Incidental thyroid nodules on CT: evaluation of 2 risk-categorization methods for work-up of nodules

Natural history and long-term follow-up of incidental thyroid nodules on CT imaging

OBJECTIVES

Incidental thyroid nodules (ITNs) are found in up to 25% of CT scans. Increased use of cross-sectional imaging has contributed to the increased incidence of thyroid cancer worldwide. ITNs pose a management dilemma since nodule malignancy rate is 5%-15% but most cancers are indolent and prognosis in differentiated thyroid cancer is excellent. Study aims are to determine prevalence of ITNs ≥1 cm on CT scans, evaluate reporting practices, assess for emergence of clinically evident thyroid cancer during 13-year follow-up and assess interim nodule growth and clinical outcomes in nodules that were further investigated.

METHODS

Direct image review of 1499 consecutive CT scans that included the thyroid, performed during January 2009 in a large NHS health board was performed. Clinical data up to January 2022 was analysed in 150 patients with at least 1 ITN ≥1 cm.

RESULTS

ITN prevalence was 11% with mean patient age 70 years and mean nodule diameter 17.5 mm. 30% of ITNs were mentioned in the CT report. During the follow-up period 11% proceeded to thyroid ultrasound, 5% fine needle aspiration, and 2% diagnostic hemithyroidectomy with no thyroid malignancy found. One hundred twenty patients (80%) were deceased by the study endpoint, none from thyroid malignancy. No patients presented with clinically evident thyroid malignancy during follow-up.

CONCLUSIONS

None of 150 ITN cases developed clinically evident thyroid malignancy in a 13-year follow-up period with 80% of patients deceased by the study endpoint from non-thyroid causes.

ADVANCES IN KNOWLEDGE

This would suggest that ITNs detected on CT do not require further investigation unless malignant appearances or significant clinical concern for thyroid malignancy.

Optimizing the screening process for TIRADS could reduce the number of unnecessary thyroid biopsies

Objective

Current Thyroid Imaging Reporting and Data Systems (TIRADS) exhibit considerable variability in size thresholds for fine-needle aspiration biopsy. This study harnesses the systematic variations among dissimilar TIRADS optimization strategies for biopsy selection.

Methods

The analysis focused on the discrepancies observed among the four widely utilized TIRADS systems: ACR-TIRADS, Kwak-TIRADS, C-TIRADS and EU-TIRADS. Subsequently, several methods derived from the combination of two TIRADS were constructed via serial testing. Last but not least, diagnostic performance was assessed through unnecessary biopsy rate (UBR), missed malignancy rate and the frequency of clinically significant missed diagnoses.

Results

A total of 699 nodules were included in the study. The accuracy for nodules consistently recommended for biopsy by the four TIRADS was merely 50.8%. Without elevating the risk of missed diagnoses, which could potentially influence prognosis as per the current literature, for eligible nodules recommended for biopsy by original TIRADS, incorporating another TIRADS in serial could further reduce the number of biopsies by 7.8-19.2%.

Conclusions

Conspicuous disparities exist in biopsy guidelines among TIRADS systems, urging increased caution among healthcare providers, particularly when they are extensively applied in patient evaluations. As evidently demonstrated by our research findings, combining recommendations from two TIRADS systems could effectively and safely lessen UBRs. These findings also advocate for the integration of prognostic-impact assessment in developing novel biopsy optimization strategies.

Significance of Incidental Thyroid Findings in a Large Community-based Lung Cancer Screening Cohort

OBJECTIVES

Investigate incidental findings of neck pathology on lung cancer screening computer tomography scans and determine clinical relevance in a population of heavy smokers.

METHODS

A retrospective chart review was conducted utilizing a database of patients who underwent a chest computed tomography (CT) through a robust community-based hospital lung cancer screening program in 2019 and 2020. Demographics, medical history, imaging reports, and any pathology results were analyzed.

RESULTS

A total of 1738 patients received a lung screening scan during the study period. The median age of the patient population was 64 (range: 50-79), 886 (51%) were male, and 1599 (92%) were Caucasian. Ninety-four (5.4%) were found to have neck findings on their CT report, including thyroid nodules, calcifications, heterogeneity or enlargements, pathologic appearing lymph nodes, or parathyroids. Forty-two patients had evidence of follow-up for their thyroid findings, and three of these ultimately underwent surgical intervention.

CONCLUSION

The results of our study demonstrate that lung cancer screening chest scans can discover clinically relevant findings in the neck. The risks and benefits of screening needs to be thoroughly evaluated. Given the relatively low incidence of findings in this population, a prospective study in conjunction with screening questionnaire for symptoms may increase the yield of incidental findings.

LEVEL OF EVIDENCE

3 Laryngoscope, 135:964-968, 2025.

Radiomics analysis of dual-energy CT-derived iodine maps for differentiating malignant from benign thyroid nodules

BACKGROUND

Many thyroid nodules are detected incidentally with the widespread use of sensitive imaging techniques; however, only a fraction of these nodules are malignant, resulting in unnecessary medical expenditures and anxiety. The major challenge is to differentiate benign thyroid nodules from malignant ones. The application of dual-energy computed tomography (DECT) and radiomics provides a new diagnostic approach. Studies applying radiomics from primary tumours on iodine maps to differentiate malignant from benign thyroid nodules are still lacking.

PURPOSE

To determine the ability of an iodine map-based radiomic nomogram in the venous phase for differentiating malignant thyroid nodules from benign nodules.

METHODS

A total of 141 patients with thyroid nodules who underwent DECT were enrolled and randomly assigned to the training and test cohorts between January 2018 and January 2019. The radiomic score (Rad-score) was derived from nine quantitative features of the iodine maps. Stepwise logistic regression analysis was used to develop radiomic, clinical and combined models. Age, normalized iodine concentration (NIC), and cyst changes were used to construct the clinical model. Receiver operating characteristic (ROC) curve analysis, sensitivity and specificity were performed to analyse the ability of the models to predict malignant thyroid nodules. Calibration analysis was used to test the fitness of the models. Decision curve analysis (DCA) and nomogram construction were also performed.

RESULTS

According to the clinical model, age (0.989 [0.984, 0.995]; p < 0.001), NIC (0.778 [0.640, 0.995]; p = 0.01), and cyst changes (0.617 [0.507, 0.751]; p < 0.001) were independently associated with malignant thyroid nodules. According to the combined model, age (0.994 [0.989, 0.999]; p = 0.01), NIC (0.797 [0.674, 0.941]; p = 0.008), cyst changes (0.786 [0.653, 0.947]; p = 0.01), and the rad-score (1.106 [1.070, 1.143]; p < 0.001) were independently associated with malignant thyroid nodules. The combined model achieved satisfactory discrimination in predicting malignant thyroid nodules and had greater predictive value in the training (AUC [areas under the curve], 0.96 vs. 0.87; p = 0.01) and test (AUC, 0.90 vs. 0.79; p = 0.04) cohorts than did the clinical model.

CONCLUSIONS

The radiomics nomogram based on iodine maps is useful to distinguish malignant thyroid nodules from benign thyroid nodules.

Incidental thyroid nodules on COVID-19-related thoracic tomography scans: a giant cohort

INTRODUCTION

Computerized thoracic tomography (CT) imaging was extensively employed, especially in the early months of the COVID-19 pandemic. An incidental thyroid nodule (ITN) is defined as a nodule not previously detected or suspected clinically but identified via an imaging study. The present study aimed to determine the incidence of thyroid nodules incidentally detected in thoracic CTs for the suspicion of COVID-19 pneumonia.

MATERIALS AND METHODS

Adult patients who underwent thoracic CT in our hospital for COVID-19 management were retrospectively identified between March 2020 and September 2020. Medical information registered in the hospital and national health system was reviewed. The prevalence of incidental thyroid nodules at CT, thyroid function test results of patients with incidental lesions, correlation of CT findings with ultrasonography (US) findings, and fine-needle aspiration biopsy (FNAB) results were evaluated.

