Ultrasound Guided FNAC for Evaluation of Neck Lumps to Improve Inadequacy Rates; A Complete Audit Cycle

Abstract

 We present a completed audit cycle evaluating inadequacy rates in neck lump and thyroid fine needle aspiration cytology with and without ultrasound scan guidance.

The first cycle of the audit was from January to July 2010 comparing free hand fine needle aspiration cytology (FNAC) with ultrasound guided fine needle aspiration cytology (USS+FNAC). Changes to practice were made, firstly all thyroid FNAC would be performed with USS+FNAC and a reduced threshold for referral for USS+FNAC for non-thyroid neck masses. The second audit cycle was completed sixteen months later to assess for an improvement in practice. 1^st phase; 155 patients, 70 freehand, 85 USS+FNAC. 50% of the thyroid FNAC freehand were inadequate compared to 18% of the thyroid USS+FNAC. 2^nd phase; 196 patients, USS+FNAC 134, freehand 62. Thyroid FNAC 105 (USS+FNAC-104, freehand-1). Inadequate USS+FNAC = 21/104 (20%). The completed audit cycle shows an increased proportion of thyroid FNACs performed by ultrasound guidance, improving from 82% to 99%, with an overall reduction of inadequate thyroid FNACs from 24% to 21%. There was a noticeable variability in the inadequacy rates from radiologist to radiologist with the head and neck senior radiologist demonstrating the lowest inadequacy rate at 9.6% in the second cycle. Although ultrasound guidance for FNAC is important for the reasons of increased sensitivity, specificity and accuracy, we have demonstrated that the operator experience and skill are just as important.