PRESS Slice Map – SpinEvolution | NMR Simulation Software

PRESS Pulse Sequence
PRESS Slice Map

See Notes in the PRESS example for more explanations.

press2D (main input file)

*******************************************************************************
** PRESS slice 2D map (based on the 'press' input file)               
** Reference:  Kaiser, L. G., Young, K., Matson, G. B. (2008)
** Numerical simulations of localized high field 1H MR spectroscopy.
** Journal of Magnetic Resonance, 195(1), 67–75.                                                                          
****** The System *************************************************************
spectrometer(MHz)  125
spinning_freq(kHz) *
channels           H1
nuclei             *
atomic_coords      *
cs_isotropic       MOL.cs ppm
csa_parameters     *
j_coupling         MOL.j
quadrupole         *
dip_switchboard    *
csa_switchboard    *
exchange_nuclei    *
bond_len_nuclei    *
bond_ang_nuclei    *
tors_ang_nuclei    *
groups_nuclei      *
******* Pulse Sequence ******************************************************
CHN 1
timing(usec)    (t128.tm) 0 (0) (t200.tm) 0 (0 0) (t200.tm) 0
power(kHz)      slr90.pwr 0  0   s180.pwr 0  0 0  s180.pwr  0
phase(deg)        90      0  0     0      0  0 0    0       0
freq_offs(kHz)     0      0  0     0      0  0 0    0       0
CHN G
timing(usec)    (t128.tm) 0 (0) (t200.tm) 0 (0 0) (t200.tm) 0
grad_offs(kHz)     0      0  0     0      0  0 0    0       0
******* Variables ***********************************************************

** slr90.pwr is the selective excitation pulse powers, kHz, for a 10 ms pulse
** s180.pwr  is the selective refocusing pulse powers, kHz, for a 10 ms pulse
** See examples/selective-pulses to investigate how these pulses work

** Specify selective pulses lengths, usec
T90 =  4000
T180 = 5000

** Specify (refocusing time)/(pulse length) ratio for the excitation pulse
** The refocusing time for the excitation pulse is given as a comment in slr90.pwr
r90 = 0.5050  // slr90

** Set up the selective excitation pulse
pulse_[1 2]_1=T90/128
psf_1_1=10000/T90

** Set up the selective refocusing pulses
pulse_[1 2]_4=T180/200
pulse_[1 2]_7=T180/200
psf_1_[4 7]=10000/T180

** Coherence pathway selected with the crusher gradinents
select_[2 5]=[-1 1]

** Localization: slice 2D map **
** G1, G2, G3 are offsets, kHz, generated by PFGs along X, Y, and Z
G3 = 0.5
scan_par1d G2/-1.5:0.1:1.5/
scan_par2d G1/-3.5:0.1:3.5/
grad_offs_[1 4 7]=G[1 2 3]

** Refocus the linear phase generated by the selective excitation pulse
pulse_[1 2]_6_1=T90*r90
grad_offs_6_1=G1

** Additional interpulse delays (due to crusher gradients etc.)
t1=1000
t2=1000
pulse_[1 2]_3_1=t1
pulse_[1 2]_6_2=t1+t2
pulse_[1 2]_8_1=t2

** Take absolute value of the signal
pdata_re=abs(complex(pdata_re,pdata_im))

x_label="ref, 180° (Offset, kHz)"
y_label="exc, 90° (Offset, kHz)"
fig_options="--contn 40 --cmap gray"
fig_title="Localization map of a PRESS slice"

******* Options ***************************************************************
rho0               F1z
observables        F1p
EulerAngles        *
n_gamma            *
line_broaden(Hz)   *
zerofill           *
FFT_dimensions     *
options       -re -macroMOL=myo-inositol -sysh6 -varppm_center_1=3.6 -py -contf
*******************************************************************************
-- A different molecule can be easily chosen by using different values for the
command line options -macroMOL=... -sysh... -varppm_center_1=...

Files referenced from the main input file:

mio-inositol.cs

mio-inositol.j

slr90.pwr

 0.0000000e+00
-2.9240431e-05
-5.5617998e-05
-8.9752483e-05
-1.3153110e-04
...
-1.3153110e-04
-8.9752483e-05
-5.5617998e-05
-2.9240431e-05
 0.0000000e+00

s180.pwr

 0.0000000e+00
-1.6446000e-03
 5.1245000e-03
 2.8855000e-03
 2.5472000e-03
 ...
 2.5488000e-03
 2.8869000e-03
 5.1258000e-03
-1.6435000e-03
 0.0000000e+00

t128.tm

t200.tm