Detection of cerebral NAD⁺ in humans at 7T

To develop ¹ H-based MR detection of nicotinamide adenine dinucleotide (NAD⁺ ) in the human brain at 7T and validate the ¹ H results with NAD⁺ detection based on ³¹ P-MRS.

¹ H-MR detection of NAD⁺ was achieved with a one-dimensional double-spin-echo method on a slice parallel to the surface coil transceiver. Perturbation of the water resonance was avoided through the use of frequency-selective excitation. ³¹ P-MR detection of NAD⁺ was performed with an unlocalized pulse-acquire sequence.

Both ¹ H- and ³¹ P-MRS allowed the detection of NAD⁺ signals on every subject in 16 min. Spectral fitting provided an NAD⁺ concentration of 107 ± 28 μM for ¹ H-MRS and 367 ± 78 μM and 312 ± 65 μM for ³¹ P-MRS when uridine diphosphate glucose (UDPG) was excluded and included, respectively, as an overlapping signal.

NAD⁺ detection by ¹ H-MRS is a simple method that comes at the price of reduced NMR visibility. NAD⁺ detection by ³¹ P-MRS has near-complete NMR visibility, but it is complicated by spectral overlap with NADH and UDPG. Overall, the ¹ H- and ³¹ P-MR methods both provide exciting opportunities to study NAD⁺ metabolism on human brain in vivo. © 2016 International Society for Magnetic Resonance in Medicine. Magn Reson Med 78:828-835, 2017. © 2016 International Society for Magnetic Resonance in Medicine.