Background: Objectives: to determine the stratification and risk of malignancy of Bethesda system’s subgroups for reporting thyroid cytopathology, in addition, compare with Thyroid Imaging Reporting and Data System [TI-RADS] in diagnosing benign and malignant thyroid nodules Method: - Retrospective cross - sectional descriptive study. Collect data of 202 thyroid nodules from 193 patients admitted at the Hospital of in Hue University of Medicine and Pharmacy during the period 6/2018 to 5/2020. Results: The average age uns 46.7 ± 14.5 years, women accounted for the majority (89.6%) and most patients had multiple thyroid nodules (79.2%). The proportion of Bethesda subgroups were : 0% (I)
38.6% (II)
0.5% (III)
30.2% (IV)
16.8% (V) and 13.9% (VI) with a malignant risk of 9% (II)
100% (III)
26.3% (IV)
76.4% (V) and 96.4% (VI). The percentage of TIRADS subgroups were: 6.9% (1)
11.4% (2)
30.2% (3)
34.2% (4) and 17.3% (5) with corresponding malignant risks were: 0% (1)
4.4% (2)
14.8% (3)
47.8% (4) and 86.8% (5). Bethesda system has sensitivity, specificity, positive diagnostic value, negative diagnostic value of 69.7%
92.8%
85.5%
and 83.6% (with the cut off are groups V and VI). TIRADS system whose sensitivity, specificity, positive diagnostic value, negative diagnostic value were 86.8%
67.5%
61.6% and 89.4% respectively (cut off were groups of 4 and 5). The area under the curve (AUC) of Bethesda V, VI subgroups was 0.81 (p <
0.001) and of TIRADS 4 and 5 subgroups was 0.25 (p <
0.001). Conclusion: The Bethesda system for reporting thyroid cytopathology was more valuable than Thyroid Imaging Reporting and Data System [TI-RADS] in diagnosing thyroid malignant nodules