Imaging of thyroid carcinoma with CT and MRI: approaches to common scenarios

Diagnostic yield of thyroid CT in differentiated thyroid carcinoma according to treatment response

OBJECTIVES

To evaluate the diagnostic yield of thyroid CT in patients with post-treatment differentiated thyroid carcinoma (DTC) stratified by treatment response.

MATERIALS AND METHODS

This retrospective study included DTC patients who underwent total thyroidectomy and radioactive iodine ablation, followed by thyroid CT. Patients were categorized into response assessment groups according to the American Thyroid Association guidelines: excellent response (ER), biochemical incomplete response (BIR), indeterminate response (IR), and structural incomplete response (SIR). Diagnostic yield was defined as the proportion of patients with recurrent tumors among all patients. The yields of ER, BIR, and IR were compared. For IR, subgroup analyses were performed based on the presence of indeterminate lesions on ultrasound (US). Chi-squared tests with Bonferroni correction were used to compare the diagnostic yields between groups.

RESULTS

A total of 450 patients (mean age, 44.9 ± 13.4 years; 164 men) were included. The overall diagnostic yield of thyroid CT was 15.3% (69/450; 95% confidence interval [CI]: 12.3-19%). Yields for the ER, BIR, and IR groups were 2% (4/201; 95% CI: 0.6-5.2%), 23.1% (12/52; 95% CI: 13.6-36.3%), and 26.9% (53/197; 95% CI: 21.2-33.5%), respectively. Among IR patients, the yield was significantly lower in US-negative patients (7.5%, 7/93; 95% CI: 3.5-15%) compared to those with indeterminate US lesions (44.2%, 46/104; 95% CI: 35.1-53.8%) (p < 0.001).

CONCLUSION

The diagnostic yield of thyroid CT varies according to the treatment response; it was low in ER and US-negative IR but higher in BIR and IR with indeterminate US lesions.

KEY POINTS

Question Guidelines recommend considering CT for follow-up in DTC based on treatment response, but the diagnostic yield of CT remains underexplored. Findings The diagnostic yield of CT was low in an ER and US-negative IR but higher in BIR and US-positive IR. Clinical relevance The diagnostic yield of thyroid CT varies according to treatment response. Utilizing CT based on treatment response may enhance the detection of recurrent tumors or clarify unclear findings on US.

Anaplastic thyroid carcinoma with bilateral internal jugular vein tumour thrombus formation: a case report

Anaplastic thyroid carcinoma (ATC) is a highly aggressive thyroid malignancy, comprising 1%-4% of thyroid cancers, with rapid local invasion and distant metastasis. We report a 57-year-old male with ATC presenting with a neck mass, hoarseness, and dysphagia. Imaging showed cancer thrombus in bilateral internal jugular veins, with a biopsy confirming ATC. This case highlights the imaging and pathological features of ATC and emphasizes the importance of ultrasound in evaluating intravascular cancer thrombus, aiding accurate diagnosis and management.

Enhancement on CT for preoperative diagnosis of metastatic lymph nodes in thyroid cancer: a comparison across experience levels

OBJECTIVES

To investigate the diagnostic performance and interobserver agreement of quantitative CT parameters indicating strong lymph node (LN) enhancement in differentiated thyroid cancer (DTC), comparing them with qualitative analysis by radiologists of varying experience.

MATERIALS AND METHODS

This study included 463 LNs from 399 patients with DTC. Three radiologists independently analyzed strong LN enhancement on CT. Qualitative analysis of strong enhancement was defined as LN cortex showing greater enhancement than adjacent muscles on the arterial phase. Quantitative analysis included the mean attenuation value (MAV) of LN on arterial phase (LNA) and venous phase (LNV), LNA normalized to the common carotid artery (NAVCCA), internal jugular vein (NAVIJV), and sternocleidomastoid muscle (NAVSCM), attenuation difference [AD; (LNA - MAVSCM)], and relative washout ratio [((LNA - LNV)/LNA) × 100]. The interobserver agreement and diagnostic performance of the quantitative and qualitative analyses were evaluated.

RESULTS

Interobserver agreement was excellent for all quantitative CT parameters (ICC, 0.83-0.94) and substantial for qualitative assessment (κ = 0.61). All CT parameters except for LNV showed good diagnostic performance for metastatic LNs (AUC, 0.81-0.85). NAVCCA (0.85, 95% CI: 0.8-0.9) and AD (0.85, 95% CI: 0.81-0.89) had the highest AUCs. All quantitative parameters except for NAVIJV had significantly higher AUCs than qualitative assessments by inexperienced radiologists, with no significant difference from assessments by an experienced radiologist.

CONCLUSION

Quantitative assessment of LN enhancement on arterial phase CT showed higher interobserver agreement and AUC values than qualitative analysis by inexperienced radiologists, supporting the need for a standardized quantitative CT parameter-based model for determining strong LN enhancement.

CLINICAL RELEVANCE STATEMENT

When assessing strong LN enhancement in DTC, quantitative CT parameters indicating strong enhancement can improve interobserver agreement, regardless of experience level. Therefore, the development of a standardized diagnostic model based on quantitative CT parameters might be necessary.

KEY POINTS

Accurate preoperative assessment of LN metastasis in thyroid cancer is crucial. Quantitative CT parameters indicating strong LN enhancement demonstrated excellent interobserver agreement and good diagnostic performance. Quantitative assessment of contrast enhancement offers a more objective model for the identification of metastatic LNs.

The evolving role of MRI in the detection of extrathyroidal extension of papillary thyroid carcinoma: a systematic review and meta-analysis

BACKGROUND

Papillary thyroid carcinoma (PTC) is the predominant form of thyroid cancer, and the presence of extrathyroidal extension (ETE) significantly impacts treatment decisions and prognosis. Accurate preoperative detection of ETE remains challenging, highlighting the need to evaluate advanced imaging techniques.This systematic review and meta-analysis aimed to investigate the diagnostic accuracy of magnetic resonance imaging (MRI) in detecting extrathyroidal extension (ETE) among patients diagnosed with papillary thyroid carcinoma (PTC).

METHOD

We conducted a comprehensive search of global databases including PubMed, Web of Science, EMBASE, and the Cochrane Library, spanning from inception to November 03, 2024. We included studies that utilized preoperative MRI to evaluate the presence of ETE. Quality assessment was carried out using the Joanna Briggs Institute (JBI) standard checklists. Data analysis was performed using Comprehensive Meta-Analysis (CMA) software version 3. The study protocol was registered in PROSPERO (CRD42024499536).

RESULT

Six studies were included in our final quantitative analysis. The included studies were classified into two groups; the first group focused on evaluating the accuracy of MRI in detecting ETE, while the second group assessed the apparent diffusion coefficient (ADC). The accuracy of MRI for overall ETE, minimal ETE (mETE), and gross ETE (gETE) was 81.0% (95% CI: 76.9%-85.6%), 72.9% (95% CI: 66.2%-78.6%), and 83.3% (95% CI: 75.2%-89.1%), respectively. MRI demonstrated a statistically significant difference in detecting gETE compared to mETE (OR = 1.85, 95% CI: 1.01-3.37, P-value = 0.045). Our analysis showed that the ADC of the lesion for b-value 500 is lower in patients with ETE compared to those without ETE (SMD = 0.95, 95% CI: 0.28-1.62, P-value = 0.005).

