Diagnostic Significance of Ultrasound-Guided Fine-Needle Aspiration Biopsy and on-Site Assessment by Pathologists for Thyroid Micronodules.

ABSTRACT

Objective: Ultrasound-guided fine-needle aspiration biopsy (US-FNAB) is a safe and effective method for screening malignant thyroid nodules. The purpose of this study was to compare the diagnostic effectiveness of US-FNAB for nodules of different sizes. Methods: A total of 1085 patients with thyroid nodules who underwent US-FNAB between January 2021 and July 2023 were included in the study. The patients were divided into three groups based on the maximum diameter of the nodules there were 324 patients with thyroid nodules ≤5 mm in Group A, 537 patients with thyroid nodules between 6 mm and 10 mm in Group B, and 224 patients with thyroid nodules >10 mm in Group C. The US-FNAB satisfactory specimen rate, biopsy time and cytopathological results for the three groups were collected and compared with the postoperative pathological results. Results: The US-FNAB satisfactory specimen rates for Groups A, B and C were 84.57% (274/324), 90.13% (484/537) and 94.64% (212/224), respectively. The average biopsy times for Groups A, B, and C were 100.84 ± 41.58 s, 91.20 ± 32.53 s, and 79.01 ± 29.62 s, respectively. In Groups A, B, and C, 103, 192 and 73 patients, respectively, underwent surgery, and the malignancy rates were 88.35%, 85.42% and 72.6%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of US-FNAB in Group A were 78.26%, 81.82%, 97.30%, 31.03%; respectively; those in Group B were 73.78%,85.71%,96.80%, and 35.82%, respectively; and those in Group C were 75.47%, 85.00%, 93.02% and 56.67%, respectively. Conclusion: The US-FNAB satisfactory specimen rate for thyroid nodules ≤5 mm was relatively low, but the size of nodules had no effect on the diagnostic sensitivity of US-FNAB; additionally, nodules ≤5 mm had a higher probability of malignancy. Therefore, it is necessary to perform US-FNAB for thyroid nodules with a diameter ≤5 mm with malignant signs.