Imaging for staging and management of thyroid cancer

What Features Predict Poorer Outcomes in Micropapillary Thyroid Carcinoma? A Retrospective Cohort Study

OBJECTIVE

Micropapillary thyroid carcinoma (MPTC), a variant of papillary thyroid carcinoma sized ≤10 mm, is increasingly detected due to advanced ultrasound. This study aimed to describe characteristics and risk assessment of patients with MPTC to predict outcomes and guide initial management.

METHODS

This retrospective cohort study (June 1980 to September 2023) assessed patients with MPTC using 2015 American Thyroid Association guidelines for risk stratification and determination of response to treatment. Outcomes ranged from excellent to structural incomplete responses.

RESULTS

Among 208 patients with papillary thyroid carcinoma with a primary tumor focus ≤10 mm, 68.8% were low risk, 29.3% intermediate risk, and 1.9% high risk. Higher risk was linked to larger tumor size (≥7 mm) (odds ratio [OR], 3.196; P value = .001) and multifocality (OR, 2.431; P value = .004). Age (OR, 0.973; P value = .048) and background Hashimoto thyroiditis (OR, 0.439; P value = .014) were found as protective factors. Excellent response to therapy was observed in 48.4% of patients, whereas structural and biochemical incomplete responses were found to be 11.2% and 7.5%. Recurrence was detected in 14 (8.18%) patients.

CONCLUSION

MPTC generally has a good prognosis and responds well to the treatment. Larger tumors (≥7 mm), younger age (<40 years), multifocality, and absence of Hashimoto thyroiditis correlate with a higher American Thyroid Association risk and poorer outcomes.

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.

Thyroid Cancer Central Lymph Node Metastasis Risk Stratification Based on Homogeneous Positioning Deep Learning

Due to the absence of definitive diagnostic criteria, there remains a lack of consensus regarding the risk assessment of central lymph node metastasis (CLNM) and the necessity for prophylactic lymph node surgery in ultrasound-diagnosed thyroid cancer. The localization of thyroid nodules is a recognized predictor of CLNM; however, quantifying this relationship is challenging due to variable measurements. In this study, we developed a differential isomorphism-based alignment method combined with a graph transformer to accurately extract localization and morphological information of thyroid nodules, thereby predicting CLNM. We collected 88,796 ultrasound images from 48,969 patients who underwent central lymph node (CLN) surgery and utilized these images to train our predictive model, ACE-Net. Furthermore, we employed an interpretable methodology to explore the factors influencing CLNM and generated a risk heatmap to visually represent the distribution of CLNM risk across different thyroid regions. ACE-Net demonstrated superior performance in 6 external multicenter tests (AUC = 0.826), surpassing the predictive accuracy of human experts (accuracy = 0.561). The risk heatmap enabled the identification of high-risk areas for CLNM, likely correlating with lymphatic metastatic pathways. Additionally, it was observed that the likelihood of metastasis exceeded 80% when the nodal margin's minimum distance from the thyroid capsule was less than 1.25 mm. ACE-Net's capacity to effectively predict CLNM and provide interpretable disease-related insights can importantly reduce unnecessary lymph node dissections by 37.9%, without missing positive cases, thus offering a valuable tool for clinical decision-making.

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.

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.

Can Routine Laboratory Tests Be Suggestive in Determining Suspicions of Malignancy in the Case of Thyroid Nodules?

Background and objectives: Thyroid nodules are a common finding in clinical practice and can be either benign or malignant. The aim of this study was to compare laboratory parameters between patients with malignant thyroid nodules and those with benign thyroid nodules. Materials and methods: A total of 845 patients were included, with 251 in the study group (malignant thyroid nodules) and 594 in the control group (benign thyroid nodules). Results: Our results show that there were statistically significant differences in several laboratory parameters, including FT3, FT4, ESR, fibrinogen, WBC, and lymphocyte percentage, between the two patient groups (p < 0.05). Conclusions: These findings suggest that certain laboratory parameters may be useful in differentiating between benign and malignant thyroid nodules and could aid in the diagnosis and treatment of thyroid cancer. However, further diagnostic tests such as fine-needle aspiration biopsy and imaging studies are typically required for an accurate diagnosis. Routine laboratory tests prove most effective when combined with other diagnostic methods to identify thyroid cancer. Although not conclusive on their own, these tests significantly suggest and guide physicians to suspect malignancy in thyroid nodules. This affirmative answer to our question, "Can routine laboratory tests be suggestive in determining suspicions of malignancy in the case of thyroid nodules?" aligns with the results of our study.

