MRI Relaxation rates of fecal microbiota from porcine stool samples and their relationship to essential metals

Motivation: This work is the first step in developing MRI methods to assess and quantify the gut microbiome in humans. Goal(s): Establish a relationship between MRI relaxation rates and bacterial metal content. Approach: An FMT procedure was applied to decompose 4 stool samples. Relaxation rates (R2* (1/T2*), R2 (1/T2), R1 (1/T1) and R2'=R2*-R2) were estimated for each component and the fecal microbiota was further analyzed with a 14-analyte ICP-MS to quantify metal content. Results: Despite the limited sample size, relaxation rates from fecal microbiota tended to increase with higher concentrations of zinc, iron, and manganese. Impact: With further validation, this could significantly impact the scope of clinical applications for abdominal MRI towards the detection of gut bacteria given their metal content.