MIQ is a lightweight macOS QuickLook preview extension for medical volume images stored in common research formats. Press Space on a supported file in Finder to instantly see an orthogonal slice view alongside a metadata panel.
Inspired by the old and deprecated DTI-TK Quick Look plugin by Gary Hui Zhang, which brought similar functionality to older versions of macOS but is incompatible with the Quick Look extension architecture of current macOS versions (support for the plugin was dropped in macOS 15 Sequoia).
- ✅ NIfTI-1 & NIfTI-2 —
.nii,.nii.gz - ✅ FreeSurfer —
.mgh,.mgz,.mgh.gz - ✅ MRtrix —
.mif,.mif.gz
All formats are supported uncompressed and gzip-compressed. The extension relies on the file extension to determine the format, so it is important that files have the correct extensions.
The app is universal for Apple Silicon (arm64) and Intel (x86_64) Macs and has been tested on Apple Silicon with macOS 14 (Sonoma), 15 (Sequoia), and 26 (Tahoe).
- 👉 Download the latest version (MIQ.app.zip)
- Extract the ZIP file and copy/move MIQ.app to your
/Applicationsfolder. - Open MIQ.app at least once to register the Quick Look preview extension.
- Press Space on any supported file in Finder.
- Optional: Configure preview settings in the MIQ app.
Tip
Staying up to date: To receive an email notification when a new release is published, click Watch → Custom → Releases at the top of this GitHub page.
MIQ is a lightweight convenience tool for quickly inspecting medical image files directly from the Finder. It prioritizes speed and ease of use over advanced visualization, and is not meant to replace dedicated medical image viewers.
By default, MIQ displays data as stored on disk, without reorienting. Depending on acquisition and processing, images may appear upside down, mirrored, or rotated. This is intentional, so you can inspect the raw data and its orientation. If desired, there is a setting to reorient to RAS or LAS. For multi-volume (4D) data, only the first volume is shown.
Previews are designed to appear almost instantly. Uncompressed files (.nii, .mgh, .mif) are memory-mapped and impose essentially no load time regardless of size. Compressed files (.nii.gz, .mgz, .mif.gz) require decompression before rendering and very large compressed volumes may take a few seconds to load.
macOS assigns Quick Look extensions to file types based on their extensions. Since .gz is a generic extension shared by many file types, MIQ must claim it broadly to handle .nii.gz and .mif.gz files. This can interfere with other Quick Look extensions that also manage .gz files (for example, extensions for compressed archives or source code).
The most recently installed extension should have priority, but this does not work consistently. You might need to deactivate another extension to reliably open gzip-compressed files with MIQ. This is a known limitation of how macOS Quick Look handles compound extensions like .nii.gz.
The extension is still in development. It was created with the support of AI coding agents. Please report any issues using GitHub Issues. If you would like to contribute, see CONTRIBUTING.md or feel free to reach out.
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PLANNED: Improved performance for compressed formats - Under consideration: Support for additional compressed formats (e.g.
.zst,.bz2). - Under consideration: Software distribution via Homebrew.
- Under consideration: Display of sform and qform orientation information
- Under consideration: Support for additional image formats. Please provide feedback if you have any requests.
- Under consideration (long term): Interactive preview.
MIQ is provided "as is" under MIT License, without warranty of any kind, express or implied. The authors and contributors accept no liability whatsoever for any direct, indirect, incidental, special, or consequential damages arising from the use or inability to use this software, including but not limited to data loss, incorrect image rendering, or any decisions made on the basis of previews generated by this tool.
Caution
This software is not a medical device and is not intended for diagnostic use. It is a developer and researcher convenience tool only. Do not use it to make clinical decisions.