Measurement of Arterial Input Function in Hyperpolarized ¹³C Studies

Recently, hyperpolarized substrates generated through dynamic nuclear polarization have been introduced to study in vivo metabolism. Injection of hyperpolarized [1-¹³C] pyruvate, the most widely used substrate, allows detection of time courses of [1-¹³C] pyruvate and its metabolic products, such as [1-¹³C] lactate and ¹³C-bicarbonate, in various organs. However, quantitative metabolic modeling of in vivo data to measure specific metabolic rates remains challenging without measuring the input function. In this study, we demonstrate that the input function of [1-¹³C] pyruvate can be measured in vivo in the rat carotid artery using an implantable coil.