DICOM nodes in message flows

Digital Imaging and Communications in Medicine (DICOM) is a standard for handling, storing, printing, and transmitting medical image information.

The Healthcare documentation uses the following definition for a DICOM image.

A DICOM image (also known as a DICOM instance or a DICOM object) is the combination of pixel data and metadata that is stored, as a single entity, in a DICOM Picture Archiving Communications System (PACS). The pixel data can take the form of a scanned image from a medical device, or encapsulated data from a DICOM Structured Report (SR). The metadata includes information that is associated with the pixel data, for example patient identity information and details of the study date and study time.

DICOMInput node

The DICOMInput node is a Service Class Provider (SCP) for the Verification and Storage service classes. The DICOMInput node can act as a proxy for a DICOM PACS by accepting DICOM C-STORE commands.

Use the DICOMInput node to receive a DICOM image from a Service Class User (SCU) node, store the DICOM image temporarily, and extract appropriate metadata from the DICOM image for processing in a message flow. You can select the presentation contexts that are made available to the SCU by using a configurable service. You can then use the features of IBM® Integration Bus to process and route the metadata to meet your requirements.

For more information about the DICOMInput node, see DICOMInput node.

DICOMOutput node

The DICOMOutput node is a Service Class User (SCU) for the Storage service class. The DICOMOutput node can store DICOM in a DICOM PACS by using the DICOM C-STORE command.

Use the DICOMOutput node to recombine DICOM metadata (from a message flow) with a DICOM image stored by the DICOMInput node and send the result to a Service Class Provider (SCP) node.

For more information about the DICOMOutput node, see DICOMOutput node.

DICOMFindMove node

The DICOMFindMove node is an SCU for the Query and Retrieve service classes. The DICOMFindMove node can issue DICOM C-FIND and C-MOVE commands to a DICOM PACS.

Use the DICOMFindMove node to query an external source for DICOM images that match criteria and optionally move the matching DICOM images to another location.

For more information about the DICOMFindMove node, see DICOMFindMove node.

Example use cases

• Collect studies for patient admission
• Second opinion or expert referral
• Clinical portal

Storage of DICOM images

DICOM images can be very large (tens or hundreds of MB) and routing these images through IBM Integration Bus would affect the performance of message flows. Instead, using a DICOMInput node, you store an incoming DICOM image in a processing directory on the file system. The metadata (attributes) from the DICOM images are extracted and propagated through the containing message flow as an XML message and the DICOM image, including the pixel data (scanned image or encapsulated data) remains on the file system.

At the other end of the message flow, by using a DICOMOutput node, you retrieve a copy of the pixel data from the processing directory of the DICOMInput node, and store it in another processing directory (reserved for the DICOMOutput node). By using the DICOMOutput node, you then recombine the processed metadata (from the message flow) with the pixel data (from the processing directory of the DICOMOutput node) and route the reconstituted DICOM image to the external destination.

Because there is a distinct copy of the DICOM image for each DICOMOutput node, if there are multiple DICOMOutput nodes in a message flow, you can combine each DICOM image with different metadata and send a unique DICOM image to each destination.

To prevent the file system from filling up with DICOM images that are no longer needed, you can automatically archive the contents of the processing directory that is used by each DICOM node after a period of time (configured in the node properties). You can then automatically delete the archived DICOM images after another period of time (configured in the node properties).

DICOM message schema

The DICOM nodes (DICOMInput, DICOMOutput and DICOMFindMove) use the same schema to describe the content of their DICOM XML messages.

For information about the DICOM message schema, see DICOM message schema.