AUTOMATED SINGLE-VOXEL PROTON MRS - TECHNICAL DEVELOPMENT AND MULTISITE VERIFICATION

To improve clinical utility, an integrated method has been developed t o automatically acquire and process single-voxel in vivo proton spectr a on a 1.5 T clinical scanner. This method includes automated adjustme nt of linear shims using a very rapid modified simplex method, automat ed water suppression, and applies a water referencing scheme to correc t for phase and residual eddy current effects. No operator interventio n is required for the acquisition and processing of these pure-absorpt ion spectra. This method was tested in a preliminary multisite trial t o determine intersite and intrasite variability of metabolite ratio me asurements. In a sample of over 100 examinations, the standard deviati on of the ratios NAA:Cr, Cho:Cr, and ml:Cr were found to be under 15% when using this method, a substantially narrower range than has been f ound in studies relying on manual adjustment of the instrument and/or manual processing. This result indicates that automated setting of acq uisition and processing parameters is of critical importance in the cl inical application of in vivo spectroscopy.