Image transfer from K-Pacs to ConQuest fails - sometimes

Dear all,

we are in the process of testing the ConQuest DICOM server in our department. The initial idea
was to use K-Pacs as SCU to store all kinds of images that come on CD/DVD from referring
institutions.

However, for a number of image series we keep getting errors when we try to transfer the
images from K-Pacs to ConQuest.

This is the process log from K-Pacs (patient name removed here for privacy reasons):

*******************************************************10.09.2008 15:45:50 ThreadID[828] : Sending images to CONQUESTSRV1 started*******************************************************[828]        >> : c-store request for Series 1.3.12.2.1107.5.2.30.26019.2008072311114414464118643.0.0.0 initiated.[DICOM SCU]        >> : Connected to: 129.129.152.141:5678[DICOM SCU]        >> : Item Type: 2[DICOM SCU]        >> : Association Accept::ReadDynamic[DICOM SCU]        >> : Presentation Context Accept, Transfer Syntax: 1.2.840.10008.1.2[828]        >> : Error: store failed for xxxx yyyy , Study: Schädel_ksb^Routine , Sequence: 0000000003*******************************************************10.09.2008 15:45:51 ThreadID[828] : Closed.Task processed with errors*******************************************************

The ConQuest console shows the following messages (with debug level set to 5):

DGATE (1.4.14, build Wed Sep 10 09:42:26 2008) is running as threaded server
Server command sent using DGATE -- option
Arena 0:
system bytes     =     385024
in use bytes     =     249704
Total (incl. mmap):
system bytes     =    1007616
in use bytes     =     872296
max mmap regions =          2
max mmap bytes   =     622592
Arena 0:
system bytes     =     380928
in use bytes     =     249576
Total (incl. mmap):
system bytes     =    1003520
in use bytes     =     872168
max mmap regions =          2
max mmap bytes   =     622592


UPACS THREAD 0: STARTED AT: Wed Sep 10 15:36:32 2008
*** connection terminated

I could successfully send exactly the same images right out of the Imagebox to
ConQuest by means of the DCMTK storescu tool. So I suspect the problem is
more on the K-Pacs side.

It is also worth mentioning that this problem only occurs for some image series.
The majority of image series can be sent from K-Pacs to ConQuest without any problem.

I would appreciate any idea of what might be going wrong here. Thank you in advance.

Best regards - Juergen

Quote from marcelvanherk

"connection terminated" shows up if the sending application hangs up before transfer is complete. I have seen StoreSCU do this if the image transfer syntax does not correspond with the requested transfer syntax [ ... ]

Hi Marcel,

thanks for your response. I have checked the encoding of the questionable DICOM image files within the K-Pacs
imagebox (i.e. those image files whose transfer from K-Pacs to ConQuest fails). It turned out that these
files are encoded in Big Endian Explicit TS while the other files (i.e. those files whose transfer from K-Pacs to
ConQuest succeed) are encoded in Little Endian.

So it seems that K-Pacs ungently drops the connection to the SCP (here: ConQuest) if the encoding
of the image files in the local imagebox does not correspond to the transfer syntax of the network association
negotiation with the remote storage SCP. I am wondering if this a bug in K-Pacs or if I am missing something
obvious here.

Just for the records: The DCMTK storescu client tool does not seem to have this problem as it happily converts
from Big Endian Explicit to Little Endian Implicit TS before sending the images to ConQuest.

Thanks again.

Juergen

Quote from marcelvanherk

big-endian does not work in conquest - yet (never fixed it and enabled it).
So that may explain. However, it is a k-pacs bug if it does not convert from
little-endian to big-endian on need, because conquest reports it cannot handle
big-endian.

I do not think that ConQuest is the culprit here. The process log indicates
that K-Pacs has negotiated Little Endian Implicit VR transfer syntax
(UID 1.2.840.10008.1.2) with ConQuest. In other words: K-Pacs has agreed
to send the data to ConQuest with Little Endian encoding.
But then K-Pacs simply drops the connection without actually converting and
sending the data if the corresponding files in the imagebox are encoded in
Big Endian TS.

I also think this is a bug in K-Pacs. I'm wondering if anybody else can confirm
this behavior. (I'm running K-Pacs 1.5 & ConQuest 1.4.14 with MySQL on Linux
if that matters.)

Best regards - Juergen