[Insight-developers] gdcm patient orientation

Tue Feb 21 12:46:04 EST 2006

Stephen,

I'll dig into the standard. I as recall, secondary capture is for devices 
that do not support DICOM, e.g.  video cameras. Image processing output of 
data that was originally DICOM is called DERIVED.

I found this in the standard.

A.8 SECONDARY CAPTURE IMAGE INFORMATION OBJECT DEFINITION
The Secondary Image (SC) Image Information Object Definition (IOD) 
specifies images that are
converted from a non-DICOM format to a modality independent DICOM format.
Examples of types of equipment that create Secondary Capture Images include:
a. Video interfaces that convert an analog video signal into a digital image
b. Digital interfaces that are commonly used to transfer non-DICOM digital 
images from an
imaging device to a laser printer
c. Film digitizers that convert an analog film image to digital data
d. Workstations that construct images that are sent out as a screen dump
e. Scanned documents and other bitmap images including hand-drawings
f. Synthesized images that are not modality-specific, such as cine-loops of 3D
reconstructions

and...

C.7.6.1.1.2 Image Type
The Image Type (0008,0008) Attribute identifies important image 
identification characteristics.
These characteristics are:
a. Pixel Data Characteristics
1. is the image an ORIGINAL Image; an image whose pixel values are based on
original or source data
2. is the image a DERIVED Image; an image whose pixel values have been derived
in some manner from the pixel value of one or more other images
b. Patient Examination Characteristics
1. is the image a PRIMARY Image; an image created as a direct result of the
Patient examination
2. is the image a SECONDARY Image; an image created after the initial Patient
examination
c. Modality Specific Characteristics
d. Implementation specific identifiers; other implementation specific 
identifiers shall be
documented in an implementation's conformance statement.
The Image Type attribute is multi-valued and shall be provided in the 
following manner:
a. Value 1 shall identify the Pixel Data Characteristics; Enumerated Values 
for the Pixel
Data Characteristics are:
ORIGINAL identifies an Original Image
DERIVED identifies a Derived Image
b. Value 2 shall identify the Patient Examination Characteristics; 
Enumerated Values for the
Patient Examination Characteristics are:
PRIMARY identifies a Primary Image
SECONDARY identifies a Secondary Image
c. Value 3 shall identify any Image IOD specific specialization (optional)
d. Other Values which are implementation specific (optional)
If the pixel data of the derived Image is different from the pixel data of 
the source images and this
difference is expected to affect professional interpretation of the image, 
the Derived Image shall
have a UID different than all the source images.

At 12:37 PM 2/21/2006, Stephen R. Aylward wrote:
>Hi,
>
>It would be great to get an expert's opinion on secondary capture 
>images.   My understanding is that after image processing the image is 
>considered a secondary capture image - results of digital subtraction are 
>one of the most commmon examples.   After blurring or edge enhancing an MR 
>image, is it still an MR image?
>
>Stephen
>
>
>
>
>
>Bill Lorensen wrote:
>>That may be because gdcm is still reporting the new series as a Secondary 
>>Capture. I'm not sure. In my local copy I have removed 0002|0002 and 
>>0008|0016 from gdcmFileHelper. I do not think the new series should be a 
>>secondary capture. Rather it is really a derived image.
>>Since 0020|0020 does not affect me, you can leave it in. But, saying the 
>>series generated by itk are Secondary Captures is not correct I believe.
>>Bill
>>At 11:13 AM 2/21/2006, Mathieu Malaterre wrote:
>>
>>>Lorensen, William E (GE, Research) wrote:
>>>
>>>>Mathieu,
>>>>My dicom checker complains:
>>>>(0x0020,0x0020)  CS  4        [L\P] # Patient Orientation
>>>>!!                            ERROR : Patient Position (0x0020,0x0020) 
>>>>must not be present
>>>>!!                                    if (0x0020, 0x0032) and (0x0020, 
>>>>0x0037) are required
>>>>In Table C.7-9 of the dicom standard:
>>>>Patient direction of rows and columns of the image. Required if imkage 
>>>>does not require Image Orientation (Patient) (0020,0037) and Image 
>>>>Position (Patient) (0020,0032). See C.7.6.1.1.1 fr further explanation.
>>>>
>>>>I think gdcm should not be adding 0020|0020 if the others are present. 
>>>>However, this does not seem to affect processing on the A/W.
>>>
>>>
>>>If I remove 0020|0020, David Clunie tools report:
>>>
>>>./dciodvfy Image0075.dcm
>>>...
>>>Error - Missing attribute Type 2C Conditional 
>>>Element=<PatientOrientation> Module=<GeneralImage>
>>>
>>>Mathieu
>>>
>>>Index: gdcmFileHelper.cxx
>>>===================================================================
>>>RCS file: /cvsroot/Insight/Insight/Utilities/gdcm/src/gdcmFileHelper.cxx,v
>>>retrieving revision 1.8
>>>diff -u -3 -p -r1.8 gdcmFileHelper.cxx
>>>--- gdcmFileHelper.cxx  20 Feb 2006 21:35:24 -0000      1.8
>>>+++ gdcmFileHelper.cxx  21 Feb 2006 15:32:18 -0000
>>>@@ -1639,12 +1639,12 @@ void FileHelper::CheckMandatoryElements(
>>>
>>>     // Patient Orientation
>>>     // Can be computed from (0020|0037) :  Image Orientation (Patient)
>>>-   gdcm::Orientation o;
>>>-   std::string ori = o.GetOrientation ( FileInternal );
>>>-   if (ori != "\\" && ori != GDCM_UNFOUND)
>>>-      CheckMandatoryEntry(0x0020,0x0020,ori);
>>>-   else
>>>-      CheckMandatoryEntry(0x0020,0x0020,"");
>>>+   //gdcm::Orientation o;
>>>+   //std::string ori = o.GetOrientation ( FileInternal );
>>>+   //if (ori != "\\" && ori != GDCM_UNFOUND)
>>>+   //   CheckMandatoryEntry(0x0020,0x0020,ori);
>>>+   //else
>>>+   //   CheckMandatoryEntry(0x0020,0x0020,"");
>>>
>>>     // Modality : if missing we set it to 'OTher'
>>>     CheckMandatoryEntry(0x0008,0x0060,"OT");
>>>_______________________________________________
>>>Insight-developers mailing list
>>>Insight-developers at itk.org
>>>http://www.itk.org/mailman/listinfo/insight-developers
>>
>>_______________________________________________
>>Insight-developers mailing list
>>Insight-developers at itk.org
>>http://www.itk.org/mailman/listinfo/insight-developers
>
>--
>=============================================================
>Stephen R. Aylward, Ph.D.
>Chief Medical Scientist
>Kitware, Inc.
>http://www.kitware.com
>_______________________________________________
>Insight-developers mailing list
>Insight-developers at itk.org
>http://www.itk.org/mailman/listinfo/insight-developers
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