Striving Toward Standardization of Reporting of Ultrasound Features of Thyroid Nodules and Lymph Nodes: A Multidisciplinary Consensus Statement

Abstract

Background:

The use of high-resolution ultrasound (US) imaging is a mainstay of the initial evaluation and long-term management of thyroid nodules and thyroid cancer. To fully capitalize on the diagnostic capabilities of a US examination in the context of thyroid disease, many clinicians consider it desirable to establish a universal format and standard of US reporting. The goals of this interdisciplinary consensus statement are twofold. First, to create a standardized set of US features to characterize thyroid nodules and cervical lymph nodes accurately, and second, to create a standardized system for tracking sequential changes in the US examination of thyroid nodules and cervical lymph nodes for the purpose of determining risk of malignancy.

Summary:

The Thyroid, Head and Neck Cancer (THANC) Foundation convened a panel of nine specialists from a variety of medical disciplines that are actively involved in the diagnosis and treatment of thyroid nodules and thyroid cancer. Consensus was achieved on the following topics: US evaluation of the thyroid gland, US evaluation of thyroid nodules, US evaluation of cervical lymph nodes, US-guided fine needle aspiration (FNA) of thyroid nodules, and US-guided FNA of cervical lymph nodes.

Conclusion:

We propose that this statement represents a consensus within a multidisciplinary team on the salient and essential elements of a comprehensive and clinically significant thyroid and neck US report with regards to content, terminology, and organization. This reporting protocol supplements previous US performance guidelines by not only capturing categories of findings that may have important clinical implications, but also delineating findings that are clinically relevant within those categories as specifically as possible. Additionally, we have included the specific features of diagnostic and therapeutic interventions that have not been previously addressed.

Introduction

The use of high-resolution ultrasound (US) imaging is a mainstay of the initial evaluation and long-term management of thyroid nodules and thyroid cancer. The detection and diagnosis of thyroid and lymph node abnormalities by US is indispensible for guiding clinical decision-making and avoiding the costs and morbidities associated with unnecessary surgical interventions. To these ends, accurate and comprehensive documentation and efficient communication of abnormalities detected by US in the diagnostic report is essential. Currently, however, thyroid and neck US is performed and interpreted by individuals representing a number of different disciplines in various settings and with different training. Each specialty has adopted different methods of performing US examinations and different approaches for reporting findings. As a result, there is a tremendous amount of variability in the structure and content of the US report and ultimately the clinical utility of the reports that are generated.

To capitalize fully on the diagnostic capabilities of an ultrasound examination in the context of thyroid disease, many clinicians consider it desirable to establish a universal format and standard of US reporting. Previous efforts to enhance and disambiguate the clinical impact of thyroid US reporting have concentrated on the development of categorical risk-stratification systems. Inspired by the Breast Imaging Reporting and Data System (BI-RADS), developed by the American College of Radiology for the classification of breast lesions, three groups of authors put forth five-point scales to score thyroid nodules for risk of malignancy based on ultrasonographic appearance (1 –3). Although potentially useful for clarifying the clinical significance of US findings, these Thyroid Imaging Reporting and Data Systems (TI-RADS) are not comprehensive tools with respect to the actual findings. Standardized reporting of thyroid nodule and lymph node features on US would be of benefit to the practicability of applying a TI-RADS system. Additionally, practice guidelines released by the American Institute of Ultrasound in Medicine (AIUM) (4) and the American Association of Clinical Endocrinologists (AACE), Associazione Medici Endocrinologi (AME), and European Thyroid Association (ETA) (5) address the indications for and performance of thyroid and neck US and provide a description of some of the specific features that should, at a minimum, be documented. However, neither endeavored to establish a specific reporting protocol for thyroid and neck US.