A systematic review and meta-analysis comparing tumor progression and complications between radiofrequency ablation and thyroidectomy for papillary thyroid carcinoma

BACKGROUND

Papillary thyroid cancer (PTC) is the most frequent thyroid cancers worldwide. The efficacy and acceptability of radiofrequency ablation (RFA) in the treatment of PTC have been intensively studied. The aim of this study is to focus on extra detailed that may influent for PTC or papillary thyroid microcarcinoma (PTMC).

MATERIALS AND METHODS

We identified a total of 1,987 records of a primary literature searched in PubMed, Embase, Cochrane Library, and Google Scholar by key words, from 2000 to 2022. The outcome of studies included complication, costs, and local tumor progression. After scrutiny screening and full-text assessment, six studies were included in the systematic review. Heterogeneity was estimated using I2, and the quality of evidence was assessed for each outcome using the GRADE guidelines.

RESULTS

Our review enrolled 1,708 patients reported in six articles in the final analysis. There were 397 men and 1,311 women in the analysis. Two of these studies involved PTC and four focused on PTMC. There were 859 patients in the RFA group and 849 patients in the thyroidectomy group. By contrast, the tumor progression of RFA group was as same as that surgical groups [odds ratio, 1.31; 95% CI, 0.52-3.29; heterogeneity (I2 statistic), 0%, p = 0.85]. The risk of complication rates was significantly lower in the RFA group than that in the surgical group [odds ratio, 0.18; 95% CI, 0.09-0.35; heterogeneity (I2 statistic), 40%, p = 0.14].

CONCLUSIONS

RFA is a safe procedure with a certain outcome for PTC. RFA can achieve a good efficacy and has a lower risk of major complications.

Nanoparticles: Promising Auxiliary Agents for Diagnosis and Therapy of Thyroid Cancers

Simple Summary

Thyroid cancer (TC) is rare relative to cancers of many other organs (breast, prostate, lung, and colon). The majority of TCs are differentiated tumors that are relatively easy to treat and have a good prognosis. However, for anaplastic TC, a rapidly growing and aggressive tumor, treatment is suboptimal because the effective drugs cause severe adverse effects. Drug delivery by nanocarriers can improve treatment by reducing side effects. This can either be mediated through better retention in the tumor tissue due to size (passive targeting) or through the attachment of specific molecules that zero in on the cancer cells (active targeting). Nanoparticles are already used for diagnosis and imaging of TC. For unresectable anaplastic TC, nanoparticle-based treatments, less suitable for deeply located cancers, could be useful, based on low-intensity focused ultrasound and near-infrared irradiation. All potential applications of nanoparticles in TC are still in the preclinical phase.

Abstract

Cancers of the endocrine system are rare. The majority are not highly malignant tumors. Thyroid cancer (TC) is the most common endocrine cancer, with differentiated papillary and follicular tumors occurring more frequently than the more aggressive poorly differentiated and anaplastic TC. Nanoparticles (NP) (mainly mesoporous silica, gold, carbon, or liposomes) have been developed to improve the detection of biomarkers and routine laboratory parameters (e.g., thyroid stimulating hormone, thyroglobulin, and calcitonin), tumor imaging, and drug delivery in TC. The majority of drug-loaded nanocarriers to be used for treatment was developed for anaplastic tumors because current treatments are suboptimal. Further, doxorubicin, sorafenib, and gemcitabine treatment can be improved by nanotherapy due to decreased adverse effects. Selective delivery of retinoic acid to TC cells might improve the re-differentiation of de-differentiated TC. The use of carbon NPs for the prevention of parathyroid damage during TC surgery does not show a clear benefit. Certain technologies less suitable for the treatment of deeply located cancers may have some potential for unresectable anaplastic carcinomas, namely those based on low-intensity focused ultrasound and near-infrared irradiation. Although some of these approaches yielded promising results in animal studies, results from clinical trials are currently lacking.

