Development of a Double Tuned ²H/31P Whole-Body Birdcage Transmit Coil for 2H and 31P MR Applications From Head to Toe at 7 T

Abstract

Deuterium ( 2H) and phosphorus ( 31P) magnetic resonance spectroscopy (MRS) are complementary methods for evaluating tissue metabolism noninvasively in vivo. Combined 2H and 31P MRS would therefore be of interest for various applications, from cancer to diabetes. Loop coils are commonly used in X-nuclei studies in the human body for both transmit and receive. However, loop coils suffer from limited penetration depth and inhomogeneous B 1 + field. The purpose of this work is to develop a double tuned 2H/ 31P whole-body birdcage transmit coil for 7 T for 2H and 31P MRS imaging (MRSI) with homogeneous excitation over a large field-of-view. The performance of the 2H/ 31P birdcage coil was assessed on B 1 + fields over a body-sized phantom at 2H and 31P frequencies using an 8-channel 2H/ 31P receive array. Using two elements of the 2H/ 31P receive array, natural abundance 2H and 31P 3D MRSI data at rest were acquired consecutively in the brain and lower leg muscles. Additionally, 2H and 31P 3D MRSI data were acquired from one volunteer 90 min after [6,6'- 2H 2]-glucose intake, using 8-channel 2H/ 31P receive array around the abdomen. The B 1 + variation of the whole-body birdcage coil over the phantom was 12.1% for 2H and 19.2% for 31P. High-quality 2H and 31P 3D MRSI data were acquired from the brain and the lower leg. Whole liver coverage was achieved in both 2H and 31P 3D MRSI data. The developed 2H/ 31P whole-body birdcage transmit coil allows simultaneous 3D mapping of glucose and energy metabolism and membrane turnover throughout the human body.