To address the optimal reporting of thyroid plus neck US as it relates to thyroid disease management, the Thyroid, Head and Neck Cancer (THANC) Foundation convened a panel of specialists from a variety of medical disciplines that are actively involved in the diagnosis and treatment of thyroid nodules and thyroid cancer. The goals of this interdisciplinary consensus statement are twofold. First, to create a standardized set of US features to characterize thyroid nodules and cervical lymph nodes accurately, and second, to create a standardized system for tracking sequential changes in the US examination of thyroid nodules and cervical lymph nodes for the purpose of determining risk of malignancy. We propose a reporting protocol that covers the salient content, terminology, and organization necessary for communicating thyroid and neck US findings in a clear and consistent fashion. To the best of our knowledge, there are no other previous multidisciplinary consensus statements on US reporting.

It is acknowledged that physicians who manage diseases of the head and neck other than those of the thyroid may find alternative methods of documentation and reporting more suitable for their purposes. Nevertheless, the recommendations contained herein may serve as a model.

Methods

A panel of physicians was established by the THANC Foundation to create this consensus statement. The panel consisted of an expert multidisciplinary team of nine clinicians who represent the following specialties: otolaryngology/head and neck surgery, endocrine surgery, endocrinology, radiology, and cytopathology. The preliminary meeting of this panel was convened in September 2013, followed by subsequent meetings held in October 2013. Phone and electronic mail communications were also conducted in order to fine-tune the final set of guidelines.

The necessary features of the following examinations were discussed and consensus was achieved: US evaluation of the thyroid gland, US evaluation of thyroid nodules, US evaluation of cervical lymph nodes, ultrasound-guided fine-needle aspiration (US-FNA) of thyroid nodules, and US-FNA of cervical lymph nodes.

Consensus Statement

Following the performance of neck US, the purpose of the evaluation should be documented, as well as the overall impression. The initial characterization of the thyroid gland after thyroid US requires, at a minimum, a characterization of the presence and size of each lobe of the thyroid and the isthmus, vascularity and the echogenicity, and any calcification patterns within the overall thyroid gland. If observed, the presence of a pyramidal lobe, extension of the thyroid into the mediastinum, tracheal deviation, and the presence of a thyroglossal duct cyst and other anomalous anatomic findings should also be characterized and documented. An initial overall impression of the disease status of the entire thyroid is noted (e.g., thyroiditis; Table 1).

Table 1.

Recommendations for the Initial Characterization of the Thyroid

Part 1—Initial characterization of thyroid
Prompt	Possible answer selections
1. Global assessment of thyroid gland	Normal, homogeneous or minimal benign change
	Solitary nodule
	Multinodular
	Diffuse thyroiditis—if selected:
	Pseudo-/micronodules (present/absent)
	Fibrous bands (present/absent)
2. Left lobe	Present—if selected:
	Size in three dimensions (anteroposterior×transverse×longitudinal, or specify format)
	Remnant—if selected:
	Size in three dimensions (anteroposterior×transverse×longitudinal, or specify format)
	Nonspecific soft tissue
	Absent
3. Right lobe	Present—if selected:
	Size in three dimensions (anteroposterior×transverse×longitudinal, or specify format)
	Remnant—if selected:
	Size in three dimensions (anteroposterior×transverse×longitudinal, or specify format)
	Nonspecific soft tissue
	Absent
4. Isthmus	Present—if selected:
	Size (anteroposterior)
	Absent
5. Echogenicity	Normal
	Diffusely heterogeneous
	Diffusely hypoechoic
6. Vascularity of entire thyroid gland	Normal
	Decreased
	Increased
7. Calcification patterns not associated with nodule	Absent
	Present—if selected:
	Describe
8. Pyramidal lobe	Not seen
	Present
9. Clinically significant thyroid nodules	Yes
	No
10. Extension into mediastinum	Absent
	Present—if selected:
	Right lobe/left lobe/both
	Is the caudal extent completely visualized? (yes/no)
11. Tracheal deviation^a	Absent
	Present, toward the left—if selected:
	Extent of deviation from midline
	Present, toward the right—if selected:
	Extent of deviation from midline
12. Thyroglossal duct cyst	Absent
	Present—if selected:
	Size in three dimensions (anteroposterior×transverse×longitudinal, or specify format)
13. Anomalous anatomic findings	Absent
	Present—if selected:
	Thryoid lobe drapes over carotid/exophytic nodules/accessory ectopic thyroid/other

If the extent of tracheal deviation from midline cannot be measured it may be reported as “minimal” or “marked.”