RESULTS

We analyzed 35,113 patients who had COVID-19-indicated CT scans. There was information about the thyroid gland in CT reports of 3049 patients. The prevalence of ITN was 3.82% (1343/35,113 patients) and thyroid heterogeneity was 1.11% (388/35,113 patients). While it was explicitly stated that no pathology was found in the patient's thyroid gland in 3.75% of patients (1318/35,113), no information was given about the thyroid gland in 91.32% of the patients (32064/35,113). Thus, the number of patients informed about their thyroid was 3049 (8.68%) and the number of patients with thyroid pathology was 1731 (4.93%). It was observed that 308 of 1731 patients (17.80%) had follow-up thyroid US. An FNAB was indicated in 238 patients (87.50%). Of the 238 patients with indication for biopsy, only 115 (48.31%) underwent a thyroid FNAB. The cytological diagnosis was benign in 59 (51.30%), non-diagnostic in 30 (26.08%), atypia of uncertain significance in 22 (19.13%), and suspected follicular neoplasia/follicular neoplasia in four patients (3.46%). Thyroidectomy was performed in six more patients due to large nodules and the final diagnosis was benign in two and papillary thyroid cancer in three patients.

CONCLUSION

Increased use of thoracic CT during the COVID-19 pandemic probably enabled improved detection of ITNs. In this large-scale study, the prevalence of thyroid nodules reported with thoracic CT was 3.82%, while thyroid cancer was detected in 1.30% of patients evaluated with US. We recommend against using thoracic CT scans as a direct means of assessing thyroid disease owing to the low number of detected cancer cases in our cohort of 35,113 patients. However, thoracic CT scans obtained for various reasons might provide the opportunity for early diagnosis and treatment of thyroid disease, including cancers.

Thyroid abnormalities identified on CT screening for lung cancer

PURPOSE

Because incidental thyroid nodules (ITNs) are common extrapulmonary findings in low-dose computed tomography (LDCT) scans for lung cancer screening, we aimed to investigate the frequency of ITNs on LDCT scans separately on baseline and annual repeat scans, the frequency of malignancy among the ITNs, and any association with demographic, clinical, CT characteristics.

METHODS

Retrospective case series of all 2309 participants having baseline and annual repeat screening in an Early Lung and Cardiac Action Program (MS-ELCAP) LDCT lung screening program from January 2010 to December 2016 was performed. Frequency of ITNs in baseline and annual repeat rounds were determined. Multivariable regression analysis was performed to identify significant predictors.

RESULTS

Dominant ITNs were seen in 2.5 % of 2309 participants on baseline and in 0.15 % of participants among 4792 annual repeat LDCTs. The low incidence of new ITNs suggests slow growth as it would take approximately an average of 16.8 years for a new ITN to be detected on annual rounds of screening. Newly detected ITNs on annual repeat LDCT were all smaller than 15 mm. Regression analysis showed that the increasing of age, coronary artery calcifications score and breast density grade were significant predictors for females having an ITN. No significant predictors were found for ITNs in males.

CONCLUSION

ITNs are detected at LDCT however, no malignancy was found. Certain predictors for ITNs in females have been identified including breast density, which may point towards a common causal pathway.

Pearls of Parathyroidectomy: How to Find the Hard to Find Ones

The treatment of hyperparathyroidism through parathyroidectomy requires careful and complete preoperative evaluation. There are multiple imaging modalities and methods available to clinicians today to aid in identifying a pathological lesion; however, each has limitations that the clinician must understand. A systematic approach to patient evaluation, imaging, and surgical exploration is necessary to ensure accurate diagnosis and maximize the chances of minimally invasive and successful surgical removal.

Sustainability and Climate Protection in Radiology - An Overview

BACKGROUND

Sustainability is becoming increasingly important in radiology. Besides climate protection - economic, ecological, and social aspects are integral elements of sustainability. An overview of the scientific background of the sustainability and environmental impact of radiology as well as possibilities for future concepts for more sustainable diagnostic and interventional radiology are presented below.The three elements of sustainability:1. EcologyWith an annually increasing number of tomographic images, Germany is in one of the leading positions worldwide in a per capita comparison. The energy consumption of an MRI system is comparable to 26 four-person households annually. CT and MRI together make a significant contribution to the overall energy consumption of a hospital. In particular, the energy consumption in the idle or inactive state is responsible for a relevant proportion.2. EconomyA critical assessment of the indications for radiological imaging is important not only because of radiation protection, but also in terms of sustainability and "value-based radiology". As part of the "Choosing Wisely" initiative, a total of 600 recommendations for avoiding unnecessary examinations were compiled from various medical societies, including specific indications in radiological diagnostics.3. Social SustainabilityThe alignment of radiology to the needs of patients and referring physicians is a core aspect of the social component of sustainability. Likewise, ensuring employee loyalty by supporting and maintaining motivation, well-being, and job satisfaction is an essential aspect of social sustainability. In addition, sustainable concepts are of relevance in teaching and research, such as the educational curriculum for residents in radiology, RADUCATION or the recommendations of the International Committee of Medical Journal Editors.

KEY POINTS

· Sustainability comprises three pillars: economy, ecology and the social component.. · Radiologies have a high optimization potential due to a significant demand of these resources.. · A dialogue between medicine, politics and industry is necessary for a sustainable radiology.. · The discourse, knowledge transfer and public communication of recommendations are part of the sustainability network of the German Roentgen Society (DRG)..

CITATION FORMAT

· Palm V, Heye T, Molwitz I et al. Sustainability and Climate Protection in Radiology - An Overview. Fortschr Röntgenstr 2023; 195: 981 - 988.

Thyroid Incidentalomas in Hospitalized Patients With COVID-19: A Single-Center Retrospective Analysis

Context

During the COVID-19 pandemic, both people with underlying diseases and previously healthy people were infected with SARS-CoV-2. In our institute, most hospitalized patients underwent chest computed tomography (CT) to evaluate pulmonary involvement and complication of COVID-19. There are currently limited data regarding thyroid CT incidentalomas in healthy people.

Objective

We aimed to investigate the prevalence and predictors of thyroid incidentalomas among hospitalized patients with COVID-19.

Methods

A single-center retrospective study included hospitalized patients aged ≥15 years with COVID-19 who underwent chest CT during April 2020 and October 2021. Thyroid incidentalomas were reviewed and identified by an experienced radiologist. Logistic regression analysis was used to determine predictors for thyroid incidentalomas.

Results

In the 1326 patients (mean age 49.4 years and 55.3% female) that were included, the prevalence of thyroid incidentalomas was 20.2%. Patients with thyroid incidentalomas were older (59.6 years vs 46.8 years, P < .001) and more often female than those without incidentalomas (63.4% vs 53.2%, P = .003). On multivariate analysis, only female sex (OR 1.56; 95% CI 1.17-2.07) and older age (OR 1.04; 95% CI 1.03-1.05) were significantly associated with thyroid incidentalomas.

Conclusion

In COVID-19 patients, the prevalence of thyroid incidentalomas identified on chest CT was higher (20.2%) than in previous studies in the general population (<1% to 16.8%). Female sex and older age were independent factors associated with thyroid incidentalomas.

The influence of papillary features on the risk of malignancy in thyroid nodules diagnosed as atypia of undetermined significance or follicular lesion of undetermined significance

BACKGROUND

The objective of this study was to the assess the risk of malignancy in thyroid lesions that were diagnosed as AUS/FLUS when using a novel cytology subclassification system that is based on the presence or absence of papillary features.

METHODS

AUS/FLUS case cytology was re-reviewed and subclassified into minor or major concern groups based upon the absence or presence of papillary features, respectively. The risk of malignancy (ROM) was calculated and compared between the two groups. Inter-pathologist agreement in case subclassification was also measured.