Imaging modalities in pregnant cancer patients

Cancer during pregnancy is increasingly diagnosed due to the trend of delaying pregnancy to a later age and probably also because of increased use of non-invasive prenatal testing for fetal aneuploidy screening with incidental finding of maternal cancer. Pregnant women pose higher challenges in imaging, diagnosis, and staging of cancer. Physiological tissue changes related to pregnancy makes image interpretation more difficult. Moreover, uncertainty about the safety of imaging modalities, fear of (unnecessary) fetal radiation, and lack of standardized imaging protocols may result in underutilization of the necessary imaging tests resulting in suboptimal staging. Due to the absence of radiation exposure, ultrasound and MRI are obvious first-line imaging modalities for detailed locoregional disease assessment. MRI has the added advantage of a more reproducible comprehensive organ or body region assessment, the ability of distant staging through whole-body evaluation, and the combination of anatomical and functional information by diffusion-weighted imaging which obviates the need for a gadolinium-based contrast-agent. Imaging modalities with inherent radiation exposure such as CT and nuclear imaging should only be performed when the maternal benefit outweighs fetal risk. The cumulative radiation exposure should not exceed the fetal radiation threshold of 100 mGy. Imaging should only be performed when necessary for diagnosis and likely to guide or change management. Radiologists play an important role in the multidisciplinary team in order to select the most optimal imaging strategies that balance maternal benefit with fetal risk and that are most likely to guide treatment decisions. Our aim is to provide an overview of possibilities and concerns in current clinical applications and developments in the imaging of patients with cancer during pregnancy.

Imaging the Human Thyroid Using Three-Dimensional Diffuse Optical Tomography: A Preliminary Study

Thyroid cancer is usually diagnosed by ultrasound imaging and fine-needle aspiration biopsy. However, diagnosis of follicular thyroid carcinomas (FTC) is difficult because FTC lacks nuclear atypia and a consensus on histological interpretation. Diffuse optical tomography (DOT) offers the potential to diagnose FTC because it can measure tumor hypoxia, while image reconstruction of the thyroid is still challenging mainly due to the complex anatomical features of the neck. In this study, we attempted to solve this issue by creating a finite element model of the human neck excluding the trachea (a void region). By reconstruction of the absorption coefficients at three wavelengths, 3D tissue oxygen saturation maps of the human thyroid are obtained for the first time by DOT.

Neoplastic pathology at the crossroads between neck imaging and cardiothoracic imaging

The thoracic inlet is located at the crossroads between imaging of the neck and the chest. Its location is an important anatomic landmark, serving as the central conducting pathway for many vital structures extending from the neck into the chest and vice versa. Many critical body systems, including the respiratory, lymphatic, neurologic, enteric, musculoskeletal, endocrine, and vascular systems, are located within this region. Neoplasms, both benign and malignant, can arise in any of the body systems located in this area. Due to the small size of this anatomic location, pathology is easily overlooked and imagers should be aware of the imaging appearance of these neoplasms, as well as which imaging modality is the most appropriate for neoplasm evaluation. This article will present an image rich, system-based discussion of the neoplastic pathology that can occur in this region. The anatomy of the thoracic inlet and the non-neoplastic pathology of the thoracic inlet have been covered in our companion article.

