I have two data sets (patients and controls). I am interested in comparing resting-state directional connectivity within specific nodes (using MNI coordinates from literature) using DCM.

Scanning protocol for resting-state data is identical between two groups but the protocol for structural data is different between two groups as following, although both data sets are collected using the same scanner and I used the same MNI template for normalization/interpolation with standard space (traditional SPM pipeline for preprocessing).

I was wondering if this difference in scanning parameters will/may bias my connectivity results in some way or the other. If so, is there any solution to this problem, and if no, how can I justify this in my manuscript.

I would really appreciate any help.

Thanks!

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Volume information for IM-0001-0001-0001.dcm

          type: siemens_dicom

    dimensions: 256 x 256 x 128

   voxel sizes: 1.000000, 1.000000, 1.330000

          type: SHORT (4)

           fov: 256.000

           dof: 0

        xstart: -128.0, xend: 128.0

        ystart: -128.0, yend: 128.0

        zstart: -64.0, zend: 64.0

            TR: 2100.00 msec, TE: 2.25 msec, TI: 1100.00 msec, flip angle: 12.00 degrees

       nframes: 1

       PhEncDir: ROW

       FieldStrength: 3.000000

ras xform present

    xform info: x_r =  -0.0202, y_r =   0.0424, z_r =  -0.9989, c_r =   -23.2439

              : x_a =  -0.9989, y_a =  -0.0441, z_a =   0.0184, c_a =    53.2183

              : x_s =   0.0433, y_s =  -0.9981, z_s =  -0.0432, c_s =   -12.5170

Orientation   : PIL

Primary Slice Direction: sagittal

voxel to ras transform:

               -0.0202   0.0424  -1.3285    58.9497

               -0.9989  -0.0441   0.0244   185.1541

                0.0433  -0.9981  -0.0575   113.3820

                0.0000   0.0000   0.0000     1.0000

voxel-to-ras determinant -1.33

ras to voxel transform:

               -0.0202  -0.9989   0.0433   181.2290

                0.0424  -0.0441  -0.9981   118.8377

               -0.7511   0.0138  -0.0325    45.4015

               -0.0000  -0.0000  -0.0000     1.0000

For patients:

Volume information for IM-0001-0001-0001.dcm

          type: siemens_dicom

    dimensions: 256 x 256 x 176

   voxel sizes: 1.000000, 1.000000, 1.000000

          type: SHORT (4)

           fov: 256.000

           dof: 0

        xstart: -128.0, xend: 128.0

        ystart: -128.0, yend: 128.0

        zstart: -88.0, zend: 88.0

            TR: 2100.00 msec, TE: 2.30 msec, TI: 1100.00 msec, flip angle: 12.00 degrees

       nframes: 1

       PhEncDir: ROW

       FieldStrength: 3.000000

ras xform present

    xform info: x_r =  -0.0000, y_r =  -0.0000, z_r =  -1.0000, c_r =     1.1441

              : x_a =  -1.0000, y_a =  -0.0000, z_a =   0.0000, c_a =    20.7797

              : x_s =   0.0000, y_s =  -1.0000, z_s =   0.0000, c_s =    17.5932

Orientation   : PIL

Primary Slice Direction: sagittal

voxel to ras transform:

               -0.0000  -0.0000  -1.0000    89.1441

               -1.0000  -0.0000   0.0000   148.7797

                0.0000  -1.0000   0.0000   145.5932

                0.0000   0.0000   0.0000     1.0000

voxel-to-ras determinant -1

ras to voxel transform:

               -0.0000  -1.0000  -0.0000   148.7797

               -0.0000  -0.0000  -1.0000   145.5932

               -1.0000  -0.0000  -0.0000    89.1441

               -0.0000  -0.0000  -0.0000     1.0000