Module: SOP Class Handler

Overview

This module defines how a specific DICOM SOP class should be processed to make a list of DisplaySet, things which can be hung in a viewport. An extension can register a SOP Class Handler Module by defining a getSopClassHandlerModule method. The SOP Class.

The mode chooses what SOPClassHandlers to use, so you could process a series in a different way depending on mode within the same application.

SOPClassHandler is a bit different from the other modules, as it doesn't provide a 1:1 schema for UI or provide its own components. It instead defines:

• sopClassUIDs: an array of string SOP Class UIDs that the getDisplaySetFromSeries method should be applied to.
• getDisplaySetFromSeries: a method that maps series and study metadata to a display set

A displaySet has the following shape:

return {
  Modality: 'MR',
  displaySetInstanceUIDD
  SeriesDate,
  SeriesTime,
  SeriesInstanceUID,
  StudyInstanceUID,
  SeriesNumber,
  FrameRate,
  SeriesDescription,
  isMultiFrame,
  numImageFrames,
  SOPClassHandlerId,
  madeInClient,
}

Example SOP Class Handler Module

import ImageSet from '@ohif/core/src/classes/ImageSet';


const sopClassDictionary = {
  CTImageStorage: "1.2.840.10008.5.1.4.1.1.2",
  MRImageStorage: "1.2.840.10008.5.1.4.1.1.4",
};


// It is important to note that the used SOPClassUIDs in the modes are in the order that is specified in the array.
const sopClassUids = [
  sopClassDictionary.CTImageStorage,
  sopClassDictionary.MRImageStorage,
];

function addInstances(instances)  {
   // Add instances to this display set, and return the display set updated.
}

const makeDisplaySet = (instances) => {
  const instance = instances[0];
  const imageSet = new ImageSet(instances);

  imageSet.setAttributes({
    displaySetInstanceUID: imageSet.uid,
    SeriesDate: instance.SeriesDate,
    SeriesTime: instance.SeriesTime,
    SeriesInstanceUID: instance.SeriesInstanceUID,
    StudyInstanceUID: instance.StudyInstanceUID,
    SeriesNumber: instance.SeriesNumber,
    FrameRate: instance.FrameTime,
    SeriesDescription: instance.SeriesDescription,
    Modality: instance.Modality,
    isMultiFrame: isMultiFrame(instance),
    numImageFrames: instances.length,
    SOPClassHandlerId: `${id}.sopClassHandlerModule.${sopClassHandlerName}`,
    addInstances,
  });

  // Note returns an array now
  return [imageSet];
};

getSopClassHandlerModule = () => {
  return [
    {
      name: 'stack,
      sopClassUids,
      getDisplaySetsFromSeries: makeDisplaySet,
    },
  ];
};

addInstances

In order to allow new SOP instances to be received and added to an existing display set, the addInstances method can be added to a display set. It is called on the display set to be updated, and returns it when it has added at least one of the instances to the display set.

More examples :

You can find another example for this mapping between raw metadata and displaySet for DICOM-SR extension.

@ohif/app usage

We use the sopClassHandlerModules in DisplaySetService where we transform instances from the raw metadata format to a OHIF displaySet format. You can read more about DisplaySetService here.