> i found dicom data set of a CT scanner and the files of this data set haven't got
> the file meta information (group 0002) and the size premble. In the
> standard P.S. 3-10
> 7 DICOM File Format seems that a file Dicom must have the file meta
> information (group 0002) and the size premble, so my question is:
> - this file is in a valid format?
> -What can I do with a file like this (I'm developing an application to
> read Dicom File).

Such files are not valid instances of the DICOM file format, but they
are not unusual. Many (mostly older) DICOM toolkits/applications create
such files. These files contain only the dataset without meta-header,
which implies that the reader has to guess the Transfer Syntax, which
cannot be deduced reliably from any part of the file.
Therefore, readers typically assume that such files are
a) Uncompressed
b) Implicit VR Little Endian Transfer Syntax

Some toolkits (such as DCMTK) contain heuristics to correctly guess
byte order and explicit/implicit VR and thus in most cases also
correctly read files in Explicit VR Little Endian or Explicit VR
Big Endian transfer syntax.

Best regards,
Marco Eichelberg

On Oct 15, 4:32 pm, Marco Eichelberg
wrote:
> > i found dicom data set of a CT scanner and the files of this data set haven't got
> > the file meta information (group 0002) and the size premble. In the
> > standard P.S. 3-10
> > 7 DICOM File Format seems that a file Dicom must have the file meta
> > information (group 0002) and the size premble, so my question is:
> > - this file is in a valid format?
> > -What can I do with a file like this (I'm developing an application to
> > read Dicom File).
>
> Such files are not valid instances of the DICOM file format, but they
> are not unusual. Many (mostly older) DICOM toolkits/applications create
> such files. These files contain only the dataset without meta-header,
> which implies that the reader has to guess the Transfer Syntax, which
> cannot be deduced reliably from any part of the file.
> Therefore, readers typically assume that such files are
> a) Uncompressed
> b) Implicit VR Little Endian Transfer Syntax
>
> Some toolkits (such as DCMTK) contain heuristics to correctly guess
> byte order and explicit/implicit VR and thus in most cases also
> correctly read files in Explicit VR Little Endian or Explicit VR
> Big Endian transfer syntax.

This heuristic (or a similar one) is explained here too:

[2.2.3 Determining the Transfer Syntax of DICOM input Streams]
http://www.dclunie.com/medical-image...tml/part2.html

You should also realize that implementing those heuristics is
extremely difficult, error prone, and you can forge properly crafted
files to make almost any heuristic fails. Which means that for those
files, you have to read it entirely to declare whether or not this is
a "DICOM file".
As a side note, try with the deflated transfer syntax too, I'll bet
most (if not all) toolkits will reject them.

And in case you are searching for exotics files, I recommend, gdcmData
& gdcmConformanceTests

* http://gdcm.sourceforge.net/wiki/ind...s_gdcmData_.3F
* http://gdcm.sourceforge.net/wiki/ind...manceTests_.3F

-Mathieu
Ps: I have also seen DICOM files with a Preamble, no File Meta Header
and then the DataSet.

On 15 Ott, 16:46, Mathieu Malaterre
wrote:
> On Oct 15, 4:32 pm, Marco Eichelberg
> wrote:
>
>
>
> > > i found dicom data set of a CT scanner and the files of this data set haven't got
> > > the file meta information (group 0002) and the size premble. In the
> > > standard P.S. 3-10
> > > 7 DICOM File Format seems that a file Dicom must have the file meta
> > > information (group 0002) and the size premble, so my question is:
> > > - this file is in a valid format?
> > > -What can I do with a file like this (I'm developing an application to
> > > read Dicom File).
>
> > Such files are not valid instances of the DICOM file format, but they
> > are not unusual. Many (mostly older) DICOM toolkits/applications create
> > such files. These files contain only the dataset without meta-header,
> > which implies that the reader has to guess the Transfer Syntax, which
> > cannot be deduced reliably from any part of the file.
> > Therefore, readers typically assume that such files are
> > a) Uncompressed
> > b) Implicit VR Little Endian Transfer Syntax
>
> > Some toolkits (such as DCMTK) contain heuristics to correctly guess
> > byte order and explicit/implicit VR and thus in most cases also
> > correctly read files in Explicit VR Little Endian or Explicit VR
> > Big Endian transfer syntax.
>
> This heuristic (or a similar one) is explained here too:
>
> [2.2.3 Determining the Transfer Syntax of DICOM input Streams]http://www.dclunie.com/medical-image-faq/html/part2.html
>
> You should also realize that implementing those heuristics is
> extremely difficult, error prone, and you can forge properly crafted
> files to make almost any heuristic fails. Which means that for those
> files, you have to read it entirely to declare whether or not this is
> a "DICOM file".
> As a side note, try with the deflated transfer syntax too, I'll bet
> most (if not all) toolkits will reject them.
>
> And in case you are searching for exotics files, I recommend, gdcmData
> & gdcmConformanceTests
>
> *http://gdcm.sourceforge.net/wiki/ind...tions#What_is_...
> *http://gdcm.sourceforge.net/wiki/ind...tions#What_is_...
>
> -Mathieu
> Ps: I have also seen DICOM files with a Preamble, no File Meta Header
> and then the DataSet.

Thank You all for your prompt answer, so that images are in Dicom
standard but we to read them however.
Thanks for the link but what is gdcm?

Thanks again for your help.

