What should be input for z_prjs?

[loneblues]

Hello. I'm trying to test the code on some QSM data.
It seems that z_prjs is vector for B1 field, is it correct?
If so, how can I acquire such information from DICOM files?
Also for voxel size, can this code deal with interpolated data (such as zip2), where slice thickness is 1.2mm with 0.6mm overlapping areas between slices?

Thanks in advance.

Best
Ho-Joon Lee

[YangGaoUQ]

Hello. I'm trying to test the code on some QSM data. It seems that z_prjs is vector for B1 field, is it correct? If so, how can I acquire such information from DICOM files? Also for voxel size, can this code deal with interpolated data (such as zip2), where slice thickness is 1.2mm with 0.6mm overlapping areas between slices?

Thanks in advance.

Best Ho-Joon Lee

Hi Ho-Joon:

Yes, z_prjs is a 3-element vector that represents the FOV orientation relative to the main field. It can be easily calculated from the DICOM files.

As per the interpolated data, I assum the iQSM/iQSM+ codes should be all good, but we have not tried. :)

best,
Yang

[YangGaoUQ]

Hello. I'm trying to test the code on some QSM data. It seems that z_prjs is vector for B1 field, is it correct? If so, how can I acquire such information from DICOM files? Also for voxel size, can this code deal with interpolated data (such as zip2), where slice thickness is 1.2mm with 0.6mm overlapping areas between slices?

Thanks in advance.

Best Ho-Joon Lee

here are the codes:

suppose that you have read the dico_info from your dicom files with dicominfo.m (matlab func)
then:

% angles!!! (z projections)
Xz = dicom_info.ImageOrientationPatient(3);
Yz = dicom_info.ImageOrientationPatient(6);
Zz = sqrt(1 - Xz^2 - Yz^2);
Zxyz = cross(dicom_info.ImageOrientationPatient(1:3),dicom_info.ImageOrientationPatient(4:6));
Zz = Zxyz(3);
z_prjs = [Xz, Yz, Zz];