RESULTS

The minor concern group had a 12.6% associated ROM, while the major concern group had a significantly higher ROM (58.4%), (P < 0.001). Based on 108 cases, the inter-pathologist agreement in case subclassification was 79%, and the κ value was 0.47.

CONCLUSIONS

The identification of papillary features significantly increases the ROM in thyroid lesions with an AUS/FLUS diagnosis.

Contrast-enhanced ultrasound and shear wave elastography in the diagnosis of ACR TI-RADS 4 and 5 category thyroid nodules coexisting with Hashimoto's thyroiditis

OBJECTIVE

This study aims to evaluate the value of contrast-enhanced ultrasound (CEUS), shear wave elastography (SWE), and their combined use in the differentiation of American College of Radiology (ACR) thyroid imaging reporting and data system (TI-RADS) 4 and 5 category thyroid nodules coexisting with Hashimoto's thyroiditis (HT).

MATERIALS AND METHODS

A total of 133 pathologically confirmed ACR TI-RADS 4 and 5 category nodules coexisting with HT in 113 patients were included; CEUS and SWE were performed for all nodules. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), accuracy, and the area under the receiver operating characteristic curve (AUC) of the SWE, CEUS, and the combined use of both for the differentiation of benign and malignant nodules were compared, respectively.

RESULTS

Using CEUS alone, the sensitivity, specificity, PPV, NPV, and accuracy were 89.2%, 66.0%, 81.3%, 78.6%, and 80.5%, respectively. Using SWE alone, Emax was superior to Emin, Emean, and Eratio for the differentiation of benign and malignant nodules with the best cutoff Emax >46.8 kPa, which had sensitivity of 65.1%, specificity of 90.0%, PPV of 91.5%, NPV of 60.8%, and accuracy of 74.4%, respectively. Compared with the diagnostic performance of qualitative CEUS or/and quantitative SWE, the combination of CEUS and SWE had the best sensitivity, accuracy, and AUC; the sensitivity, specificity, PPV, NPV, accuracy, and AUC were 94.0%, 66.0%, 82.1%, 86.8%, 83.5%, and 0.80 (95% confidence interval: 0.713, 0.886), respectively.

CONCLUSION

In conclusion, CEUS and SWE were useful for the differentiation of benign and malignant ACR TI-RADS 4 and 5 category thyroid nodules coexisting with HT. The combination of CEUS and SWE could improve the sensitivity and accuracy compared with using CEUS or SWE alone. It could be a non-invasive, reliable, and useful method to differentiate benign from malignant ACR TI-RADS 4 and 5 category thyroid nodules coexisting with HT.

Prospective study and proposal of an outcome predictive nomogram in a consecutive prospective series of differentiated thyroid cancer based on the new ATA risk categories and TNM

INTRODUCTION

The personalized management of differentiated thyroid cancer (DTC) is currently based on the postoperative TNM staging system and the ATA risk stratification system (RSS), both updated in 2018 and 2015, respectively.

PURPOSE

We aimed to evaluate the impact of the last two editions of TNM and ATA RSS in the prediction of persistent/recurrent disease in a large series of DTC patients.

PATIENTS AND METHODS

Our prospective study included 451 patients undergone thyroidectomy for DTC. We classified the patients according to TNM (both VIII and VII ed.) and stratified them according to the ATA RSS (both 2015 and 2009). We then evaluated the response to the initial therapy after 12-18 months according to the ATA "ongoing" risk stratification, and analyzed the variables associated with persistent/recurrent disease by multivariate analysis.

RESULTS

The performance of the last two ATA RSSs was not significantly different. By staging patients according to the VIII or VII TNM editions, we found significant differences only in the distribution of patients with structural disease classified in stages III and IV. At multivariate analysis, only T-status and N-status were independently associated with persistent/recurrent disease. Overall, ATA RSSs and TNMs showed low predictive power in terms of persistent/recurrent disease (by Harrell's test).

CONCLUSIONS

In our series of DTC patients, the new ATA RSS as well as the VIII TNM staging provided no additional benefit compared to the previous editions. Moreover, the VIII TNM staging system may underestimate disease severity in patients with large and numerous lymph node metastases at diagnosis.

Evaluation of Guideline Adherence and Subsequent Follow-Up Outcomes for Incidental Thyroid Nodules Detected in Hybrid Academic-Community Practice

OBJECTIVE

Incidental thyroid nodules (ITNs) are common, and variability regarding follow-up and recommendation practices exist. The study purpose was to determine adherence to the American College of Radiology (ACR) ITN criteria and analyze recommendation outcomes.

METHODS

ITNs listed in the impression section on computed tomography, magnetic resonance imaging, and positron emission tomography studies over a 6-month period were included. Report recommendations were compared with ACR white paper criteria for adherence (concordant recommendation) or nonadherence (discordant recommendation). Reader characteristics, further ITN workup, and pathology were recorded. A P value less than 0.05 was used for significance.

RESULTS

Three hundred fifty patients (mean age, 64.6 years) were included with a median ITN size of 18-mm. Most nodules (289/350) were reported on computed tomography and were identified for follow-up due to size (235/350). Only 39 of 350 reports (11.1%) did not follow ACR recommendations. Patient age was significantly related to recommendation adherence (P < 0.05) as opposed to radiologist practice type (ie, community-based or academic) which was not. Nonadherence most often involved recommending ultrasound follow-up for nonactionable small ITNs. The rate of fine-needle aspiration biopsy from concordant ITNs was significantly higher than discordant ITNs (P < 0.05). Six patients, all with concordant recommendations, had malignant final pathology results.

CONCLUSION

Recommendation adherence to the ACR ITN criteria was high, approaching 90%. Nonadherence was mostly due to recommending thyroid ultrasound when not indicated and was correlated with a younger patient age. The rate of fine-needle aspiration biopsy stemming from nonindicated ultrasounds was significantly lower and did not result in the diagnosis of any malignancies.

Dual-source dual-energy computed tomography-derived quantitative parameters combined with machine learning for the differential diagnosis of benign and malignant thyroid nodules

Background

This study aimed to investigate the ability of quantitative parameter-derived dual-source dual-energy computed tomography (DS-DECT) combined with machine learning to distinguish between benign and malignant thyroid nodules.

Methods

Patients with thyroid nodules and pathological surgical results who underwent preoperative DS-DECT were selected. Quantitative parameter-derived DS-DECT was applied to classify benign and malignant nodules. Then, machine learning and binary logistic regression analysis models were constructed using the DS-DECT quantitative parameters to distinguish between benign and malignant nodules. The receiver operating characteristic curve was used to assess the diagnostic performance. The DeLong test was used to compare the diagnostic efficacy.

Results

One hundred and thirty patients with 139 confirmed thyroid nodules were involved in the study. The malignant group had a significantly higher iodine concentration_nodule (arterial phase) (P=0.001), normalized iodine concentration (arterial phase) (P=0.002), iodine concentration difference (P<0.001), spectral curve slope (nonenhancement) (P=0.007), spectral curve slope (arterial phase) (P=0.001), effective atomic number (nonenhancement) (P<0.001), and effective atomic number (arterial phase) (P=0.039) than the benign group. The binary logistic regression analysis model had an AUC (area under the curve) of 0.76, a sensitivity of 0.821, and a specificity of 0.667. The machine learning model had an AUC of 0.86, a sensitivity of 0.822, specificity of 0.791 in the training cohort, an AUC of 0.84, a sensitivity of 0.727, and specificity of 0.750 in the testing cohort.

Conclusions

Multiple quantitative parameters of DS-DECT combined with machine learning could differentiate between benign and malignant thyroid nodules.

