How to Open DICOM Images From a Hospital CD or USB

What's on a Typical Imaging Disc

Discs follow a common layout defined by the DICOM standard for media, although every vendor adds its own extras:

Image files frequently have names like IM000001 or I0000123 with no extension. That's normal; viewers identify them from their contents.

Why the Bundled Viewer Often Fails

The program on the disc was built to start automatically on Windows. It often fails because:

• Autorun is disabled on modern Windows for security, so nothing starts when you insert the disc.
• You're on a Mac, Chromebook or tablet, and the program only runs on Windows.
• The viewer is old and doesn't work on current Windows versions.
• Security software blocks it, because running programs from removable media is a common attack route.
• There's no disc drive on your computer at all.

None of these affect the images themselves.

Step 1: Copy the Disc to Your Computer

Working from a copy is faster than reading a disc repeatedly, and it protects you if the disc gets scratched.

1. Insert the disc, or connect an external USB disc drive if your computer lacks one.
2. Open the disc in File Explorer (Windows) or Finder (Mac). If a viewer pops up, close it.
3. Create a new folder, for example CT 2026-10, and copy everything from the disc into it.
4. Check that the copy is about the same total size as the disc's contents.

Don't rename, sort or delete files inside the DICOM folder. Viewers rely on the files' contents, and DICOMDIR relies on the exact paths.

If you don't have a disc drive at all, ask the imaging department whether they can provide a USB stick or secure download link instead; many now do.

Step 2: Open the Images in a Viewer

In the Browser

You can open the copied DICOM folder in a browser-based viewer:

1. Choose Open folder and select the folder you copied (or select its DICOM subfolder).
2. The viewer reads each file, skips anything that isn't an image, and groups images into studies and series.
3. Pick a series and scroll through the slices.

If your browser doesn't support folder selection, compress the folder into a ZIP and open that instead. Files are decoded on your device rather than uploaded. Large studies need enough memory, so close other heavy tabs; the viewer handles up to about 3,000 files or 1.5 GB per session.

In a Desktop Viewer

Desktop viewers such as Weasis, Horos or RadiAnt can import the folder or read the DICOMDIR directly. How to open DICOM files compares the options.

Troubleshooting Common Problems

The Viewer Says Some Files Aren't DICOM

That's expected. Discs include the viewer program, its libraries, autorun files and PDFs. A good viewer skips them and reports how many were ignored.

There Are Several Series and You Don't Know Which Is Which

A study often includes scout images (a quick overview used to plan the scan), several sequences or reconstructions, and sometimes the same images at different slice thicknesses. The series description, from the file's metadata, gives each one a name. What a DICOM file is explains studies and series.

Images Look Too Dark or Too Bright

Adjust the window and level, or use a preset. See DICOM window and level.

Some Images Won't Display

A few discs contain compressed formats or video clips a particular viewer can't decode. Try a different viewer for those series.

The Disc Won't Read at All

Try another drive, clean the disc gently, or request a new copy from the imaging provider. Discs degrade, so keeping a copy on your computer or a backup drive is worthwhile.

Keep Your Images Private

Imaging discs contain personal health information in every file: name, date of birth, patient ID and often the hospital's details. Store copies somewhere private, and think twice before uploading them to sites that process files on their servers. Read what patient information is stored in DICOM files before sharing images with anyone outside your care team.

Summary

Ignore the bundled viewer, copy the entire disc, and open the copied folder in any DICOM viewer. The images are standard DICOM files, so they'll work on Windows, Mac, Chromebook or tablet.