[ITK Community] [Insight-users] Image Intensities Changed During DICOM Read-Write-Read in ITK 3.20 vs. ITK 4.4.1

[Bill Lorensen]

I probably will not get to this before the release.


On Wed, Dec 4, 2013 at 12:12 PM, Yi-Yu Chou <yiyu.chou at gmail.com> wrote:
> Hi Bill,
>
> It appears the bug "Acquisition Matrix" is still not corrected when running
> with itk4.5_rc02.
> Are you going to fix it in the new released itk ?
>
> Many thanks !!
>
> Yi-Yu
>
>
> On Fri, Oct 18, 2013 at 8:24 PM, Constantine Zakkaroff <mnkz at leeds.ac.uk>
> wrote:
>>
>> Hi Bill,
>>
>> It appears the bug with slope and intercept being processed incorrectly
>> still shows up in ITK 4.4.2.
>>
>> Is there an explanation why in the original DICOM file rescale slope is
>> 7.1, but in order to see the same image stats (min, max, etc.) it needs to
>> be saved with the rescale slope value of 1.0?
>>
>> Also, I believe I mentioned it a while ago, but there wasn't much feedback
>> on this: some tag values get unexpected values. For example, compare the
>> following tag values in the original DICOM file:
>>
>> (0010,21C0) Pregnancy Status VR: US Length: 2 Value: 4
>> (0018,0088) Spacing Between Slices VR: DS Length: 4 Value: 17.0
>> (0018,1310) Acquisition Matrix VR: US Length: 8 Value: 0 144 144 0
>>
>> and saved file:
>>
>> (0010,21C0) Pregnancy Status VR: US Length: 2 Value: 52
>> (0018,0088) Spacing Between Slices VR: DS Length: 2 Value: 1
>> (0018,1310) Acquisition Matrix VR: US Length: 12 Value: 23600 13361 23604
>> 13361 23604 48
>>
>> As suggested earlier, I use the same GDCMImageIO object for reading and
>> writing.
>>
>> Many thanks,
>> Constantine
>>
>>
>> On 16/08/2013 19:13, Bill Lorensen wrote:
>>>
>>> Constantine,
>>>
>>> You found a bug in itk's dicom IO. I'll report it and prepare a patch to
>>> fix it for future users.
>>>
>>> As a workaround, which should work for ITK 3 and ITK4 and hopefully
>>> after I fix the bug:
>>>
>>> 1) If you want to retain the input dicom entries, you should create a
>>> GDCMImageIO and use it for both the input and output.
>>> 2) To work around the itk dicom bug, add these lines AFTER the stats
>>> filter:
>>>    // Set rescale slope and intercept to 1 and 0
>>>    imageReader0->Update();
>>>    typedef itk::MetaDataDictionary   DictionaryType;
>>>    DictionaryType & dict =
>>> imageReader0->GetOutput()->GetMetaDataDictionary();
>>>    itk::EncapsulateMetaData<std::string>( dict, "0028|1052", "0.0");
>>>    itk::EncapsulateMetaData<std::string>( dict, "0028|1053", "1.0");
>>>
>>> NOTE: You need to #include "itkMetaDataObject.h"
>>>
>>> I've attached the your program with all of these changes. Thanks for
>>> your patience,
>>>
>>> Bill
>>>
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>



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