Hi Folks<br><br>I use mri_convert to create nifti files from the dicom images from a 3T GE scanner.<br><br>One of the option for mri_convert is &quot;-zgez&quot; with the following description from the mri_convert help:<br>



<br>&quot; -zgez, --zero_ge_z_offset set c_s=0 (appropriate for dicom files from GE machines with isocenter scanning)&quot;<br>
<br> Before the scan we &quot;landmark&quot; the subject; that is we set a point on the head coil to &quot;0&quot; and  then proceed with the scan.<br>Pardon the naive question, but does &quot;isocenter scanning&quot; refer to this step ? <br>


<br>Also I created two nifti files with and without this flag; the only differences in the two headers were with in quartern_z field.<br><br>without flag quartern_z  = -50.061 and with the flag quartern_z  = -90. (and one entry each in srow_z, sform, qform and vox2ras were also affected)<br>

<br>Our scan has 180 slices and to me quartern_z  = -90 seems the right one. is this correct ? <br>Thanks<br>Mehul<br><br><br><br><br><br><br><br><br><br><br><br>