Noninvasive monitoring of chronic kidney disease using pH and perfusion imaging.

Chronic Kidney Disease (CKD) is a cardinal feature of methylmalonic acidemia (MMA), a prototypic organic acidemia. Impaired growth, low activity, and protein restriction affect muscle mass and lower serum creatinine, which can delay diagnosis and management of renal disease. We have designed an alternative strategy for monitoring renal function based on administration of a pH sensitive MRI agent and assessed this in a mouse model. This protocol produced three metrics: kidney contrast, ~4% for severe renal disease mice compared to ~13% and ~25% for moderate renal disease and healthy controls, filtration fraction (FF), ~15% for severe renal disease mice compared to ~79% and 100% for moderate renal disease and healthy controls, and variation in pH, ~0.45 units for severe disease mice compared to 0.06 and 0.01 for moderate disease and healthy controls. Our results demonstrate that MRI can be used for early detection and monitoring of CKD.