 576 PTC patients from our center were selected to evaluate the performance of the three nomograms using the receiver operating characteristic curve (ROC), calibration curves, and decision curve analyses (DCA). Three new variables were added to calibrate the model, including assessment of LN status on ultrasound (US-SLLNM), the distance from the tumor to the capsule (Capsular distance), and the number of central lymph node dissections (CLND number). Univariate and multivariate logistic regression analyses were used to screen independent predictors to reconstruct the model, and 1000 Bootstrap internal validations were performed. Results: SLLNM were present in 69/576 patients (12.0%). In external validation, the area under the ROC curves (AUCs) for Hu 2020, Wang 2020, and Zhao 2023 nomograms were 0.695 (95% CI:0.633-0.766), 0.792 (95% CI=0.73-0.845), and 0.769 (95% CI:0.713-0.824), respectively. The calibration curves for the three models were overall poorly fitted; DCA showed some net clinical benefit. Model differentiation and net clinical benefit improved by adding three new variables. Based on multivariate analysis, female, age, and maximum tumor diameter ≤ 10 mm, located at the upper pole, Capsular distance < 0mm, US-SLLNM, CLND number ≤ 5 were identified as independent predictors of SLLNM and were used to construct the new model. After 1000 Bootstrap internal validations, the mean AUC of the model was 0.870 (95% CI:0.839-0.901), the calibration curve was close to the ideal curve, and the net clinical benefit was significant. Conclusion: Overall, these nomograms were well differentiated and provided some net clinical benefit, but with varying degrees of underestimation or overestimation of the actual risk and high false-negative rates. New dynamic nomogram was constructed based on the addition of new variables and larger samples, showing better performance.

The superior value of radiomics to sonographic assessment for ultrasound-based evaluation of extrathyroidal extension in papillary thyroid carcinoma: a retrospective study.

BACKGROUND: Extrathyroidal extension was related with worse survival for patients with papillary thyroid carcinoma. For its preoperative evaluation, we measured and compared the predicting value of sonographic method and ultrasonic radiomics method in nodules of papillary thyroid carcinoma. PATIENTS AND METHODS: Data from 337 nodules were included and divided into training group and validation group. For ultrasonic radiomics method, a best model was constructed based on clinical characteristics and ultrasonic radiomic features. The predicting value was calculated then. For sonographic method, the results were calculated using all samples. RESULTS: For ultrasonic radiomics method, we constructed 9 models and selected the extreme gradient boosting model for its highest accuracy (0.77) and area under curve (0.813) in validation group. The accuracy and area under curve of sonographic method was 0.70 and 0.569. Meanwhile. We found that the top-6 important features of xgboost model included no clinical characteristics, all of whom were high-dimensional radiomic features. CONCLUSIONS: The study showed the superior value of ultrasonic radiomics method to sonographic method for preoperative detection of extrathyroidal extension in papillary thyroid carcinoma. Furthermore, high-dimensional radiomic features were more important than clinical characteristics.

Prediction model for lateral lymph node metastasis of papillary thyroid carcinoma in children and adolescents based on ultrasound imaging and clinical features: a retrospective study.

BACKGROUND: The presence of lateral lymph node metastases (LNM) in paediatric patients with papillary thyroid cancer (PTC) is an independent risk factor for recurrence. We aimed to identify risk factors and establish a prediction model for lateral LNM before surgery in children and adolescents with PTC. METHODS: We developed a prediction model based on data obtained from 63 minors with PTC between January 2014 and June 2023. We collected and analysed clinical factors, ultrasound (US) features of the primary tumour, and pathology records of the patients. Multivariate logistic regression analysis was used to determine independent predictors and build a prediction model. We evaluated the predictive performance of risk factors and the prediction model using the area under the receiver operating characteristic (ROC) curve. We assessed the clinical usefulness of the predicting model using decision curve analysis. RESULTS: Among the minors with PTC, 21 had lateral LNM (33.3%). Logistic regression revealed that independent risk factors for lateral LNM were multifocality, tumour size, sex, and age. The area under the ROC curve for multifocality, tumour size, sex, and age was 0.62 (p = 0.049), 0.61 (p = 0.023), 0.66 (p = 0.003), and 0.58 (p = 0.013), respectively. Compared to a single risk factor, the combined predictors had a significantly higher area under the ROC curve (0.842), with a sensitivity and specificity of 71.4% and 81.0%, respectively (cutoff value = 0.524). Decision curve analysis showed that the prediction model was clinically useful, with threshold probabilities between 2% and 99%. CONCLUSIONS: The independent risk factors for lateral LNM in paediatric PTC patients were multifocality and tumour size on US imaging, as well as sex and age. Our model outperformed US imaging and clinical features alone in predicting the status of lateral LNM.

