<p>The “American College of Radiology-Thyroid Imaging Reporting and Data System (ACR-TIRADS)” and “British Thyroid Association (BTA)” U-Score are scoring systems with excellent diagnostic accuracy. However, studies comparing these scoring systems resulted in heterogenous outcomes. This study aims to compare the diagnostic performance of both “ACR-TIRADS” and “BTA U-score” in the detection of malignant thyroid nodules by correlating final histology with ultrasound features. This retrospective diagnostic cohort study was conducted in Universiti Malaya, and included 391 patients who underwent thyroid surgery over a 6-year period. 255 patients were available for final analysis. Two radiologists with different degrees of experience, independently reviewed all ultrasound images and classified the nodules according to ACR-TIRADS and BTA U-score. Ultrasound (US) scores were then correlated with the histopathology reports to determine the diagnostic accuracy – sensitivity, specificity, accuracy, positive and negative predictive values. Cohen’s Kappa coefficient was used to measure the inter-rater agreement between the two radiologists. Similar values were seen in the diagnostic accuracy of both scoring systems: sensitivity (BTA:88.9% vs. ACR:84.1%), specificity: (BTA:29.2% vs. ACR:26.0%), PPV: (55.7% vs. 53.2%) and accuracy (BTA:59% vs. ACR:55.1%). BTA showed higher negative predictive values (NPV) compared with ACR-TIRADS (72.45 vs. 62.1%). Moderate inter-observer agreement was observed between the two radiologists (Cohen’s K: ACR-TIRADS: 0.5 vs. BTA U-score: 0.5 with a 95% CI). Comparable diagnostic accuracy in the detection of malignant thyroid nodules was seen when ACR-TIRADS and BTA U-score scoring systems were used, although BTA had higher NPV in predicting benign nodules in this population.</p>