Every DICOM Format This Viewer Opens
Updated July 2026 · 8 min read
"Supports DICOM" is one of the least informative claims a viewer can make. DICOM is not a single file format — it is a family of transfer syntaxes, dozens of modality-specific object types, and a set of "retained" non-image objects that most mobile apps silently drop. A patient CD can contain a CT volume compressed with JPEG 2000, a radiotherapy structure set, a presentation state that carries the radiologist's annotations, and a PDF report — and a viewer that only handles the first of those is showing you a fraction of the study. This page lists precisely what MedScan decodes and renders on iPad and iPhone, entirely on-device.
Transfer Syntaxes and Codecs
The transfer syntax defines how pixel data is encoded inside a DICOM file. Get this wrong and a viewer either refuses the file or shows garbage. MedScan decodes all mainstream syntaxes:
| Codec | Typical source | Notes |
|---|---|---|
| Uncompressed (Explicit/Implicit VR Little Endian) | Raw pixel data; default for many CT/MR archives | Largest files, fastest decode |
| JPEG Baseline (8-bit) | Ultrasound, secondary capture, some X-ray | Lossy; universal compatibility |
| JPEG Lossless | CR/DX radiography, archives that must preserve every bit | Bit-exact reconstruction |
| JPEG-LS | High-throughput lossless archives | Faster than JPEG 2000 at similar ratios |
| JPEG 2000 | Modern PACS, CBCT exports, WSI pyramids | Lossless and lossy modes; wavelet-based |
| RLE | Legacy archives, some ultrasound and NM | Simple run-length lossless scheme |
In practice this means studies exported from any mainstream CT, CBCT, MRI, or radiography system — and anything a standards-compliant PACS serves over DICOMweb — open without transcoding. For background on how transfer syntaxes fit into the standard, see the DICOM format guide.
Retained Objects: The Part Most Mobile Viewers Skip
Beyond images, DICOM defines objects that carry derived or presentation information. They are the difference between seeing pixels and seeing the study as it was actually read and processed. MedScan renders all of the following:
Why this matters: if a colleague sends a CT with a SEG produced by a research tool, or an oncology case arrives with RTSTRUCT contours, a viewer that ignores those objects makes the accompanying images borderline useless. GSPS is the sneakiest of the group — a study can look "wrong" (odd windowing, missing arrows) simply because the viewer never applied the presentation state that came with it. MedScan applies GSPS live, on top of the referenced images, and lets you toggle it.
Multiframe and Cine
Ultrasound clips, angiography (XA) runs, fluoroscopy loops, and cardiac cine MRI arrive as multiframe objects — one DICOM instance containing dozens or hundreds of frames. MedScan plays these with cine controls and frame-accurate scrubbing, and every individual frame remains available to the measurement tools: calibrated millimeter distances and HU ROI statistics, with annotations stored per slice.
Volumes: MPR, 3D, and PET/CT Fusion
Cross-sectional series are treated as true volumes, not slice stacks. MedScan reconstructs axial, sagittal, coronal, and free oblique planes, with slab projections (MIP, MinIP, Average) for vessels and airways, plus full 3D volume rendering. Co-registered PET and CT series fuse into a single blended view for metabolic-plus-anatomic reading, and two studies — say, a current CT and a prior — can be reviewed in side-by-side comparison. For dental work, the same volume engine drives the arch-curve panoramic reformat with cross-sections described in the dental CBCT guide.
Whole-Slide Imaging (WSI)
Digital pathology slides in DICOM WSI form are tiled, pyramidal images that routinely exceed a gigapixel. MedScan navigates them with deep-zoom rendering — smooth pan and zoom from whole-slide overview down to cellular detail — the same interaction model as desktop slide viewers, on an iPad.
Import and Export Paths
- Import: ZIP archives, DICOMDIR structures, plain folders, and patient CDs — via Files, AirDrop, cloud drives, or directly from a PACS over DICOMweb (QIDO-RS/WADO-RS).
- Export: DICOM Secondary Capture, so an annotated view can be saved back as a standards-compliant DICOM object.
- Privacy: every decode and render happens on-device. No account, no cloud upload, fully offline.
What MedScan Does Not Do
Honest limits, stated plainly: MedScan reads DICOM only — no NIfTI or other research formats. It performs no AI analysis and offers no diagnostic conclusions; it is a professional viewer and measurement tool, and it is not a medical device.
FAQ
Which DICOM compression codecs can MedScan decode?
JPEG 2000 (lossless and lossy), JPEG Lossless, JPEG-LS, baseline 8-bit JPEG, and RLE, plus uncompressed little-endian transfer syntaxes. That covers the overwhelming majority of studies exported by modern CT, CBCT, MRI, and X-ray equipment and by PACS archives.
Does MedScan open DICOM SEG segmentations?
Yes. DICOM Segmentation objects (SEG) are rendered as colored label overlays on the source images, so segmentations produced by research pipelines or contouring workstations can be reviewed slice by slice on the iPad.
Can MedScan display RTSTRUCT and RTDOSE from radiotherapy planning?
Yes. RT Structure Sets are drawn as contour overlays on the referenced CT slices, and RT Dose objects are rendered so dose distributions can be reviewed alongside the anatomy. MedScan is a viewer, not a planning system, and is not a medical device.
What is GSPS and how does MedScan handle it?
A Grayscale Softcopy Presentation State stores how an image was presented — window/level, annotations, shutters, spatial transforms. MedScan applies GSPS as a live overlay on the referenced images, so you see the study the way the original reader saw it.
Does MedScan open DICOM Structured Reports and encapsulated PDFs?
Yes. Structured Reports (SR) are parsed and displayed as readable reports, and PDFs encapsulated in DICOM wrappers open directly — common for dose reports, referral letters, and echo measurements shipped on patient CDs.
Can MedScan play multiframe and cine series?
Yes. Multiframe objects — ultrasound clips, XA/fluoroscopy runs, cardiac cine MRI — play back with cine controls, and single frames remain available to the measurement tools.
Does MedScan support whole-slide microscopy images?
Yes. DICOM Whole Slide Imaging (WSI) pyramids are rendered with deep-zoom navigation, so multi-gigapixel pathology slides can be panned and zoomed smoothly on an iPad.
Does MedScan open NIfTI or analyze images with AI?
No. MedScan is dedicated to the DICOM standard and does not read NIfTI. It also performs no AI analysis or diagnosis — it is a professional viewer with measurement tools, and it is not a medical device.