Authors: Dr Heather King (Foundation Year 1), Miss Aidah Isa (Consultant ENT Surgeon) Introduction: British Thyroid Society (BTA) guidelines in July 2014 recommend the use of U and Thy grading in the assessment of thyroid nodules. Thyroid nodules graded thy 1 are non-diagnostic. Aim: To determine the thy 1 rate of FNA at a single centre district general hospital in Inverness, UK and correlate this to radiologist performing the FNA as well as size and grading of thyroid nodule.

Retrospective analysis of U and Thy classifications of patients with histology from 1st November 2022 to 16th August 2023.

Patients who met the criteria n=64. Age range 20-85, female n=50, male n=14. Radiologists who performed FNAs n=7. Nodules graded thy 1 n=14. Thy 1 grade per radiologist: 5; 4; 2; 1; 1; 1; 0. Thy 1 grade per size of nodule: <1cm n=1; 1-1.9cm n=2; 2-2.9cm n=1; 3-3.9cm n=3; 4-4.9cm n=5; 5-5.9cm n=0; 6-6.9cm n=1; 7-7.9cm n=3; not reported n=1. U grades of thyroid nodules classified thy 1: U1 n=0; U2 n=5; U3 n=8; U4 n=1; U5 n=0; not reported n=0.

14 out of 64 thyroid nodules in this study were graded thy 1. There is an apparent correlation between thy 1 grading with radiologist performing FNA procedure suggesting further training may be required. Thy 1 nodules were most commonly measured at 4-4.9cm. Thy 1 nodules were most commonly subsequently classified U3 (indeterminate lesions) which highlights the importance of adequate sampling in the first instance.