Correlation of Ultrasound Thyroid Imaging Reporting and Data System with Histopathology findings among patients in Uganda

Abstract

Background: Ultrasonography (US) is a noninvasive modality for the initial assessment of thyroid nodules. Thyroid Imaging Reporting and Data System (TI-RADS) has demonstrated good performance in differentiating malignant thyroid nodules. However, the correlation of ACR TI-RADS with FNNA cytology is unusual in our setting. The study aims at correlating TI-RADS with cytology among patients referred for US-guided fine-needle none aspiration (FNNA) cytology at Mulago National Referral Hospital (MNRH). Methods: This was a hospital-based cross-sectional study that recruited 132 patients with thyroid nodules. Spearman’s correlation was used to establish a relationship between TI-RADS and FNNA cytology findings. The diagnostic accuracy of TI-RADS was assessed using sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios. Results: Of 132 study participants 90% (n=117) were females and the mean age of 41±13. One hundred sixty-one thyroid nodules were analyzed. More than half of the thyroid nodules (54.7%, n=87) were solid or almost solid, 96.9% (n=154) were shaped wider than tall, with 57.2% (n=91) having smooth margins while 83.7% (n=133) were hyperechoic or isoechoic and 88.7% (n=141) had none or large comet-tail artifact. TR3 was the commonest at 42.9% (n=69). The proportion of malignancy for TR4 and TR5 were 73.3% and 85.7% respectively. The correlation between ACR TI-RADS and the Bethesda system of thyroid classification scores was r=0.577. The sensitivity, specificity, PPV, NPV, positive and negative likelihood ratios of ACR TI-RADS were 90.9%, 98.5%, 90%, 99.3%, 62.3, and 0.1 respectively. Conclusion: We found that ACR TI-RADS classification is an appropriate and non-invasive method for assessing thyroid nodules in routine practice. It can safely reduce the number of unnecessary FNNA in a significant proportion of benign thyroid lesions. Thyroid nodules classified as TR3 should be followed routinely. ACR TI-RADS should be standardized as the screening tool in resource-limited areas.