The impact of the use of the ACR-TIRADS as a screening tool for thyroid nodules in a cancer center

BACKGROUND

The Thyroid Imaging Reporting and Data System (TIRADS) was created to assess risk of thyroid nodules through ultrasound. Plenty classifications methods for thyroid nodules have already been created, but none of them have yet achieved global utilization. This study analyzed the performance of the American College of Radiology (ACR) TIRADS, its reproducibility and the impact of its utilization as a screening method in a large Cancer Center cohort.

METHODS

Thyroid nodules which underwent fine-needle aspiration (FNA) in a 1-year period were selected, with their ultrasound images retrospectively classified according to the ACR TI-RADS. Cytological evaluation of the nodules and final histology (whenever available) was used to assess risk of neoplasm (RON) and risk of malignancy (ROM) associated to each ACR-TIRADS category. Further analyses were also carried out according to recommendation or not of FNA by the ACR-TIRADS and nodule size. Inter-observer agreement for the system was also assessed.

RESULTS

A total of 1112 thyroid nodules were included. RON for each category according to final cytological diagnosis was 0% for TR1 and TR2, 2.1% for TR3; 15.6% for TR4 and 68.9% for TR5. No significant difference was observed between the RON of the categories for cases above or below 1.0 cm. Nodules that met the criteria for FNA had 3 times greater chance of a positive outcome. Substantial agreement (kappa 0.77) was seen between two different observers.

CONCLUSIONS

ACR TI-RADS scoring system has demonstrated to be an accurate method to stratify thyroid nodules in a Cancer Center, with a high reproducibility.

Cost-Effectiveness of Follow-up Ultrasound for Incidental Thyroid Nodules on CT

Background: Thyroid nodules are common incidental findings on CT. Existing professional society recommendations, based primarily on expert opinion, advise follow-up ultrasound for nodules above size cut-offs in patients of all ages. Purpose: To evaluate the cost-effectiveness of current recommendations as well as of other age- and size-based follow-up strategies for thyroid nodules incidentally detected on CT, using a simulation model. Methods: By using a simulation model with 1,000,000 adult patients with nodules measuring ≤40 mm and having no suspicious features, we evaluated size cut-offs from 5 to 25 mm under an age maximum from 25 to 65 years, as well as follow-up versus no follow-up above the age maximum. For each strategy, patient survival was determined by disease-specific and baseline mortality rates, as well as surgical mortality. Costs and quality-adjusted life years (QALYs) were tabulated. A probabilistic sensitivity analysis was performed varying model parameters. Results: All cost-effective strategies recommended no follow-up for patients above the age cut-offs (which varied from 25 to 65 years). In the base case simulation, 8 strategies were cost-effective under a willingness-to-pay threshold of $100,000/QALY. Of these, the strategy yielding the highest QALYs was follow-up for patients <60 years old with nodules ≥10 mm and no follow-up for patients ≥60 years old, with an incremental cost-effectiveness ratio of $50,196/QALY (95% CI $39,233 - $67,479). In the probabilistic sensitivity analysis, if the 10-year disease-specific survival of untreated cancer was >94% of patients with treated cancer, then no follow-up for any nodules was optimal. Conclusion: Follow-up ultrasound for thyroid nodules incidentally detected on CT is likely not cost-effective in older patients. Follow-up for most thyroid nodules in younger patients may be cost-effective. Clinical Impact: Future societal recommendations may account for the limited benefit of obtaining follow-up for incidental thyroid nodules on CT in older patients.

The New Era of TIRADSs to Stratify the Risk of Malignancy of Thyroid Nodules: Strengths, Weaknesses and Pitfalls

Simple Summary

The aim of this review is to provide the reader with a comprehensive overview of thyroid imaging and reporting data systems used for thyroid nodules, so as to understand how nodules are scored with all existing systems. Both ultrasound based risk stratification systems and indications for fine-needle aspirations are described. Systems are compared by analyzing their strengths and weaknesses. Studies show satisfactory sensitivities and specificities for the diagnosis of malignancy for all systems, and none of them have shown a real significant advantage over the others in terms of raw diagnostic value. Interobserver agreement is also very similar for all systems, fairly adequate to robust. Dimensional cut-offs for fine-needle aspiration are quite similar and all RSSs seem to reduce effectively the number of unnecessary FNAs. Merging all existing systems in a common international one is desirable.

Abstract

Since 2009, thyroid imaging reporting and data systems (TI-RADS) have been playing an increasing role in the field of thyroid nodules (TN) imaging. Their common aims are to provide sonologists of varied medical specialties and clinicians with an ultrasound (US) based malignancy risk stratification score and to guide decision making of fine-needle aspiration (FNA). Schematically, all TI-RADSs scores can be classified as either pattern-based or point-based approaches. The main strengths of these systems are their ability (i) to homogenize US TN descriptions among operators, (ii) to facilitate and shorten communication on the malignancy risk of TN between sonologists and clinicians, (iii) to provide quantitative ranges of malignancy risk assessment with high sensitivity and negative predictive values, and (iv) to reduce the number of unnecessary FNAs. Their weaknesses are (i) the remaining inter-observer discrepancies and (ii) their insufficient sensitivity for the diagnosis of follicular cancers and follicular variant of papillary cancers. Most common pitfalls are degenerating shrinking nodules and confusion between individual and coalescent nodules. The benefits of all TI-RADSs far outweigh their shortcomings, explaining their rising use, but the necessity to improve and merge the different existing systems remains.

Incidental Thyroid Nodules on Imaging: Relevance and Management

Incidental thyroid nodules (ITNs) are commonly detected on imaging examinations performed for other reasons, particularly computed tomography (CT) (and now PET-CT and even PET-MR imaging), MR imaging, and sonography, primarily a consequence of the increasing sensitivity of these diagnostic modalities. Appropriate management of ITNs is crucial to avoid the cost and medical consequences of unnecessary workups.

Exploring physicians and patients' perspectives for current interventions on thyroid nodules using a MCDA method

BACKGROUND

The detection of thyroid cancer has rapidly increased over last few decades without an increase in disease specific mortality. Several studies claim that the diagnose of thyroid nodules through routine ultrasound imaging is often the trigger for cascade effects leading to unnecessary follow-up over many years or to invasive treatment. The objective of this study was to explore physicians' and patients' insights and preferences regarding the current interventions on thyroid nodules.

METHODS

An online survey was developed using a comprehensive multi-criteria decision analysis (MCDA) framework, the EVIdence based Decision-Making (EVIDEM). The EVIDEM core model used in this study encompassed 13 quantitative criteria and four qualitative criteria. Participants were asked to provide weights referring to what matters most important in general for each criterion, performance scores for appraising the interventions on thyroid nodules and their consideration of impact of contextual criteria. Normalized weights and standardized scores were combined to calculate a value contribution across all participants, additionally differences across physicians and patients' group were explored.

RESULTS

48 patients and 31 physicians were included in the analysis. The value estimate of the interventions on thyroid nodules reached 0.549 for patients' group and 0.5 was reported by the physicians' group, compared to 0.543 for all participants. The highest value contributor was 'Comparative effectiveness' (0.073 ± 0.020). For the physicians' group, 'Comparative safety' (0.050 ± 0.023) was given with higher value. And for the patients' group, 'Type of preventive benefits' (0.059 ± 0.022) contributed more positively to the value estimation. 51% participants considered 'Population priorities and access' having a negative impact on the interventions of nodules.66% participants thought that the 'system capacity' had a negative impact.

CONCLUSION

Our study shows participants' preferences on each criterion, i.e., physician indicated keeping the interventions safe and effective more important, patients indicated quality of life after receiving interventions more important. Through comparison among participants, differences have been highlighted, which can make better communication between physicians and patients. This study provides a supportive decision-making for healthcare providers when they explored the interventions on thyroid nodules.

