Detection of cerebral NAD + in humans at 7T

Purpose 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. Methods 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. Results 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. Conclusions 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.