It should be noted that the different specialties have adopted a different order of defining the dimensions of the thyroid gland, nodules, and lymph nodes with respect to the anteroposterior, transverse, and longitudinal measurements. The order of reporting should be specified in the report and recorded consistently throughout to avoid ambiguity as well as to ensure that subsequent measurements on the same structures are recorded in a similar fashion.

It is advisable to document the presence of nonsuspicious nodules and their location so that the information is present in the final report. However, in some cases details about specific nonsuspicious nodules may be very limited, such as in multinodular glands with all nodules having a similar sonographic appearance. The presence of clinically significant thyroid nodules should always be documented in detail, including their number, size in three dimensions, and location. Comprehensive characterization of each clinically significant thyroid nodule should address the following features: taller-than- wide shape, internal architecture, nodule echogenicity, nodule contour, suspicion of extrathyroidal extension, nonsuspicious echogenic foci, calcifications, and nodule vascularity (Table 2). Calcifications are defined as microcalcifications if they measure approximately 1 mm in diameter (6). The most commonly used grading system for thyroid nodule vascularity is a one through four diagnostic scale (7).

Table 2.

Recommendations for Assessing Clinically Significant Thyroid Nodules

Part 2—Ultrasound assessment of clinically significant thyroid nodules
Prompt	Possible answer selections
Overview of assessment of the thyroid for nodules
1. Left lobe	Clinically significant nodules (yes/no)—if yes:
	# of nodules to be characterized
	Multiple nonsuspicious nodules (yes/no)—if yes:
	# of nodules/too numerous to count
	Multiple coalescent nonsuspicious nodules (yes/no)
2. Right lobe	Clinically significant nodules (yes/no)—if yes:
	# of nodules to be characterized
	Multiple nonsuspicious nodules (yes/no)—if yes:
	# of nodules/too numerous to count
	Multiple coalescent nonsuspicious nodules (yes/no)
3. Isthmus	Clinically significant nodules (yes/no)—if yes:
	# of nodules to be characterized
	Multiple nonsuspicious nodules (yes/no)—if yes:
	# of nodules/too numerous to count
	Multiple coalescent nonsuspicious nodules (yes/no)
For each clinically significant nodule
4. General	Size in three dimensions (anteroposterior×transverse×longitudinal, or specify format)
	Location
	Taller than wide (yes/no)
5. Nodule contour	Completely smooth and well-defined
	Lobulated/irregular
	Indistinct
	Infiltrative
6. Extrathyroidal extension	Absent
	Suspect—if selected:
	Invasion of: strap muscle/posterior margin of thyroid/trachea/carotid artery or jugular vein/cannot be assessed/other
7. Internal architecture	Cystic
	Solid
	Mixed cystic/solid – if selected:^a
	% cystic: 0–25%/26–50%/51–75%/76–100%
	Solid component: nodular/not nodular
	Spongiform
	Complex—if selected:
	Septate/hemorrhagic/mural nodule
8. Nodule echogenicity	Isoechoic
	Hypoechoic
	Hyperechoic
	Mixed echogenicity
	Profoundly hypoechoic
	Anechoic/cyst
9. Nonsuspicious echogenic foci (select all that apply)	Colloid
	Nonshadowing foci indeterminate for microcalcifications
	Comet tail artifact
	Ring-down artifact
	Fibrosis
10. Calcifications (select all that apply)	None
	Micro
	Macro—if selected:
	Central linear/central curvilinear/coarse
	Peripheral—if selected:
	Thick, irregular and/or interrupted/thin, more than 50% (“eggshell”)/Thin, less than or equal to 50% (“eggshell”)
11. Vascularity	(Grade 1) No detectable vascularity
	(Grade 2) Vascularity detected, peripheral only
	(Grade 3) Low vascularization, predominantly centrally with or without peripheral vascularization
	(Grade 4) High vascularization centrally with or without peripheral vascularization

If mixed cystic/solid is indicated, then the US report should note that the features of echogenicity, calcifications, and vascularity refer to the solid component of the mixed cystic/solid nodule.

