Absolute Metabolite Quantification in Human Brain Using Short Echo-Time CSI and a Phased-Array Headcoil.

Petra Pouwels¹, Marjan Steenweg², Frederik Barkhof³, Marjo van der Knaap²

Absolute metabolite concentrations in human brain were obtained from short echo-time CSI (TR/TE 3000/30 ms, 6 averages, 19 minutes) using a phased-array headcoil. A voxel-wise calibration was based on a combination of transmitter amplitude and water reference scans obtained with both body- and headcoil (<1 minute each). This provided a reproducible and homogeneous quantification as demonstrated in a phantom. In vivo, high quality spectra were obtained in 37 subjects between 2 and 19 years. Metabolite concentrations showed similar regional distributions and age-related variations as previously observed with quantitative single-voxel MRS, demonstrating the applicability of CSI for quantitative MRS at high spatial resolution.