Troubleshooting Null Response in DICOM Process Integration

Hello,

First of all; thanks for your time reading this post, and thanks for your answers and help. I am really grateful.

We have the following need: Send a DICOM Find Document to get the complete list of a patient's studies from an Outbound System, which we simulate with the tool called "dcm4che" specifically with these two commands:

1º.Initialize a DICOM database in simulator. We will use this database to run queries using DICOM C-FIND commands:

./dcmdir -c ./shared/DICOMDIR --fs-id SAMPLEDICOMS --fs-desc ./shared/dicom/descriptor ./shared/dicom

2ºStart simulated DICOM archive that uses the previous initialized DICOM database for query/retrieve. This will receive C-FIND and C-MOVE commands:

./dcmqrscp --ae-config ./shared/ae.properties -b VNAPRE:11223 --dicomdir ./shared/DICOMDIR

We create a DICOM Document with dummy data to simulate the FIND command as follows:

/// Class Procesos.DICOM.EnrutadorConsultarEstudiosVNAv01r00.Code Extends Ens.BP.Context
{

...

ClassMethod responseTarjetaC002ToFindDicom(responseTarjetaC002 As Mensajes.Response.GestionPacientes.TSI.consultaDatosPacienteResponse) As EnsLib.DICOM.Document
{
	set findDicom = ##class(EnsLib.DICOM.Document).%New()
	set tSC = findDicom.SetValueAt("76", "CommandSet.CommandGroupLength")
	set tSC = findDicom.SetValueAt("1.2.840.10008.5.1.4.1.2.2.1", "CommandSet.AffectedSOPClassUID")
	set tSC = findDicom.SetValueAt("32", "CommandSet.CommandField")
	set tSC = findDicom.SetValueAt("1", "CommandSet.MessageID")
	set tSC = findDicom.SetValueAt("0", "CommandSet.Priority")
	set tSC = findDicom.SetValueAt("65278", "CommandSet.CommandDataSetType")
	
	set tSC = findDicom.SetValueAt("STUDY", "DataSet.QueryRetrieveLevel")
	;set tSC = findDicom.SetValueAt("732831", "DataSet.PatientID")// Paciente Prueba Negrin con 2 imagenes dadas por Siemes de una botellaset tSC = findDicom.SetValueAt("988333", "DataSet.PatientID") 
	
	set tSC = findDicom.SetValueAt("", "DataSet.AccessionNumber")
	set tSC = findDicom.SetValueAt("", "DataSet.StudyDescription")
	set tSC = findDicom.SetValueAt("", "DataSet.ModalitiesInStudy")
	set tSC = findDicom.SetValueAt("", "DataSet.ImageType")
	set tSC = findDicom.SetValueAt("", "DataSet.StudyDate")
	
	quit findDicom
}

...

Storage Default
{
<Data name="CodeDefaultData">
<Subscript>"Code"</Subscript>
<Value name="1">
<Value>todosEstudios</Value>
</Value>
</Data>
<DefaultData>CodeDefaultData</DefaultData>
<Type>%Storage.Persistent</Type>
}

}

We have included this Parent Class as the Bussiness' Process context superclass:

We call this function inside a <code> block, get the response (which is the dummy DICOM Find document), and then we <call> the DICOM Bussiness Process, being visually as:

Being as .cls language as:

<scope xpos='335' ypos='1600' xend='335' yend='2150' >
<code name='C002 a Consulta DICOM' xpos='335' ypos='1700' >
<![CDATA[
  set context.consultaDICOM = context.responseTarjetaC002ToFindDicom(context.responseTarjetaC002)]]>
</code>
<call name='ConsultarEstudiosFind' target='Procesos.DICOM.ConsultarEstudiosMedianteFind' async='0' xpos='335' ypos='1800' >
<request type='Ens.Request' >
<assign property="callrequest" value="context.consultaDICOM" action="set" />
</request>
<response type='Ens.Response' >
<assign property="context.respuestaDICOM" value="callresponse" action="set" />
</response>
</call>
<code name='LOG' xpos='335' ypos='1900' >
<![CDATA[
  $$$LOGWARNING("Despues del call ConsultarEstudiosFind")]]>
</code>
<faulthandlers>
<catchall xpos='335' ypos='2000' xend='200' yend='350' >
<code name='LOG ERROR' xpos='200' ypos='250' >
<![CDATA[
  $$$LOGERROR($System.Status.GetErrorText(context.%LastError))]]>
</code>
</catchall>
</faulthandlers>
</scope>
<code name='Informar Demograficos' xpos='335' ypos='2250' >
<![CDATA[
  set response = context.informarDemograficosPaciente(context.responseTarjetaC001, context.respuestaDICOM)]]>
</code>
</case>

