Susanne Heinzer-Schweizer1, Nicola De Zanche1,2, Matteo Pavan1, Giel Mens3, Urs Sturzenegger4, Anke Henning1, Peter Boesiger1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Department of Medical Physics , Cross Cancer Institute and University of Alberta, Edmonton, Canada; 3Philips Healthcare, Best, Netherlands; 4Philips AG Healthcare, Zurich, Switzerland
Absolute quantification is an indispensable tool to precisely determine metabolite changes. Calibration with ERETIC (Electric REference To access In vivo Concentrations), whereby a synthetic reference signal is injected during the acquisition of spectra, was used to determine quantitative in-vivo metabolite concentrations in volunteers. Brain 1H MRS spectra were acquired and cross-validated against the internal water reference method. The results of both calibration techniques were in good agreement in healthy tissue. In addition, the ERETIC setup was perfected by substitution of the electrical by an optical signal transmission line to eliminate fluctuations of the ERETIC signal intensity due to parasitic coupling.