Analyze

A very simple and useful format for volumes such as tomographic and dynamic studies. Compatibility with the SPM software is our main concern.

scaling factors / quantitation:

Officially there is none. Quantified images are saved as floats unless you specify one of the -b16 or -b8 options. SPM howerver does use the imd.funused[1] item in the header structure to define a global scaling factor. You must select the specific -spm option as well as a quantitation -qs or -qc in order to use this entry.

patient/slice orientations:

We do interpret the 'orient' field which speaks about transverse, sagittal or coronal, but always consider it as supine-headfirst! The "flipped" or "unflipped" versions have no meaning for (X)MedCon because the official definition is not clear about the distiction between both. Does "flipped" mean supine or prone; headfirst or feetfirst ... or vice versa? For those who use Analyze for SPM: a proper Analyze image for SPM has a totally reversed coordinate system in relation to (X)MedCon. SPM wants the slices to be oriented as follows:

(X)MedCon likes to see it patient based. When your files are supine-headfirst-transverse and stored patient based (like with ECAT 951 PET scans); you should flip dimensions and/or reverse slices for SPM.

extra notes:

- The format is not capable to store the patient name.

- In the command-line utility you can now specify the -optspm option to manually give the "origin" values when converting to Analyze SPM. By the way, for (X)MedCon these values have no meaning.

- SPM Analyze files can use an "offset" value in the header to define an offset in bytes to the voxel data in the image file. To enable it you should give the -spm argument option.