Value of Diffusion Weighted MRI with Quantitative ADC Map in Diagnosis of Malignant Thyroid Disease

Thyroid nodule is a common disease in clinical practice. The diagnosis of malignant thyroid tumors determines the treatment strategy. Among a number of methods have claimed to help evaluating thyroid nodules, ultrasound is a usable one in spite of several disadvantages (dependent on the physician/technician, incomparable, etc.) and magnetic resonance imaging (MRI) accompanied by quantitative apparent diffusion coefficient (ADC) is a promising diagnostic tool. This study was designed to investigate the usefulness of ADC cut-off values and the protocol of thyroid MRI derived from quantitative diffusion weighted imaging (DWI) in differentiating benign and malignant thyroid nodules. The study was conducted on 93 patients with 128 thyroid nodules, diagnosed and underwent surgery at Hanoi Medical University Hospital. All the patients took thyroid MRI with different b levels (from 200 to 800). ADC value was calculated to each b level, and the statistical tests were conducted with the Statistical Package for Social Sciences (SPSS—Windows and Mac version 20) and STATA 12. The mean ADC with all the b ranging from 200 to 800 of malignant groups was significantly higher than the group of benign lesions (p from <0.001 to 0.01). We chose b = 500 as a standard b-value in the protocol of thyroid MRI. The ADC cut-off point for distinguishing malignant from benign thyroid lesions: 1.7 × 10⁻³ mm²/s with high accuracy (87.1%, 95% CI: 79.59–92.07%). The study revealed that quantitative diffusion weighted MRI with ADC measurement could potentially quantitatively differentiate between benign and malignant thyroid nodules.

[Imaging of medullary thyroid carcinoma]

BACKGROUND

About 10% of thyroid cancers are medullary thyroid carcinoma (MTC) and can occur sporadically, familially and in the context of type II multiple endocrine neoplasia (MEN). Imaging plays a pivotal role in screening family members and in diagnosis.

DIAGNOSTIC METHODS

Diagnosis is based on ultrasound (US), thyroid scintigraphy, serum calcitonin and carcinoembryonic antigen (CEA) as well as fine needle biopsy. High-resolution US is the most important imaging method for locoregional staging, combined with computed tomography (CT) of the mediastinum. Positron emission tomography (PET-CT) using 18-F-DOPA is particularly suited for suspected occult metastases in case of rising tumor markers in serum.

FINDINGS AND COURSE OF DISEASE

Diagnosis is made based on cytologic findings in a hypoechoic, cold thyroid nodule, combined with an elevation of serum calcitonin and CEA. US is the most important imaging modality during routine follow-up. CT is indicated for suspected mediastinal, lung, or liver metastases. CT should be replaced by MRI as early as possible to prevent significant cumulative radiation doses over time.

RECENT CLINICAL DEVELOPMENTS

Although MTC is curable by surgery only, owing to its radio- and chemoresistance, the disease will often progress only slowly, and even patients with metastases will frequently survive 10 years or longer. For more aggressive variants and late symptomatic stages, targeted drugs that have the potential to indicate stabilization or even a partial remission of the disease are under clinical investigation or already approved.

Metastatic Nongestational Choriocarcinoma to the Brain: Case Report and Proposed Treatment Recommendations

BACKGROUND

Nongestational choriocarcinoma (NGC) is a rare germ cell tumor, accounting for <0.6% of all gestational tumors, and has a poor prognosis when metastasized. NGC with metastasis to the brain is reported even less frequently. Gestational choriocarcinoma (GC) when metastasized to the brain has a higher morbidity and mortality but has been known to be a chemosensitive and radiosensitive lesion, and NGC is chemoresistant with an even worse prognosis. Currently, there is no consensus for treatment for metastatic NGC to the brain.

CASE DESCRIPTION

This 66-year-old postmenopausal female presented with left upper extremity weakness more pronounced in her hand and a workup demonstrating a hemorrhagic lesion over the right frontal parietal lobe. Her metastatic workup was negative, leading to a craniotomy for resection of the mass. The pathology was consistent with metastatic GC of nongestational origin.

