Test-Retest Repeatability of Human Neurochemical Profiles Measured at 3 Versus 7 T

Melissa Terpstra¹, Uzay E. Emir¹, Lynn E. Eberly¹, Gulin Oz¹

Although increased precision of metabolite quantification at ultra-high field has been demonstrated, accompanying improvements in test-retest reproducibility have not been evaluated. Therefore, ¹H MR spectra were measured four times from each of four participants at both 3T and 7T. Outstanding spectral quality and reproducibility were achieved at 3T using commercially available hardware. While the Cramer-Rao lower bounds (CRLB) were universally lower at 7T than at 3T, the coefficients of variance (CV) were comparable at the two field strengths. Therefore, at the achieved spectral quality, factors other than quantification precision appear to limit inter-session reproducibility at 7T.