MIQ is a lightweight macOS QuickLook extension for medical volume images. Press Space on a supported file in Finder to instantly get an interactive orthogonal slice view alongside a metadata panel. A Windows counterpart, MIQ-Win, is also available.
See it in action in the short video at the bottom of this page.
- Instant, interactive preview — press Space for the 2×2 orthogonal slice and metadata view
- Built for speed — memory-mapping, partial decompression, and network volumes read only what's needed for the first preview
- 4D support — scrub through timepoints/volumes interactively
- Segmentation coloring — including automatic label-color detection for FreeSurfer-style parcellations
- Finder thumbnails — optional file-icon slice previews while browsing
- Fully configurable — orientation display, intensity windowing, label colors, and metadata panel content/order, all from the main app
Supported formats:
- ✅ NIfTI-1 & NIfTI-2 —
.nii,.nii.gz - ✅ FreeSurfer —
.mgh,.mgz,.mgh.gz - ✅ MRtrix —
.mif,.mif.gz - ✅ NRRD —
.nrrd(only the single-file variant with attached header)
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 and extension can be installed manually or via the package manager Homebrew.
The app is a universal binary for Apple Silicon (arm64) and Intel (x86_64) Macs and has been tested on macOS 14 (Sonoma), 15 (Sequoia), and 26 (Tahoe).
- 👉 Download the latest release (MIQ.app.zip)
- Unzip and move
MIQ.appto your/Applicationsfolder. - Open
MIQ.appat least once to register the Quick Look extension. - Press Space on any supported file in Finder.
- Optional: Customize the preview in the MIQ app.
MIQ updates itself. Open the MIQ app and choose MIQ → Check for Updates…, or leave Automatically check for updates enabled in Settings → About. MIQ only runs while its window is open, so checks happen when you open it; when a new version is available, MIQ downloads and installs it in place and relaunches. No manual download or replacing of MIQ.app is needed.
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Install on the command line:
brew tap marcoduering/miq brew trust --cask marcoduering/miq/miq brew install --cask miq
-
Open
MIQ.app(in/Applications) at least once to register the Quick Look extension. -
Press Space on any supported file in Finder.
-
Optional: Customize the preview in the MIQ app.
The cask is marked auto_updates, so the app updates itself via MIQ → Check for Updates… (see above). To update through Homebrew instead:
brew update
brew upgrade --cask miq --greedyMIQ 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.
Use the settings (main app) to tailor the preview and thumbnails to your needs. The app's Usage panel documents the full set of preview and 4D-scrubbing gestures.
By default, MIQ displays data as stored on disk, without reorienting. Images may appear upside down, mirrored, or rotated depending on acquisition. This is by design, so you can inspect the raw data as-is. Optional settings reorient to Neurological or Radiological view.
macOS Quick Look routes files to extensions by file name suffix. Several kinds of tools, including archive utilities, source-code viewers, and format-specific extensions like MIQ, need to claim the broad .gz suffix to support compound extensions such as .nii.gz/.mif.gz. When more than one installed extension claims .gz, which one macOS shows isn't always consistent; this is general Quick Look behavior, not specific to MIQ. If a gzip-compressed file isn't opening with MIQ's preview, try deactivating other .gz-handling extensions.
MIQ is free and open source, in active development, and was created with the support of AI coding agents. Report issues or feature suggestions via GitHub Issues, or see CONTRIBUTING.md to contribute. If MIQ is useful to you, consider sponsoring the project (entirely optional, always appreciated).
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.