The DICOM Process which is being invoked, is very basic:

Class Procesos.DICOM.ConsultarEstudiosMedianteFind Extends EnsLib.DICOM.Process [ ClassType = persistent, ProcedureBlock ]
{

/// This parameter names the operation used to provide storageParameter SETTINGS = "OperationDuplexName";/// This keeps track of the OriginatingMessageIDProperty OriginatingMessageID As%Integer;/// This is the incoming document from the business SserviceProperty DocumentFromService As EnsLib.DICOM.Document;/// This keeps track of the current state of the processProperty CurrentState As%String [ InitialExpression = "OperationNotConnected" ];/// This is the name of the operation providing storageProperty OperationDuplexName;/// Añadimos 11 10 2023 para guardar el listado de estudiosProperty respuestaConsultaEstudios As Mensajes.Response.DICOM.consultarEstudiosDatosPacienteVNAResponse;/// Messages received here are instances of EnsLib.DICOM.Document sent to this/// process by the service or operation config items. In this demo, the process is ever/// in one of two states, the Operation is connected or not.
Method OnMessage(pSourceConfigName As%String, pInput As%Library.Persistent) As%Status
{
    #dim tSC As%Status = $$$OK#dim tMsgType As%String#dim tFindRequest As EnsLib.DICOM.Document
    do {
        #; If its a document sent from the serviceIf pSourceConfigName'=..OperationDuplexName {
                        
            set..respuestaConsultaEstudios = ##class(Mensajes.Response.DICOM.consultarEstudiosDatosPacienteVNAResponse).%New()	 			 		
            set..respuestaConsultaEstudios.patients = ##class(EsquemasDatos.DICOM.Patient).%New()
            
            #; If the operation has not been connected yetIf..CurrentState="OperationNotConnected" {
                #; We are in the process of establishing the connection to the operation,
                #; Keep hold of the incoming documentSet..DocumentFromService=pInput
                
                Set tSC=..EstablishAssociation(..OperationDuplexName)
                
            } elseif..CurrentState="OperationConnected" {
                
                
                #; We can forward the document to the operationSet tSC=..SendRequestAsync(..OperationDuplexName,..DocumentFromService,0) 
            }
            
        } elseif pSourceConfigName=..OperationDuplexName {
            
            #; We have received a document from the operationSet tMsgType=pInput.GetValueAt("CommandSet.CommandField",,.tSC)
            If$$$ISERR(tSC) Quit
            #; Should only EVER get a C-FIND-RSP$$$ASSERT(tMsgType="C-FIND-RSP")
        
            #; TODO: Do Something With the Find Response(s)if pInput.GetValueAt("CommandSet.Status",,.tSC)=0
            {
            Set tSC=..ReleaseAssociation(..OperationDuplexName)	
            quit
            }
            else
            {
                
            ; Escribimos 11 / 10 / 2023 para responder con los datos de cada estudio DICOM remitido por Sistema Destino		    	set study = ##class(EsquemasDatos.DICOM.Study).%New()
            set study.accessionNumber = pInput.GetValueAt("DataSet.AccessionNumber",,.tSC) if$$$ISERR(tSC) quitset study.description = pInput.GetValueAt("DataSet.StudyDescription",,.tSC) if$$$ISERR(tSC) quitset study.modality = pInput.GetValueAt("DataSet.ModalitiesInStudy",,.tSC) if$$$ISERR(tSC) quitset study.type = pInput.GetValueAt("DataSet.ImageType",,.tSC) if$$$ISERR(tSC) quitset study.data = pInput.GetValueAt("DataSet.StudyDate",,.tSC) if$$$ISERR(tSC) quitdo..respuestaConsultaEstudios.patients.studies.Insert(study)	
                
            ; Añadimos 11 / 10 / 2023 para enviar la respuesta DICOM al Enturador Padre;Set tSC=..SendRequestAsync("EnrutadorConsultarEstudiosVNAv01r00",pInput,0);Set tSC=..SendRequestAsync("EnrutadorConsultarEstudiosVNAv01r00",study,0);Set tSC=..SendRequestAsync("EnrutadorConsultarEstudiosVNAv01r00",QueryRsp,0);Set tSC=..SendRequestSync("EnrutadorConsultarEstudiosVNAv01r00",QueryRsp,0)
            }
        }
    } while (0)
    