Following the evaluation of the thyroid, neck US should assess cervical lymph nodes consistent with the recent AIUM guidelines. An evaluation of lymph nodes in the neck does not require documentation of every lymph node visualized, especially those that have a typical benign appearance. However, comprehensive characterization of each clinically significant lymph node should address the following features: size, location defined by neck compartment, internal architecture, presence or absence of a hilum, shape, calcifications, vascularity, and suspicion of invasion of nearby structures (Table 3).

Table 3.

Recommendations for Characterizing Cervical Lymph Nodes

Part 3—Ultrasound characteristics of cervical lymph nodes
Prompt	Possible answer selections
1. Purpose of lymph node evaluation	Screening (brief survey at initial or follow-up US for uncharacterized nodule)
	Mapping (preoperative detailed exam)
	Surveillance (thyroid cancer follow-up)
2. Overall impression	No suspicious lymph nodes
	Multiple flat, likely benign lymph nodes, not measured
	Multiple small lymph nodes associated with thyroiditis
	Prominent likely benign lymph nodes
	Suspicious lymph nodes
For each suspicious lymph node
3. General	Size in three dimensions (anteroposterior×transverse×longitudinal, or specify format)
	Location, neck compartment
4. Internal architecture	Solid and homogeneously hypoechoic
	Solid and heterogeneous
	Cystic component
5. Hilum	Not detected
	Detected
	Indeterminate
6. Shape	Round
	Oval
	Irregular
7. Calcifications	Absent
	Present
	Indeterminate
8. Vascularity	None
	Hilar vascular pattern only
	Peripheral only
	Chaotic/diffuse
	Increased vascularity within a solid element of a partially cystic lymph node
	Indeterminate
9. Suspicion of invasion of nearby structures	Absent
	Present—if selected:
	Muscle/vascular/tracheal/nerve

Additional findings noted on neck US evaluation, including abnormalities associated with neck masses, the parathyroid glands, or salivary glands should be described based on the neck geography and US features.

If FNA biopsy of a thyroid nodule or lymph node is performed with US guidance (US-FNA), the technique used and all diagnostic testing performed on the specimen should be reported and properly associated with the correct nodule or lymph node (Table 4).

Table 4.

Recommendations for Reporting Diagnostic Interventions

Part 4—Diagnostic/therapeutic intervention
Prompt	Possible answer selections
For each thyroid nodule
1. Was the nodule cystic?	No
	Yes—if selected:
	Volume of fluid withdrawn
	Cystic fluid characterization: bloody/straw colored/water clear/green or golden colloid/brown/purulent
2. Was the aspirate sent for biochemical analyses?	Tg level
	Calcitonin level
	CEA level
	PTH level
Technique of biopsy procedure
3. Was onsite cytopathology assessment of adequacy performed?	No
	Yes
4. Type of needle	Fine—if selected:
	Gauge of needle: 22/23/25/27/Other
	Core
5. # of passes made	#
6. Specimen preparation	Smear/slides
	CytoLyt/liquid-based
	Flow cytometry
	Other
Diagnosis from biopsy procedure
7. Bethesda cytology classification (8)	Nondiagnostic or Unsatisfactory
	Benign
	Atypia of undetermined significance or follicular lesion of undetermined significance
	Follicular neoplasms or suspicious for a follicular neoplasm
	Suspicious for malignancy
	Malignant
8. Molecular markers	Gene expression analysis
	Specify test
	Positive/negative/fail
	BRAF—if performed:
	Positive/negative/fail
	RAS—if performed:
	Positive/negative/fail
	RET/PTC—if performed:
	Positive/negative/fail
	PAX8/PPARγ—if performed:
	Positive/negative/fail
	Other marker—if performed:
	Specify marker
	Positive/negative/fail
9. Immunocytochemical markers (immunostains)	Yes—if selected:
	Describe
	No
For each lymph node
10. FNA result	Benign
	Malignant
	Indeterminate
11. Was the aspirate sent for biochemical analyses?	Tg level
	Calcitonin level
	CEA level
	PTH level
12. Was the lymph node cystic?	No
	Yes—if selected:
	Bloody
	Straw colored
	Water clear
	Brown
	Purulent