CONCLUSION

Our findings demonstrate that MRI has substantial accuracy in detecting ETE in PTC, especially for gross ETE. This suggests MRI could be a valuable tool in preoperative planning, helping to guide surgical decision-making by more precisely identifying patients at higher risk. However, the limited number of studies underscores the need for further research to confirm MRI's role in routine clinical practice and to refine imaging protocols for more accurate differentiation between minimal and gross ETE.

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.

Role of CT imaging in addressing resectability issues in differentiated thyroid cancer: imaging-based Mahajan grading system for TI and ETE

Background and objective

Extrathyroidal extension (ETE) is the term used to describe the growth of the primary thyroid tumor beyond the thyroid capsule. ETE is a critical prognostic marker for thyroid tumors, necessitating accurate preoperative assessment. This study aims to evaluate the diagnostic performance of computed tomography (CT)-based grading for ETE and tracheal invasion (TI) for preoperative prediction in patients with differentiated papillary thyroid carcinoma (PTC) and compare the diagnostic accuracy with ultrasound (US).

Materials and methods

This retrospective study was approved by our institutional review board. Preoperative US and CT were performed for 83 patients who underwent surgery for PTC between 1 January 2010 and 31 December 2020. The US and CT features of ETE and TI of each case were retrospectively and independently investigated by two radiologists. The diagnostic performances of US and CT, including their specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) for ETE, and their accuracy in predicting ETE and TI were analyzed. As per the grading for ETE on USG and CT, lesions were graded into three grades and Mahajan grading was also devised on CT to predict the TI and graded into four grades.

Results

The accuracy and specificity of CT are relatively good for identifying tumor infiltration into the adjacent structures and range from 82% to 87% and 95% to 98%, respectively. It, however, has a low sensitivity, between 14.3% and 77.78%, when compared to US, which suggests that in case of any doubt regarding CT evidence of tumor infiltration into surrounding structures, additional clinical examination must be performed. CT showed better sensitivity (78%) and specificity (75%) in detecting TI compared to previous studies. The diagnostic accuracy of CT Mahajan grading was 91.5% with p <0.005 in the prediction of TI.

Conclusion

Preoperative US should be regarded as a first-line imaging modality for predicting minimal ETE, and CT should be additionally performed for the evaluation of maximal ETE. The specificity and PPV of CT are higher than those of US in detecting overall ETE and TI of PTC. The US- and CT-based grading systems have the potential to optimize preoperative surgical planning.

Incidence of Persistence and Recurrence of Differentiated Thyroid Cancer in Post-surgical Cases From a Tertiary Care Hospital in Dubai, United Arab Emirates

Background Despite the excellent prognosis of differentiated thyroid carcinoma, recurrence remains a major concern. However, the persistence of thyroid cancer post-thyroidectomy is not uncommon. We aimed to characterise patients who underwent re-operative surgery for differentiated thyroid carcinoma and analyse the percentage of re-operations that truly were for "recurrent" disease versus the management of persistent disease. Methods We conducted a retrospective review of the hospital database, analysing patients who visited the nuclear medicine department at Mediclinic City Hospital, a tertiary care hospital in Dubai, United Arab Emirates, between 2015 and 2022. The study included patients with differentiated thyroid carcinoma who underwent re-operations after total thyroidectomy. Recurrence was defined as the development of disease after a patient had undetectable thyroglobulin and negative radiological scans within one year of the first surgery. Cases were categorised as "recurrent", "persistent", or "unable to classify" in the event of missing data. Results Out of 836 patients diagnosed with differentiated thyroid carcinoma who visited the nuclear medicine department, 71 underwent re-operations. The mean age of these patients was 44.4 years (CI 41.7-47.0), of whom 78.9% were females. Almost half (46.5%) underwent re-operations within the first year, and 98.6% were diagnosed with papillary thyroid carcinoma. We were able to classify 63.4% of cases (n=45) as persistent disease, while 24 cases were categorised as "unable to classify". Only two cases met the criteria for recurrent disease. Conclusion The majority of cases previously classified as "recurrent" in differentiated thyroid carcinoma were found to be a persistent disease, possibly indicating inadequate therapy. Further research may be required to explore the reasons behind this eye-opening rate of disease persistence. This highlights an area for improvement in the management and future outcomes of differentiated thyroid carcinoma patients.

Spatial and temporal analysis of thyroid cancer incidence in Guilan Province, Northern Iran, 2009-2018

BACKGROUND

Thyroid cancer is one of the most common malignancies of the endocrine system, the fifth most common malignancy in women worldwide, and the second most common cancer in women over 50 in 2019. It is the sixth most common cancer in both sexes and the third most common cancer in women in Guilan province. This study was conducted to describe the geographic variation and investigate any changes in the trend of the thyroid cancer incidence rate.

METHODS

This study was conducted on the data of the Guilan University of Medical Sciences cancer registration system. The crude and age-standardized incidence rate was calculated per 100,000 person-years. Joinpoint regression analysis evaluated the time trends and annual percent changes (APC). The incidence rate was estimated separately for each city and high-risk areas were shown on the province map using GIS software.

RESULTS

1742 cases of thyroid cancer (83.7 % in women and 16.3 % in men) were registered in Guilan province from 2009 to 18. The incidence of thyroid cancer was 5.1-fold higher in women than men. The results of the joinpoint regression analysis showed that the age-standardized incidence rate of thyroid cancer in both sexes has increased significantly over ten years (APC: 26.4; 95 %CI: 22.5-30.4), (P-value < 0.001). In our study, Astaneh-ye Ashrafiyeh, Lahijan, and Langarud cities were identified as high-risk areas of the province for both sexes.

CONCLUSION

The trend of incidence of thyroid cancer in Guilan province is increasing. Also, a wide geographical variation was found in the incidence of thyroid cancer.

Comprehensive Review of the Imaging Recommendations for Diagnosis, Staging, and Management of Thyroid Carcinoma

Thyroid cancer is the most common head and neck cancer (HNC) in the world. In this article, we comprehensively cover baseline, posttreatment, and follow-up imaging recommendations for thyroid carcinomas along with the eighth edition of the tumor, node, metastasis (TNM) staging system proposed by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC). We include characterization and risk stratification of thyroid nodules on ultrasound (US) proposed by various international bodies. Management guidelines (depending upon the type of thyroid carcinoma) based on the international consensus recommendations (mainly by the American Thyroid Association) are also extensively covered in this article, including the role of a radioiodine scan. The management of recurrent disease is also briefly elucidated in this article. In addition, we cover the risk factors and etiopathogenesis of thyroid carcinoma along with the non-imaging diagnostic workup essential for thyroid carcinoma management, including the significance of genetic mutations. US is the diagnostic imaging modality of choice, with US-guided fine needle aspiration (FNA) being the procedure of choice for tissue diagnosis. The roles of computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) in thyroid carcinoma staging are also specified. Through this article, we aim to provide a comprehensive reference guide for the radiologists and the clinicians in the pursuit of optimal care for patients with thyroid carcinoma.