Neck CT imaging and correlation with thyroid cancer incidence across age, gender and race

OBJECTIVE

Incidental detection of thyroid cancers has been proposed as a cause of thyroid cancer increases over past decades, but few studies assess the impact of imaging utilization on thyroid cancer incidence. This study quantifies neck CT prevalence and its relationship with thyroid cancer incidence as a function of age, sex and race.

DESIGN AND PATIENTS

Medical records of over 1 million patients at our institution were retrospectively analysed to quantify neck CT prevalence from 2004 to 2011 (study period). A national cancer database was used to compute thyroid cancer incidences over the study period and a reference period (1974-81) and to calculate change in thyroid incidence between the two periods. Both populations were partitioned into demographic subgroups of varying age, sex and race. Linear correlation between neck imaging and thyroid cancer incidence changes among subgroups was assessed using Pearson's correlation.

RESULTS

Neck CT imaging and change in thyroid cancer incidence varied across all examined demographic variables, particularly age. When stratifying by age, CT use correlated strongly with recent national thyroid cancer incidence (R = .97) and with 30-year change in thyroid cancer incidence (R = .87). Across all demographic subgroups, CT prevalence correlated strongly and positively with change in thyroid cancer incidence (R = .60), greater for whites (R = .60) and blacks (R = .70) than other races (R = .28).

CONCLUSION

Differences in neck CT usage strongly and positively correlates with the variation in thyroid cancer trends based on age, gender and race.

Update on ACR TI-RADS: Successes, Challenges, and Future Directions, From the AJR Special Series on Radiology Reporting and Data Systems

The American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) is an ultrasound-based risk stratification system (RSS) for thyroid nodules that was released in 2017. Since publication, research has shown that ACR TI-RADS has a higher specificity than other RSSs and reduces the number of unnecessary biopsies of benign nodules compared with other systems by 19.9-46.5%. The risk of missing significant cancers using ACR TI-RADS is mitigated by the follow-up recommendations for nodules that do not meet criteria for biopsy. In practice, after a nodule's ultrasound features have been enumerated, the ACR TI-RADS points-based approach leads to clear management recommendations. Practices seeking to implement ACR TI-RADS must engage their radiologists in understanding how the system addresses the problems of thyroid cancer overdiagnosis and unnecessary surgeries by reducing unnecessary biopsies. This review compares ACR TI-RADS to other RSSs and explores key clinical questions faced by practices considering its implementation. We also address the challenge of reducing interobserver variability in assigning ultrasound features. Finally, we highlight emerging imaging techniques and recognize the ongoing international effort to develop a system that harmonizes multiple RSSs, including ACR TI-RADS.

The undiagnosed potential clinically significant incidental findings of neck CTA: A large retrospective single-center study

To assess the prevalence and missed reporting rate of potential clinically-significant incidental findings (IFs) in the neck CTA scans.All consecutive patients undergoing neck CTA imaging, from January 1, 2017 to December 31, 2018, were retrospectively evaluated by a radiologist for the presence of incidental findings in the upper chest, lower head and neck regions. These incidental findings were subsequently classified into 3 categories in terms of clinical significance: Type I, highly significant, Type II, moderately significant; and Type III, mildly or not significant. Type I and Type II IFs were determined as potential clinically significant ones and were retrospectively analyzed by another 2 radiologists in consensus. The undiagnosed findings were designated as those that were not reported by the initial radiologists. The differences in the rate of unreported potential clinically significant IFs were compared between the chest group and head or neck group.A total of 376 potential clinically significant IFs were detected in 1,698 (91.19%) patients, of which 175 IFs were classified as highly significant findings (Type I), and 201 (53.46%) as moderately significant findings (Type II). The most common potential clinically significant findings included thyroid nodules (n = 88, 23.40%), pulmonary nodules (n = 56, 14.89%), sinus disease (n = 39, 10.37%), intracranial or cervical artery aneurysms (n = 30, 7.98%), enlarged lymph nodes (n = 24, 6.38%), and pulmonary embolism (n = 19, 5.05%). In addition, 184 (48.94%) of them were not mentioned in the initial report. The highest incidence of missed potential clinical findings were pulmonary embolism and pathologic fractures and erosions (100% for both). The unreported rate of the chest group was significantly higher than that of the head or neck one, regardless of Type I, Type II or all potential clinically significant IFs (χ = 32.151, χ = 31.211, χ = 65.286, respectively; P < .001 for all).Important clinically significant incidental findings are commonly found in a proportion of patients undergoing neck CTA, in which nearly half of these patients have had potential clinically significant IFs not diagnosed in the initial report. Therefore, radiologists should beware of the importance of and the necessity to identify incidental findings in neck CTA scans.

Thyroid Incidentalomas: Practice Considerations for Radiologists in the Age of Incidental Findings

Radiologists very frequently encounter incidental findings related to the thyroid gland. Given increases in imaging use over the past several decades, thyroid incidentalomas are increasingly encountered in clinical practice, and it is important for radiologists to be aware of recent developments with respect to workup and diagnosis of incidental thyroid abnormalities. Recent reporting and management guidelines, such as those from the American College of Radiology and American Thyroid Association, are reviewed along with applicable evidence in the literature. Trending topics, such as artificial intelligence approaches to guide thyroid incidentaloma workup, are also discussed.

Active surveillance in low risk papillary thyroid carcinoma

In recent decades, while the incidence of thyroid cancer has increased exponentially around the world, mortality has remained stable. The vast majority of this increase is attributable to the identification of intrathyroidal papillary microcarcinomas, which exhibit slow growth rates with indolent courses. A diagnosis of thyroid cancer based upon the presence of these small tumors could be considered as an overdiagnosis, as the majority of these tumors would not likely result in death if left untreated. Although surgical resection was the classical standard therapy for papillary microcarcinomas, active surveillance (AS) has emerged over the last three decades as an alternative approach that is aimed to recognize a minority group of patients who will clinically progress and would likely benefit from rescue surgery. Despite the encouraging results of AS, its implementation in clinical practice is strongly influenced by psychosocial factors. The aim of this review is to describe the epidemiology, clinical evolution, prognostic factors, and mortality of papillary thyroid microcarcinomas. We also summarize the AS strategy according to published evidence, characterize the criteria for selecting patients for AS according to risk factors and environmental characteristics, as well as analyze the current limitations for AS implementation.

Classification and Regression Tree (CART) model of sonographic signs in predicting thyroid nodules malignancy

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Taller-than-wide thyroid nodules are more likely to require surgery.

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A taller-than-wide, solid and hypoechoic thyroid nodule is likely a Bethesda 4 or 5.

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Taller-than-wide sonographic sign is the strongest in predicting thyroid malignancy.

Purpose

To develop a Classification and Regression Tree (CART) model in order to recognize the most suspicious sonographic features of thyroid nodules and efficiently guide their management.

Methods

791 thyroid fine needle aspiration cytology (FNAC) performed under ultrasound guidance between January 2015 and January 2017 were reviewed. Retrieved data consisted in qualitative (patient’s gender, composition, echogenicity, shape, margins and echogenic foci of the nodule) and quantitative (patient’s age and maximal diameter of the nodule) variables as well as the Bethesda score.

Results

Patients were 48.5 ± 13.7 years old with female to male ratio of 8:2. The nodules had median size of 2.3 (1.5–3.5) cm with a majority of solid (62.5 %) and isoechoic (50.8 %) features. 700 nodules (88.5 %) had a wider-than-tall shape, 600 (75.9 %) smooth margins and 113 (14.3 %) ill-defined ones. Echogenic foci were absent in 388 nodules (49.1 %) and, when present, largely dominated by punctate foci (32.5 %). Bethesda classes 3, 4 and 5, which require surgery, represented only 10.6 % of cases. They were significantly correlated with the taller-than-wide shape and with solid or predominantly solid features. There was no significant correlation between echostructure and Bethesda scores but we did find more nodules classified Bethesda 4 and 5 in the categories hypoechoic and severely hypoechoic. In the CART model we developed, the sequence leading to most nodules classified Bethesda 4 and 5 is: taller-than-wide shape, solid composition and hypoechoic or severely hypoechoic feature.

