Abstract
Two-pulse phase-modulated (TPPM) (1)H-decoupling pulse sequence repeats a pair of 180(o) RF pulses while changing the signs of the RF phase modulation angle and has been widely used for the (13)C NMR of organic solids. TPPM was introduced into the (13)C MRS pulse sequence on a clinical 3T MR scanner, and the (1)H-decoupling performance was compared with conventional (1)H-decoupling schemes using aqueous solutions containing glucose and oyster glycogen. The (13)C C1-glucose peaks were (1)H-decoupled using TPPM with B(2) = 500 Hz, and the optimal RF phase modulation angle was up to 30(o). Cycling sidebands were not observed when TPPM was used but were observed when WALTZ-16 was used. The (13)C C1-glycogen peak was (1)H-decoupled even with reducing TPPM duration to 8 ms, which reduced simulated specific absorption rate (SAR) to 39%. In conclusion, the TPPM (1)H decoupling is applicable to clinical MR scanners, and the low-SAR sequence may be more valuable at 7T.