Dicom Brush

A TypeScript/JavaScript library for manipulating DICOM images, enabling redaction (masking) of image regions, metadata extraction, and transfer syntax transcoding.

Features

• ImageBrush: Apply redaction areas to DICOM images
• ImageReader: Extract technical metadata and specific frames
• ImageTranscoder: Transcode DICOM files between transfer syntaxes (pack/unpack)
• Utils: Utility functions for DICOM tag manipulation

Installation

Install the package using your preferred package manager:

# Using npm
npm install @cic-it-nancy/dicom-brush

# Using pnpm
pnpm add @cic-it-nancy/dicom-brush

# Using Yarn
yarn add @cic-it-nancy/dicom-brush

Usage

Loading DICOM files

The library uses dcmjs to read and write DICOM files. You first need to obtain a dicomDict object using dcmjs:

import { data } from 'dcmjs';
import { ImageTranscoder, ImageBrush } from '@cic-it-nancy/dicom-brush';

// Load DICOM file using dcmjs
const dicomDict = data.DicomMessage.readFile(blob);

Transcoding

import { ImageTranscoder } from '@cic-it-nancy/dicom-brush';

// Initialise the transcoder (required once)
await ImageTranscoder.init();

// Transcode a DICOM file
const transcoder = new ImageTranscoder(dicomDict);

// Transcode to a different transfer syntax
const result = transcoder.transcode('1.2.840.10008.1.2.1'); // Explicit VR Little Endian

// Helper methods for common operations
const unpacked = transcoder.unpack();  // Unpack to Implicit VR Little Endian
const packed = transcoder.pack();      // Pack to JPEG 2000 Lossless

Redaction

import { ImageBrush } from '@cic-it-nancy/dicom-brush';

const brush = new ImageBrush(dicomDict);

// Add redaction area (x, y, width, height in pixels)
brush.addRedactionArea({
  x: 100,
  y: 100,
  width: 50,
  height: 50
});

// Apply the redaction
brush.apply();

// Get the modified DICOM dictionary
const redactedDicom = brush.getDicomDict();

Reading image information

import { ImageReader } from '@cic-it-nancy/dicom-brush';

const imageInfo = ImageReader.readImageInfo(dicomDict);

console.log(imageInfo.rows);           // Number of rows
console.log(imageInfo.columns);        // Number of columns
console.log(imageInfo.numberOfFrames); // Total frames
console.log(imageInfo.transferSyntaxUID);

Supported Transfer Syntaxes

Transfer syntax support depends on the dcmjs-codecs library, which provides WebAssembly-based codecs. Currently supported:

• Uncompressed:

  • Implicit VR Little Endian (1.2.840.10008.1.2)
  • Explicit VR Little Endian (1.2.840.10008.1.2.1)
  • Deflated Explicit VR Little Endian (1.2.840.10008.1.2.1.99)
  • Explicit VR Big Endian (1.2.840.10008.1.2.2)

• JPEG:

  • JPEG Baseline (1.2.840.10008.1.2.4.50)
  • JPEG Lossless (1.2.840.10008.1.2.4.70)

• JPEG 2000:

  • JPEG 2000 Lossless (1.2.840.10008.1.2.4.90)

• RLE Lossless (1.2.840.10008.1.2.5)

Note: The actual supported transfer syntaxes are determined by dcmjs-codecs. Check the dcmjs-codecs repository for the most up-to-date list.

Technical details

• Build output: CJS (lib/cjs/) and ESM (lib/esm/)
• TypeScript: Strict mode, type declarations available in types/index.d.ts
• Dependencies: dcmjs (0.50.1) for DICOM I/O, dcmjs-codecs (0.0.8) for transcoding

Project structure

dicom-brush/
├── src/          # TypeScript source files
├── lib/
│   ├── cjs/      # CommonJS build
│   └── esm/      # ES Module build
├── types/        # TypeScript type definitions
├── README.md
└── Transfer Syntax.md

Authors & Contributors

• CIC-IT Nancy — Author
• Pierre 'AlasDiablo' M (GitHub) — Contributor

License

GNU Lesser General Public License v3.0 (LGPL-3.0) - CIC-IT Nancy