Comparison of STEAM and sLASER to quantify acetylcarnitine at rest using long TE 1H-MRS in human skeletal muscle with a surface or birdcage coil at 7T

Long echo time 1H-MRS has been used to determine in vivo acetylcarnitine (ACCT) concentrations in the skeletal muscle. At ultra-high field (UHF), STEAM-based 1H-MRS was used for this purpose, in combination with a knee birdcage coil. However, STEAM suffers from an inherent 50% signal loss and a knee coil often does not fit around the upper leg in obese volunteers. Here, we demonstrated that sLASER, in combination with a surface coil, provides high signal-to-noise ratio (SNR) and can be used as an alternative method at 7T to detect physiologically low ACCT concentrations at rest in both lean and obese volunteers.