Detecting white adipose tissue browning in mice with in vivo R2* mapping at 9.4T MRI

Motivation: The research and application of white adipose tissue (WAT) browning, a promising strategy to combat obesity, are limited by the lack of sensitive and non-invasive imaging methods. Goal(s): To explore the potential of R2* as an imaging biomarker for WAT browning. Approach: We investigated WAT browning induced by long-term CL316,243 stimulation in mice and quantified the changes in R2*, fat-water fraction (FWF), UCP1 expression, and iron content. Results: We observed increased R2* and decreased FWF during WAT browning. The UCP1 expression of WAT was strongly correlated with R2* and FWF, and the R2* was highly correlated with the ex vivo iron content. Impact: We demonstrated R2* may be a more valuable and specific biomarker, especially specific circumstances involving iron-regulated pathways and interventions for WAT browning, which may offer a novel strategy for monitoring and regulating WAT metabolism to combat obesity and metabolic diseases.