    Quit tSC
}

/// This method is called by the framework on successful establishment of an association
Method OnAssociationEstablished(pSourceConfigName As%String, pInput As EnsLib.DICOM.Notify.Established) As%Status
{
    #dim tSC As%Status = $$$OKIf pSourceConfigName=..OperationDuplexName {
        
        #; The association with the operation has been completed, operation is now connectedSet..CurrentState="OperationConnected"Set tSC=..OnMessage(..ServiceDuplexName,"")
        
    } else {
        
        #; Need to establish an associaton with the operation (we will be called back here at 
        #; OnAssociationEstablished()Set tSC=..EstablishAssociation(..OperationDuplexName)
    }
    
    Quit tSC
}

Method OnAssociationReleased(pSourceConfigName As%String, pInput As EnsLib.DICOM.Notify.Released) As%Status
{
    #dim tSC As%Status = $$$OK
        #; The association between this process and the operation has been released, so we are now
        #; not connected to the operationSet..CurrentState="OperationNotConnected"; Añadimos 11 10 2023Set tSC=..SendRequestAsync("EnrutadorConsultarEstudiosVNAv01r00",..respuestaConsultaEstudios,0)
    
    Quit tSC
}

/// This callback is called by the framework when an Association is rejected
Method OnAssociationRejected(pSourceConfigName As%String, pInput As EnsLib.DICOM.Notify.Rejected) As%Status [ Final ]
{
 
    
    Quit$$$ERROR($$$EnsDICOMPeerRejectedAssociation)
}

/// This callback is called by the framework when an association encounters an error
Method OnAssociationErrored(pSourceConfigName As%String, pInput As EnsLib.DICOM.Notify.Errored) As%Status [ Final ]
{
    
    
    Quit pInput.Status
}

/// This callback is called by the framework when an association is aborted
Method OnAssociationAborted(pSourceConfigName As%String, pInput As EnsLib.DICOM.Notify.Aborted) As%Status [ Final ]
{

    Quit$$$ERROR($$$EnsDICOMPeerRequestedAbort)
}

/// This method is called when any error occurs. Returning the same error will cause the BusinessProcess to set its/// status to error and close down
Method OnError(request As%Library.Persistent, ByRef response As%Library.Persistent, callrequest As%Library.Persistent, pErrorStatus As%Status, pCompletionKey As%String) As%Status
{

    
    #; If we are in conversation with the operation, we neet to tell the operation to ABORT its associationIf..CurrentState="OperationConnected" {
        
        #; Form an abort messageSet tCommandAbort=##class(EnsLib.DICOM.Command.Abort).%New($$$ABORTSOURCESERVICEUSER,$$$ABORTREASONNOTSPECIFIED)
        
        #; Send it to the operationDo..AbortAssociation(..OperationDuplexName,tCommandAbort)
    }
    Quit pErrorStatus
}

Storage Default
{
<Data name="QueryDefaultData">
<Subscript>"Query"</Subscript>
<Value name="1">
<Value>OriginatingMessageID</Value>
</Value>
<Value name="2">
<Value>DocumentFromService</Value>
</Value>
<Value name="3">
<Value>CurrentState</Value>
</Value>
<Value name="4">
<Value>OperationDuplexName</Value>
</Value>
<Value name="5">
<Value>listadoEstudios</Value>
</Value>
<Value name="6">
<Value>response</Value>
</Value>
<Value name="7">
<Value>respuestaConsultaEstudos</Value>
</Value>
<Value name="8">
<Value>respuestaConsultaEstudios</Value>
</Value>
</Data>
<DefaultData>QueryDefaultData</DefaultData>
<Type>%Storage.Persistent</Type>
}

}

Here comes what we do not understand:

We do process each study inside the following part:

 		} elseif pSourceConfigName=..OperationDuplexName {
	 		
	 		#; We have received a document from the operationSet tMsgType=pInput.GetValueAt("CommandSet.CommandField",,.tSC)
			If$$$ISERR(tSC) Quit
			#; Should only EVER get a C-FIND-RSP$$$ASSERT(tMsgType="C-FIND-RSP")
		
			#; TODO: Do Something With the Find Response(s)if pInput.GetValueAt("CommandSet.Status",,.tSC)=0
			{
			Set tSC=..ReleaseAssociation(..OperationDuplexName)	
			quit
			}
			else
			{
		    	