Tg, thyroglobulin; CEA, carcinoembryonic antigen; PTH, parathyroid hormone; FNA, fine-needle aspiration.

Finally, when available, the clinical and cytologic diagnoses of all thyroid nodules and lymph nodes should be carefully documented (Table 5). A synoptic and/or narrative summary to highlight pertinent positive findings should be included in the final US report.

Table 5.

Recommendations for Describing the Overall Diagnosis

Part 5—Overall diagnosis for encounter
Prompt	Possible answer selections
1. Final thyroid clinical diagnosis	Normal
	Nodular thyroid—no FNA recommended
	Nodularity pending cytologic diagnosis
	Heterogeneity consistent with thyroiditis
	Enlarged thyroid with tracheal deviation and/or substernal extension
	Posttreatment changes
	Previous diagnosis of thyroid cancer
	Other
2. Final thyroid cytologic diagnosis	List all established by biopsy:
	Nondiagnostic or unsatisfactory/benign/atypia of undetermined significance or follicular lesion of undetermined significance/follicular neoplams or suspicious for a follicular neoplasm/suspicious for malignancy/malignant
3. Final lymph node clinical diagnosis	No suspicious lymph nodes
	Lymph node or soft tissue of indeterminate significance
	Suspicious lymph node, inaccessible for FNA
	Lymph node pending cytologic diagnosis
4. Final lymph node cytologic diagnosis	List all established by biopsy:
	Benign/malignant/indeterminate

FNA, fine-needle aspiration.

Discussion

High-resolution US is the most sensitive test currently available to detect and characterize thyroid nodules and lymph nodes in the neck (9,10), capable of detecting thyroid nodules as small as 2 mm (11). Thyroid and neck US is utilized for a variety of reasons, including the evaluation of the thyroid gland for palpable or laboratory abnormalities or abnormalities detected on other imaging examinations, follow-up imaging of previously detected thyroid nodules, evaluation for regional nodal metastases in patients with proven or suspected thyroid cancer before thyroidectomy, and evaluation for locoregional recurrence following thyroidectomy for thyroid cancer (4,12). Additionally, US guidance improves the targeting precision of FNA biopsy to definitively assess suspicious nodules and lymph nodes (9).

A critical feature of US reports is a focus on risk stratification of thyroid nodules and lymph nodes for thyroid malignancy and lymphadenopathy that may represent metastatic thyroid cancer (5). No single feature of thyroid nodules on US examination can absolutely diagnose or exclude thyroid malignancy (9,13 –16). However, the existence of US features suggestive of malignancy increases the risk of thyroid cancer and increases the strength of indication for FNA biopsy.

Up to 20% of patients with differentiated thyroid cancer develop postoperative locoregional recurrences in the thyroid bed or cervical lymph nodes (17), and US plays an important role in long-term surveillance for thyroid cancer recurrence. Neck US is particularly useful for the detection of locoregional recurrence in patients with differentiated thyroid cancer (12,18 –20) and is highly sensitive and specific when used in combination with FNA (21 –23). In addition, preoperative US has been shown to be a useful adjunct to physical examination for surgical planning. Preoperative US is effective at identifying metastatic lymph nodes undetected by palpation alone in patients undergoing an initial thyroid operation or an operation for persistent or recurrent disease, and providing valuable information to inform the extent of a neck operation and helping to avoid subsequent reoperations (24,25).

