MRIcroGL

MRIcroGL is a free volume viewer for medical images, built by Chris Rorden’s lab for neuroimaging researchers. It also opens any 3D DICOM series, which is why dental researchers, students and clinic IT staff look for an MRIcroGL download when they want to see a CBCT volume as a rendered 3D model without buying software.

Be clear about what it is: a research tool, not a dental practice product. It has no patient database, no implant library and no dental reporting, and the project does not claim regulatory clearance for diagnosis. Use it for exploring, teaching and research, and keep clinical decisions in your cleared planning software.

MRIcroGL at a glance

What it does

• Shows 2D slices and 3D volume renderings of the same dataset, using single-pass GLSL raycasting on the graphics card.
• Reads NIfTI (its native format), DICOM, MGH/MGZ, MHD/MHA, NRRD, AFNI and several other formats.
• Includes a graphical front end for converting DICOM series to NIfTI with the dcm2niix converter.
• Lets you draw regions of interest on a volume and save them as separate images.
• Works with drag and drop: drop a folder or file on the window and the volume opens.
• Has a built-in scripting language, so a rendering setup (camera angle, colour scheme, clipping) can be repeated exactly for many scans.
• Runs on a normal laptop as long as the graphics driver supports OpenGL 2.1; the source can also be built for OpenGL 3.3 Core.

How dental teams use it

Dental use is indirect. MRIcroGL does not know that a scan is a jaw, but a CBCT export is an ordinary 3D DICOM series, so the viewer handles it like any other volume.

Look at a CBCT volume without the vendor viewer

1. Export the CBCT study as DICOM from your imaging software.
2. Start MRIcroGL and drag the folder, or one file of the series, onto the window.
3. Switch between slice views and the rendered 3D view, and change the colour and opacity settings until bone and teeth stand out.

Prepare data for research

1. Open the DICOM series and use the converter dialog to write a NIfTI file.
2. Check that orientation and slice count look right in the viewer.
3. Pass the NIfTI file to your analysis pipeline, for example ITK-based tools or ImageJ / Fiji.

Teach volume rendering

Because it is free, light and scriptable, students can load an anonymised scan on their own computer and learn how window levels, opacity and clipping change what a 3D image shows. Always remove patient identifiers before sharing a scan with students.

Install and first run

• Windows: download the Windows zip from the official project page, extract it and run the executable. Keep the Resources folder next to the program, because some features need it.
• macOS: use the macOS disk image from the project page. The program is built natively for both Intel and Apple Silicon Macs. Because it is not from the App Store, macOS may ask you to confirm the first launch.
• Linux: extract the Linux archive and run the executable; a separate build exists for older Ubuntu releases.
• If the 3D view is black or very slow, update the graphics driver. Remote desktop sessions and virtual machines often lack OpenGL support.

Limitations

• It is not a dental or clinical product: no implant planning, no nerve tracing, no panoramic reconstruction and no patient records.
• The newest release dates from July 2022, so it will not add support for newer vendor-specific DICOM variants by itself. Some vendor CBCT exports may need conversion first.
• It is not cleared for diagnosis. Do not use it as the basis for treatment decisions.
• Documentation and support are community-based, through the project’s discussion forums.

MRIcroGL vs alternatives

If you only need to open patient images in a dental clinic, the vendor viewer that came with your sensor or CBCT unit is the better tool.

FAQ

Is MRIcroGL free?

Yes. It is distributed under a BSD-style open-source licence and costs nothing to download or use.

Where do I get the MRIcroGL download for Windows?

From the official project pages on NITRC or GitHub. Choose the Windows zip, extract it and run the program; it does not need an installer.

Is there MRIcroGL for Linux and Mac?

Yes. Builds for Linux and macOS are published alongside the Windows version, and the Mac build runs natively on Apple Silicon.

Can MRIcroGL convert DICOM to NIfTI?

Yes. It includes a graphical interface for the dcm2niix converter, so you can turn a DICOM series into a NIfTI file from within the program.

Can I use MRIcroGL for dental CBCT?

You can open and render a CBCT DICOM series for viewing or research. It has no dental planning tools and is not cleared for diagnosis.

Does MRIcroGL support scripting?

Yes. It has a built-in scripting language for repeating a rendering setup across many scans.

How do I cite MRIcroGL?

Check the citation guidance on the project’s GitHub and NITRC pages, which list the preferred reference for publications.

What is the difference between MRIcroGL and MRIcron?

Both come from the same lab. MRIcroGL adds fast 3D volume rendering on the graphics card, while MRIcron is the older, simpler slice viewer.

Last checked against official sources: 9 October 2026 (developer website: nitrc.org). Versions and licence terms change — confirm on the developer's site before deploying in a clinic.