			; Escribimos 11 / 10 / 2023 para responder con los datos de cada estudio DICOM remitido por Sistema Destino		    	set study = ##class(EsquemasDatos.DICOM.Study).%New()
		    set study.accessionNumber = pInput.GetValueAt("DataSet.AccessionNumber",,.tSC) if$$$ISERR(tSC) quitset study.description = pInput.GetValueAt("DataSet.StudyDescription",,.tSC) if$$$ISERR(tSC) quitset study.modality = pInput.GetValueAt("DataSet.ModalitiesInStudy",,.tSC) if$$$ISERR(tSC) quitset study.type = pInput.GetValueAt("DataSet.ImageType",,.tSC) if$$$ISERR(tSC) quitset study.data = pInput.GetValueAt("DataSet.StudyDate",,.tSC) if$$$ISERR(tSC) quitdo..respuestaConsultaEstudios.patients.studies.Insert(study)	
		    	
		    ; Añadimos 11 / 10 / 2023 para enviar la respuesta DICOM al Enturador Padre;Set tSC=..SendRequestAsync("EnrutadorConsultarEstudiosVNAv01r00",pInput,0);Set tSC=..SendRequestAsync("EnrutadorConsultarEstudiosVNAv01r00",study,0);Set tSC=..SendRequestAsync("EnrutadorConsultarEstudiosVNAv01r00",QueryRsp,0);Set tSC=..SendRequestSync("EnrutadorConsultarEstudiosVNAv01r00",QueryRsp,0)
			}
 		}

And then, we send it back to the original BPL visual process, via the following line written inside the method "OnAssociationReleased"

Set tSC=..SendRequestAsync("EnrutadorConsultarEstudiosVNAv01r00",..respuestaConsultaEstudios,0)
 

We do get that response, in the <call>, as you can see:

However here comes the issue:

⚫️😮 We do not know why there is a "ghost" NULL additions response being returned from the DICOM Process to the Visual BPL:

It is important for us to prevent that NULL response, because the undersired effect, is that is overwrittes the [29] response which is the correct one.

To be more precise, adter that <call>, we do a <code> to join a previous response (which is not important for this topic), and the [29] response:

Being the code:

ClassMethod informarDemograficosPaciente(responseTarjetaC001 As Mensajes.Response.GestionPacientes.TSI.IdentificacionResponse, respuestaDICOM As Mensajes.Response.DICOM.consultarEstudiosDatosPacienteVNAResponse) As Mensajes.Response.DICOM.consultarEstudiosDatosPacienteVNAResponse
{
	$$$LOGINFO("respuestaDICOM: "_respuestaDICOM)
	$$$LOGINFO("respuestaDICOM.patients: "_respuestaDICOM.patients)
	$$$LOGINFO("respuestaDICOM.patients.studies: "_respuestaDICOM.patients.studies)
	$$$LOGINFO("respuestaDICOM.patients.studies.Size: "_respuestaDICOM.patients.studies.Size)
	
	set response = ##class(Mensajes.Response.DICOM.consultarEstudiosDatosPacienteVNAResponse).%New()
	set response.responseStatus = "OK"set response.patients = ##class(EsquemasDatos.DICOM.Patient).%New()
	set response.patients.firstName = responseTarjetaC001.nombre
	set response.patients.middleName = responseTarjetaC001.apellido1
	set response.patients.lastName = responseTarjetaC001.apellido2
	set response.patients.gender = responseTarjetaC001.sexo
	set response.patients.birthDate = responseTarjetaC001.fechaNacimiento

	for i = 1:1:respuestaDICOM.patients.studies.Size {
		do response.patients.studies.Insert(respuestaDICOM.patients.studies.GetAt(i))
	}
	quit response
}

However, the variable "respuestaDICOM" holds the response [30] which is NULL and not the [29], so it causes an Exception, at the following line:

$$$LOGINFO("respuestaDICOM.patients: "_respuestaDICOM.patients)

Being on the visual trace:

Why does the DICOM Process generate a NULL response at step [30]?

How could we prevent (stop) it, to make that NULL response not being forwarded from the DICOM Process to the Basic BPL?

How would we just get the [29] response as needed, without having the [30] overwritting it?

Could you help us please?

Thanks.

The DICOM Process code is 99% from:

https://github.com/intersystems-ib/iris-dicom-sample/blob/master/iris/s…

We have also read:

https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cl…

Again thank you.