pynetdicom C_GET failing with No presentation context for 'CT Image Storage' has been accepted by the peer for the SCP role

wdtj · Dec 28th 2020

I am trying to use pynetdicom for the first time. I have it and the ConQuest DICOM server installed on my PC. I am able to get the pynetdicom echo example working, but when I try the pynetdicom Storage SCU example (https://pydicom.github.io/pyne…ble/examples/storage.html) it fails with:

Code

No presentation context for 'CT Image Storage' has been accepted by the peer for the SCP role

Problem is, the example has negotiated the CT Image Storage context as far as I can see. Here's the logging from pynetDicom:

Code

pydev debugger: starting (pid: 39132)
I: Requesting Association
D: Request Parameters:
D: ======================= OUTGOING A-ASSOCIATE-RQ PDU ========================
D: Our Implementation Class UID:      1.2.826.0.1.3680043.9.3811.1.5.3
D: Our Implementation Version Name:   PYNETDICOM_153
D: Application Context Name:    1.2.840.10008.3.1.1.1
D: Calling Application Name:    PYNETDICOM      D: Called Application Name:     ANY-SCP         D: Our Max PDU Receive Size:    16382
D: Presentation Contexts:
D:   Context ID:        1 (Proposed)
D:     Abstract Syntax: =Patient Root Query/Retrieve Information Model - GET
D:     Proposed SCP/SCU Role: Default
D:     Proposed Transfer Syntaxes:
D:       =Implicit VR Little Endian
D:       =Explicit VR Little Endian
D:       =Deflated Explicit VR Little Endian
D:       =Explicit VR Big Endian
D:   Context ID:        3 (Proposed)
D:     Abstract Syntax: =CT Image Storage
D:     Proposed SCP/SCU Role: SCP
D:     Proposed Transfer Syntaxes:
D:       =Implicit VR Little Endian
D:       =Explicit VR Little Endian
D:       =Deflated Explicit VR Little Endian
D:       =Explicit VR Big Endian
D: Requested Extended Negotiation: None
D: Requested Common Extended Negotiation: None
D: Requested Asynchronous Operations Window Negotiation: None
D: Requested User Identity Negotiation: None
D: ========================== END A-ASSOCIATE-RQ PDU ==========================
D: Accept Parameters:
D: ======================= INCOMING A-ASSOCIATE-AC PDU ========================
D: Their Implementation Class UID:    1.2.826.0.1.3680043.2.135.1066.101
D: Their Implementation Version Name: 1.5.0/WIN32
D: Application Context Name:    1.2.840.10008.3.1.1.1
D: Calling Application Name:    PYNETDICOM      D: Called Application Name:     ANY-SCP         D: Their Max PDU Receive Size:  32768
D: Presentation Contexts:
D:   Context ID:        1 (Accepted)
D:     Abstract Syntax: =Patient Root Query/Retrieve Information Model - GET
D:     Accepted SCP/SCU Role: Default
D:     Accepted Transfer Syntax: =Implicit VR Little Endian
D:   Context ID:        3 (Accepted)
D:     Abstract Syntax: =CT Image Storage
D:     Accepted SCP/SCU Role: Default
D:     Accepted Transfer Syntax: =Implicit VR Little Endian
D: Accepted Extended Negotiation: None
D: Accepted Asynchronous Operations Window Negotiation: None
D: User Identity Negotiation Response: None
D: ========================== END A-ASSOCIATE-AC PDU ==========================
I: Association Accepted
I: Sending Get Request: MsgID 1
I: I: # Request Identifier
I: (0008,0052) CS [PATIENT]                                # 1 QueryRetrieveLevel
I: (0010,0010) PN [Wrench, Fred]                           # 1 PatientName
I: D: ========================== OUTGOING DIMSE MESSAGE ==========================
D: Message Type                  : C-GET RQ
D: Message ID                    : 1
D: Affected SOP Class UID        : Patient Root Query/Retrieve Information Model - GET
D: Identifier                    : Present
D: Priority                      : Low
D: ============================ END DIMSE MESSAGE =============================
D: pydicom.read_dataset() TransferSyntax="Little Endian Implicit"
I: Received Store Request
D: ========================== INCOMING DIMSE MESSAGE ==========================
D: Message Type                  : C-STORE RQ
D: Presentation Context ID       : 3
D: Message ID                    : 59647
D: Affected SOP Class UID        : CT Image Storage
D: Affected SOP Instance UID     : 1.3.6.1.4.1.33997.3232235894.19152.1608672548.1.1.1
D: Move Originator               : PYNETDICOM
D: Data Set                      : Present
D: Priority                      : Medium
D: ============================ END DIMSE MESSAGE =============================
E: No presentation context for 'CT Image Storage' has been accepted by the peer for the SCP role
D: pydicom.read_dataset() TransferSyntax="Little Endian Implicit"
D: ========================== INCOMING DIMSE MESSAGE ==========================
D: Message Type                  : C-GET RSP
D: Presentation Context ID       : 1
D: Message ID Being Responded To : 1
D: Affected SOP Class UID        : Patient Root Query/Retrieve Information Model - GET
D: Remaining Sub-operations      : 0
D: Completed Sub-operations      : 0
D: Failed Sub-operations         : 5
D: Warning Sub-operations        : 0
D: Identifier                    : None
D: Status                        : 0xFE00
D: ============================ END DIMSE MESSAGE =============================
D: I: Get SCP Result: 0xFE00 (Cancel)
I: Sub-Operations Remaining: 0, Completed: 0, Failed: 5, Warning: 0
D: pydicom.read_dataset() TransferSyntax="Little Endian Implicit"
C-GET query status: 0xfe00
I: Releasing Association