First-Generation Radiolabeled Cyclic Peptides for Molecular Imaging of Platelet-Derived Growth Factor Receptor α.

Occult nodal spread and metastatic disease require longstanding imaging and biochemical assessments for thyroid cancer, a disease that has a propensity for diffuse, small-volume disease. We have developed a 64Cu-labeled platelet-derived growth factor receptor α (PDGFRA) antibody for immuno-PET of PDGFRA in metastatic papillary thyroid cancer (PTC). The present work describes the discovery of small cyclic PDGFRA-targeting peptides, their binding features, and radiolabeling with positron emitter gallium-68 (68Ga) for in vitro and in vivo characterization in thyroid cancer models. Phage-display technology with two separate libraries and seven different cell lines was used through three rounds of biopanning as well as flow cytometry and comparative analysis with recombinant protein to select specific peptide sequences. Phenotypic binding analysis was completed by using phosphorylation and cell migration assays. In vitro protein binding was analyzed with thermophoresis and flow cytometry using the fluorescent-labeled PDGFRA peptide. Peptide candidates were modified with the NOTA chelator for radiolabeling with 68Ga. In vitro cell uptake was studied in various thyroid cancer cell lines. In vivo studies of 68Ga-labeled peptides included metabolic stability and PET imaging. From the original library (1013 compounds), five different peptide groups were identified based on biopanning experiments with and without the α subunit of PDGFR, leading to ∼50 peptides. Subsequent phenotypic screening revealed two core peptide sequences (CP16 and CP18) that demonstrated significant changes in the level of PDGFRA phosphorylation and cell migration. Alanine scan sublibraries were created from these two lead peptide sequences, and peptides were radiolabeled using 68Ga-GaCl3 at pH 4.5, resulting in RCP > 95% within 34-40 min, including SPE purification. Cyclic peptide CP18.5 showed the strongest effects on cell migration, flow cytometry, and binding by visual interference color assay. 68Ga-labeled PDGFRA-targeting peptides showed elevated cell and tumor uptake in models of thyroid cancer, with 68Ga-NOTA-CP18.5 being the lead candidate. However, metabolic stability in vivo was compromised for 68Ga-NOTA-CP18.5 vs 68Ga-NOTA-CP18 but without impacting tumor uptake or clearance profiles. First-generation radiolabeled cyclic peptides have been developed as novel radiotracers, particularly 68Ga-NOTA-CP18.5, for the molecular imaging of PDGFRA in thyroid cancer.

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Objective: To analyze the radiomic and clinical features extracted from 2D ultrasound images of thyroid tumors in patients with Hashimoto's thyroiditis (HT) combined with papillary thyroid carcinoma (PTC) using machine learning (ML) models, and to explore the diagnostic performance of the method in making preoperative noninvasive identification of cervical lymph node metastasis (LNM). Methods: A total of 528 patients with HT combined with PTC were enrolled and divided into two groups based on their pathological results of the presence or absence of LNM. The groups were subsequently designated the With LNM Group and the Without LNM Group. Three ultrasound doctors independently delineated the regions of interest and extracted radiomic features. Two modes, radiomic features and radiomics-clinical features, were used to construct random forest (RF), support vector machine (SVM), LightGBM, K-nearest neighbor (KNN), and XGBoost models. The performance of these five ML models in the two modes was evaluated by the receiver operating characteristic (ROC) curves on the test dataset, and SHapley Additive exPlanations (SHAP) was used for model visualization. Results: All five ML models showed good performance, with area under the ROC curve (AUC) ranging from 0.798 to 0.921. LightGBM and XGBoost demonstrated the best performance, outperforming the other models (P<0.05). The ML models constructed with radiomics-clinical features performed better than those constructed using only radiomic features (P<0.05). The SHAP visualization of the best-performing models indicated that the anteroposterior diameter, superoinferior diameter, original_shape_VoxelVolume, age, wavelet-LHL_firstorder_10Percentile, and left-to-right diameter had the most significant effect on the LightGBM model. On the other hand, the superoinferior diameter, anteroposterior diameter, left-to-right diameter, original_shape_VoxelVolume, original_firstorder_InterquartileRange, and age had the most significant effect on the XGBoost model. Conclusion: ML models based on radiomics and clinical features can accurately evaluate the cervical lymph node status in patients with HT combined with PTC. Among the 5 ML models, LightGBM and XGBoost demonstrate the best evaluation performance.

