QSMbly: Browser-Based Quantitative Susceptibility Mapping

A complete Quantitative Susceptibility Mapping (QSM) pipeline that runs entirely in your web browser using WebAssembly. No installation, no backend servers, no data uploads — just pure client-side MRI processing.

ACCESS QSMbly HERE

Features

• Completely Private: All processing happens locally in your browser — your data never leaves your computer
• Zero Installation: No Python, MATLAB, or specialized software required
• Cross-Platform: Works on Windows, macOS, Linux, and even mobile devices
• Interactive: Real-time visualization with NiiVue, adjustable contrast, and masking thresholds
• Portable: Static files can be hosted anywhere (GitHub Pages, local server, etc.)
• Comprehensive: 20+ algorithms covering the complete QSM pipeline

Algorithms

QSMbly's QSM algorithms are provided by QSM.rs, a standalone Rust library compiled to WebAssembly. See the QSM.rs README for a complete list of supported algorithms with citations.

Quick Start

Option 1: Use Online

1. Visit qsmbly.neurodesk.org
2. Upload DICOM files or NIfTI magnitude/phase images
3. Set acquisition parameters (Echo Time, Field Strength)
4. Run the pipeline

Option 2: Run Locally

git clone https://github.com/astewartau/qsmbly.git
cd qsmbly
./run.sh
# Open http://localhost:8080

Building from Source

Prerequisites

1. Install Rust: https://rustup.rs/
2. Install wasm-pack:

   cargo install wasm-pack

Build and Run

# Standard build (maximum browser compatibility)
./build.sh

# SIMD-accelerated build (faster, requires modern browsers)
./build.sh --simd

# Start development server
./run.sh

SIMD Acceleration

The --simd flag enables 128-bit SIMD vectorization for faster processing of iterative algorithms. This provides approximately 2-4x speedup for element-wise operations.

Browser	Minimum Version
Chrome	91+ (May 2021)
Firefox	89+ (June 2021)
Safari	16.4+ (March 2023)
Edge	91+ (May 2021)

Running Tests

npm install
npm test

Repository Structure

qsmbly/
├── index.html              # Main application interface
├── build.sh                # WASM build script
├── run.sh                  # Development server
├── test.sh                 # Rust test runner
├── js/
│   ├── qsm-app-romeo.js    # Main application logic
│   ├── qsm-worker-pure.js  # Web worker for pipeline execution
│   ├── app/
│   │   └── config.js       # Centralized configuration
│   ├── controllers/        # UI controllers (file I/O, pipeline, viewer, etc.)
│   ├── modules/            # UI modules (NIfTI utils, masking, viewer)
│   └── workers/            # Web workers (DiCompare)
├── css/
│   └── modern-styles.css   # Application styling
├── wasm/                   # Compiled WebAssembly (served to browser)
├── rust-wasm/              # WASM binding layer
│   ├── Cargo.toml          # Depends on qsm-core
│   └── src/lib.rs          # Thin wasm_bindgen wrappers (59 exports)
├── dcm2niix/               # DICOM-to-NIfTI conversion (WASM)
├── schemas/                # DiCompare validation schemas
├── niivue/                 # NiiVue neuroimaging viewer
└── nifti-js/               # NIfTI reader (JavaScript)

Technical Stack

• QSM.rs: Core QSM algorithms (Rust, compiled to WebAssembly)
• wasm-bindgen: JavaScript/WASM interop
• NiiVue: WebGL neuroimaging viewer
• dcm2niix: DICOM conversion (WASM build)
• Pyodide: Python in browser (for DiCompare validation)

License

This project is licensed under the MIT License — see the LICENSE file for details.

Issues & Support

• Bug Reports: GitHub Issues
• Feature Requests: GitHub Discussions