The diagnosis and management of thyroid nodules and thyroid cancer is optimally performed in a multidisciplinary setting. Standardization of US reporting is intended to facilitate consistent and clear communication among the various physicians involved in the management of patients with thyroid nodules and thyroid cancer. Thus, it is important to determine the minimum necessary comprehensive data set in a multidisciplinary forum to best reflect the essential elements that are deemed to be important by each specialty. We propose that this statement represents a consensus within a multidisciplinary team on the salient features of a comprehensive thyroid and neck US report. The recommendations made by this panel are intended to augment the AIUM 2013 Practice Guidelines for the Performance of a Thyroid and Parathyroid Examination (4) and the American Association of Clinical Endocrinologists (AACE), Associazione Medici Endocrinologi (AME), and European Thyroid Association (ETA) Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules (5) to render in greater detail the necessary features of a comprehensive and clinically significant thyroid US report that relate to the risk stratification of thyroid nodules and lymph nodes based on US features.

In addition to the AIUM and AACE/AME/ETA recommendations, we have suggested including the following features to characterize the lobes of the thyroid gland: the presence of tracheal deviation and calcification patterns not associated with a nodule. For significant abnormalities of the thyroid, we have suggested including suspicion of extrathyroidal extension. We also specify the descriptive features for nodules related to echogenicity, calcifications, nonsuspicious echogenic foci. For each abnormal lymph node visualized on US exam, we add: suspicion of invasion into nearby structures. We have also suggested the routine inclusion of notes regarding significant parathyroid, neck mass or unexpected findings on neck US.

Overall, we have supplemented the AIUM US performance guidelines and the AACE/AME/ETA guidelines by not only capturing categories of findings that may have important clinical implications, but also delineating findings that are clinically relevant within those categories as specifically as possible. Additionally, we have included the specific features of diagnostic and therapeutic interventions that are not included in either statement. For these reasons, we believe that we offer a more comprehensive picture of the essential elements of a clinically significant US report.

We recognize the inherent tradeoff in the length and conciseness of a final thyroid and neck US report that accompanies our recommendations. This is a noteworthy and unfortunate feature of reports generated by many current electronic medical record systems, where it may be difficult for a reader to ascertain significant positive findings among numerous negative findings. Therefore, we recommend that a synoptic and/or narrative summary to highlight pertinent positive findings should be prominently included in the final US report.

Standardized reporting of thyroid US would provide a structural underpinning for the adoption of a TI-RADS reporting system, and a summary of positive suspicious findings may dovetail with a TI-RADS categorization scheme. Horvath et al. (1) first proposed a scheme that assigned levels of risk of malignancy to various US patterns involving 10 features, while Park et al. (2) devised an equation to predict the probability of malignancy based on 12 variables. Both groups then created 5 categories to stratify thyroid nodules based on the risk of malignancy. Kwak et al. (3) later put forth a simplified system in which nodules are stratified based only on the total number of concerning US features observed 1 of 5 variables. Concerns have been raised regarding the practicability of widespread adoption of a TI-RADS system, given their complexity (3). Standardized reporting of US findings would represent a step toward effective TI-RADS utilization.

The adoption of any comprehensive reporting tool represents an increase in time expenditures associated with reporting US results. Thus, a major challenge to facilitating widespread adoption of a comprehensive reporting tool is integration into user workflow. The development and employment of a properly designed electronic reporting system holds promise as a solution to tackle issues of workflow integration and efficiency.

We propose that the five ideal features of an electronic reporting system dedicated to thyroid and neck US are: (1) the ability to facilitate the easy and efficient entry of information in a manner that readily fits into the normal clinician workflow; (2) the ability to create an automatic narrative and generate automatic electronic correspondence (e.g., e-mails or faxes) to interested parties in order to optimize communication yet avoid the need for dictating and sending physician letters; (3) the ability to satisfy necessary documentation for purposes of billing for performing US and US-FNA; (4) the ability to capture and make accessible, for review and comparison, the necessary data, including US descriptions, images, and video clips as desired; (5) the ability to easily query the system for the purpose of clinical research.