CONCLUSIONS

Because of its chemosensitive nature, reports of optimal metastatic GC treatment include radiation alone, chemotherapy without radiation, surgical resection, or combined multimodal therapy. No recommendations for NGC metastasized to the brain have been reported. We propose a systematic workup for hemorrhagic brain lesions to include the proposed imaging modalities and serum markers, including β-human chorionic gonadotropin, to aid early diagnosis. Based on a review of the literature, we recommend surgical resection with adjuvant therapy for accessible symptomatic metastatic GC and NGC to the brain for optimal patient outcomes. Chemotherapy and radiation alone without surgical resection can be considered for asymptomatic GC metastasis to the brain.

Imaging Evaluation of the Head and Neck Oncology Patient

Imaging plays a multifaceted role in the diagnosis and characterization of head and neck oncological patients and is integral to their care. Given the complexity of treatment, a multimodality approach is often necessary. With the advent of new technologies, imaging can also be used to predict tumor behavior and treatment response. In this chapter, with selected case examples, we describe the various imaging modalities available and offer suggestions on their utilization.

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.

Accuracy of preoperative MRI to assess lateral neck metastases in papillary thyroid carcinoma

Primary treatment of papillary thyroid carcinoma (PTC) with lateral lymph node metastasis is surgery, but the extent of lateral neck dissection remains undefined. Preoperative imaging is used to guide the extent of surgery, although its sensitivity and specificity for defining the number and level of affected lymph nodes on the lateral neck is relatively modest. Our aim was to assess the role of preoperative magnetic resonance imaging (MRI) in predicting the requisite levels of neck dissection in patients with regionally metastatic PTC, with a focus on Levels II and V. All patients with PTC and lateral neck metastasis who had undergone neck dissection at the Department of Otorhinolaryngology—Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland from 2013 to 2016 and had a preoperative MRI available were retrospectively reviewed. A head and neck radiologist re-evaluated all MRIs, and the imaging findings were compared with histopathology after neck dissection. In the cohort of 39 patients, preoperative MRI showed concordance with histopathology for Levels II and V as follows: sensitivity of 94 and 67%, specificity of 20 and 91%, positive predictive value of 56 and 75%, and negative predictive value of 75 and 87%, respectively. In PTC, MRI demonstrated fairly high specificity and negative predictive value for Level V metastasis, and future studies are needed to verify our results to omit prophylactic dissection of this level. Routine dissection of Level II in patients with regionally metastatic PTC needs to be considered, as MRI showed low specificity.

Approach to intensely enhancing neck nodes

Cervical node evaluation is one of the most common problems encountered by a radiologist. Here, we present a pictorial review of intensely enhancing neck nodes. While enhancement in a cervical node is a common radiologic finding on contrast-enhanced computed tomography scan, only few conditions cause intense enhancement in cervical nodes. We discuss the common causes of intensely enhancing neck nodes along with pertinent radiologic features and key differentiating points that aid radiologists in reaching a diagnosis. In addition, we discuss certain potential non-nodal mimics, which need to be excluded.

The surgical approach to managing differentiated thyroid cancer

In recent decades, our understanding of thyroid cancer has improved significantly with the recognition that differentiated thyroid cancer (DTC) has good survival and oncological outcomes. Along with the recent rise in the detection of otherwise subclinical tumours due to improved diagnostics, there has been much debate on how aggressive one should be when performing thyroid and lymph node surgery. The use of risk stratification to categorize patients into low, intermediate and high risk has led to a more tailored approach to treating differentiated thyroid cancer. This ensures patients are not subject to preventable morbidity from overtreatment while maintaining good outcomes. We discuss the approach to primary thyroid and lymph node surgery by reviewing the current literature.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

A mathematical model using computed tomography for the diagnosis of metastatic central compartment lymph nodes in papillary thyroid carcinoma

OBJECTIVES

The purpose of this study was to establish a potential mathematical model for the diagnosis of the central compartment lymph node (LN) metastases of papillary thyroid carcinoma (PTC) using CT imaging.

METHODS

303 patients with PTC were enrolled. We determined the optimal cut-off points of LN size and nodal grouping by calculating the diagnostic value of each cut-off point. Then, calcification, cystic or necrotic change, abnormal enhancement, size, and nodal grouping were analysed by univariate and multivariate statistical methods. The mathematical model was obtained using binary logistic regression analysis, and a scoring system was developed for convenient use in clinical practice.

