The objective of this study was to investigate the feasibility of non-contrast ultrasonography in imaging brown adipose tissue, which plays a role in adipogenesis, thermogenesis, angiogenesis, immune cell interactions, and neurite outgrowth. No previous study has examined ultrasonography for this purpose. Ultrasonography is a less costly method than radiation exposure and may guide future research. Methods: The study evaluated perirenal adipose tissue thickness, subcutaneous adipose tissue thickness, cold sensation scores, and demographic data in 167 patients. Due to its richness in brown fat, it was hypothesized that increased perirenal fat thickness might reduce the sensation of cold. Adipose tissue thickness was measured using ultrasonography. Patients rated their frequency of feeling cold in daily life on a scale of 1-10. Results: The study found that females (p = 0.001) and individuals with normal weight (p = 0.018) felt colder. Male gender (p < 0.001), aging (p < 0.001), and a higher body mass index (p < 0.001) were associated with increased perirenal adipose tissue thickness. A negative correlation was identified between cold sensation scores and fat tissue thickness (perirenal: r = − 0.247, p = 0.001; subcutaneous: r = − 0.172, p = 0.027). As subcutaneous adipose tissue thickness increased, perirenal adipose tissue thickness also increased (r = 0.554, p < 0.001). Furthermore, increases in age (p = 0.033) and weight (p < 0.001) were linked to greater subcutaneous adipose tissue thickness. Conclusion: This is the first study to examine if assessment using non-contrast ultrasound can reveal information about the activity of brown adipose tissue. The results indicate that the thickness of perirenal adipose tissue correlates with diminished cold sensitivity and is influenced by gender, age, and body mass index. This finding could facilitate additional investigations into the function of brown adipose tissue in thermoregulation. 

Zeynep Yüce Uçar is a medical doctor who has received training in radiology, forensic medicine, and aerospace medicine. Her research interests focus on the quantitative evaluation of brown adipose tissue and perirenal fat using radiologic imaging methods. Uçar is particularly interested in investigating the relationship between fat distribution and metabolic parameters through advanced imaging techniques. She aims to contribute to the integration of quantitative radiology and imaging biomarkers into clinical research to enhance the understanding of metabolic and physiological mechanisms observable in medical imaging.