MM

On Oct 16, 2:19 pm, vas...@yahoo.com wrote:
> On 15 Ott, 16:46, Mathieu Malaterre
> wrote:
>
>
>
> > On Oct 15, 4:32 pm, Marco Eichelberg
> > wrote:
>
> > > > i found dicom data set of a CT scanner and the files of this data set haven't got
> > > > the file meta information (group 0002) and the size premble. In the
> > > > standard P.S. 3-10
> > > > 7 DICOM File Format seems that a file Dicom must have the file meta
> > > > information (group 0002) and the size premble, so my question is:
> > > > - this file is in a valid format?
> > > > -What can I do with a file like this (I'm developing an application to
> > > > read Dicom File).
>
> > > Such files are not valid instances of the DICOM file format, but they
> > > are not unusual. Many (mostly older) DICOM toolkits/applications create
> > > such files. These files contain only the dataset without meta-header,
> > > which implies that the reader has to guess the Transfer Syntax, which
> > > cannot be deduced reliably from any part of the file.
> > > Therefore, readers typically assume that such files are
> > > a) Uncompressed
> > > b) Implicit VR Little Endian Transfer Syntax
>
> > > Some toolkits (such as DCMTK) contain heuristics to correctly guess
> > > byte order and explicit/implicit VR and thus in most cases also
> > > correctly read files in Explicit VR Little Endian or Explicit VR
> > > Big Endian transfer syntax.
>
> > This heuristic (or a similar one) is explained here too:
>
> > [2.2.3 Determining the Transfer Syntax of DICOM input Streams]http://www.dclunie.com/medical-image-faq/html/part2.html
>
> > You should also realize that implementing those heuristics is
> > extremely difficult, error prone, and you can forge properly crafted
> > files to make almost any heuristic fails. Which means that for those
> > files, you have to read it entirely to declare whether or not this is
> > a "DICOM file".
> > As a side note, try with the deflated transfer syntax too, I'll bet
> > most (if not all) toolkits will reject them.
>
> > And in case you are searching for exotics files, I recommend, gdcmData
> > & gdcmConformanceTests
>
> > *http://gdcm.sourceforge.net/wiki/ind...tions#What_is_...
> > *http://gdcm.sourceforge.net/wiki/ind...tions#What_is_...
>
> > -Mathieu
> > Ps: I have also seen DICOM files with a Preamble, no File Meta Header
> > and then the DataSet.
>
> Thank You all for your prompt answer, so that images are in Dicom
> standard but we to read them however.
> Thanks for the link but what is gdcm?

you are kiddin', right ? You cannot possibly be serious ...

Did you scroll to the top of the page I sent you ?

http://gdcm.sourceforge.net/wiki/ind...hat_is_GDCM.3F

-M

On 16 Ott, 16:28, Mathieu Malaterre
wrote:
> On Oct 16, 2:19 pm, vas...@yahoo.com wrote:
>
>
>
> > On 15 Ott, 16:46, Mathieu Malaterre
> > wrote:
>
> > > On Oct 15, 4:32 pm, Marco Eichelberg
> > > wrote:
>
> > > > > i found dicom data set of a CT scanner and the files of this data set haven't got
> > > > > the file meta information (group 0002) and the size premble. In the
> > > > > standard P.S. 3-10
> > > > > 7 DICOM File Format seems that a file Dicom must have the file meta
> > > > > information (group 0002) and the size premble, so my question is:
> > > > > - this file is in a valid format?
> > > > > -What can I do with a file like this (I'm developing an application to
> > > > > read Dicom File).
>
> > > > Such files are not valid instances of the DICOM file format, but they
> > > > are not unusual. Many (mostly older) DICOM toolkits/applications create
> > > > such files. These files contain only the dataset without meta-header,
> > > > which implies that the reader has to guess the Transfer Syntax, which
> > > > cannot be deduced reliably from any part of the file.
> > > > Therefore, readers typically assume that such files are
> > > > a) Uncompressed
> > > > b) Implicit VR Little Endian Transfer Syntax
>
> > > > Some toolkits (such as DCMTK) contain heuristics to correctly guess
> > > > byte order and explicit/implicit VR and thus in most cases also
> > > > correctly read files in Explicit VR Little Endian or Explicit VR
> > > > Big Endian transfer syntax.
>
> > > This heuristic (or a similar one) is explained here too:
>
> > > [2.2.3 Determining the Transfer Syntax of DICOM input Streams]http://www.dclunie.com/medical-image-faq/html/part2.html
>
> > > You should also realize that implementing those heuristics is
> > > extremely difficult, error prone, and you can forge properly crafted
> > > files to make almost any heuristic fails. Which means that for those
> > > files, you have to read it entirely to declare whether or not this is
> > > a "DICOM file".
> > > As a side note, try with the deflated transfer syntax too, I'll bet
> > > most (if not all) toolkits will reject them.
>
> > > And in case you are searching for exotics files, I recommend, gdcmData
> > > & gdcmConformanceTests
>
> > > *http://gdcm.sourceforge.net/wiki/ind...tions#What_is_...
> > > *http://gdcm.sourceforge.net/wiki/ind...tions#What_is_...
>
> > > -Mathieu
> > > Ps: I have also seen DICOM files with a Preamble, no File Meta Header
> > > and then the DataSet.
>
> > Thank You all for your prompt answer, so that images are in Dicom
> > standard but we to read them however.
> > Thanks for the link but what is gdcm?
>
> you are kiddin', right ? You cannot possibly be serious ...
>
> Did you scroll to the top of the page I sent you ?
>
> http://gdcm.sourceforge.net/wiki/ind...tions#What_is_...
>
> -M

Really I don't know, it seems gdcm is Dicom library, but I don't
understand how can I use it. Sorry for my not knowledge about it. I'm
not so expert in Dicom, I studied the standard to implement some
software to be compatible with Dicom 3.0 to export in Dicom format and
to read Dicom format, nothing else....

MM