[18F]FDG PET/CT can trigger relevant oncological management changes leading to favorable outcome in iodine-negative thyroid cancer patients

BACKGROUND

In patients with iodine-negative thyroid cancer (TC), current guidelines endorse an [18F]FDG PET/CT to identify dedifferentiated sites of disease. We aimed to determine the rate of oncological management changes triggered by such a molecular imaging approach, along with the impact on outcome.

METHODS

42 consecutive patients with negative findings on [131I] whole body scan were scheduled for [18F]FDG PET/CT and treatment based on PET results were initiated. To determine the impact on oncological management, we compared the therapeutic plan prior to and after molecular imaging. Based on imaging follow-up, the rate of controlled disease (CD, defined as stable disease, complete or partial response) was also recorded, thereby allowing to assess whether [18F]FDG-triggered management changes can also lead to favorable outcome.

RESULTS

We observed no alterations of the treatment plan in 9/42 (21.4%) subjects (active surveillance in 9/9 [100%]). Oncological management was changed in the remaining 33/42 (78.6%; systemic treatment in 9/33 [27.3%] and non-systemic treatment in 24/33 [72.7%]). Among patients receiving non-systemic therapy, the following changes were noted: surgery in 20/24 (83.3%) and radiation therapy in 4/24 (16.7%). In the systemic group, tyrosine kinase inhibitor (TKI) was prescribed in 8/9 (88.9%), while radioiodine therapy based on a TKI-mediated redifferentiation approach was conducted in 1/9 (11.1%). In 26 subjects with available follow-up, rate of CD was 22/26 (84.6%) and among those, 15/22 (68.1%) had experienced previous management changes based on PET/CT findings.

CONCLUSIONS

In subjects with iodine-negative TC, [18F]FDG PET/CT triggered relevant management changes along with disease control in the vast majority of patients. As such, in dedifferentiated TC, [18F]FDG PET/CT may serve as a relevant management tool and therapeutic decision-aid in the clinic.

Techniques for Thyroidectomy and Functional Neck Dissection

Thyroidectomy is a commonly performed surgery for thyroid cancer, Graves' disease, and thyroid nodules. With the increasing incidence of thyroid cancer, understanding the anatomy and surgical techniques is crucial to ensure successful outcomes and minimize complications. This review discusses the anatomical considerations of the thyroid and neck, including lymphatic drainage and the structures at risk during thyroidectomy. Emphasis is placed on the significance of cautious dissection to preserve critical structures, such as the parathyroid glands and recurrent laryngeal nerve. Neck dissection is also explored, particularly in cases of lymph node metastasis, in which its proper execution is essential for better survival rates. Additionally, this review evaluates various thyroidectomy techniques, including minimally invasive approaches, highlighting their potential benefits and limitations. Continuous surgical knowledge and expertise updates are necessary to ensure the best results for patients undergoing thyroidectomy.

Using a CT-based scale to evaluate disease extension and the resectability of locally advanced thyroid cancer

OBJECTIVES

To establish a computed tomography (CT)-based scale to evaluate the resectability of locally advanced thyroid cancer.

METHODS

This twin-centre retrospective study included 95 locally advanced thyroid cancer patients from the 1st centre as the training cohort and 31 patients from the 2nd centre as the testing cohort, who were categorised into the resectable and unresectable groups. Three radiologists scored the CT scans of each patient by evaluating the extension to the recurrent laryngeal nerve (RLN), trachea, oesophagus, artery, vein, soft tissue, and larynx. A 14-score scale (including all comprised structures) and a 12-score scale (excluding larynx) were developed. Receiver-operating characteristic (ROC) analysis was used to evaluate the performance of the scales. Stratified fivefold cross-validation and external verification were used to validate the scale.

RESULTS

In the training cohort, compromised RLN (p < 0.001), trachea (p = 0.001), oesophagus (p = 0.002), artery (p < 0.001), vein (p = 0.005), and soft tissue (p < 0.001) were predictors for unresectability, while compromised larynx (p = 0.283) was not. The 12-score scale (AUC = 0.882, 95%CI: 0.812-0.952) was not inferior to the 14-score scale (AUC = 0.891, 95%CI: 0.823-0.960). In subgroup analysis, the AUCs of the 12-score scale were 0.826 for treatment-naïve patients and 0.976 for patients with prior surgery. The 12-score scale was further validated with a fivefold cross-validation analysis, with an overall accuracy of 78.9-89.4%. Finally, external validation using the testing cohort showed an AUC of 0.875.

CONCLUSIONS

The researchers built a CT-based 12-score scale to evaluate the resectability of locally advanced thyroid cancer. Validation with a larger sample size is required to confirm the efficacy of the scale.

CLINICAL RELEVANCE STATEMENT

This 12-score CT scale would help clinicians evaluate the resectability of locally advanced thyroid cancer.

KEY POINTS

• The researchers built a 12-score CT scale (including recurrent laryngeal nerve, trachea, oesophagus, artery, vein, and soft tissue) to evaluate the resectability of locally advanced thyroid cancer. • This scale has the potential to help clinicians make treatment plans for locally advanced thyroid cancer.

Imaging of Pediatric Cervical Lymphadenopathy

There is a wide variety of disease entities in children, which can present with cervical adenopathy. The spectrum of pathology and imaging appearance differs in many cases from that seen in adults. This review aims to compare the strengths and limitations of the various imaging modalities available to image pediatric patients presenting with cervical adenopathy, provide guidance on when to image, and highlight the imaging appearance of both common and uncommon disorders affecting the cervical nodes in children to aid the radiologist in their clinical practice.

Nanomaterials: a promising multimodal theranostics platform for thyroid cancer

Thyroid cancer is the most prevalent malignant neoplasm of the cervical region and endocrine system, characterized by a discernible upward trend in incidence over recent years. Ultrasound-guided fine needle aspiration is the current standard for preoperative diagnosis of thyroid cancer, albeit with limitations and a certain degree of false-negative outcomes. Although differentiated thyroid carcinoma generally exhibits a favorable prognosis, dedifferentiation is associated with an unfavorable clinical course. Anaplastic thyroid cancer, characterized by high malignancy and aggressiveness, remains an unmet clinical need with no effective treatments available. The emergence of nanomedicine has opened new avenues for cancer theranostics. The unique features of nanomaterials, including multifunctionality, modifiability, and various detection modes, enable non-invasive and convenient thyroid cancer diagnosis through multimodal imaging. For thyroid cancer treatment, nanomaterial-based photothermal therapy or photodynamic therapy, combined with chemotherapy, radiotherapy, or gene therapy, holds promise in reducing invasiveness and prolonging patient survival or alleviating pain in individuals with anaplastic thyroid carcinoma. Furthermore, nanomaterials enable simultaneous diagnosis and treatment of thyroid cancer. This review aims to provide a comprehensive survey of the latest developments in nanomaterials for thyroid cancer diagnosis and treatment and encourage further research in developing innovative and effective theranostic approaches for thyroid cancer.

