Dynamic T2* Relaxometry of Hyperpolarized [1-13C]pyruvate MRI in the Human Brain and Kidneys

We present dynamic T2* measurements for HP [1-13C]pyruvate and metabolites in a healthy human brain volunteer and two RCC patients at 3T. The T2* of pyruvate was shown to vary during the acquisition, whereas the T2* of lactate and bicarbonate was constant through time and across organs. The T2* of lactate was constant at gray matter (30.1±5.9ms), white matter (33.8±7.6ms), healthy kidney (38.94±6.9ms) and tumor (33.27±6.4ms), and the T2* of bicarbonate over whole-brain (109.5±12.8ms) and kidney (64.6±15.8ms). These relaxometry measurements will be useful for future sequence optimization and can be included in kinetic modeling to harmonize data across different TEs.