Module: SOP Class Handler

Overview

This module defines how a specific DICOM SOP class should be processed to make a displaySet, something that 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,
}

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,
];

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}`,
  });

  return imageSet;
};

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

More examples :

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

@ohif/viewer 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.