Real-world applicability of differentiated thyroid cancer guidelines.

OBJECTIVE: Thyroid cancer (TC) is the most common endocrine malignancy with constantly growing incidence. Radioiodine ablation is a safe and effective method for managing TC. Recently various Guidelines (GL) have been published on whom should be ablated, when and under which circumstances. Our study compares 6 GL with a given patient cohort. Additionally, we evaluated each GL's quality via an independent tool. MATERIAL AND METHODS: We compared six Guidelines (GL) for TC ablation on a cohort of 336 patients, implementing GL retrospectively: 2009 and 2016 American Thyroid Association (ATA), European Thyroid Association's (ETA) Consensus Statement, UK's National Institute for Health and Care Excellence (NICE), German position paper from Surgery and Nuclear Medicine (German) and European Association of Nuclear Medicine and Society of Nuclear Medicine and Molecular Image (EANM/SNMMI). Quality assessment was conducted using the Appraisal of Guidelines, Research and Evaluation instrument II (AGREE II). RESULTS: Results showed significant variability among GL. American Thyroid Association 2016, a clear improvement of the ATA 2009, presents a large grey area of "probable ablation candidates". European Thyroid Association and NICE agree that only a small portion of our ablated patients would benefit from it and the AGREE II tool shows a lack of applicability, but very good scores elsewhere. German and EANM/SNMMI GL agree that most of our clinical decisions to ablate were correct and their AGREE II scores are the highest in all six domains. CONCLUSION: Considering that dynamic risk classification plays a major role in determining the most appropriate treatment, it appears that the guidelines should be updated in order to support individualized patient management. However, it is the experience of the individual physician that will determine the final decision.

Comparison of ultrasound findings of papillary thyroid carcinoma subtypes based on the 2022 WHO classification of thyroid neoplasms.

Purpose: The present study aimed to analyze and compare sonographic features of papillary thyroid carcinoma (PTC) subtypes to determine whether ultrasound (US) may aid in differentiating particular subtypes. Methods: This retrospective study enrolled 133 patients diagnosed with 142 histopathologically proven PTCs as per the fifth edition of the World Health Organization classification of thyroid neoplasms between January 2013 and May 2023. US features based on the American College of Radiology and European Thyroid Imaging and Reporting Data Systems (TIRADS), and histopathological characteristics of nodules were assessed and compared. Results: Histopathological analysis yielded 55 (38.7%) classic PTC, 32 (22.5%) invasive encapsulated follicular variant (IEFV) PTC, 20 (14.1%) oncocytic subtype, 14 (9.9%) non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), 11 (7.8%) infiltrative follicular subtype, 7 (4.9%) tall cell subtype, 2 (1.4%) solid subtype, and 1 (0.7%) diffuse sclerosing subtype. The US findings indicating malignancy, such as taller-than-wide shape, irregular margins, echogenic foci, and higher TIRADS categories, were more frequently demonstrated in nodules with classic PTC and the tall cell subtype, in line with their histopathological features. Conversely, IEFV-PTC and NIFTP rarely exhibited these high-risk sonographic features. US appearance of the oncocytic subtype more frequently overlapped with IEFV-PTC, yet hypo/very hypoechoic nodules with larger nodular diameters and higher TIRADS scores may favor the diagnosis of this subtype. Conclusion: US features of certain subtypes may guide the differential diagnosis regarding shape, margin, echogenic foci, and TIRADS category of nodules; however, definitive subtyping is not yet possible using US images alone.

Differentiated thyroid cancer with osteo-granulomatousinflammation: A case report.

