Viewing GE in vivo spectroscopy data

A data file typically consists of several FIDs acquired with up to 8 separate coils.  wxNUTS imports this data as having 3 dimensions, where the third dimension is the different coils.  On import, the first slice of the first coil is displayed.  Sometimes, the first slice is all zeroes, in which case, it is ignored. 

Executing the usual processing commands (eg., EM, FT, phasing) will process all FIDs.  The slices (FIDs or spectra)  in a selected coil can be viewed as a stacked plot (SP) or step-wise using View (VW), or a chosen slice can be displayed with the slice command (SL).  To view slices from another coil, execute the command

"coil n"    where n is the number of the desired coil

Note that the coil number and slice number are shown in the gray status bar, at the bottom right.

Typically, the user wants to sum a specified range of slices for each coil.  The following command accomplishes this:

"sum n m"  where n is the first slice to include in the sum, and m is the last slice to include in the sum

After a sum operation, there is only a single slice for each coil.  Any slices not included in the sum are no longer contained in the modified data file.  After summing, the data consists of 2 dimensions, and the separate coils are now available in the second dimension.  This means the data for different coils can be viewed as a stacked plot (SP) or step-wise using View (VW).  A chosen spectrum can be displayed with the slice command (SL), and then can be individually examined, integrated, line-fit, plotted, etc

Often, spectra obtained from different coils are out of phase.  To phase a chosen spectrum, first display that spectrum.  PH, PE or QP can be used to adjust the phase, BUT it is important to issue each of these commands followed by "this", so the program knows the phasing is to be applied only to the displayed spectrum, and not to all spectra in the data set.

Last updated: 3/16/10.