Diagnostic significance of MRI versus CT using identical PET data in patients with recurrent differentiated thyroid cancer: A PET/MRI study

In this retrospective study we compared magnet resonance imaging (MRI) and computed tomography (CT) each combined with identical 2-deoxy-2-[18F] fluoro-D-glucose or 2-[18F] F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) data in patients with recurrent differentiated thyroid cancer (DTC). In total 42 patients with DTC were examined. All patients underwent FDG PET/MRI and CT, the latter originating from one of the following examinations: I-131 single photon emission computed tomography/CT (32/42), low dose FDG PET/CT (5/42) or diagnostic FDG PET/CT (5/42). Two readers assessed FDG PET/MRI as well as FDG PET/CT, with the latter CT coming from one of the above examinations performed at a maximum temporal interval of 5 days from PET/MRI. Local recurrence, cervical lymph node - and pulmonary metastases were assessed in a consensus read. Lesions rated with a high malignancy score (score 4 or 5) were further analyzed. Every malignant lesion was verified if it was identified by one of both or by both modalities. In 20 of 42 patients altogether 100 malignant lesions were present. In 11/20 patients in total 15 local recurrences (15 in MRI/ 9 in CT: 9 CT/MRI, 6 MRI only, 0 CT only; P = .04) were found with a statistically significant better performance of MRI. Regarding lymph node metastases, in total 13 lesions (12 in MRI/ 8 in CT: 7 CT/MRI, 5 MRI only, 1 CT only; P = .22) in 8/20 patients were found with no significant difference between both modalities. Furthermore, in 9/20 patients in total 72 lung lesions (40 in MRI/ 63 in CT: 31 CT/MRI, 9 MRI only, 32 CT only; P = .001) were found with a statistically significant better performance of CT. In 33/42 patients follow up was available and supported the observations. In patients with recurrent DTC, PET/MRI showed superiority compared to PET/CT in evaluation of the neck region. PET/MRI was inferior to PET/CT in evaluation of the lung. PET/MRI in combination with a low dose CT of the lung may thus represent the ideal staging tool in patients with recurrent DTC.

Diagnostic value of CT enhancement degree in lymph node metastasis of papillary thyroid cancer: A comparison of enhancement, ratio, and difference

OBJECTIVES

To evaluate the value of computed tomography (CT) enhancement degree in diagnosing lymph node (LN) metastasis in papillary thyroid carcinoma (PTC) by determining the ratio and difference between the Hounsfield units (HU) of CT enhancement and plain scan of the LNs, as well as between the HU of CT-enhanced LNs and the sternocleidomastoid muscle.

METHODS

The plain and enhanced CT findings of 114 metastasis-positive LNs in 89 cases and 143 metastasis-negative LNs in 114 cases of PTC were analyzed retrospectively. Plain HU of LNs (PN_HU), enhanced HU of LNs (EN_HU), and enhanced HU of the sternocleidomastoid muscle (EM_HU) were measured. The EN_HU, difference between EN_HU and PN_HU (EN-PN_HU), ratio of EN_HU to PN_HU (EN/PN_HU), difference between EN_HU and EM_HU (EN-EM_HU), and ratio of EN_HU to EM_HU (EN/EM_HU) in metastasis-positive and metastasis-negative LN groups were calculated, the corresponding diagnostic efficacy for differentiating metastasis-positive from metastasis-negative LNs in PTC were sought using the receiver-operating curve. The interobserver agreement between readers was assessed using the interobserver correlation coefficient (ICC).

RESULTS

The EN_HU of 114 metastasis-positive LNs and 143 metastasis-negative LNs was 113.39 ± 24.13 and 77.65 ± 15.93, EN-PN_HU was 65.84 ± 21.72 HU and 34.07 ± 13.63 HU, EN/PN_HU was 2.36 (1.98, 2.75) and 1.76 (1.54, 2.02), EN-EM_HU was 49.42 ± 24.59 HU and 13.27 ± 15.41 HU, and EN/EM_HU was 1.79 ± 0.40 and 1.21 ± 0.24, respectively (all P < 0.001). The area under the curve, cutoff value, sensitivity, specificity, and accuracy of EN_HU for identifying metastasis-positive and metastasis-negative LNs were 0.895, 97.3 HU, 0.746, 0.895, and 0.829, EN-PN_HU was 0.894, 47.8 HU, 0.807, 0.874, and 0.844, EN/PN_HU was 0.831, 1.9, 0.877, 0.650, and 0.751, EN-EM_HU was 0.890, 26.4 HU, 0.807, 0.839, and 0.825, and EN/EM_HU was 0.888, 1.5, 0.728, 0.902, and 0.825, respectively. The readers had an excellent interobserver agreement on these five parameters (ICC = 0.874-0.994).

CONCLUSION

In the preoperative evaluation of LN metastasis in PTC, EN_HU, EN-PN_HU, EN-EM_HU, and EN/EM_HU had similarly high diagnostic efficacy, with EN_HU, EN-PN_HU, and EN/EM_HU having higher specificity and EN-PN_HU and EN-EM_HU having higher sensitivity.

The progress of radiomics in thyroid nodules

Due to the development of Artificial Intelligence (AI), Machine Learning (ML), and the improvement of medical imaging equipment, radiomics has become a popular research in recent years. Radiomics can obtain various quantitative features from medical images, highlighting the invisible image traits and significantly enhancing the ability of medical imaging identification and prediction. The literature indicates that radiomics has a high potential in identifying and predicting thyroid nodules. So in this article, we explain the development, definition, and workflow of radiomics. And then, we summarize the applications of various imaging techniques in identifying benign and malignant thyroid nodules, predicting invasiveness and metastasis of thyroid lymph nodes, forecasting the prognosis of thyroid malignancies, and some new advances in molecular level and deep learning. The shortcomings of this technique are also summarized, and future development prospects are provided.

Validation of Ultrasound Risk Stratification Systems for Cervical Lymph Node Metastasis in Patients with Thyroid Cancer

Simple Summary

Ultrasound (US) malignancy risk stratification systems (RSS) for cervical lymph nodes (LNs) have not been fully established in patients with thyroid cancer. In this study, we assessed the malignancy risks of each US feature and risk category from the Korean Society of Thyroid Radiology (KSThR) and the European Thyroid Association (ETA). Both systems effectively classified malignancy risks; however, 15.1% of LNs were unclassifiable in ETA RSS. Suspicious US features of hyperechogenicity, cystic change, echogenic foci, and abnormal vascularity were independently associated with metastasis. When the primary tumor characteristics were assessed, tumor multiplicity was associated with metastasis in the indeterminate LN group. We refined this system and proposed an RSS based on the KSThR system for cervical LNs in patients with thyroid cancer.

Abstract

A malignancy risk stratification system (RSS) for cervical lymph nodes (LNs) has not been fully established. This study aimed to validate the current RSS for the diagnosis of cervical LN metastasis in thyroid cancer. In total, 346 LNs from 282 consecutive patients between December 2006 and June 2015 were included. We determined the malignancy risk of each ultrasound (US) feature and performed univariable and multivariable logistic regression analyses. Each risk category from the Korean Society of Thyroid Radiology (KSThR) and the European Thyroid Association (ETA) was applied to calculate malignancy risks. The effects of size, number of suspicious features, and primary tumor characteristics were analyzed to refine the current RSS. Suspicious features including echogenic foci, cystic change, hyperechogenicity, and abnormal vascularity were independently predictive of malignancy (p ≤ 0.045). The malignancy risks of probably benign, indeterminate, and suspicious categories were 2.2–2.5%, 26.8–29.0%, and 85.8–87.4%, respectively, according to the KSThR and ETA criteria. According to the ETA criteria, 15.1% of LNs were unclassifiable. In indeterminate LNs, multiplicity of the primary tumor was significantly associated with malignancy (odds ratio, 6.53; p = 0.004). We refined the KSThR system and proposed a US RSS for LNs in patients with thyroid cancer.