By standardizing the documentation of US findings, a dedicated electronic reporting system promises to facilitate adherence to reporting guidelines and standards. Properly designed, a computer program could effectively transform reporting into a process of selecting relevant findings from a predetermined set of options based on reporting standards. In the interest of physician efficiency, clinicians could simply associate the appropriate selections to individual nodules or lymph nodes in a three-dimensional computer-generated anatomic map.

Clear organization of US findings within a dedicated electronic system has additional advantages. Notably, a dedicated thyroid and neck US reporting system could assist tracking sequential changes in suspicious nodules and lymph nodes. An electronic system could organize past information on individual nodules and lymph nodes, perform a comparison to current imaging findings, and highlight changes and discrepancies with ease. Automation of these tasks would significantly reduce the time required to understand a patient's history and maximize physicians' ability to focus on clinical decision-making. Additionally, the results of further diagnostic testing ought to be associated with the correct nodule or lymph node. For this reason, we have included diagnostic testing in our reporting protocol. We recognize that the final results of diagnostic studies other than US, such as FNA biopsy and molecular testing are not available at the time of the US report. It would be important for a reporting tool to be a dynamic instrument, with new information being added and associated with the correct nodule or lymph node as it becomes available. Finally, an electronic reporting system could further ameliorate concerns regarding the practicability of a TI-RADS categorization system by automatically calculating a TI-RADS score for each thyroid nodule.

Conclusion

We have formulated a multidisciplinary consensus on the relevant and necessary features of a comprehensive thyroid and neck US report with regards to content, terminology and organization. The standardization of US examination reporting in a manner consistent with current schemes of risk stratification based on US features promises to enhance patient care by facilitating the diagnosis and long-term surveillance of thyroid nodules and thyroid cancer.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

References

Horvath

, Majlis

, Rossi

, Franco

, Niedmann

, Castro

, Dominguez

. 2009. An ultrasonogram reporting system for thyroid nodules stratifying cancer risk for clinical management. J Clin Endocrinol Metab, 94:1748–1751.

Park

J-Y

, Lee

, Jang

, Kim

, Yi

, Lee

, Kim

. 2009. A proposal for a thyroid imaging reporting and data system for ultrasound features of thyroid carcinoma. Thyroid, 19:1257–1264.

Kwak

, Han

, Yoon

, Moon

, Son

, Park

, Jung

, Choi

, Kim

E-K

. 2011. Thyroid imaging reporting and data system for US features of nodules: a step in establishing better stratification of cancer risk. Radiology, 260:892–899.

American Institute of Ultrasound in Medicine; American College of Radiology; Society for Pediatric Radiology; Society of Radiologists in Ultrasound. 2013. AIUM practice guideline for the performance of a thyroid and parathyroid ultrasound examination. J Ultrasound Med, 32:1319–1329.

Gharib

, Papini

, Paschke

, Duick

, Valcavi

, Hegedus

, Vitti

. 2010. American Association of Clinical Endocrinologists, Associazione Medici Endocrinologi, and European Thyroid Association medical guidelines for clinical practice for the diagnosis and management of thyroid nodules. J Endocrinol Invest, 33:1–50.

Triggiani

, Guastamacchia

, Licchelli

, Tafaro

. 2008. Microcalcifications and psammoma bodies in thyroid tumors. Thyroid, 18:1017–1018.

Fukunari

, Nagahama

, Sugino

, Mimura

, Ito

. 2004. Clinical evaluation of color Doppler imaging for the differential diagnosis of thyroid follicular lesions. World J Surg, 28:1261–1265.

Cibas

, Ali

. 2009. The Bethesda system for reporting thyroid cytopathology. Am J Clin Pathol, 132:658–665.

Solbiati

, Osti

, Cova

, Tonolini

. 2001. Ultrasound of thyroid, parathyroid glands and neck lymph nodes. Eur Radiol, 11:2411–2424.

10.

Tan

, Gharib

, Reading

. 1995. Solitary thyroid nodule: comparison between palpation and ultrasonography. Arch Intern Med, 155:2418.

