Dual-Polarity GRAPPA (DPG) demo

This collection of Matlab code and data presents one implementation of the method described in "Dual-Polarity GRAPPA for simultaneous reconstruction and ghost correction of EPI data." Magn Reson Med. 76(1):32-44, Jul 2016. http://dx.doi.org/10.1002/mrm.25839

Data source

EPI gradient-echo BOLD data

• 3T Siemens Trio
• 32 Channel Head coil
• TR 3sec
• TE 30msec
• Echo Spacing 770usec

• 2.0mm isotropic resolution

• 96x60 matrix size

• 192x120 (mm) FOV
• 32 slices, 2mm thick

collected on 2015-05-18, data file MID902

Demo Filelist:

data/dpg_acs1.nd     ACS data, with the first readout acquired using RO+
data/dpg_acs2.nd     ACS data, with the first readout acquired using RO-
data/dpg_C.nd        The PLACE ACS image, formed from a combination of dpg_acs1 and dpg_acs2

data/dpg_k.nd        one frame of R=2 EPI data
data/dpg_k_pcref.nd  navigator data for dpg_k, to perform traditional Nyquist ghost correction
data/y.nd            NGC coefficients, derived from dpg_k_pcref and used with phzapply.m
data/y_acs2.nd       NGC coefficients, derived from A and B and used with phzapply.m

dpg_cal.m       the DPG calibration code
dpg_recon.m     the DPG reconstruction code
phzshift.m      calculates the coordinate shift between two k-space data sets using SIEPCM
phzapply.m      a script to apply standard Nyquist ghost correction coefficients
fif.m           a 2D FFT macro script
ifi.m           a 2D FFT macro script
readnd.m        script to read the .nd data files

runthis.m       the main demo script
runthis2.m      an alternate demo script (w/o GESTE/PLACE acs data)