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Format guide

DICOMDIR: what it is and how to open it on iPhone, iPad or PC

DICOMDIR is the index file at the root of a medical imaging CD, DVD or USB stick. It lists which DICOM files belong to which patient, study and series. To view it on iPhone or iPad, copy the entire disc folder — DICOMDIR plus the image folders next to it — to Files and import the folder in Ossidex. Full disc walkthrough: open a DICOM CD on iPhone or iPad.

By the Ossidex team · How we write and check these pages · Updated

Download on the App StoreFree to download · iPhone & iPad · iOS 17+

Typical disc layout

DISC/
├── DICOMDIR            ← index
├── DICOM/  (or IMAGES/, DICOMRM/, PAT0001/…)
│   └── … hundreds of image files, often without extension
├── Viewer.exe / autorun.inf   ← Windows viewer (not needed)
└── README / Report.pdf

The DICOMDIR alone contains no images. Copy it together with the folders it references.

Open a DICOMDIR disc on iPhone or iPad

  1. Copy the whole disc. On a Mac or PC, copy the entire disc to a folder (or plug a USB-C stick or card reader into an iPad).
  2. Move it to Files. AirDrop the folder, put it in iCloud Drive, or zip it and send it to yourself.
  3. Import the folder. In Ossidex, tap + → Files, select the folder (not a single file) and import.
  4. Open the study. Ossidex reads the DICOMDIR, groups the series and opens the first one.

“DICOMDIR not found” and other problems

ProblemWhyFix
Only DICOMDIR was copiedThe index points to files that are not thereCopy the whole disc
DICOMDIR is broken or incompleteSome burning software writes invalid indexesOssidex falls back to scanning every file in the folder
Only a single DICOMDIR file was sentSender attached just the indexAsk for the full folder as a ZIP
Disc has only an .exeImages may be inside a self-extracting archiveRun it on Windows or ask the clinic for plain DICOM

On a Mac

Macs cannot open DICOMDIR natively. Desktop options include free viewers such as Horos and Weasis. The Ossidex iPad app is also installable on Apple silicon Macs through the App Store (listed as “Designed for iPad, not verified for macOS”). See discs that only have a Windows viewer.

What is inside a DICOMDIR

The DICOMDIR is itself a small DICOM file. It contains a tree of records — patient → study → series → image — and each image record points to a file on the disc by a relative path such as DICOM\PAT00001\STD00001\SER00001\IMG00001. File names on discs are limited to eight upper-case characters without extensions, which is why the images often look like meaningless names.

Import options compared

What you importResult
The whole disc folderBest: DICOMDIR and all images are read
A ZIP or ISO of the discSame result; Ossidex unpacks it first
Only the DICOM/ subfolderWorks — Ossidex scans the files directly
Only the DICOMDIR fileNo images; import the folder instead
Only the Windows viewer (.exe)Ossidex suggests importing the whole folder

Recent versions also handle the most common “it won’t open” cases from real discs: if you pick the disc’s Windows viewer (.exe) instead of the images, Ossidex suggests importing the whole folder; DICOM files without unique identifiers (UIDs) and JPEG images without a file extension are still imported; and helper files that come with the disc viewer no longer trigger a password prompt.

Several patients on one disc

A DICOMDIR can list several patients and studies — common on discs from dental imaging centres that burn a day’s work together. Ossidex imports each patient separately, so the library stays tidy and you can delete what you do not need.

Frequently asked questions

Can I open DICOMDIR without the disc viewer?

Yes. The viewer on the disc is just one program that can read the standard DICOM files; any DICOM viewer, including Ossidex, reads them too.

Do I need the DICOMDIR file at all?

It helps, but Ossidex can build the study from the image files even without it.

Why does Windows show the disc as empty folders?

Hidden or extension-less files can look empty in some file browsers. Copy the whole disc anyway; the images are usually there.

Can I open a DICOMDIR from a USB stick?

Yes. Plug the stick into an iPad (USB-C or with an adapter), then import the folder from the Files app.

Sources

Related pages

  • Open a DICOM CD on iPhone or iPad

    Open a CT, MRI or CBCT disc from a hospital or dental clinic on iPhone or iPad: copy the disc folder, import it in Ossidex, and skip the Windows viewer.

  • Disc with only a Windows .exe viewer

    Dental and hospital discs often ship a Windows-only viewer. The images next to it are standard DICOM — copy the whole folder and open it on iPad, iPhone or Mac.

  • What is a DICOM file? The medical imaging format explained

    DICOM is the standard file format for medical images like CT, MRI and X-ray. What is inside a DICOM file, how studies and series work, and how to open one.

  • Study won’t open: fixes

    Fixes for DICOM studies that will not open: incomplete downloads, only the viewer copied, proprietary files, password archives, portal links, memory.

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