A mediastinal malignant thyroid paraganglioma: A case report and literature review

Introduction and importance

Thyroid cancer is the most common endocrine malignancy, while primary paraganglioma of the thyroid gland (TP) is an unusual tumour and in rare cases, this disease tends to mimic thyroid cancer. They are rare extra-adrenal neuroendocrine tumours originating from the neural crest, and are found almost exclusively in the head and neck area.

Case presentation

We present a case of a 53-year-old man, in whom a mediastinal lesion originating from the left lobe of the thyroid gland was found on routine ultrasound and subsequent computed tomography (CT).

Clinical discussion

Total thyroidectomy and lymph dissection were performed. A review of the literature was made and a discussion was held regarding the diagnosis, the importance of surgical treatment and further behaviour.

Conclusion

Surgical removal of the thyroid gland is the main treatment, followed by radiation therapy. The diagnosis and differential diagnosis with other thyroid tumours is extremely important in terms of subsequent behaviour and prognosis.

•

Lesions like the one we described should be operated on.

•

Examination of surgical specimen is more accurate than transcutaneous biopsy.

•

Cervicotomy is an appropriate approach but extension to sternotomy could occur.

Bilateral thyroid adenomas in an alpaca

A 7-year-old neutered male alpaca (Vicugna pacos) was presented for evaluation of a 3-year history of large, bilateral, firm ventral cervical masses causing esophageal and tracheal impingement. Ultrasound examination, radiographic evaluation, histopathological findings, and magnetic resonance imaging confirmed the masses to be bilateral thyroid adenomas. Conservative medical treatment by unilateral chemical ablation, using 10% formalin by aspiration technique, was performed on the left mass. Chemical ablation proved to be effective in decreasing the size of the mass, with no apparent adverse effects. To our knowledge, this case is the first known report of bilateral thyroid adenomas in an alpaca, a condition previously described in humans, horses, dogs, and cats.

Clinical value of SMI Combined with Low-Dose CT Scanning in differential diagnosis of Thyroid Lesions and Tumor Staging

Objectives

To investigate the clinical value of Superb Microvascular Imaging (SMI) combined with low dose CT scanning in differential diagnosis of thyroid lesions and tumor staging.

Methods

A total of 120 patients with thyroid nodules admitted to the Chinese PLA General Hospital from January 2017 to July 2020 were selected. Paired design was adopted in this study. SMI and SMI combined with low-dose CT scanning were respectively carried out to these patients. The results were judged by two senior imaging physicians and two senior sonographers respectively. And t-test, χ² test, Pearson correlation coefficient check and other methods were adopted to comparatively analyze the above two methods and the pathological results after operation or puncture.

Results

Compared with pathologic findings, the coincidence rate of SMI was 40%, and the coincidence rate of SMI combined with low dose CT scanning was 84%. The difference was significant (p=0.00); among the 120 thyroid nodule patients, 50 were diagnosed as malignant by pathological diagnosis, and 70 as benign; 27 malignant cases and 93 benign cases were detected by SMI; 48 malignant cases and 72 benign cases were detected by SMI combined with low dose CT scanning. The sensitivity and accuracy of the latter were significantly higher than those of the former, and the difference was statistically significant (p=0.00); the enhancement, edge sharpness and homogeneity of SMI increased with the increase of tumor malignancy, showing positive correlation property.

Conclusion

SMI combined with low dose CT scanning has a higher diagnostic coincidence rate. Its sensitivity and accuracy are significantly superior. With the increase of tumor malignancy, the enhancement and unhomogeneity of SMI increase, and the edge is more blurred. That suggests: with the increase of tumor malignancy, neovascularization in the tumor is more obvious and more unevenly distributed; the increase of edge blur indicates more obvious tumor infiltration. The method has considerable clinical value for predicting the malignancy of tumors.

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.

Radiomics in Differentiated Thyroid Cancer and Nodules: Explorations, Application, and Limitations

Radiomics is an emerging technique that allows the quantitative extraction of high-throughput features from single or multiple medical images, which cannot be observed directly with the naked eye, and then applies to machine learning approaches to construct classification or prediction models. This method makes it possible to evaluate tumor status and to differentiate malignant from benign tumors or nodules in a more objective manner. To date, the classification and prediction value of radiomics in DTC patients have been inconsistent. Herein, we summarize the available literature on the classification and prediction performance of radiomics-based DTC in various imaging techniques. More specifically, we reviewed the recent literature to discuss the capacity of radiomics to predict lymph node (LN) metastasis, distant metastasis, tumor extrathyroidal extension, disease-free survival, and B-Raf proto-oncogene serine/threonine kinase (BRAF) mutation and differentiate malignant from benign nodules. This review discusses the application and limitations of the radiomics process, and explores its ability to improve clinical decision-making with the hope of emphasizing its utility for DTC patients.

2020 Imaging Guidelines for Thyroid Nodules and Differentiated Thyroid Cancer: Korean Society of Thyroid Radiology

Imaging plays a key role in the diagnosis and characterization of thyroid diseases, and the information provided by imaging studies is essential for management planning. A referral guideline for imaging studies may help physicians make reasonable decisions and minimize the number of unnecessary examinations. The Korean Society of Thyroid Radiology (KSThR) developed imaging guidelines for thyroid nodules and differentiated thyroid cancer using an adaptation process through a collaboration between the National Evidence-based Healthcare Collaborating Agency and the working group of KSThR, which is composed of radiologists specializing in thyroid imaging. When evidence is either insufficient or equivocal, expert opinion may supplement the available evidence for recommending imaging. Therefore, we suggest rating the appropriateness of imaging for specific clinical situations in this guideline.

Second Malignancies after Radiation Therapy: Update on Pathogenesis and Cross-sectional Imaging Findings

A wide spectrum of second cancers occur as late complications of radiation therapy (RT) used to treat various malignancies. In addition to the type and dose of radiation, lifestyle, environmental, and genetic factors are important to the development of second malignancies in cancer survivors. Typically, RT-induced malignancies (RTIMs) are biologically aggressive cancers with a variable period of 5-10 years for hematologic malignancies and 10-60 years for solid tumors between RT and the development of the second cancer. Although carcinomas and leukemias commonly develop after low-dose RT, sarcomas occur in tissues or organs that receive high-dose RT. Angiosarcomas and unclassified pleomorphic sarcomas are the two most common RT-associated sarcomas; other sarcomas include malignant peripheral nerve sheath tumors, leiomyosarcomas, osteosarcomas, chondrosarcomas, and dedifferentiated or pleomorphic liposarcomas. Select RTIMs show tumor genetic characteristics that allow accurate diagnosis. Nearly all cutaneous angiosarcomas after RT for breast cancer and 90% of RT-associated malignant peripheral nerve sheath tumors are characterized by MYC gene amplifications and loss of H3 K27me3 expression, respectively. Classic papillary thyroid carcinomas that develop after RT frequently harbor RET/PTC rearrangements and have a favorable prognosis, despite their advanced stage at patient presentation. Select RTIMs demonstrate characteristic imaging findings and typically develop in the prior radiation field. Imaging is essential to early diagnosis, characterization, localization, and staging of RTIMs. Familiarity of radiologists with the diverse spectrum of RTIMs is essential for early diagnosis and optimal management. An invited commentary by Shapiro is available online. ^©RSNA, 2021.