Conclusions

Taller-than-wide, solid or predominantly solid, hypoechoic or severely hypoechoic nodules are likely to require surgery and might benefit from FNAC.

Active surveillance for prostate and thyroid cancers: evolution in clinical paradigms and lessons learned

The adverse effects of overdiagnosis and overtreatment observed in men with clinically insignificant prostate cancers after the introduction of prostate-specific antigen-based screening are now being observed in those with thyroid cancer, owing to the introduction of new imaging technologies. Thus, the evolving paradigm of active surveillance in prostate and thyroid cancers might be valuable in informing the development of future active surveillance protocols. The lessons learned from active surveillance and their implications include the need to minimize the use of broad, population-based screening programmes that do not incorporate patient education and the need for individualized or shared decision-making, which can decrease the extent of overtreatment. Furthermore, from the experience in patients with prostate cancer, we have learned that consensus is required regarding the optimal selection of patients for active surveillance, using more-specific evidence-based methods for stratifying patients by risk. In this Review, we describe the epidemiology, pathology and screening guidelines for the management of patients with prostate and thyroid cancers; the evidence of overdiagnosis and overtreatment; and provide overviews of existing international active surveillance protocols.

Evolving Understanding of the Epidemiology of Thyroid Cancer

The incidence of thyroid cancer worldwide has increased significantly over the past 3 decades, due predominantly to an increase in papillary thyroid cancer. Although most of these cancers are small and localized, population-based studies have documented a significant increase in thyroid cancers of all sizes and stages, in addition to incidence-based mortality for papillary thyroid cancer. This suggests that the increasing incidence of thyroid cancer is due in large part to increasing surveillance and overdiagnosis, but that there also appears to be a true increase in new cases of thyroid cancer.

Incidental Thyroid Nodules in the National Lung Screening Trial: Estimation of Prevalence, Malignancy Rate, and Strategy for Workup

RATIONALE AND OBJECTIVES

There is limited research on the prevalence of incidental thyroid nodules (ITNs) in the United States screening population and on the appropriate evaluation of computed tomography (CT)-detected ITNs. The purpose of this study is to determine the prevalence of ITNs in the National Lung Screening Trial (NLST) and develop a workup strategy for ITNs.

MATERIALS AND METHODS

CT images were obtained for subjects with documented thyroid abnormalities in the CT screening arm of the NLST, subjects diagnosed with thyroid malignancies, and control subjects. Several size thresholds were compared to determine how many nodules would be further evaluated and how many thyroid malignancies would be missed had each threshold been applied at the time of workup.

RESULTS

Thyroid nodules were reported in 0.7% (117 of 17,309 subjects). In 663 control subjects without reported thyroid nodules, thyroid nodules were identified in 78 (11.8%). Reported nodules were larger than unreported nodules (21.3 vs 16.9 mm, P = .03). Thyroid malignancies were diagnosed in 0.1% (22 of 17,309). If a 20-mm rather than a 10-mm cutoff were used to determine which nodules should be further evaluated, all malignancies would be detected, but 24 rather than 62 patients would require workup, for a workup reduction rate of 48.7% (38 of 78).

CONCLUSIONS

Less than 1% of subjects in the NLST had reported ITNs. The true prevalence of ITNs was estimated to be 11.8%, which provides a better approximation of the number of patients who could potentially receive workup. A 20-mm rather than a 10-mm cutoff would reduce the workup rate by almost 50% while still capturing all malignancies.

Effect of Tumor Size on Risk of Metastatic Disease and Survival for Thyroid Cancer: Implications for Biopsy Guidelines

BACKGROUND

In many risk-stratification systems, the decision to biopsy thyroid nodules is determined by their sonographic features and size. Nevertheless, even low-suspicion nodules are often biopsied at small size thresholds because it is assumed that larger malignant nodules are associated with poorer outcomes. The aim of this study was to quantify the effect of thyroid cancer tumor size on survival and risk of T4 stage, nodal disease, and distant metastases.

METHODS

The Surveillance, Epidemiology, and End Results 18 database was queried to obtain tumor size, staging information, and survival data for cases of differentiated thyroid cancer (DTC) and non-DTC reported between 2004 and 2014. Observed probabilities of tumor extent at diagnosis, including regional nodal disease and distant metastases, as a function of size and tumor histology were estimated for thyroid cancers measuring between 1 and 150 mm. A multivariate Cox regression model was used to describe all-cause mortality as a function of patient and tumor characteristics, and the functional dependence of mortality on size was computed.

RESULTS

A total of 112,128 patients were analyzed, with 67% having thyroid cancers ≥1 cm, and 29% ≥ 2.5 cm. For DTC tumors <4 cm, the risk of local invasion, nodal metastases, or distant metastases was low, and there was no size threshold associated with a sharp rise in adverse outcomes. For DTC tumors <4 cm, the probability of distant metastases was <3%. Older age, male sex, non-DTC histology, T4 stage, and regional and distant metastatic disease increased the all-cause mortality rate. Tumor size did not increase the mortality rate above baseline until tumors were >2.5 cm.

CONCLUSION

Increasing tumor size does not affect survival until a threshold of 2.5 cm. Since the dimension of nodules on ultrasound has been shown to be larger than their size at gross pathology, these findings suggest that recommended size thresholds to biopsy low-suspicion thyroid nodules can be increased.

The presence of papillary features in thyroid nodules diagnosed as atypia of undetermined significance or follicular lesion of undetermined significance increases cancer risk and should influence treatment

BACKGROUND

The objective of this study was to evaluate the influence of papillary features on risk of malignancy (ROM) within the Atypia of Undetermined Significance or Follicular Lesion of Undetermined Significance (AUS-FLUS) Bethesda System for Reporting Thyroid Cytopathology (BSRTC) diagnostic category.

METHODS

A Retrospective review of cases with an AUS-FLUS diagnosis that underwent a thyroidectomy was carried out, and cases were subcategorized based upon the presence of papillary features.

RESULTS

For the entire study population there were 93 (22%) of 427 FNAB specimens that had an AUS-FLUS diagnosis, and a 32% associated ROM. Papillary features were identified in 44 FNAB specimens (47% of the AUS-FLUS cases or 10% of the entire study population), and when present had a 45% ROM. The 49 FNAB specimens (53%) that did not exhibit papillary features had a significantly lower ROM (20%) than those that did have papillary features (p = 0.0069).

CONCLUSIONS

The presence of papillary features in a thyroid FNAB with an AUS-FLUS diagnosis is common, and is associated with a higher ROM than is currently suggested by the BSRTC.

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.

The effect of routine radiological reporting of thyroid incidentalomas on rates of thyroid needle biopsy, thyroid surgery and detection of thyroid malignancy

OBJECTIVE

This study looked at the effect of a changing radiology reporting policy to routinely review the thyroid gland where visible and report on any thyroid lesion, recommending further investigation as appropriate.

CONTEXT

Incidentaloma is a term used to describe a lesion found on imaging unrelated to the clinical issue under investigation. There is variability in the radiological reporting of thyroid incidentalomas and conflicting recommendations as to how these lesions should be managed.

DESIGN

Data were collected retrospectively during a two-year period, including 12 months before and 12 months after the change in reporting policy and categorized according to whether the lesion under investigation was a thyroid incidentaloma or a symptomatic thyroid lesion.

PATIENTS

All patients undergoing ultrasound-guided fine-needle aspiration cytology or core biopsy were included.

MEASUREMENTS

The effects of the change in policy were analysed including rates of needle biopsy, rates of malignancy and subsequent surgical intervention.

