Evaluating the Role of Resistive Index in Pediatric Hashimoto’s Thyroiditis Diagnosis and the Impact of Vitamin D Treatment on Resistive Index

Abstract

Objectives: Thyroid ultrasonography combined with color Doppler imaging represents one of the most reliable and non-invasive tools for assessing patients with Hashimoto’s thyroiditis. Growing evidence suggests that vitamin D deficiency contributes to the pathophysiology of this autoimmune disorder and may influence its progression toward hypothyroidism. This study aimed to explore the role of ultrasonography and color Doppler evaluation in children with Hashimoto’s thyroiditis and to determine the effect of vitamin D supplementation on resistive index values, as well as on serum thyroid hormone and antibody levels. Materials and methods: Eighty-four children were enrolled in this study, consisting of 45 diagnosed with Hashimoto’s thyroiditis and 39 age- and sex-matched healthy controls. In all participants, serum concentrations of 25-hydroxyvitamin D, calcium, phosphorus, alkaline phosphatase, thyroid hormones, and thyroid antibodies were analyzed. Both groups underwent grayscale ultrasonography and color Doppler evaluation of the thyroid gland. The patient group received oral vitamin D supplementation at approximately 2,000 IU daily. After two months of treatment, all biochemical and sonographic assessments were repeated. Results: Patients with Hashimoto’s thyroiditis demonstrated significantly higher grayscale ultrasonography grades compared with controls. Free thyroxine and vitamin D levels were notably lower among patients. Following vitamin D supplementation, anti-thyroid peroxidase antibody titers decreased significantly, accompanied by a statistically meaningful reduction in resistive index values in the right, left, and overall thyroid lobes. Conclusion: Although the resistive index alone does not appear to be a reliable diagnostic indicator for Hashimoto’s thyroiditis, vitamin D supplementation was associated with reductions in both resistive index values and anti-thyroid peroxidase antibody levels. Further controlled trials including untreated patients are warranted to confirm these findings. © The Author(s) 2025.