Ultrasound remains the most commonly performed dedicated imaging evaluation of the thyroid. There is high variability in the reporting of thyroid nodules and nodule characterization. The Thyroid Imaging, Reporting and Data System (TI-RADS) was introduced by the American College of Radiology (ACR) in 2017 to standardize reporting of thyroid nodules and to offer guidelines for appropriate clinical management. TI-RADS scoring provides an ultrasound-based risk stratification system to identify potentially malignant nodules that warrant fine needle aspiration biopsy (FNAB) or continued imaging surveillance. Since its introduction, ACR TI-RADS has gained increasing acceptance by radiologists and their referring colleagues. This study was performed to assess the views of radiologists with varying levels of experience, who have implemented this classification system into their practice.
Materials and Methods:
This single center study was performed as a quality assurance initiative. An electronic survey was conducted between 6/4/2020 – 6/25/2020 among twelve radiologists who regularly interpret thyroid sonogram using the ACR TI-RADS. The mean post-graduate experience was 7 years. Eight surveys were completed, with a response rate of 8/12 (67%).
When asked whether a colloid nodule with comet tail artifacts should be scored as TR1 (0 point for composition, with no further point for other categories), 87.5% of respondents answered yes, and 12.5% indicated no, citing concern regarding the presence of solid component potentially harboring malignant cells. Regarding significant interval growth of a nodule as defined by the ACR TI-RADS, when asked what the appropriate recommendation would be for a nodule that meets criteria for significant growth but remains below the size threshold for FNAB, 75% indicated they would recommend a 1 year follow-up, 12.5% would recommend FNAB, and 12.5% would recommend short-term follow-up. Regarding correlative imaging with thyroid scintigraphy, when asked if their recommendation would change based on results of thyroid scintigraphy, 75% responded no, 25% responded yes. Survey responses were more divided when respondents were asked to identify the sonographic feature that is the most challenging to score, with the majority (37%) indicating nodule margin as the most challenging category. Additional challenges identified with the ACR TI-RADS include differentiating small solid hypoechoic nodules from cystic nodules, distinguishing punctate echogenic foci from normal parenchymal bright echogenic dots or comet tail artifacts. Feedback from radiologists regarding pitfalls and limitations includes the need for management guidelines of nodules that exhibit significant interval growth but not meeting threshold for FNAB.
This study highlights contemporary opinions of practicing radiologists regarding the clinical application of ACR TI-RADS and its pitfalls. These results provide insights that could help inform ongoing efforts aimed at improving the next version of TI-RADS.