Polarization transfer for sensitivity-enhanced MRS using a single radio frequency transmit channel.

Abstract

Polarization transfer techniques are used to enhance sensitivity and improve localization in multinuclear MRS, by transferring polarization from highly polarized or even hyperpolarized nuclei to less sensitive spin systems. Clinical MR scanners are in general not equipped with a second radio frequency (RF) transmit channel, making the conventional implementation of polarization transfer techniques such as distortionless enhanced polarization transfer (DEPT) impossible. Here we present a DEPT sequence using pulses sequentially that can be used on a single RF transmit channel (SC-DEPT). Theoretical simulations, phantom measurements, and in vivo results from human brain at 3 T show that the SC-DEPT method performs as well as the conventional DEPT method. The results indicate that an independent second RF transmit channel for simultaneous pulsing at different nuclear frequencies is not needed for polarization transfer, facilitating the use of these methods with common clinical systems with minor modifications in the RF architecture.