OBJECTIVE: Cryptococcus, a genus of fungi, primarily includes Cryptococcus neoformans and Cryptococcus gattii, both known to cause human infections. Skeletal infections are rare, and there have been no reported cases of bone cryptococcal infection in conjunction with differentiated thyroid carcinoma. SUBJECT AND METHODS: A 56-year-old female presented with a one-month history of "cough and throat irritation." Chest CT revealed scattered small nodules in both lungs,suggestive of metastasis.There was minimal inflammation in both lungs, and scattered lymph nodes were observed in the mediastinum and upper pulmonary hilum. RESULTS: The patient was diagnosed with differentiated thyroid carcinoma complicated by cryptococcal infection. Antifungal treatment with itraconazole 200mg/day was initiated, and after 3 months, clinical symptoms disappeared, with a reduction in lung nodules observed in follow-up chest CT. CONCLUSION: When diagnosing distant metastasis in differentiated thyroid carcinoma, a comprehensive analysis combining imaging studies and serum thyroid globulin plays a complementary role, as illustrated in this case of differentiated thyroid carcinoma concurrent with cryptococcal infection.

Predictive value of the single most suspicious ultrasound feature in subcentimeter thyroid nodules: a retrospective observational cohort study.

PURPOSE: Proper management of subcentimeter thyroid nodules remains challenging for both clinicians and patients. Conducting extensive sonographic research using a safe and inexpensive tool for identifying thyroid nodules is necessary. The aim of this study was to identify whether having the highest-risk ultrasound (US) characteristic suggests that US-guided fine-needle aspiration (FNA) biopsy of subcentimeter nodules is more appropriate for the identification of malignancy than active surveillance (AS) or surgery. METHODS: The data of patients with highly suspicious subcentimeter thyroid nodules and US characteristic data who underwent surgery were retrospectively examined. RESULTS: Among a total of 556 subcentimeter nodules, 223 (40.1%) were benign, and 333 (59.9%) were malignant, with a mean maximal nodule size of 8.1 mm. In addition to age younger than 45 years, several US features were significantly associated with malignancy: irregular margins, the presence of microcalcifications, and taller-than-wide shapes (P < 0.001). Multivariate analysis also revealed that a taller-than-wide shape (OR = 8.988, P = 0.0015) was an independent factor associated with malignancy in subcentimeter thyroid nodules. The diagnostic performance of preoperative FNA was classified as a malignancy, with a sensitivity of 98.4%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 76.9%. CONCLUSIONS: This is one of the few reports based on actual data of the most suspicious US features in subcentimeter thyroid nodules. A taller-than-wide shape US feature is most significantly associated with malignancy. FNA is a simple, accurate, and reliable preoperative method for diagnosing malignant subcentimeter thyroid nodules with highly suspicious US characteristics. AS was less appropriate than FNA for subcentimeter nodules with a taller-than-wide shape, especially in patients ≤ 45 years of age.

Zirconium- 89 Labeled Antibody K1-70 for PET Imaging of Thyroid-stimulating Hormone Receptor Expression in Thyroid Cancer.