Imaging and Imaging-Based Management of Pediatric Thyroid Nodules

Thyroid nodules are less frequent in children than adults. Childhood thyroid nodules carry specific features, including a higher risk of malignancy than nodules in adults, rendering them unique in terms of management. Subsequently, they should be considered a distinct clinical entity with specific imaging recommendations. Initial evaluation requires a thorough workup, including clinical examination, and a detailed personal and familial history to determine the presence of possible risk factors. Laboratory and radiologic evaluation play an integral part in the diagnostic algorithm, with ultrasonography (US) being the first diagnostic test in all patients. US elastography has been recently introduced as an incremental method, reducing the subjectivity of the clinical diagnosis of nodule firmness associated with increased malignancy risk. However, fine-needle aspiration biopsy (FNAB) remains the mainstay in the diagnostic work-up of thyroid nodules and is documented to be best method for differentiating benign from malignant thyroid nodules. In addition, thyroid scintigraphy provides functional imaging information, which has a role both in the diagnostic management of thyroid nodules and during follow up in malignancies. Finally, despite providing additional information in certain clinical scenarios, ¹⁸F-fludeoxyglucose Positron Emission Tomography (¹⁸F-FDG-PET), computed tomography (CT), and magnetic resonance imaging (MRI) imaging are not routinely recommended for the evaluation of patients with newly detected thyroid nodules or in all cases of thyroid cancer. The objective of this review is to summarize the concepts in imaging and imaging-based management of nodular thyroid disease in the pediatric population, acknowledging the unique features that this patient group carries and the specific approach it requires.

Value of CT Features in the Diagnosis of Papillary Thyroid Tumors in Incidental Thyroid Nodules

The present work has investigated the value of computed tomography (CT) features in the diagnosis of papillary thyroid tumors in the incidental thyroid nodules (ITNs). In the 82 enrolled patients, 101 thyroid nodules were incidentally found by the neck CT scanning, among which 49 were histologically confirmed to be papillary thyroid carcinoma (PTC) while the other 52 were nodular goiter (NG). The tumor location, size, shape, tiny calcification, cystic change, and signs of an irregular ring, marginal defects, and enhanced blurring were all depicted by CT features. Both univariate and multivariate analyses were employed to identify independent predictors of PTC. The univariate analysis of PTC and NG showed that four CT features were statistically significant, including tiny calcification and signs of an irregular ring, marginal defects, and enhanced blurring. Furthermore, the multivariate logistic regression model indicated that signs of an irregular ring, marginal defects, and enhanced blurring were strongly correlated with PTC, of which the odds ratio (OR) was 27.374 (95% CI: 5.871∼127.636), 28.587 (95% CI: 4.139∼197.460), and 4.315 (95% CI: 0.858∼21.694), respectively. In the predictive model of PTC, the value of sensitivity, specificity, accuracy, and Youden index was 87.8%, 94.2%, 91.1%, and 0.82 with a likelihood ratio of 15.1. Therefore, the signs of an irregular ring, marginal defects, and enhanced blurring may be helpful in the diagnosis of PTC in incidentally found thyroid nodules.

Disorders of neural crest derivates in oncoradiological practice

Hundreds of articles discuss the imaging characteristics and molecular background of prominent gastrointestinal (GI) motility disorders and tumors of the peripheral nervous system, but according to our knowledge an article focusing on the classification and developmental background of these heterogeneous diseases is not to be found. Our aim is to give insight on the common features of several diseases and tumors, starting with their common source of origin, the neural crest (NC). The NC is a transient cell population of the embryo, which differentiates into several organs/structures of our body (sympathetic trunk, adrenal medulla). Although the incidence of the individual tumors of NC cells is not high by themselves, the summation of these incidences may be relevant in the daily routine. In the introduction we mention the most prominent developmental routes and molecular pathways of NC cells, which is crucial to understand the pathogenesis and the wide range of involved cell types from the colon to the adrenal gland. We summarized the most important, useful pathological findings and imaging techniques from the X-ray to the positron emission tomography—computed tomography (CT) in order to help the identification of these diseases. This article may help to better understand NC lineage and its unique, diverse role during ontogeny, which may influence the radiologists to change several convictions, or understand better the background and/or connections of a wide range of tumors and syndromes.

Magnetic Resonance Imaging Characteristics of Papillary Thyroid Carcinoma for the Prediction of Cervical Central Compartment Lymph Node Metastasis

OBJECTIVE

Cervical lymph node metastasis (LNM) is associated with local recurrence and distant metastasis in papillary thyroid carcinoma (PTC). This study was to assess magnetic resonance imaging (MRI) characteristics for predicting cervical LNM in PTC.

MATERIALS AND METHODS

A total of 119 patients with 154 PTC examined by MRI were assessed. According to inclusion and exclusion criteria, 78 subjects (78 tumors) were included in the final analysis. Conventional MRI findings and apparent diffusion coefficient were recorded. Descriptive statistics for LNM, sensitivity, specificity, and accuracy of various features were obtained. Multivariate logistic regression was performed for identifying independent variables for predicting LNM. Receiver operating characteristic curves were used to assess the diagnostic performance of the independent variables and model.

RESULTS

There were 31 node-positive and 47 node-negative PTCs in this study. Node-positive patients significantly differed from the node-negative group in age (P = 0.039), long/short diameter of lymph nodes (both P < 0.001), lymph nodes cystic change (P = 0.005), tumor size (P < 0.001), poorly defined tumor margin in contrast-enhanced imaging (P < 0.001), and thyroid contour protrusion sign (P < 0.001). Satisfactory interobserver agreement was obtained between the 2 examiners (Cohen κ of 0.871 and 0.872). Thyroid contour protrusion sign and poorly defined tumor margin were identified as independent predictive factors of LNM in PTC (both P < 0.05), with area under the curves of 0.813 and 0.851, and accuracies of 0.810 and 0.838. When the independent factors were combined, the diagnostic performance was improved with an area under the curve of 0.944 and an accuracy of 0.884.

CONCLUSIONS

Thyroid contour protrusion sign and poorly defined tumor margin in contrast-enhanced imaging could be 2 important predicted findings for cervical LNM in PTC.

Prediction of Immunohistochemistry of Suspected Thyroid Nodules by Use of Machine Learning-Based Radiomics

OBJECTIVE. The purpose of this study was to develop and validate a radiomics model for evaluating immunohistochemical characteristics in patients with suspected thyroid nodules. MATERIALS AND METHODS. A total of 103 patients (training cohort-to-validation cohort ratio, ≈ 3:1) with suspected thyroid nodules who had undergone thyroidectomy and immunohistochemical analysis were enrolled. The immunohistochemical markers were cytokeratin 19, galectin 3, thyroperoxidase, and high-molecular-weight cytokeratin. All patients underwent CT before surgery, and a 3D slicer was used to analyze images of the surgical specimen. Test-retest and Spearman correlation coefficient (ρ) were used to select reproducible and nonredundant features. The Kruskal-Wallis test (p < 0.05) was used for feature selection, and a feature-based model was built by support vector machine methods. The performance of the radiomic models was assessed with respect to accuracy, sensitivity, specificity, corresponding AUC, and independent validation. RESULTS. Eighty-six reproducible and nonredundant features selected from the 828 features were used to build the model. The best performance of the cytokeratin 19 model yielded accuracy of 84.4% in the training cohort and 80.0% in the validation cohort. The thyroperoxidase and galectin 3 predictive models yielded accuracies of 81.4% and 82.5% in the training cohort and 84.2% and 85.0% in the validation cohort. The performance of the high-molecular-weight cytokeratin predictive model was not good (accuracy, 65.7%) and could not be validated. CONCLUSION. A radiomics model with excellent performance was developed for individualized noninvasive prediction of the presence of cytokeratin 19, galectin 3, and thyroperoxidase based on CT images. This model may be used to identify benign and malignant thyroid nodules.

