Front Page › Forums › BioMap › Mapping mz values in t2m files to img intensities
- This topic has 4 replies, 4 voices, and was last updated 14 years, 5 months ago by
Kenneth Chan.
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November 2, 2010 at 3:37 pm #1304
Markus Stoeckli
ModeratorIf the t2m file contains valid data, the size should be 4 times the size of the data dimension, since the m/z values are stored as single precission floats.
markus
November 13, 2010 at 5:44 am #1313Ralf Tautenhahn
ParticipantI am having the same problem. I cannot find out the how to match the t2m to the image dimensions.
The 4800 imaging tool was used.In my example, the filesize is
10412992256Image dimension as reported by nifti-tools are:
$ nifti_tool -disp_hdr -infiles img.hdr
name offset nvals values
——————- —— —– ——
..
dim 40 8 4 15250 424 152 1 0 0 0
..
datatype 70 1 4The number of values int the t2m file is 80786 (file size 323144).
So the number of values is the t2m is 80786/15250 = 5.297443 times higher than the data dimension.
The datatype is 4 = signed short = 2 bytes
According to the file size 10412992256 / (424 * 152) / 2 bytes = 80786So it looks like the data dimension is 80786 (and not 15250), which would make sense with the t2m file. I understand that dimensionfor the ANALYZE format is limited to 32768 and it therefore shows a different value in the header.
But how can datatype 4,signed short, 2 bytes (2^16=65536) address 80786 m/z indices ?
I guess, binning is used ?
How can I find out the binning details (offset, bin size) ?Thank you for your help!
Ralf.
PS: Is there any plan to support imzML as an output format for the imaging tools ?
That would be really helpful and get rid of all these limitations of the ANALYZE file format.November 15, 2010 at 12:48 pm #1314Markus Stoeckli
Moderator[b]Ralf wrote:[/b]
[quote]So it looks like the data dimension is 80786 (and not 15250), which would make sense with the t2m file. I understand that dimensionfor the ANALYZE format is limited to 32768 and it therefore shows a different value in the header.[/quote]Yes, your observation is correct. When importing in BioMap/TissueView, the routine checks for the file size and uses this to calculate the dimensions if it’s above 2^16. The import filter then allows to select a reduced mass range or to bin data points. This is annoying, but the MRI guys did not think that we’d ever need more values 😉 . This is one of the reasons why we came up with imzML.
[quote]Is there any plan to support imzML as an output format for the imaging tools?[/quote]
Yes, we are currently building a tool for the FlashQuant systems which will output imzML. This code might then be ported to the 4000 Series software, if there should be a demand…
Markus
November 15, 2010 at 8:01 pm #1315Kenneth Chan
ParticipantMarkus wrote:
[quote]Yes, we are currently building a tool for the FlashQuant systems which will output imzML. This code might then be ported to the 4000 Series software, if there should be a demand…[/quote]
demand! We actually consider FlashQuant for imaging, but didn’t have money + it will eat up time on our one and only 4000 trap. That said, we will have to port some of our ANALYZE codes:(KC
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