[Insight-users] Bugs (maybe) in itkDicomImageIO.cxx and questions

[Alberto Bert]

Hi,

I'm really interested in your work on reading DICOM images from separate
files. I need to do that and I don't wont to re-invent something already
done. Please keep me informed.

Alberto

On ott 22 at 02:38-0400, Mark Foskey wrote:
> There are definitely problems with this file.  I am in the process of 
> adding the key you mentioned as a step towards reading a directory full 
> of slices into a single 3D image.  A am also cleaning up some 
> infelicities in the code, including the unfreed memory.
> 
> Streams are automatically closed by their destructors, when they go out 
> of scope.
> 
> This has been on my plate for some time.  Thanks for handing me a fork.
> 
> Feng Ma wrote:
> >Hi,
> >
> > I worked a little bit with file itkDicomImageIO.cxx to read CT dicom 
> >files. I found a few place that are possibly bugs.
> >
> > 1. In method CanReadFile(), inputStream is not closed. Nor is it closed 
> >in CheckTagTable(). I am not experienced in C++. Does an open stream 
> >need not to be closed?
> >
> > 2. In method ReadImageInformation(), array value, spac1value, 
> >spac2value are not freed in the end of this method. inFile stream is not 
> >closed.
> >
> >
> > Below are my questions.
> >
> > 1. Dicom header size. I printed out m_InputPosition, which is supposed 
> >to be the dicom header size. I read one image and got the header size 
> >2522 (which is a 512x512 2 bytes CT image, file size 526812). this 
> >number is different from what I got from commecial merge library. The 
> >mergelib number is 2524 which is closer to the guess 
> >526812-512x512x2=2524. This happens in many files. Is the header size 
> >reported by itkDicomImageIO class possibly wrong?
> >
> > 2. Unable to read image position tag (0x0020 0x0032). This tag is very 
> >important to determine the z-value of the dicom image in a volume. When 
> >I add a segment of code to read this tag, method GoToTag() simply can 
> >not find it. I posted my code segment here. The last few lines in the 
> >posted method CheckTagTable() is what I added. I did rewind the file 
> >pointer before call GoToTag(). What's could be wrong?
> >
> >Btw, my ITK version is Oct 7 CVS version.
> >
> >Thank you very much.
> >
> >-Feng
> >
> >**** Run output ****
> >fma@ctreg1:/r2net/space_fma1/vhds/test 728 % 
> >../../Devel/ITKDebug/bin/DicomImageViewer 
> >/r2net/space_fma2/data/LV00000500/LV00000500_152.dcm
> >Loading File: /r2net/space_fma2/data/LV00000500/LV00000500_152.dcm
> >Can not locate position tag 0x0020 0x0032
> >Header Size: 2522
> >...Done Loading File
> >
> >**** Code segment of CheckTagTable() ****
> >
> >bool DicomImageIO::CheckTagTable(std::ifstream & inputStream,std::list 
> ><Tag> &TableOfTags) const
> >{
> > long int i, j;
> > long int max;
> > Tag tagcurrent;
> > unsigned char c;
> > char chaine[4];
> >
> > i=0;
> > //0x7FE0 and 0x0010 is the last tag before data pixel
> > if(!DicomImageIO::GoToTheEndOfHeader(inputStream,i,tagcurrent))
> > {
> >   return (false);
> > }
> > else
> > {
> >   TableOfTags.push_back(tagcurrent);
> >   max=i;
> >   //start the reading of the Stream from the begining
> >   inputStream.seekg(0);
> >   i=0;
> > }
> >
> > ////0x0028 and 0x0010 >> tag before the number of rows
> > if(!DicomImageIO::GoToTag(inputStream,0x0028,0x0010,i,max,tagcurrent))
> > {
> >   return false;
> > }
> > else
> > {
> >   TableOfTags.push_back(tagcurrent);
> > }
> >
> > //0x0028 and 0x0011 >> tag before the number of columns
> > if(!DicomImageIO::GoToTag(inputStream,0x0028,0x0011,i,max,tagcurrent))
> > {
> >   return false;
> > }
> > else
> > {
> >   TableOfTags.push_back(tagcurrent);
> > }
> >
> > //0x0028 and 0x0030 >> tag before each the value of spacing
> > if(!DicomImageIO::GoToTag(inputStream,0x0028,0x0030,i,max,tagcurrent))
> > {
> >   //if there is no information about the spacing, we set the value 
> >compt to 0
> >   tagcurrent.Balise1[1]=0x28;
> >   tagcurrent.Balise1[0]=0x00;
> >   tagcurrent.Balise2[1]=0x30;
> >   tagcurrent.Balise2[0]=0x0;
> >   tagcurrent.compt=0;  //
> >   TableOfTags.push_back(tagcurrent);
> >   //start the reading of the Stream from the begining
> >   inputStream.seekg(0);
> >   i=0;
> > }
> > else
> > {
> >   TableOfTags.push_back(tagcurrent);
> > }
> >
> > //0x0028 and 0x0100 >> tag before the number of bits allocated
> > if(!DicomImageIO::GoToTag(inputStream,0x0028,0x0100,i,max,tagcurrent))
> > {
> >   return false;
> > }
> > else
> > {
> >   TableOfTags.push_back(tagcurrent);
> > }
> >
> > //0x0028 and 0x0103 >> tag before the place of sample representation
> > if(!DicomImageIO::GoToTag(inputStream,0x0028,0x0103,i,max,tagcurrent))
> > {
> >   return false;
> > }
> > else
> > {
> >   TableOfTags.push_back(tagcurrent);
> > }
> >
> > i = 0;
> > inputStream.seekg(0);
> > ////0x0020 and 0x0032 >> tag before value of position
> > if(DicomImageIO::GoToTag( inputStream,0x0020,0x0032,
> >                            i,max,tagcurrent)){
> >    std::cout << "Position tag located.\n";
> > }
> > else
> >    std::cout << "Can not locate position tag 0x0020 0x0032\n";
> >
> > return(true);
> >}
> >
> >
> >
> >
> >
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> 
> -- 
> Mark Foskey    (919) 843-5436   Computer-Aided Diagnosis and Display Lab
> mark_foskey@unc.edu             Department of Radiology, CB 7515, UNC
> http://www.cs.unc.edu/~foskey   Chapel Hill, NC  27599-7515
> 
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