th  - 1987 - 51st ENC Conference

WK26
LINE SHAPES IN ONE-DIMENSIONAL
CHEMICAL SHIFT IMAGING
P.B. Barker W, D. Bailes a, D. Bryant a and B.D. Ross
Huntington Medical Research Institute, Pasadena, CA 91105.
aplcker International, Wembley, Middlesex.
It has recently been demonstrated that the two-dimensional NMR
technique of Marecl (I) gives good spatially locallsed 31p spectra In
clinical applications (2). In some instances the spectral resolution may be
degraded by the "phase-twlst" line shape (3) which is encountered as a
result of the phase-modulation of the NMR signals as a function of their
spatial coordinates
This poster presents a variation of the data processing methods
developed in conventional high-resolution NMR to retain pure absorption
llneshapes (4). The method requires the recording of two data sets for
each phase-encode gradient amplitude; in one case the gradient amplitude
is positive, in the other negative. These two data sets are then processed
conventionally using complex Fourier transformations; linear combinations
• of the two frequency domain data matrices are then used to cancel the
dispersion components of the line shape. Other equivalent processing
methods are possible; for instance, linear combinations of the original
time-domain data matrices may be used in conj.unction with the
processing method of States (5). Whilst this is slightly more efficient in
terms of processing time and disk storage, the method used largely
• depends on the ease-of Implementation on the available spectrometer
system.The improvements offered are expected to be particularly
noticeable In the extension to multl-dlmenslonaI chemlcal shift Imaging.
( 1 ) T.H. Mareci and H.R. Brooker, J. Magn. Reson., 57, 157 (I 984).
(2) D. Bailes et. al., J. Magn. Reson., submitted for publication
(3) G. Bodenhausen, R. Freeman, R. Niedermeyer and D.L. Turner, J. Magn.
Reson., 26, 133 (1977).
(4) J. Keeler and D. Neuhaus, J. Magn. Resort., 63, 454 ( ] 985).
(5) D.J. States, R.A. Haberkorn and D.J. Ruben, J. Hagn. Resort., 48, 286
(1982).