Keywords:
Head and neck, Ultrasound, Biopsy, Pathology
Authors:
G. Hinton, S. Prowse
DOI:
10.26044/ranzcr2022/R-0080
Results
126 thyroid FNA’s were performed in the period from September 2020 to March 2021. 73 (58%) were diagnostic defined as Bethesda category 2-6 and 53 (42%) were non-diagnostic defined as Bethesda category 1. The only factor with a clear trend impacting diagnostic rate observed in this audit was the level of experience of the performing clinician with consultants having a diagnostic rate of 65% (43 procedures), registrars having a diagnostic rate of 57% (54 procedures) and resident medical officers having a diagnostic rate of 48% (29 procedures). Interestingly size of nodule did not affect the diagnostic rate as I would have predicted with nodules 0-10mm having a diagnostic rate of 42% (12 samples), 11-20mm 53% diagnostic (43 samples) and >21mm 37% diagnostic (71 samples).
Procedural technique was fairly consistent throughout the audit with a 25 gauge needle used in all but 5 cases, noting needle gauge was not documented in 33 cases. The number of passes performed also remained quite consistent throughout with 2 passes performed in 24 cases, 3 passes performed in 82 cases, 4 passes performed in 14 cases, 5 passes performed in 1 case and not documented in 5 cases. The diagnostic rate was slightly lower for 2 passes (46%) compared to 62% for 3 passes and 58% for 4 passes.
77 (61%) of procedures were indicated based on ACR TIRADS criteria with 47 (37%) not indicated based on TIRADS criteria (37%). 2 were not able to be assessed either due to TIRADS not being reported or no available prior imaging. The diagnostic rate however was similar across the not indicated vs indicated thyroid FNAs 57% vs 58%.
Five of the 126 samples returned findings suspicious or diagnostic for malignancy (Bethesda category 4 or 5). Of these 2 were classified as TIRADS 5 on US, 2 were TIRADS 4 and one had no available diagnostic US.
Seven of the 126 patients had undergone an operative procedure at the time of auditing with papillary carcinoma diagnosed in 3 patients, with TIRADS scores of 4, 4 and 5 at diagnostic ultrasound. Follicular thyroid carcinoma was diagnosed in 1 patient with a TIRADS score of 3. Hashimoto’s thyroiditis was diagnosed in 1 patient with a TIRADS score of 3. Follicular adenoma with multinodular goitre was diagnosed in 1 patient with a TIRADS score of 4.