11.

Simeone

, Daniels

, Hall

, McCarthy

, Kopans

, Butch

, Mueller

, Stark

, Ferrucci

Jr , Wang

. 1987. Sonography in the follow-up of 100 patients with thyroid carcinoma. AJR Am J Roentgenol, 148:45–49.

12.

Cooper

, Doherty

, Haugen

, Kloos

, Lee

, Mandel

, Mazzaferri

, McIver

, Pacini

, Schlumberger

. 2009. Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer: the American Thyroid Association (ATA) Guidelines Taskforce on thyroid nodules and differentiated thyroid cancer. Thyroid, 19:1167–1214.

13.

Kim

E-K

, Park

, Chung

, Oh

, Kim

, Lee

, Yoo

. 2002. New sonographic criteria for recommending fine-needle aspiration biopsy of nonpalpable solid nodules of the thyroid. AJR Am J Roentgenol, 178:687–691.

14.

Papini

, Guglielmi

, Bianchini

, Crescenzi

, Taccogna

, Nardi

, Panunzi

, Rinaldi

, Toscano

, Pacella

. 2002. Risk of malignancy in nonpalpable thyroid nodules: predictive value of ultrasound and color-Doppler features. J Clin Endocrinol Metab, 87:1941–1946.

15.

Frates

, Benson

, Doubilet

, Cibas

, Marqusee

. 2003. Can color Doppler sonography aid in the prediction of malignancy of thyroid nodules?. J Ultrasound Med, 22:127–131.

16.

Wienke

, Chong

, Fielding

, Zou

, Mittelstaedt

. 2003. Sonographic features of benign thyroid nodules interobserver reliability and overlap with malignancy. J Ultrasound Med, 22:1027–1031.

17.

Schlumberger

. 1998. Papillary and follicular thyroid carcinoma. N Engl J Med, 338:297–306.

18.

Frasoldati

, Pesenti

, Gallo

, Caroggio

, Salvo

, Valcavi

. 2003. Diagnosis of neck recurrences in patients with differentiated thyroid carcinoma. Cancer, 97:90–96.

19.

Antonelli

, Miccoli

, Ferdeghini

, Di Coscio

, Alberti

, Iacconi

, Baldi

, Fallahi

, Baschieri

. 1995. Role of neck ultrasonography in the follow-up of patients operated on for thyroid cancer. Thyroid, 5:25–28.

20.

Stack

Jr , Ferris

, Goldenberg

, Haymart

, Shaha

, Sheth

, Sosa

, Tufano ftATASAC, Ralph

. 2012. American Thyroid Association consensus review and statement regarding the anatomy, terminology, and rationale for lateral neck dissection in differentiated thyroid cancer. Thyroid, 22:501–508.

21.

Krishnamurthy

, Bedi

, Caraway

. 2001. Ultrasound‐guided fine‐needle aspiration biopsy of the thyroid bed. Cancer Cytopathology, 93:199–205.

22.

Sutton

, Reading

, Charboneau

, James

, Grant

, Hay

. 1988. US-guided biopsy of neck masses in postoperative management of patients with thyroid cancer. Radiology, 168:769–772.

23.

Rodriguez

, Reus

, Moreno

, Martinez

, Soria

, Carrasco

, Parrilla

. 1997. High-resolution ultrasound associated with aspiration biopsy in the follow-up of patients with differentiated thyroid cancer. Otolaryngol Head Neck Surg, 117:694–697.

24.

Stulak

, Grant

, Farley

, Thompson

, van Heerden

, Hay

, Reading

, Charboneau

. 2006. Value of preoperative ultrasonography in the surgical management of initial and reoperative papillary thyroid cancer. Arch Surg, 141:489–496.

25.

Kouvaraki

, Shapiro

, Fornage

, Edeiken-Monro

, Sherman

, Vassilopoulou-Sellin

, Lee

, Evans

. 2003. Role of preoperative ultrasonography in the surgical management of patients with thyroid cancer. Surgery, 134:946–954.