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Version: Version 3.2 - Cornerstone3D Volume API 🚧

Module: Data Source

Overview

The internal data structure of OHIF’s metadata follows naturalized DICOM JSON, A format pioneered by dcmjs. In short DICOM metadata headers with DICOM Keywords instead of tags and sequences as arrays, for easy development and clear code.

We have built a standard for fetching and mapping data into OHIF’s native format, which we call DataSources, and have provided one implementation of this standard.

You can make another datasource implementation which communicates to your backend and maps to OHIF’s native format, then use any existing mode on your platform. Your data doesn’t even need to be DICOM if you can map some proprietary data to the correct format.

The DataSource is also a place to add easy helper methods that platform-specific extensions can call in order to interact with the backend, meaning proprietary data interactions can be wrapped in extensions.

const getDataSourcesModule = () => [
{
name: 'exampleDataSource',
type: 'webApi', // 'webApi' | 'local' | 'other'
createDataSource: dataSourceConfig => {
return IWebApiDataSource.create(/* */);
},
},
];

Default extension provides two main data sources that are commonly used: dicomweb and dicomjson

import { createDicomWebApi } from './DicomWebDataSource/index.js';
import { createDicomJSONApi } from './DicomJSONDataSource/index.js';

function getDataSourcesModule() {
return [
{
name: 'dicomweb',
type: 'webApi',
createDataSource: createDicomWebApi,
},
{
name: 'dicomjson',
type: 'jsonApi',
createDataSource: createDicomJSONApi,
},
];
}

Custom DataSource

You can add your custom datasource by creating the implementation using IWebApiDataSource.create from @ohif/core. This factory function creates a new "Web API" data source that fetches data over HTTP.

You need to make sure, you implement the following functions for the data source.

platform/core/src/DataSources/IWebApiDataSource.js
function create({
query,
retrieve,
store,
reject,
parseRouteParams,
deleteStudyMetadataPromise,
getImageIdsForDisplaySet,
getImageIdsForInstance,
}) {
/* */
}

You can take a look at dicomweb data source implementation to get an idea extensions/default/src/DicomWebDataSource/index.js

Static WADO Client

If the configuration for the data source has the value staticWado set, then it is assumed that queries for the studies return a super-set of the studies, as it is assumed to be returning a static list. The StaticWadoClient performs the search functionality manually, by interpreting the query parameters and then applying them to the returned response. This functionality may be useful for other types of DICOMweb back ends, where they are capable of performing queries, but don't allow for querying certain types of fields. However, that only works as long as the size of the studies list isn't too large that client side selection isn't too expensive.

DicomMetadataStore

In OHIF-v3 we have a central location for the metadata of studies, and they are located in DicomMetadataStore. Your custom datasource can communicate with DicomMetadataStore to store, and fetch Study/Series/Instance metadata. We will learn more about DicomMetadataStore in services.