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So the log shows that the CT Image Storage Context was accepted, but with SCP/SCU Role: Default, whatever that means. When I debug through the pynetdicom processing I see that there is a CT context, but only for the SCP role.

ConQuest shows it's sent the DICOM file and then got disconnected.

And of course the code (only minor changes from the pynetdicom example:

Code

from pydicom.dataset import Dataset

from pynetdicom import AE, evt, build_role, debug_logger
from pynetdicom.sop_class import (    PatientRootQueryRetrieveInformationModelGet,    CTImageStorage
)

debug_logger()

# Implement the handler for evt.EVT_C_STORE
def handle_store(event):    """Handle a C-STORE request event."""    ds = event.dataset    ds.file_meta = event.file_meta
    # Save the dataset using the SOP Instance UID as the filename    ds.save_as(ds.SOPInstanceUID, write_like_original=False)
    # Return a 'Success' status    return 0x0000

handlers = [(evt.EVT_C_STORE, handle_store)]

# Initialise the Application Entity
ae = AE()

# Add the requested presentation contexts (QR SCU)
ae.add_requested_context(PatientRootQueryRetrieveInformationModelGet)
# Add the requested presentation context (Storage SCP)
ae.add_requested_context(CTImageStorage)

# Create an SCP/SCU Role Selection Negotiation item for CT Image Storage
role = build_role(CTImageStorage, scp_role=True)

# Create our Identifier (query) dataset
# We need to supply a Unique Key Attribute for each level above the
#   Query/Retrieve level
ds = Dataset()
ds.QueryRetrieveLevel = 'PATIENT'
ds.PatientName = 'Wrench, Fred'

# Associate with peer AE at IP 127.0.0.1 and port 11112
assoc = ae.associate('127.0.0.1', 5679, ext_neg=[role], evt_handlers=handlers)

if assoc.is_established:
    # Use the C-GET service to send the identifier
    responses = assoc.send_c_get(ds, PatientRootQueryRetrieveInformationModelGet)
    for (status, identifier) in responses:
        if status:
            print('C-GET query status: 0x{0:04x}'.format(status.Status))
        else:
            print('Connection timed out, was aborted or received invalid response')

    # Release the association
    assoc.release()
else:
    print('Association rejected, aborted or never connected')

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I've googled and googled until my googler was sore. Any help would be appreciated.

marcelvanherk · Dec 29th 2020

Hi,

I have not used pynetdicom myself but a colleague has and it works. An idea, in C-GET you must specify what kind of images you want to get. My client does a query for the SOPClassUID and then passes when opening C-GET. Where do you do that in your code?

