Dissolved hyperpolarized xenon-129 MRI in human kidneys

Abstract

Purpose: To assess the feasibility of using dissolved hyperpolarized xenon-129 (¹²⁹ Xe) MRI to study renal physiology in humans at 3 T.

Methods: Using a flexible transceiver RF coil, dynamic and spatially resolved ¹²⁹ Xe spectroscopy was performed in the abdomen after inhalation of hyperpolarized ¹²⁹ Xe gas with 3 healthy male volunteers. A transmit-only receive-only RF coil array was purpose-built to focus RF excitation and enhance sensitivity for dynamic imaging of ¹²⁹ Xe uptake in the kidneys using spoiled gradient echo and balanced steady-state sequences.

Results: Using spatially resolved spectroscopy, different magnitudes of signal from ¹²⁹ Xe dissolved in red blood cells and tissue/plasma could be identified in the kidneys and the aorta. The spectra from both kidneys showed peaks with similar amplitudes and chemical shift values. Imaging with the purpose-built coil array was shown to provide more than a 3-fold higher SNR in the kidneys when compared with surrounding tissues, while further physiological information from the dissolved ¹²⁹ Xe in the lungs and in transit to the kidneys was provided with the transceiver coil. The signal of dissolved hyperpolarized ¹²⁹ Xe could be imaged with both tested sequences for about 40 seconds after inhalation.

Conclusion: The uptake of ¹²⁹ Xe dissolved in the human kidneys was measured with spectroscopic and imaging experiments, demonstrating the potential of hyperpolarized ¹²⁹ Xe MR as a novel, noninvasive technique to image human kidney tissue perfusion.

Keywords: 129Xe; hyperpolarized xenon; kidney MRI; physiology; renal.