RESULTS

There was a 122% increase in thyroid incidentalomas undergoing needle biopsy, the majority of these were detected on computed tomography. The number of malignancies increased from 1 to 4 from year 1 to year 2. All patients were >35 years old. One patient had a positron emission tomography (PET)-detected cancer, two of four of the non-PET-detected malignancies were <1.5 cm.

CONCLUSION

This study posits that routine radiological reporting of thyroid incidentalomas, with further investigation when clinically appropriate, is warranted. The results suggest that lesion size and CT characteristics are not reliable criteria to triage patients for investigation/biopsy.

1.5-2 cm tumor size was not associated with distant metastasis and mortality in small thyroid cancer: A population-based study

Most guidelines for the diagnosis and management of thyroid nodules have suggested fine-needle aspiration as a diagnostic tool, with some of these previously published guidelines suggesting a cutoff size of 1.5 cm. In thyroid cancers (1–2 cm), we hypothesized that tumors 1.5 cm or larger had more unfavorable clinical outcomes than ones smaller than 1.5 cm nodules. Using the Surveillance, Epidemiology, and End Results database, we identified 14,117 patients diagnosed with only primary thyroid cancer between 1988 and 2007. After multivariable adjustment, we found that having a tumor 1.5 cm or larger in size was not associated with distant metastasis [adjusted odds ratio, 1.18; 95% confidence interval (CI), 0.95 to 1.48; P = 0.14] or the two causes of death (adjusted subdistributional hazard ratio (SDHR), 1.40; 95% CI, 0.96 to 2.04; P = 0.08 for thyroid cancer mortality; adjusted SDHR, 1.06; 95% CI, 0.88 to 1.27; P = 0.55 for noncancer mortality). Using a population-based cohort, in patients with primary thyroid cancer with a tumor size of 1.5–2 cm, there was no increased association with distant metastasis or probability of death, when compared with patients with primary thyroid cancer with a tumor size of 1.0–1.5 cm.

ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee

classification that is widely used in breast imaging, their authors chose to apply the acronym TI-RADS, for Thyroid Imaging, Reporting and Data System. In 2012, the ACR convened committees to (1) provide recommendations for reporting incidental thyroid nodules, (2) develop a set of standard terms (lexicon) for ultrasound reporting, and (3) propose a TI-RADS on the basis of the lexicon. The committees published the results of the first two efforts in 2015. In this article, the authors present the ACR TI-RADS Committee's recommendations, which provide guidance regarding management of thyroid nodules on the basis of their ultrasound appearance. The authors also describe the committee's future directions.

Applying Criteria of Active Surveillance to Low-Risk Papillary Thyroid Cancer Over a Decade: How Many Surgeries and Complications Can Be Avoided?

BACKGROUND

The 2015 American Thyroid Association guidelines acknowledged that "an active surveillance management approach can be considered as an alternative to immediate surgery" in patients with low-risk papillary thyroid carcinoma (PTC). The aim of this study was to determine the proportion of PTC that would meet the criteria for active surveillance and the surgeries and complications that could have been avoided.

METHODS

A total of 681 patients with thyroid cancer who underwent thyroid surgery from 2003 to 2012 were retrospectively reviewed. A decision-making framework for active surveillance was applied to patients with PTC in nodules measuring ≤1.5 cm on ultrasound. Patients were identified as suitable for active surveillance based on imaging and patient characteristics. These patients were reviewed for management and outcomes.

RESULTS

PTC was diagnosed based on fine-needle aspiration histology of Bethesda V or VI in thyroid nodules in 243 patients. Of these, 77 patients had nodules measuring ≤1.5 cm on ultrasound, and 56/77 (23%) patients met the criteria for surveillance: 15/243 (6%) patients met the criteria with a ≤1 cm size threshold, and 41/243 (17%) met the criteria with a 1.1-1.5 cm threshold. Of the 56 patients who met the criteria for active surveillance, 52 underwent total thyroidectomy, and four had a lobectomy. Forty-five (80%) patients had elective central nodal dissection, and 14 had nodal metastases on pathology (all <4 mm). Three patients had permanent complications from surgery, including vocal cord paralysis, hypoparathyroidism, and a chipped tooth from intubation. No patients died or had recurrent disease.

CONCLUSION

Future programs in the United States should consider increasing the size threshold for active surveillance of PTC to 1.5 cm, since this will allow up to one quarter of patients to be eligible instead of only 6% with a 1 cm size threshold. Without an active surveillance program, the majority of patients with low-risk cancers have thyroidectomy and carry a small risk of permanent complications.

The Incidental Thyroid Lesion in Parathyroid Disease Management

Objective

The incidental thyroid lesion is a common finding during general imaging studies. Their management has been the subject of numerous studies and recommendations. Parathyroid disease workup necessitates imaging investigation of the adjacent thyroid gland and therefore provides a unique window to the perioperative management of thyroid incidentaloma. The specific prevalence of incidental thyroid lesions in the context of parathyroid disease is unknown. We seek to investigate its prevalence during parathyroid workup and surgery and to ascertain if there was a change in management of these patients.

Study Design

Five-year retrospective database review.

Setting

Tertiary care medical center.

Subjects and Methods

The source and indication for referral, preoperative investigation findings, and management of the incidental thyroid lesions were examined. The actual procedure performed and final pathology results were assessed.

Results

A total of 98 patients and 106 operations, including revision surgeries, were identified. There were 21 incidental thyroid lesions (21.4%) detected, whereby 15 patients underwent fine-needle aspirations and 12 subsequently had diagnostic hemithyroidectomies. This decision was made preoperatively in 5 patients and intraoperatively in 7 patients at the time of parathyroid surgery. Along with other pathologies, there were 7 patients with micropapillary thyroid carcinoma identified.

Conclusions

In our series, the prevalence of incidental thyroid lesion and thyroid malignancy is comparable to the general population. The management of the initial parathyroid disease in our patients was altered by the imaging and cytological findings of these thyroid lesions. This has implications on perioperative counseling of the thyroid and parathyroid disease.

Incidental thyroid nodules on thoracic contrast-enhanced computed tomography in clinical practice during a 10-year period: Characteristics, clinical outcomes, and factors contributing to further evaluation

The purposes of this study were to assess the prevalence, malignancy rate, and characteristics of incidental thyroid nodules (ITNs), and to identify factors that contribute the additional workup by ultrasound.The medical records and imaging features of ITNs reported via thoracic computed tomography (CT) were retrospectively reviewed to determine the size, multiplicity, attenuation, shape, and presence of calcification. To identify the factors associated with additional workup, we compared the workup and non-workup groups in terms of nodule characteristics, indications, and CT slices. We identified factors that could distinguish malignant ITNs from non-malignant nodules.A total of 60,921 thoracic CT scans met the inclusion criteria, and ITNs were reported using formal radiology in 2733 patients (4.5%). Among all patients with reported ITNs, 546 (20.0%) underwent further workup. Of these patients, 62 (2.3%, 62/2773) were diagnosed with malignant nodules. Multivariable analysis identified multiple factors associated with additional workup, including female sex, younger age, larger nodule size, calcification, anteroposterior to transverse dimension ratio >1, heterogeneous attenuation in the nodule, and scanning indications such as infection or screening. However, only calcification was associated with malignant nodules (odds ratio [OR] = 2.313; 95% confidence interval [CI], 1.301-4.113).We observed discordance between the numbers of reported ITNs and case with additional workup and identified multiple factors associated with additional workup. We have, therefore, demonstrated a need for reliable subsequent evaluation guidelines and note that the appearance of calcification in an ITN on imaging may be a factor indicating the need for additional workup.

Improving Access to Image-guided Procedures at an Integrated Rural Critical Access Hospital: Ultrasound-guided Thyroid Biopsy Program

PURPOSE

Critical access hospitals face difficulty providing all services locally and may need to refer patients off-site for additional care. Providing on-site minimally invasive biopsies, may obviate visits to tertiary or quaternary care centers. This study aims to assess feasibility and outcomes of an ultrasound-guided thyroid biopsy program in a critical access hospital.

