A literature review was performed assessing interobserver agreement (IA) using ACR TI-RADS, with the following objectives: Identify which categories and assessors were more prone to interobserver variability Whether interobserver variability resulted in substantial difference to radiology recommendations Whether any intervention had been shown to result in increased IA

Thyroid nodules are a common incidental finding, with mostly benign aetiology Multiple risk stratification systems have been created – the most recent being ACR TI-RADS Nodules are assessed against five categories: composition, echogenicity, shape, margins and echogenic foci[1] Cumulation of points in each category results in a TI-RADS level, where management suggestion is based on size Poor reproducibility may lead to poorer sensitivity and specificity and cause confusion for referrers, misinterpreting change in TI-RADS score on progress studies as disease progression, rather than change attributable...

Key terms “interobserver variability” or “interobserver agreement” or “observer variability” and “TI-RADS” were combined on Medline. Studies were excluded if published in a language other than English, or did not pertain to ACR TI-RADS. Following exclusions, 9 studies were included. All studies conveyed IA using the Kappa statistic. This has previously been interpreted as: K=0.81-0.99 almost perfect agreement K=0.61-0.8 substantial agreement K=0.41-0.6 moderate agreement K=0.21-0.4 fair agreement K=0.1-0.2 poor agreement K<0 less than chance agreement[2] Percentage agreement was provided for most studies. Of note, one...

Radiology experience or subjective rating of greater comfort levels using TI-RADS did not necessarily correlate with greater IA in either radiologists or sonographers In some studies, less experienced radiologists could achieve similar or greater IA than more experienced radiologists Margins, echogenicity and punctate echogenic foci consistently showed poorer IA compared to other categories There is suggestion that IA can be improved following intervention, although further studies are required

[1] F. N. Tessler et al., “ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee,” J. Am. Coll. Radiol., vol. 14, no. 5, pp. 587–595, 2017. [2] M. Itani, R. Assaker, M. Moshiri, T. J. Dubinsky, and M. K. Dighe, “Inter-observer Variability in the American College of Radiology Thyroid Imaging Reporting and Data System: In-Depth Analysis and Areas for Improvement,” Ultrasound Med. Biol., vol. 45, no. 2, pp. 461–470, 2019. [3] H. Liu et al., “Variability in the interpretation...