Setting | Procedure |
---|---|
3.1 | SPM settings and procedures used to effect spatial normalization |
A | SPM defaults were set so that bounding box was same as MNI MRI templates found in SPM99 and orientation changed to radiologic convention. |
B | Individual ADD images were normalized to 18F-DOPA template created in-house in MNI space (ADD images were used for this iterative maneuver as ADD images contain information reflecting cerebral blood flow and nonspecific binding and, therefore, have greater anatomic detail than Ki maps.). |
C | Having normalized ADD images to MNI space, Ki maps were normalized by applying ADD image transformation parameters (This is problematic if native space ADD and Ki images are not in alignment.). |
D | Normalization quality was inspected in SPM99, comparing spatially normalized Ki and ADD images with 18F-DOPA template and MNI single-subject MRI. |
3.2 | SPM settings used when performing within-group and between-group analysis |
A | Subjects were entered into SPM such that baseline and follow-up smoothed normalized Ki maps were conditions 1 and 2, respectively. |
B | There were no covariates and SPM options were set to no global normalization, no nuisance variables, and no grand mean scalings. |
C | Analysis lower threshold was set to zero and upper threshold to absolute. By choosing these options, it was variance in voxel-by-voxel Ki values that were being compared, rather than differences in scaled or proportional values. |
ADD image in this case is summed image of integrated 18F-DOPA signal from 30 to 90 min; MRI is magnetic resonance image.