Abstract
INTRODUCTION: Thyroid disorders are among the most prevalent endocrine diseases worldwide, with rising incidence linked to aging, lifestyle, and environmental factors. Early identification of both functional and structural abnormalities is essential to prevent complications. This study aimed to investigate the coherence between thyroid function as measured by thyroid-stimulating hormone (TSH) and free thyroxine (FT4) tests and ultrasound-based thyroid classification according to the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS). METHODS: This retrospective cross-sectional study included patients in Tabuk, Saudi Arabia, who underwent thyroid ultrasound alongside TSH and FT4 tests within two weeks. Thyroid nodules were classified using TI-RADS. Demographic, clinical, and laboratory data were extracted from electronic records, and statistical analyses examined associations between hormone levels, ultrasound findings, and clinical variables (p < 0.05). RESULTS: A total of 102 patient records were included in the study. Most participants were female and overweight, with a mean body mass index (BMI) of 30.2 ± 4.6 kg/m(2). The majority were euthyroid (58.3%) or subclinical hypothyroid (27.8%); most nodules were benign (TI-RADS 2-3). BMI showed a moderate positive correlation with TSH (ρ = 0.20, p = 0.041) and a negative correlation with FT4 (ρ = -0.20, p = 0.040). No significant relationship was observed between TI-RADS classification and thyroid hormone levels (p > 0.05). CONCLUSIONS: Structural thyroid changes identified by ultrasound appeared largely independent of hormonal status. Meanwhile, BMI demonstrated a modest physiological association with thyroid function reflected in TSH and/or FT4 levels. These findings emphasize the need for integrated biochemical and imaging evaluation to enhance diagnostic precision in the assessment of thyroid disease.