Re: [Gdcm2] GDCM cannot get rescale intercept/slope/type from nested objects with undefined length

[David G. <dav...@gm...>]

DCS = DICOM Conformance Statement
PMS = Philips Medical Systems

(I don't recognize the acronyms either, I'm just guessing from context!)


On Thu, Aug 17, 2017 at 10:38 AM, <k3...@fr...> wrote:

> Thanks for this detailed answer.
>
> Could you explain me what DCS and PMS stand for?
>
> Here is the output of gdcminfo for that image:
> MediaStorage is 1.2.840.10008.5.1.4.1.1.4 [MR Image Storage]
> TransferSyntax is 1.2.840.10008.1.2 [Implicit VR Little Endian: Default
> Transfer Syntax for DICOM]
> NumberOfDimensions: 2
> Dimensions: (160,160,1)
> SamplesPerPixel    :1
> BitsAllocated      :16
> BitsStored         :12
> HighBit            :11
> PixelRepresentation:0
> ScalarType found   :UINT16
> PhotometricInterpretation: MONOCHROME2
> PlanarConfiguration: 0
> TransferSyntax: 1.2.840.10008.1.2
> Origin: (-73.2212,-67.9772,129.333)
> Spacing: (1,1,3)
> DirectionCosines: (1,0,0,0,1,0)
> Rescale Intercept/Slope: (-3142,1.53455)
> Orientation Label: AXIAL
>
> I guess we should blame ITK right? :)
> Thanks
>
> Florent
>
> ----- Mail original -----
> De: "Mathieu Malaterre" <mat...@gm...>
> À: k3...@fr...
> Cc: "gdcm-developers" <gdc...@li...>
> Envoyé: Jeudi 17 Août 2017 14:18:29
> Objet: Re: [Gdcm2] GDCM cannot get rescale intercept/slope/type from
> nested objects with undefined length
>
> On Thu, Aug 17, 2017 at 2:10 PM, Mathieu Malaterre
> <mat...@gm...> wrote:
> > Salut Florent :)
> >
> > On Thu, Aug 17, 2017 at 11:16 AM,  <k3...@fr...> wrote:
> >> Hi,
> >>
> >> I am trying to read a DICOM series (multi-echo series from Philips) but
> I need to check some DICOM tags first:
> >> - 0028,1052: rescale intercept
> >> - 0028,1053: rescale slope
> >> - 0028,1054: rescale type
> >
> > So you are dealing with legacy MR Image Storage instance(s) from
> > Philips Medical System.
> >
> >> Unfortunately GDCM is not able to find that tags through ITKs API
> (gdcmIO->GetMetaDataDictionary()), but when I use gdcmdump to search for
> DICOM tags manually I am able to find the tags but in nested objects with
> "undefined length":
> >>
> >> (2001,1068) ?? (SQ) (Sequence with undefined length)          # u/l,1
> ?LinearModalityGLTrafo
> >>       (fffe,e000) na (Item with undefined length)
> >>         (0028,1052) ?? (DS) [-12095]                              # 6,1
> Rescale Intercept
> >>         (0028,1053) ?? (DS) [5.90720390720390]                    #
> 16,1 Rescale Slope
> >>         (0028,1054) ?? (LO) [normalized]                          #
> 10,1 Rescale Type
> >>         (2001,0010) ?? (LO) [Philips Imaging DD 001]              #
> 22,1 Private Creator
> >>         (2001,1077) ?? (CS) [LINEARMODALITY]                      #
> 14,1 GL TrafoType
> >>         (2001,10c1) ?? (LO) [LinearModalityGLTrafo ]              #
> 22,1 Nested Object Type Name
> >>       (fffe,e00d)
> >> (fffe,e0dd)
> >
> > Well since the public tag is nested within a private tags, this means
> > it belong to the extended SOP Class definition. In case you have
> > access to the DCS of PMS for that particular instance, you should be
> > able to implement support for it.
> >
> >> Is there a way to fix that? Did you ever see that kind of nested
> objects? Is there a configuration on the Philips workstation to avoid that
> kind of nested objects?
> >> Thanks.
> >
> > I am not 100% convince there is anything to 'fix', could you please
> > send us the output of gdcminfo on that image. This will tell whether
> > the issue is really at GDCM level or at ITK level. I did implement
> > support for those Philips 'Combine MR Rescale option', since GDCM
> > 2.6.x
>
> I forgot to answer the last question: yes you can avoid this kind of
> object, since by definition MR Image Storage cannot store Rescale
> Intercept/Slope.
>
> See for example:
> https://groups.google.com/d/msg/comp.protocols.dicom/
> M4kdqcrs50Y/fJVGWNsgAwAJ
>
> --
> Mathieu
>