Ungated, Free-breathing MRI Quantification of Renal Metabolic Rate of Oxygen via Conservation of Flow and Mass

Motivation: During early stages of diabetic kidney disease, renal metabolic rate of oxygen (rMRO2) may be elevated due to increased filtration rate and ATP demand that subsequently lowers oxygen availability to kidney tissue. Goal(s): Develop a non-invasive MRI-based sequence to quantitatively estimate rMRO2 during free-breathing as a potential biomarker for early diagnosis of kidney disease. Approach: An ungated, free-breathing MRI sequence was developed and tested in healthy volunteers that simultaneously measures blood flow rate and venous oxygen saturation at the left renal vein. Results: Estimated whole-organ renal metabolic parameters were consistent between free-breathing and breath-hold acquisitions. Impact: Renal metabolic rate of oxygen can be a potential biomarker for early-stage detection of diabetic kidney disease. Non-invasive, ungated, and free-breathing MRI-based oximetry can quantify whole-organ renal metabolic parameters when patients cannot hold their breath for extended periods.