[Insight-users] about the DicomImageIO

[Miller, James V (Research)]

If you use DICOMImageIO2, does the spacing come back correctly? It may not
because neither DICOMImageIO2 or DicomImageIO is looking for tag
0x0018,0x0088
 
In the DICOM "standard", there is no universally selected manner to
determine the spacing between slices. Some vendors use a specific tag for
slice spacing, some use a specific tag for slice location (and you have to
compare two adjacent slices to determine the spacing), and some use the
ImagePositionPatient tags to specify the 
location of slices (and you have to compare two adjacent slices to determine
the spacing). None of these are required by the standard. And sometimes the
values
in them are plain wrong.
 
The best way we have found to determine the spacing between slices is to use
the ImagePositionPatient tags.  This is what DICOMImageIO2 uses so it may
report the correct spacing even though it is not looking for tag
0x0018,0x0088.
 
 
 

-----Original Message-----
From: Yixun Liu [mailto:yxliu at fudan.edu.cn]
Sent: Wednesday, July 28, 2004 5:13 AM
To: insight-users at itk.org
Subject: [Insight-users] about the DicomImageIO


Hi ITKusers,
 
         I intend to use the itkImageSeriesReader combined with the
itkDicomImageIO to read DICOM series. The spacing obtained by the
itkDicomImageIO is 0.9735x0.9735x1. However, when I use the tool Dicom2 to
read the tag of the DICOM file, I find the spacing between the slices is
3.000000 which is shown below.
 
 
          Echo Number(s) (0018,0086)         1-n       IS [1]
 Magnetic Field Strength (0018,0087)     1          DS [15000]
  Spacing Between Slices (0018,0088)   1         DS [3.000000]
       Echo Train Length (0018,0091)         1        IS [0]
        Percent Sampling (0018,0093)         1       DS [100.000000] 
 
Why the itkImageIO can not read the correct spacing between the slices?
 
Thanks a lot
 
Regards,
 
Yixun Liu

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