Updated WHO nomenclature of head and neck lesions and associated imaging findings

This article reviews the imaging features of head and neck lesions with updated 2017 World Health Organization (WHO) nomenclature. The major WHO changes include refined terminology of existing entities, descriptions of new tumor types, elimination of defunct categories, and updated biological characterization of various tumor types. In particular, the updates pertaining to the following conditions will be reviewed: tumors of the oral cavity and oropharynx, including HPV-positive or HPV-negative squamous cell carcinoma, small cell carcinoma; tumors of the hypopharynx, larynx, trachea, and parapharyngeal space, including nomenclature revisions for laryngeal neuroendocrine tumors; tumors of the nasal cavity and paranasal sinuses including newly added entities such as NUT carcinoma and biphenotypic sinonasal sarcoma; odontogenic and maxillofacial bone tumors, including the reversal of terminology for certain cystic lesions; tumors of the salivary glands, including updated terminology related to high-grade transformation and polymorphous adenocarcinomas tumors; temporal bone lesions including modifications of the nomenclature and classification criteria; tumor-like lesions of the neck and lymph nodes, with a discussion encompassing developmental cysts, metastases of unknown primary, and heterotopia-associated neoplasia; and mucosal melanoma. Familiarity with the proper WHO terminology for conditions that might be mentioned in differential diagnoses and a general understanding of the behavior of head and neck lesions can help optimize imaging assessment and reporting.

Vascular anomaly imaging mimics and differential diagnoses

Vascular anomalies can be correctly diagnosed in the majority of instances using the combination of clinical history, physical examination and imaging. In certain cases, the clinical work-up may be inconclusive or unavailable to the radiologist, and the imaging findings can be nonspecific, yielding more than one possible diagnosis. In this pictorial essay, we discuss diagnoses that can mimic vascular anomalies and highlight key differentiating imaging features.

Current trends in the features of male thyroid cancer: Retrospective evaluation of their prognostic value

This study aimed to compare the clinicopathologic characteristics and oncologic outcomes of papillary thyroid cancer (PTC) patients according to sex. Then, we validated prognostic variables to determine whether sex is a significant prognostic factor for PTC.Between January 2007 and December 2010, 1232 men and 7276 women PTC patients underwent surgery. The patient characteristics and 5-year oncologic outcomes were compared. The stepwise Cox proportional hazards model determined the significance of survival variables.Men PTC patients had more lymph node (LN) metastases than women, both in the total (P < .0001) and hemithyroidectomy (P < .0001) patients. Men and women showed similar 5-year recurrence-free survivals, both in total (P = .815) and hemithyroidectomy (P = .148) patients. The tumor size and the number of positive central nodes were associated with tumor recurrence, but not sex.Sex was not an independent prognostic factor for tumor recurrence. Multicenter clinical studies with long-term follow-ups are needed to validate these results.

The value of the computer-aided diagnosis system for thyroid lesions based on computed tomography images

Background

Thyroid nodules are commonly found at palpation amounting to 4-7% of the asymptomatic population and 50% of the cases are found at autopsy. Only a small proportion of thyroid nodules are malignant. The major challenge is the differential diagnosis of benign or malignant thyroid nodules, so we aim to develop the computer-assisted diagnostic method based on computed tomography (CT) images for thyroid lesions.

Methods

In this study, we retrospectively collected 52 benign and 46 malignant thyroid nodules from 90 patients in CT examinations, together with the pathologist findings and radiology diagnosis. The first-order statistic and gray-level co-occurrence matrix features were extracted from thyroid computed tomography images. These texture features were used to assess the malignancy risk of the thyroid nodules. Several classification algorithms, including support vector machine, linear discriminant analysis, random forest, and bootstrap aggregating, were applied in the prediction. Leave-one-out cross-validation was used to evaluate the performance of thyroid cancer recognition.

Results

In thyroid cancer identification based on a computed tomography image, we found the system using 17 texture features and support vector machine performed well. The accuracy, area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value, were 0.8673, 0.9105, 0.9130, 0.8269, 0.8235 and 0.9146, respectively.

Conclusions

The proposed computer-aided diagnosis system provides a good assessment of the malignancy-risk of the thyroid nodules, which may help radiologists to improve the accuracy and efficiency of thyroid diagnosis.

Surveillance for Differentiated Thyroid Cancer Recurrence

Serum thyroglobulin monitoring along with anatomic and functional imaging play key roles in the surveillance of patients with differentiated thyroid cancer after initial treatment. Among patients with a disease stage justifying thyroid remnant ablation or with suspected metastatic disease, radioiodine whole-body scans are essential in the months after surgery. For patients with low to moderate-risk cancers, ultrasonography of the neck (with measurement of serum thyroglobulin on thyroid hormone replacement) are the best initial diagnostic modalities, and are often the only tests required. In individuals suspected of having distant metastases, CT, MRI, and 18F-FDG PET can make important contributions in localizing residual disease and monitoring its progression and responses to therapy, provided they are used in the appropriate setting.

Anaplastic Carcinoma Thyroid in a Young Child – an Extremely Rare Occurrence

Anaplastic thyroid carcinoma (ATC), one of the most aggressive malignancies, is extremely rare in childhood. We present a case of 5-yearold child who presented with rapidly progressing thyroid swelling and stridor, for which she underwent emergency tracheostomy and biopsy. Histopathological features were suggestive of ATC and the patient died within two months after diagnosis. ATC, though very rare in childhood, should be kept in the differential diagnoses of rapidly enlarging neck masses in children. To the best of our knowledge, this is the youngest case of ATC reported in literature.

3T magnetic resonance spectroscopy as a powerful diagnostic modality for assessment of thyroid nodules

OBJECTIVE

Magnetic resonance spectroscopy (MRS) is a powerful tool for structural studies of chemical compounds and biomolecules and also documented promising findings as a potential imaging technology in thyroid oncology. This prospective study was to ascertain the clinical significance of 3 Tesla MRS in the evaluation of patients with thyroid nodules (TNs) as an ancillary diagnostic technique for thyroid carcinoma.

MATERIALS AND METHODS

Magnetic resonance spectroscopy at 3T at echo- times (TEs) 136 and 270 ms was carried out on 15 patients with total number of 32 TNs larger than 1 cm3, which all were surgically resected. Choline (Chol) to creatine (Cr) ratio was assessed at 136 and 270 TEs on each nodule and a receiver operating characteristic (ROC) curve was used to determine optimal cut-off point. The findings were compared with histopathology of thyroid specimens.