METHODS

In this HIPAA compliant, IRB approved study, the Interventional Radiology (IR) database of a 19-bed, island, rural, critical access hospital without onsite pathology services affiliated with our quaternary care institution was retrospectively reviewed to identify all thyroid biopsies that were performed on site since inception of the service in April 2014 through August 2016. A specialized biopsy and specimen collection protocol was created as each specimen was transferred to and analyzed by the pathology department at our affiliated quaternary care institution.

RESULTS

Two IR physicians carried out thyroid biopsies on 34 nodules in 29 patients during the study period. The mean age of patients was 56.5 ± 14.0, with a range of 35-85 and 86% female, 14% male. 94.1% of nodules had adequate material for interpretation on the first biopsy and 97.1% upon repeat biopsy. Ultimately, 5 patients (with 6 nodules) underwent surgical resection at the integrated quaternary care center. Surgical resection identified one atypical follicular adenoma, one follicular variant of papillary thyroid carcinoma, two papillary carcinomas, and two Hürthle cell tumors.

CONCLUSION

IR thyroid biopsy services may be successfully provided in the rural setting without onsite pathology analysis and adequacy checks, enhancing patient access and streamlining care while also expanding the reach of tertiary care centers.

Thyroid computed tomography imaging: pictorial review of variable pathologies

Abstract

Focal and diffuse thyroid abnormalities are commonly encountered during the interpretation of computed tomography (CT) exams performed for various clinical purposes. These findings can often lead to a diagnostic dilemma, as the CT reflects the nonspecific appearances. Ultrasound (US) examination has a superior spatial resolution and is considered the modality of choice for thyroid evaluation. Nevertheless, CT detects incidental thyroid nodules (ITNs) and plays an important role in the evaluation of thyroid cancer.

In this pictorial review, we cover a wide spectrum of common and uncommon, incidental and non-incidental thyroid findings from CT scans. We also discuss the most common incidental thyroid findings, best practices for their evaluation, and recommendations for their management. In addition, we explore the role of imaging in the assessment of thyroid carcinoma (before and after treatment) and preoperative thyroid goiter, as well as localization of ectopic and congenital thyroid tissue.

Teaching Points

• Thyroid disorders tend to have non-specific CT appearances.

• ITNs are common on neck CT.

• ITN management depends on nodule size, age, health status, lymphadenopathy, and invasion.

• CT is used in assessment of cancer extension, mass effect, invasion, and recurrence.

• CT plays a role in preoperative planning in patients with symptomatic goiter.

Extra-cardiac findings in cardiovascular magnetic resonance: what the imaging cardiologist needs to know

Cardiovascular magnetic resonance (CMR) is an established non-invasive technique to comprehensively assess cardiovascular structure and function in a variety of acquired and inherited cardiac conditions. A significant amount of the neck, thorax and upper abdomen are imaged at the time of routine clinical CMR, particularly in the initial multi-slice axial and coronal images. The discovery of unsuspected disease at the time of imaging has ethical, financial and medico-legal implications. Extra-cardiac findings at the time of CMR are common, can be important and can change clinical management. Certain patient groups undergoing CMR are at particular risk of important extra-cardiac findings as several of the cardiovascular risk factors for atherosclerosis are also risk factors for malignancy. Furthermore, the presence of certain extra-cardiac findings may contribute to the interpretation of the primary cardiac pathology as some cardiac conditions have multi-systemic extra-cardiac involvement. The aim of this review is to give an overview of the type of extra-cardiac findings that may become apparent on CMR, subdivided by anatomical location. We focus on normal variant anatomy that may mimic disease, common incidental extra-cardiac findings and important imaging signs that help distinguish sinister pathology from benign disease. We also aim to provide a framework to the approach and potential further diagnostic work-up of incidental extra-cardiac findings discovered at the time of CMR. However, it is beyond the scope of this review to discuss and determine the clinical significance of extracardiac findings at CMR.

Computed tomography features of benign and malignant solid thyroid nodules

BACKGROUND

No previous study has investigated computed tomography (CT) features of benign and malignant solid thyroid nodules using detailed CT features and histopathological results.

PURPOSE

To assess CT features of benign and malignant solid thyroid nodules in patients who underwent thyroid surgery.

MATERIAL AND METHODS

From January to April 2014, 151 consecutive patients underwent neck CT before thyroid surgery. In each case, neck CT was retrospectively examined by a single radiologist. We evaluated the diagnostic accuracy of specific CT features for differentiating malignant from benign thyroid nodules using histopathological results as a reference standard.

RESULTS

Of 173 thyroid nodules in 142 patients, 162 (mean diameter, 12.8 ± 10.3 mm; range, 5.0-93.7 mm) were visualized on neck CT. Of 162 nodules in 133 patients, 116 were malignant and 46 were benign as confirmed by histopathology. A multivariate logistic regression analysis showed a significant difference between malignant and benign thyroid nodules in the degree and pattern of nodular enhancement, but there were no significant differences in other CT features. In particular, thyroid nodules with exophytic configuration, irregular margin, taller-than-wide shape, punctate calcifications, or homogeneously decreased enhancement showed a high malignancy rate.

CONCLUSION

The study demonstrated that the degree and pattern of nodular enhancement are helpful CT features for differentiating malignant from benign solid thyroid nodules.

Overdiagnosis of thyroid cancer: answers to five key questions

Thyroid cancer fulfills the criteria for overdiagnosis by having a reservoir of indolent cancers and practice patterns leading to the diagnosis of incidental cancers from the reservoir. The occurrence of overdiagnosis is also supported by population-based data showing an alarming rise in thyroid cancer incidence without change in mortality. Because one of the activities leading to overdiagnosis is the workup of incidental thyroid nodules detected on imaging, it is critical that radiologists understand the issue of overdiagnosis and their role in the problem and solution. This article addresses 1) essential thyroid cancer facts, 2) the evidence supporting overdiagnosis, 3) the role of radiology in overdiagnosis, 4) harms of overdiagnosis, and 5) steps radiologists can take to minimize the problem.

Benign and Malignant Thyroid Incidentalomas Are Rare in Routine Clinical Practice: A Review of 97,908 Imaging Studies

PURPOSE

Thyroid nodules incidentally identified on imaging are thought to contribute to the increasing incidence of thyroid cancer. We aim to determine the true rate of incidental thyroid nodule reporting, malignancy rates of these nodules, and to compare these findings with rates of detection by dedicated radiology review.

METHODS

A cross-sectional analysis was done to determine the prevalence of thyroid nodules in radiologist reports by analyzing all reports for CT, PET, and MRI scans of the head, neck, and chest as well as neck ultrasounds performed at a tertiary care center from 2007 to 2012. Retrospective chart review was performed on patients with a reported thyroid nodule to determine clinical outcomes of these nodules. Radiology reports were compared with dedicated radiology review of 500 randomly selected CT scans from the study group to determine the difference between clinical reporting and actual prevalence of thyroid nodules.

RESULTS

97,908 imaging studies met inclusion criteria, and 387 (0.4%) thyroid incidentalomas were identified on radiology report. One hundred and sixty three (42.1%) of these nodules were worked up with fine-needle aspiration, diagnosing 27 thyroid cancers (0.03% of all studies, 7.0% of reported incidentalomas). The prevalence of incidentalomas clinically reported was 142/100,000 CT scans, 638/100,000 MRIs, 358/100,000 PET scans, and 6,594/100,000 ultrasounds. In contrast, review of CT scans screening for thyroid nodules had a prevalence of 10%.

CONCLUSION

Routine clinical reporting of incidental thyroid nodules is far less common than on dedicated review.

IMPACT

These data contradict the notion that incidentalomas contribute significantly to rising thyroid cancer rates.