Marcel

wdtj · Dec 29th 2020

Thanks for the reply. From what I see in the examples from pynetdicom, the context is added to the AE object before the associate(). When the associate() is called, the Associate Request is sent (which includes the contexts). The peer then accepts or rejects the contexts. In the log I see the CTImageStorage context is requested and the peer approves the context on the response. I then do the C-GET and Conquest sends the Dicom file but apparently pynetdicom rejects the response saying the Context is not available.

I do also have a request out on StackExchange, hoping someone with pinetdicom experience might help. Since the pinetdicom examples SHOULD work, I was more interested here in seeing if there was some compatibility issue with ConQuest.

Thanks.

marcelvanherk · Dec 30th 2020

Hi,

I will ask my colleague (may take some days).

By the way, what Conquest version?

Marcel

wdtj · Dec 30th 2020

1.5.0b. Thanks.

marcelvanherk · Dec 30th 2020

OK,

C-GET is supported.

Marcel

marcelvanherk · Jan 13th 2021

Hi,

Here is his code:

Python

##
#  @file       simpleDicomQR.py
#  @author     Gareth Price
#  @date       23/9/2016
#  @version    0.01
#
#  @brief      Classes to perform operations on remote PACS using PyNetDicom libraries
#
#  Copyright (C) 2016 The Christie NHS
#  Foundation Trust
##

#  VERSION HISTORY
#  Version:    0.01
#  Date:       23/8/2016
#  Update:     Origin
#  Author:     Gareth Price
#
#  Version:    0.02
#  Date:       06/01/2021
#  Update:     Extracted from classes to simple single file runtime
#  Author:     Gareth Price

#NOTE - This code was writen in 2016 against older libraries. The notes below show the versions of pydicom and pynetdicom
#it was writen against
# - PyDicom 1.0.0a - There are many code changes required between 0.99 and 1.0 versions of pydicom, comes from github
#latest - not an official release https://github.com/darcymason/pydicom
# - PyNetDicom - 0.9.0 - The official PyPI distribution is 2.7 only. The 3.5 port (with significantly different syntax)
#comes from a fork - https://github.com/scaramallion/pynetdicom3
#Both of these are cloned to Downloads and then installed via setup.py

#Using a standard version of conquest 1.5.0b - naming as in distribution localhost, CONQUESTSRV1, 5678

import pydicom
import pynetdicom3
from pynetdicom3.pdu_primitives import SCP_SCU_RoleSelectionNegotiation

# ===================================================================================================
# Retrieve image data from PACS
# ===================================================================================================
class pacsRetrieveClass():

    """Retrieve data from remote PACS"""

    def __init__(self):
        self.connected = False

    def connectPACS(self):
        """"Connect to remote PACS"""
        self.AE = pynetdicom3.AE('localdicom', 9999, scu_sop_class=[pynetdicom3.VerificationSOPClass]+pynetdicom3.QueryRetrieveSOPClassList+pynetdicom3.StorageSOPClassList,
                                 scp_sop_class=[pynetdicom3.VerificationSOPClass]+pynetdicom3.StorageSOPClassList,
                                 transfer_syntax=[pydicom.uid.ImplicitVRLittleEndian,pydicom.uid.ExplicitVRLittleEndian,
                                        pydicom.uid.ExplicitVRBigEndian])  # netdicom local dicom SCU/SCP
        ext_neg = []
        for context in self.AE.presentation_contexts_scu:
            tmp = SCP_SCU_RoleSelectionNegotiation()
            tmp.sop_class_uid = context.AbstractSyntax
            tmp.scu_role = False
            tmp.scp_role = True
            ext_neg.append(tmp)

        self.AE.OnAssociateResponse = self.onAssociateResponse
        self.AE.OnAssociateRequest = self.onAssociateRequest
        self.association = self.AE.associate('localhost', 5678, 'CONQUESTSRV1',
                                             ext_neg=ext_neg)  # Request association with remote SCP/SCU
        self.connected = True

