Validation of American Thyroid Association Ultrasound Risk Assessment of Thyroid Nodules Selected for Ultrasound Fine-Needle Aspiration

Thyroid. 2017 Aug;27(8):1077-1082. doi: 10.1089/thy.2016.0555. Epub 2017 Jul 18.


Objective: The aim of this study was to validate the American Thyroid Association (ATA) sonographic risk assessment of thyroid nodules.

Methods: The ATA sonographic risk assessment was prospectively applied to 206 thyroid nodules selected for ultrasound-guided fine-needle aspiration (US-FNA), and analyzed with The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), as well as surgical pathology for the subset undergoing surgical excision.

Results: The analysis included 206 thyroid nodules averaging 2.4 cm (range 1-7 cm; standard error of the mean 0.07). Using the ATA US pattern risk assessment, nodules were classified as high (4%), intermediate (31%), low (38%), and very low (26%) risk of malignancy. Nodule size was inversely correlated with sonographic risk assessment, as lower risk nodules were larger on average (p < 0.0001). Malignancy rates determined by cytology/surgical pathology were high 100%, intermediate 11%, low 8%, and very low 2%, which were closely aligned with ATA malignancy risk estimates (high 70-90%, intermediate 10-20%, low 5-10%, and very low 3%). ATA US pattern risk assessment also appropriately predicted the proportion of nodules classified as malignant or suspicious for malignancy through TBSRTC classification-high (77%), intermediate (6%), low (1%), and very low 0%-as well as benign TBSRTC classification-high (0%), intermediate (47%), low (61%), and very low (70%) (p < 0.0001). Malignancy rates of surgically excised, cytologically indeterminate nodules followed ATA sonographic risk stratification (high 100%, intermediate 21%, low 17%, and very low 12%; p = 0.003).

Conclusion: This prospective study supports the new ATA sonographic pattern risk assessment for selection of thyroid nodules for US-FNA based upon TBSRTC and surgical pathology results. In the setting of indeterminate cytopathology, nodules categorized as atypia of undetermined significance/follicular lesion of undetermined significance with ATA high-risk sonographic patterns have a high likelihood of being malignant.

Keywords: ATA guidelines; thyroid cancer; thyroid nodules; thyroid ultrasound; ultrasound.

Publication types

  • Validation Study

MeSH terms

  • Adenocarcinoma, Follicular / diagnostic imaging
  • Adenocarcinoma, Follicular / pathology
  • Adenocarcinoma, Follicular / surgery
  • Adenoma, Oxyphilic / diagnostic imaging
  • Adenoma, Oxyphilic / pathology
  • Adenoma, Oxyphilic / surgery
  • Adult
  • Biopsy, Fine-Needle
  • Calcinosis / diagnostic imaging
  • Calcinosis / pathology
  • Calcinosis / surgery
  • Carcinoma, Papillary / diagnostic imaging
  • Carcinoma, Papillary / pathology
  • Carcinoma, Papillary / surgery
  • Diagnosis, Differential
  • Female
  • Hospitals, Teaching
  • Humans
  • Male
  • Ohio
  • Practice Guidelines as Topic*
  • Prospective Studies
  • Risk Assessment*
  • Societies, Scientific
  • Thyroid Cancer, Papillary
  • Thyroid Gland / diagnostic imaging*
  • Thyroid Gland / pathology
  • Thyroid Gland / surgery
  • Thyroid Neoplasms / diagnostic imaging*
  • Thyroid Neoplasms / pathology
  • Thyroid Neoplasms / surgery
  • Thyroid Nodule / diagnostic imaging*
  • Thyroid Nodule / pathology
  • Thyroid Nodule / surgery
  • Tumor Burden
  • Ultrasonography
  • United States

Supplementary concepts

  • Thyroid cancer, Hurthle cell
  • Thyroid cancer, follicular