PURPOSE: Thyroid-stimulating hormone receptor (TSHR) is a G-protein coupled receptor that is highly expressed on benign and malignant thyroid tissues. TSHR binding and activation has long been a component of thyroid cancer molecular imaging and radiotherapy, by promoting expression of the sodium-iodide symporter (NIS) and incorporation of I-131 into thyroid hormones. Here, we report the radiosynthesis and preclinical evaluation of a Zirconium-89 (89Zr) labeled TSHR antibody to serve as a positron emission tomography (PET) diagnostic correlate for therapeutic agents targeting TSHR without reliance on NIS. PROCEDURES: TSHR human monoclonal antibody K1-70 was conjugated to chelator desferrioxamine-p-benzyl-isothiocyanate, followed by labeling with Zr-89, yielding the radiotracer 89Zr-DFO-TSHR-Ab. The in vitro cellar uptake and binding affinity of 89Zr-DFO-TSHR-Ab were analyzed in three new TSHR stable overexpressing tumor cell lines and their corresponding wild types (WT) with low or no TSHR expression. 89Zr-DFO-TSHR-Ab PET/CT imaging of TSHR expression was evaluated in tumor mouse models bearing one TSHR-positive tumor and other negative control with or without the coinjection of antibody K1-70, and then verified by radiotracer biodistribution study and tumor immunohistochemistry (IHC). RESULTS: The conjugate DFO-TSHR-Ab was labeled with Zr-89 at 37 °C for 60 min and purified by PD-10 column in radiochemical yields of 68.8 ± 9.9%, radiochemical purities of 98.7 ± 0.8%, and specific activities of 19.1 ± 2.7 mCi/mg (n = 5). In vitro cell studies showed 89Zr-DFO-TSHR-Ab had significantly high uptake on TSHR expressing tumor cells with nanomolar affinity and high potency. Preclinical PET/CT imaging revealed that 89Zr-DFO-TSHR-Ab selectively detected TSHR expressing thyroid tumors and displayed improved in vivo performance with the coinjection of unlabeled TSHR antibody K1-70 leading to higher uptake in TSHR expressing tumors than parental WT tumors and physiologic tissues; this observation was confirmed by the biodistribution and immunostaining analyses. CONCLUSIONS: We synthesized 89Zr-labeled antibody K1-70 as a new radiopharmaceutical for PET imaging of TSHR. 89Zr-DFO-TSHR-Ab has high radioactive uptake and retention in TSHR expressing tumors and cleared quickly from most background tissues in mouse models. Our study demonstrated that 89Zr-DFO-TSHR-Ab has the potential for PET imaging of TSHR-positive thyroid cancer and monitoring TSHR-targeted therapy.

Thyroid hemiatrophy associated with papillary thyroid carcinoma.

PURPOSE: The present study aimed to investigate CT imaging features, pathological findings, and prognosis in patients with thyroid hemiatrophy (THA) associated with papillary thyroid carcinoma (PTC). METHODS: This retrospective study included 225 patients with histopathologically proven PTC treated by surgical resection who underwent preoperative CT scanning. On CT images, THA was defined as thyroid parenchymal hemiatrophy on the ipsilateral side of PTC. CT findings, overall survival, and disease-free survival were compared between patients with and without THA. Pathological findings were also assessed in PTCs with and without THA. RESULTS: THA was observed in 35 of 225 (16%) patients with PTC. Atrophic thyroid parenchyma was observed in the right lobe of 20 patients (57%) and in the left lobe of the remaining 15 patients (43%). With respect to the solid components within PTCs, contrast-enhanced CT attenuation (114.2 ± 18.2 vs. 126.7 ± 31.3 HU; p < 0.05) and CT attenuation change for contrast-enhanced CT minus unenhanced CT (60.2 ± 18.1 vs. 72.3 ± 31.0 HU; p < 0.05) were significantly lower in PTCs with THA than in those without THA. Histopathologically, almost all PTCs with THA (97%) had keloid-like collagen, which is broad bundles of hypocellular collagen with bright eosinophilic hyalinization, typically observed in keloid. However, no significant differences were observed in the prognosis between the two groups. CONCLUSION: THA was occasionally observed in patients with PTC. Weak contrast-enhancement was distinct characteristic of PTC patients with THA, which is probably caused by keloid-like collagen.

Development and Multicenter, Multiprotocol Validation of Neural Network for Aberrant Right Subclavian Artery Detection.

PURPOSE: This study aimed to develop and validate a convolutional neural network (CNN) that automatically detects an aberrant right subclavian artery (ARSA) on preoperative computed tomography (CT) for thyroid cancer evaluation. MATERIALS AND METHODS: A total of 556 CT with ARSA and 312 CT with normal aortic arch from one institution were used as the training set for model development. A deep learning model for the classification of patch images for ARSA was developed using two-dimension CNN from EfficientNet. The diagnostic performance of our model was evaluated using external test sets (112 and 126 CT) from two institutions. The performance of the model was compared with that of radiologists for detecting ARSA using an independent dataset of 1683 consecutive neck CT. RESULTS: The performance of the model was achieved using two external datasets with an area under the curve of 0.97 and 0.99, and accuracy of 97% and 99%, respectively. In the temporal validation set, which included a total of 20 patients with ARSA and 1663 patients without ARSA, radiologists overlooked 13 ARSA cases. In contrast, the CNN model successfully detected all the 20 patients with ARSA. CONCLUSION: We developed a CNN-based deep learning model that detects ARSA using CT. Our model showed high performance in the multicenter validation.