RESULTS

30 mm(2) for LNs area (size) and two LNs as the nodal grouping criterion had the best diagnostic value. The mathematical model was: p = e (y) /(1+ e (y) ), y = -0.670-0.087 × size + 1.010 × cystic or necrotic change + 1.371 × abnormal enhancement + 0.828 × nodal grouping + 0.909 × area. We assigned the value for cystic or necrotic change, abnormal enhancement, size and nodal grouping value as 25, 33, 20, and 22, respectively, yielding a scoring system.

CONCLUSIONS

This mathematical model has a high diagnostic value and is a convenient clinical tool.

KEY POINTS

• Papillary thyroid carcinoma has a relatively high rate of metastasis. • CT has unique advantages in evaluating the central compartment. • The mathematical model can improve the diagnosis of CT imaging. • Corresponding scoring system is a convenient clinical tool.

Nuclear medicine imaging of endocrine neoplasms

Endocrine tumors are hormonally active benign or malignant neoplasms arising within endocrine organs or from specialized cells of the amine precursor uptake and decarboxylation system. The detection rate of these tumors is increasing as a result of sensitive biochemical tests and high-resolution diagnostic imaging. Medical imaging has become a key component in the diagnosis and staging of endocrine malignancies; however, despite the impressive advances in computed tomography (CT) and MRI, detection of small primary tumors and metastases continues to be a challenge. Functional imaging techniques use radiopharmaceuticals targeted at unique tumor cellular processes in order to provide sensitive and highly specific whole-body imaging. Functional imaging allows prediction of the efficacy of radionuclide or receptor-based therapies and surveillance after therapy. Advances in imaging have not been limited to radiopharmaceuticals. Hybrid scanner technology in the form of PET/CT and single photon emission computed tomography (SPECT)/CT, designed to combine functional images with anatomic maps, has further improved the diagnostic accuracy. High-resolution hybrid imaging when deployed with novel PET and SPECT radiopharmaceuticals has the potential to dramatically change, individualize, and optimize imaging plans based on the histological grade, degree of differentiation, and genetic profile of each patient's endocrine neoplasm.

The usefulness and accuracy of sentinel lymph node biopsy using single photon emission computed tomography/computed tomography with 99mTc phytate to detect locoregional lymph node metastases in patients with papillary thyroid carcinoma

Purpose

Regional lymph node (LN) metastases are detected in 57-85% of patients with papillary thyroid carcinoma (PTC) and are associated with increased tumor recurrence. However, the management of lymphatic disease in patients with PTC has been ongoing source of debate. We have prospectively assessed the usefulness and accuracy of sentinel LN (SLN) biopsy for the detection of LN metastases in patients with PTC on preoperative imaging using single photon emission computed tomography/computed tomography (SPECT/CT) and 99mTc phytate.

Methods

We prospectively assessed 39 patients with PTC who had risk factors for recurrence or with the necessity of intraoperative LN sampling for suspicious LN metastases on preoperative imaging from August 2010 to March 2011. The patients underwent preoperative lymphoscintigraphy and SPETC/CT and intraoperative SLN biopsy (SLNB).

Results

99mTc lymphoscintigraphy and SPECT/CT localized SLN in 38 patients (97.4%), with the gamma probe identifying 2.15 mean SLNs in the lateral neck of the 39 patients. Skip metastasis was found in one patient, and lateral compartment LN metastasis in 17 (43.5%). The sensitivity, specificity, and accuracy of SLNB for lateral compartment LN metastasis were 88.2%, 100%, and 94.8%, respectively. SLNB was more accurate and useful for lateral than for central compartment LN metastasis.

Conclusion

SPECT/CT improved SLN detection and anatomical localization compared with lymphoscintigraphy. SLNB in patients with risk factors for recurrence or the necessity of intraoperative LN sampling for suspected LN metastases on preoperative imaging was accurate in detecting LN metastases and may help in deciding whether to perform lateral compartment dissection in patients with PTC.