Doppler-Scintigraphy Combination with Thyroxine Profiling Enhances Diagnostic Accuracy of Thyroid Lesions: A...

Background: The characterization of thyroid lesions is essential in clinical practice. Recent advances in imaging modalities, including nuclear imaging (NM), color Doppler ultrasonography, and sonography, have markedly improved the diagnostic accuracy for thyroid nodules. Objective: To assess thyroid diseases using Doppler ultrasound, nuclear scintigraphy, and sonography. Results: In this cross-sectional single-center study, 144 patients were examined to determine their thyroid structure and function using a multimodal imaging approach. Fine-needle aspiration cytology (FNAC) indicated that most thyroid nodules were benign (62.5%), with 37.5% being malignant. Doppler vascularity demonstrated a sensitivity of 70.4% and a specificity of 40% (AUC = 0.514) for malignancy detection, while scintigraphy uptake in hypofunctioning nodules (nodules with decreased radionuclide uptake) showed a sensitivity of 37% and a specificity of 54.4% (AUC = 0.388). Thyroxine hormone levels showed a sensitivity of 57.4% and a specificity of 45.6% (AUC = 0.503) for detecting malignant thyroid nodules. In multivariate logistic regression, increased Doppler vascularity remained an independent predictor of malignancy (OR = 2.39; 95% CI: 1.15-4.96; p = 0.019), whereas decreased scintigraphic uptake showed a borderline effect (OR = 1.82; p = 0.069); high T4 level and increased uptake were not significant predictors. The combined Doppler ultrasound, scintigraphy, and thyroxine level model yielded an AUC of 0.72 (95% CI: 0.63-0.81), markedly higher than any single parameter. At the optimal Youden threshold (0.43), the model achieved 79.6% sensitivity, 68.2% specificity, and 72.4% accuracy, highlighting the superior diagnostic performance of the integrated approach for pre-FNAC stratification of thyroid malignancies. There was a strong, significant linear association between thyroxine levels and thyroid scintigraphy uptake (p-value < 0.001). Most patients with normal thyroxine levels exhibited decreased uptake (66.1%), whereas a minority (6.5%) demonstrated elevated uptake levels. This study found a strong correlation between mixed-echogenicity nodules and thyroid scintigraphy uptake (p-value = 0.019). Mixed-echogenicity nodules were most often associated with reduced uptake (57.8%), and hypoechoic nodules often had normal uptake (57.1%). Conclusions: The complementary integration of color Doppler vascularity, Tc-99m thyroid scintigraphy, and serum thyroxine levels yields superior Doppler-scintigraphy uptake correlation, increases the overall diagnostic accuracy, and offers a practical, non-invasive algorithm for differentiating benign from malignant thyroid nodules prior to FNAC or surgery.