Evaluation of thyroid nodules – review of agreement between U grade and TI-RADS scoring tools in a single ultrasound unit

Petra Williams, Clinical Imaging Derriford Hospital

Background and purpose:

BTA guidelines recommend use of U grade for evaluation of thyroid nodules.

An initial department review had been performed of 50 thyroid ultrasound studies where thyroid nodules were assessed, looking at the reporting styles. This identified that rather than consistent use of the U grade, there was a broad range of reporting styles, with most reporters using a descriptive approach and occasional use of U grade by some reporters. 2 reporters occasionally used the TI-RADS scoring system. To provide more consistent reports for referring clinicians, this study sought to assess the level of agreement between the U grade and TI-RADS tools by our reporters, and to assess inter-observer agreement for each tool and agreement between tools.


8 experienced reviewers independently assessed the same images of 10 thyroid lesions and provided a U and TI-RADS score based on that imaging.  Intra-class correlation was used to assess agreement between reviewers.  Kappa analysis was used to assess agreement between scoring systems.


There was a high degree of agreement between raters using both the U grading (ICC 0.7. 95th CI:0.48-0.89) and TI-RADS scoring systems (ICC 0.75. 95th CI=0.55-0.91).  There was no significant difference in inter-rater agreement between the scoring systems.  There was also a high degree of agreement between the U and TI-RADS scoring systems (K=0.84; SE=0.14).


There is a high degree of inter-rater agreement in use of both the U and TI-RADS scoring systems.  There is also good agreement between the U and TI-RADS scoring systems. There is no evidence in our department to promote one scoring system over another. Individual ultrasound units should agree a single scoring system by consensus with their surgical colleagues.

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