RESULTS

There were 23 benign and 9 malignant lesions (7 papillary and 2 follicular thyroid carcinomas). The mean values of Chol/Cr at 136 and 270 TEs was 2.28 ± 3.65 and 1.52 ± 1.67 respectively and the difference between benign and malignant nodules was only significant at 136 TEs. The study revealed that Chol/ Cr ratio cut-off point of 2.5 best correlates with histopathology results (sensitivity = 75%; specificity = 100%; PPV = 100%; NPV= 92%).

CONCLUSION

This preliminary study showed that 3T magnetic resonance spectroscopy might be a specific modality for the evaluation of thyroid nodules in differentiation of benign from malignant thyroid tissue. However, a larger series would give much greater confidence that this state-of-the-art technology will worth pursuing in clinical practice.

Diagnostic value of computed tomography (CT) histogram analysis in thyroid benign solitary coarse calcification nodules

This study was to investigate the diagnostic value of the computed tomography (CT) histogram in thyroid benign solitary coarse calcification nodules (BSCNs). A total of 89 thyroid solitary coarse calcification nodules (coarse calcification ≥5 mm, no definite soft tissue around calcification) confirmed either by surgery or histopathological examination in 86 cases enrolled from January 2009 to December 2015 were evaluated. These included 56 BSCNs and 33 malignant solitary coarse calcification nodules (MSCNs). Overall, 27 cut-off values were calculated by N (4≤N≤30) times of 50 Hounsfield units (HU) in the range of 200 to 1500 HU, and each cut-off value and the differences in the corresponding area percentages in the CT histogram were recorded for BSCN and MSCN. The optimal cut-off value and the corresponding area percentage were established by receiver operating characteristic (ROC) curve analysis. In the 19 groups with an ROC area under curve (AUC) of more than 0.7, at a cut-off value of 800 HU and at an area percentage of no more than 93.8%, the ROC AUC reached the maximum of 0.79, and the accuracy, sensitivity, and specificity were 75.3%, 80.4%, and 66.7%, respectively. At a cut-off value of 1050 HU and at an area percentage of no more than 93.6%, the accuracy, sensitivity, and specificity were 71.9%, 60.7%, and 90.9%, respectively. At a cut-off of 1150 HU and area of no more than 98.4%, the accuracy, sensitivity, and specificity were 70.8%, 57.1%, and 93.9%, respectively. At a cut-off of 600 HU and area of no more than 12.1%, the accuracy, sensitivity, and specificity were 61.8%, 39.3%, and 100.0%, respectively. Compared with the cut-off value of 800 HU and an area percentage of no more than 93.8%, the sensitivity of cut-off values and minimum areas of 1050 HU and 93.6%, of 1150 HU and 98.4%, and of 600 HU and 12.1%, was gradually decreasing; however, their specificity was gradually increasing. This can provide an important basis for reducing the misdiagnosis and unnecessary surgical trauma.

Incidental finding of papillary thyroid carcinoma on CT examination of mandibular lesion: Case report

The number of significant incidental findings identified on radiographic examinations has increased. In total, 169 patients, 87 males and 82 females, with a mean age of 67.3 years (range, 17-92 years), as well as 65 patients (38.5%), 43 (66.2%) female and 22 (33.8%) male had abnormal findings in the thyroid for one year in our institution. Thyroid nodules are the most common incidental findings on oral and maxillofacial evaluations. Computed tomography (CT) and magnetic resonance imaging (MRI) examination are frequently used to detect thyroid abnormality. The present study reported a case of papillary thyroid carcinoma (PTC) detected following CT and MRI examination of a mandibular lesion. The CT examination of the oral and maxillofacial region included the thyroid, which must be examined carefully to detect various diseases, including PTC. Collaboration between radiologists and clinicians is important to manage these incidental findings.

Chapter 4 Thyroid Malignancy: Staging and Restaging

Determining the extent of disease is necessary for guiding the management of thyroid carcinomas. Diagnostic imaging, including ultrasound, computed tomography, magnetic resonance imaging, and nuclear medicine scans, plays an essential role in staging and restaging of thyroid carcinomas. This article reviews the approaches and imaging findings for evaluating the primary tumor, regional lymph node metastases, and distant metastases. In addition, potential pitfalls are discussed and depicted.

Thyroid nodule recognition in computed tomography using first order statistics

Background

Computed tomography (CT) is one of the popular tools for early detection of thyroid nodule. The pixel intensity of thyroid in CT image is very important information to distinguish nodule from normal thyroid tissue. The pixel intensity in normal thyroid tissues is homogeneous and smooth. In the benign or malignant nodules, the pixel intensity is heterogeneous. Several studies have shown that the first order features in ultrasound image can be used as imaging biomarkers in nodule recognition.

Methods

In this paper, we investigate the feasibility of utilizing the first order texture features to identify nodule from normal thyroid tissue in CT image. A total of 284 thyroid CT images from 113 patients were collected in this study. We used 150 healthy controlled thyroid CT images from 55 patients and 134 nodule images (50 malignant and 84 benign nodules) from 58 patients who have undergone thyroid surgery. The final diagnosis was confirmed by histopathological examinations. In the presented method, first, regions of interest (ROIs) from axial non-enhancement CT images were delineated manually by a radiologist. Second, average, median, and wiener filter were applied to reduce photon noise before feature extraction. The first-order texture features, including entropy, uniformity, average intensity, standard deviation, kurtosis and skewness were calculated from each ROI. Third, support vector machine analysis was applied for classification. Several statistical values were calculated to evaluate the performance of the presented method, which includes accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area of under receiver operating characteristic curve (AUC).

Results

The entropy, uniformity, mean intensity, standard deviation, skewness (P < 0.05), except kurtosis (P = 0.104) of thyroid tissue with nodules have a significant difference from those of normal thyroid tissue. The optimal classification was obtained from the presented method. The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) are 0.880, 0.821, 0.933, 0.917, 0.854, and 0.953 respectively.

Conclusion

First order texture features can be used as imaging biomarkers, and the presented system can be used to assist radiologists to recognize the nodules in CT image.

Diagnostic value of CT artifacts for solitary coarse calcifications in thyroid nodules

This study aimed to estimate the diagnostic value of CT artifacts for solitary coarse calcifications (SCC) in thyroid nodules. A total of 78 SCCs (coarse calcifications >2 mm, no definite mass lesion around calcification) in 63 cases received surgery from Jan 2009 to Jun 2014 were enrolled, including 52 nodular goiters (NG) in 41 cases and 26 papillary thyroid carcinomas (PTC) in 22 cases. The CT artifacts in NGs and PTCs were recorded, and its sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate and accuracy for the diagnosis of NG were calculated. CT artifacts were more often observed around the SCCs in NG cases (P<0.05), its sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate and accuracy for the diagnosis of NG were 80.7%, 76.9%, 87.5%, 66.7%, 23.1%, 33.3% and 79.5%, and there was no intergroup difference about the CT artifacts in SCCs (P>0.05). CT artifacts are important for the diagnosis of SCCs in thyroid nodules to tell benign from malignancy, and CT artifacts around the SCC are helpful for the diagnosis of NG and no artifacts indicate a larger probability of PTC.