[Dcmlib] Re: Patient Position

[Jean-Pierre ROUX]

>I am really sorry JP but I need to abuse of your patience again 
>because I cannot understand gdcm classes functions!!

No problem.
It's the best way for us to know what's easy to understand and what it's not.

>Here it follows my sourc to read dicoms but I can't get patient position...
>"de" is NULL and I do not know what to do.
>I really believe the best gdcm feature to be introduced is... 
>documentation :-)

You're right !
I started writting something, during the summer, but I never finished it ...
I think I have to do it ...

>
>
> gdcm::DicomDir *e1;

Probabely, your main error comes from this line...
a DICOMDIR is *not* a directory, with DICOM images, but a 'Dicom 
document' (its header has the same structure than Dicom images.
It contains a summary of a tree-like stucture :
--> Patient
   --> Study
     --> Serie
       -->Image
for all the files held in a 'root directory'.
It's mainly used on CD, in order to avoid clinical softwares to have 
to open *all* the images to get, for instance, all the patients names 
that are stored on the CD ...

> AnsiString fold;
> fold = dicom_folder;
> fold = fold + "\\."; // root directory to scan

OK.
Let's suppose the directory contains only one Serie (the 'pronto' 
images are like that)

std::string fName = "anyone of the files";
gdcm::File *f = new gdcm::File();
f->SetFileName(fName);
f->Load();

> if( !f->IsReadable() )
> {
>   AnsiString error_str;
>   error_str = "File " + AnsiString(fName) + " is not readable. 
>Operation failed.";
>   Application->MessageBox( error_str.c_str() , NULL, MB_OK | MB_ICONERROR );
>
>   delete f;
>   return false;
  }

// One of the files is loaded.

   gdcm::DocEntry *de1 = f->GetDocEntry(0x0018,0x5100);
   gdcm::DocEntry *de2 = f->GetDocEntry(0x0020,0x0020);
   if (!de1 or !de2)
   {
          --> no Patient Position / Patient Orientation ?!
          --> stop everything.
 
   }

   std::string patPosition = GetDocEntryValue(de1);
   std::string patOrientation = GetDocEntryValue(de2);

   gdcm::Orientation o;
   double typeOrientation = o.TypeOrientation(f);

  gdcm::SerieHelper *sh = new gdcm::SerieHelper();
  sh->SetDirectory( fold, true);
  gdcm::FileList *l = sh->GetFirstCoherentFileList();

// according to typeOrientation, you can decide to 'reverse sort' or not.
  sh->SetSortOrderToReverse();

  sh->OrderFileList(l);

  vtkGdcmReader *reader = vtkGdcmReader::New();
  reader->SetCoherentFileList(l);

// according to what you get in patPosition and patOrientation
// and what you know your soft has to display,
// you pass a fonction you wrote to reorganize the pixel
// (you can find in Examples/vtkgdcmSerieViewer.cxx
// an example of 'mirror' function, and some others)
  reader->SetUserFunction (userSuppliedFunction);
  reader->Update();

With no coding, you can see what you'll get bu using :

vtkgdcmViewer dirname=yourProntoImageDirectory mirror
or
vtkgdcmViewer dirname=yourProntoImageDirectory reverse
etc
(just hit any key to see all the images, one by one, as they are loaded)

JP

>
> e1 = new gdcm::DicomDir();
> e1->SetDirectoryName(fold.c_str());
> e1->Load();
>
> // Test if the DicomDir is readable
> if( !e1->IsReadable() )
> {
>   AnsiString error_str;
>   error_str = "Directory " + AnsiString(dicom_folder) + " is not 
>readable. Operation failed.";
>   Application->MessageBox( error_str.c_str() , NULL, MB_OK | MB_ICONERROR );
>
>   delete e1;
>   return false;
> }
>
> gdcm::DocEntry* de = e1->GetDocEntry(0x0018,0x5100);
> if (!de) <<<---- NULL
> {
>   Application->MessageBox( "no Patient Position ?!?", NULL, MB_OK | 
>MB_ICONERROR );
>   delete e1;
>   return false;
> }
>
>patient position and patient orientation tags exists and with dicom2 utility:
>       Patient Position (0018,5100)            1    CS [HFS]
>       Patient Orientation (0020,0020)        2    CS [L\P]
>
>thank you again,
>Luca

   Jean-Pierre ROUX
   CREATIS - CNRS UMR 5515, INSERM U 630
   Laboratoire de Radiologie Experimentale
   Hopital Cardiologique
   28 Avenue du Doyen LEPINE
   B.P. Lyon-Montchat
   69394 Lyon Cedex 03
 
   Tel      : (+33) 04 72 35 74 12
   Fax      : (+33) 04 72 68 49 16
   URL      : http://www.creatis.univ-lyon1.fr
   e-mail   : jpr at creatis.univ-lyon1.fr