Abstract
Background/Objectives: Ultra-Micro Angiography (UMA) is an advanced Doppler technique designed to improve the visualization of slow blood flow in small vessels. The Subtraction UMA (sUMA) setting enhances these features by removing background tissue interference, allowing for more precise assessments of microvascularity. This study aims to establish reference values for thyroid vascularity using sUMA technology, providing a foundation for future research in thyroid pathology. Methods: This prospective, single-center study included 106 healthy participants with no evidence of thyroid disease based on biochemical and ultrasound evaluations. All participants underwent multiparametric ultrasound, followed by sUMA to assess thyroid vascularity. The quantitative sUMA measurements were performed using the color pixel percentage (CPP), and three measurements were taken in each thyroid lobe. The median CPP values were calculated and analyzed. Statistical analysis was conducted to evaluate intraobserver reliability and to examine correlations between CPP values and demographic characteristics. Results: The study cohort had a mean age of 41.2 ± 16.3 years, with a predominance of women (82%). CPP sUMA measurements demonstrated excellent feasibility (100%) and intraobserver reliability, with an intraclass correlation coefficient of 0.905 for the right thyroid lobe and 0.897 for the left lobe. The median CPP for the right and left lobes was 26.5% and 27.1%, respectively, with no significant difference between lobes (p = 0.8799). Conclusions: sUMA technology is a reliable and reproducible method for evaluating thyroid microvascularity in healthy individuals. These reference values provide a foundation for future studies investigating thyroid pathology, potentially enhancing the accuracy of diagnostic assessments in clinical practice.