    def onAssociateResponse(self,association):
        print("Association response received")

    def onAssociateRequest(self,association):
        print("Association resquested")
        return True

    def isConnected(self):
        if(not hasattr(self,'association')):
            self.connected = False
            return False
        if(self.association.is_alive()):
            self.connected = True
            return True
        else:
            self.connected = False
            return False

    def echoRemotePACS(self):
        """Simple Echo SCU implementation"""
        if(not self.connected):
            self.connectPACS()
        if self.association.is_established:
            status = self.association.send_c_echo()
            if('Success' in status.status_type):
                self.connected = True
                print("Echo sucessful")
                return True
            else:
                self.connected = False
                print("Echo failed")
                return False

    def queryRemotePACS(self):
        """CFind to get all patient names on the server (ie just the HEAD EXP2 image included with conquest"""
        self.isConnected()
        if (not self.connected):
            self.connectPACS()

        #Build query
        self.query = pydicom.dataset.Dataset()  # Default query for all patients
        self.query.PatientID = ''  # Add additional data elements as required
        self.query.PatientName = ''
        self.query.SeriesInstanceUID = ''
        self.query.QueryRetrieveLevel = "PATIENT"  # Change level as required

        if self.association.is_established:
            print("DICOM query all patients")
            responses = self.association.send_c_find(self.query,query_model='P')  # Patient Root informmation model
            patientIDs = []
            patientNames = []
            for (status, dataset) in responses:
                if (hasattr(dataset, 'PatientID')):
                    patientIDs.append(dataset.PatientID)
                if (hasattr(dataset, 'PatientName')):
                    patientNames.append(dataset.PatientName)
        print("Find query returned patinet IDs and names")
        print(patientIDs)
        print(patientNames)

    def onStore(self,dataset):
        """Method to call when acting as store SCP """

        meta = pydicom.dataset.Dataset()
        meta.TransferSyntaxUID = pydicom.uid.ImplicitVRLittleEndian #Need to explicitly add file metadata and Transfer Syntax to get pixel uncompression to work in pydicom
        meta.MediaStorageSOPClassUID = dataset.SOPClassUID
        meta.MediaStorageSOPInstanceUID = dataset.SOPInstanceUID
        meta.ImplementationClassUID = pynetdicom3.pynetdicom_uid_prefix

        dataset.file_meta = meta    #Need to explicitly add file metadata and Transfer Syntax to get pixel uncompression to work in pydicom
        dataset.is_little_endian = True
        dataset.is_implicit_VR = True


        print("Saving data retrieved via CGet")
        dataset.save_as('E:\\Temp\\dicomExampleCGetData'+str(self.imgNbr)+'.dcm',write_like_original=False)
        self.imgNbr=self.imgNbr+1

        return 0x0000   #Return success

    def retrieveSeriesCGet(self):
        """Given patient ID retrive images"""
        self.isConnected()
        if (not self.connected):
            self.connectPACS()

        self.imgNbr=0   #Update to allow multiple images to be saved with different filenames
        self.AE.on_c_store = self.onStore   #Assign cStore method

        #Query data structure
        self.retrieveQuery = pydicom.dataset.Dataset()
        self.retrieveQuery.QueryRetrieveLevel = "PATIENT"
        self.retrieveQuery.PatientID = '0009703828'

        if self.association.is_established:
            print("DICOM retrieve patient ")
            responses = self.association.send_c_get(self.retrieveQuery, query_model='P')
            if responses is not None:
                for response in responses:
                    pass

#===================================================================================================
#Main
#===================================================================================================
if __name__=="__main__":    #Test for pacsClasses

    pacs = pacsRetrieveClass()
    pacs.connectPACS()
    pacs.echoRemotePACS()
    pacs.queryRemotePACS()
    pacs.retrieveSeriesCGet()

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pynetdicom C_GET failing with No presentation context for 'CT Image Storage' has been accepted by the peer for the SCP role

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