What is the mosaic format?

From what a Philipps engineer told me DICOM is supposed to be able to
handle 3 and 4dimensional data eventually (xmedcon can handle 3 dim
data in several slices in one file). But there is no conformance
statement out (which I think is not a real reason since none of the
producers feel too obligated to any standard) so at the moment only
one slice per file is DICOM standard.

Siemens built a format formally complying to the standard by setting
the slices together in one plane.

Even though the Siemens' idea was/is good, it was problematic
converting the data into other formats. While (X)medcon did a great
job in converting normal 1slice/1file data it couldn't handle mosaic
data. So I took the libmdc from medcon put a hack around it and could
convert mosaic files. This wild hack was put proberly into medcon by
Eric Nolf (thanks a lot) around April 2001. Everything was fine.

After a discussion in the spm-mailing list I couldn't be nice and
quiet (having a solution for my own data) but had to write to
everybody why they didn't use the solution medcon gave them. They sent
me some data. Needles to say Siemens created a whole new version of
their mosaic DICOM files :-((((

What to do? (After Eric put in the new -fmosaic option in 0.7.7)

For older Siemens Vision dicoms the automatic mosaic (option -mosaic)
might work. If it doesn't. Use the -fmosaic option with the apropriate
numbers for your format (you can try with xmedcon first using the
medcon option dialog).

Look at your converted voxel sizes. If they are to small try the
-mfixv (for xy Plane sizes) or the -gap option (for slice
thickness). I still didn't give up the idea of automatic detection but
I need Siemens insider info for that. I you (or someone you know) know
something about the tags coding this info pleas send me a message.


R.M. Rutschmann <Rutschmann@gmx.net> 30.4.2002

Update 9.10.2002:

I did get information by a Siemens programmer. Unfortunatly he told me 
that there is no way of getting the relevant information from the DICOM 
format. According to him the information I got for the old format is 
unreliable. So unless somebody comes up with a real good idea I give up 
on automatic detection. -fmosaic must be good enough.