Viewer Overview
Flywheel includes an integrated medical image viewer that lets you open, inspect, and annotate images directly in the platform without leaving your workflow.
V2 viewer VS V3 viewer
Flywheel currently offers two viewers: the V2 viewer and the V3 viewer. Both are built on the OHIF Viewer open-source framework, but they differ in their underlying technology, user interface, supported image formats, and available features. The V3 viewer features a completely redesigned interface developed by Flywheel, offering a significantly improved user experience compared to the V2 viewer.
The V2 viewer is currently the default viewer on most Flywheel sites. The V3 viewer is available as a secondary viewer on all sites running Flywheel v19.3 or later. Sites can configure the V3 viewer as their default viewer — contact your sales representative for more information.
The V3 viewer is the recommended viewer for most use cases. It is actively developed and is the only viewer that supports 21 CFR Part 11 compliant workflows.
The V2 viewer is the legacy viewer. It is in maintenance mode — no new features are being developed — and is planned for deprecation in the future. It remains available for workflows that require non-DICOM image formats or specific features not yet available in the V3 viewer.
Comparison
| V3 viewer | V2 viewer | |
|---|---|---|
| Status | Actively developed | Legacy — maintenance only |
| Recommended for | Most use cases | Non-DICOM formats; V2-specific features |
| OHIF version | V3 | V2 |
| Rendering | 3D, GPU-accelerated (Cornerstone3D) | Primarily 2D (Cornerstone) |
| Image formats | DICOM | DICOM, NIfTI, TIFF, PNG, JPEG, MHD/RAW |
| Image loading | Faster — no indexing required | Slower — DICOM indexing required |
| 21 CFR Part 11 compliant | Yes | No |
| MPR and 3D rendering | Yes | MPR only |
| 2D annotations | Yes | Yes |
| 3D segmentations | Yes | Limited |
| TMTV mode | Yes | No |
| Reader tasks | Yes | Yes |
| Viewer configuration | Limited | Extensive |
V3 viewer
The V3 viewer is built on OHIF v3 and Cornerstone3D, providing full 3D, GPU-accelerated rendering. It supports multi-planar reconstruction (MPR), 3D volume rendering, 2D annotations, 3D segmentations, and a dedicated TMTV mode for PET/CT oncology workflows. The viewer interface has been fully redesigned by Flywheel to deliver a modern, intuitive user experience. New viewer features are developed exclusively for the V3 viewer.
Key characteristics of the V3 viewer:
- No DICOM indexing required — images open faster than in V2
- No UID uniqueness constraints — duplicate DICOM UIDs within a project do not prevent images from opening
- DICOM only — non-DICOM image formats are not yet supported
V2 viewer
The V2 viewer is the legacy viewer, built on OHIF v2 and Cornerstone. It is in maintenance mode — critical fixes are applied but no new features are being developed. Flywheel plans to deprecate the V2 viewer in a future release.
DICOM data must be indexed before it can be opened in the V2 viewer.
Consider using the V2 viewer when you need to:
- Open non-DICOM image formats such as NIfTI, TIFF, PNG, JPEG, or MHD/RAW
- Use hanging protocols to automatically arrange multi-series studies in the viewer
- Access ophthalmology-specific tools such as the interactive ETDRS grid, fundus rings, scale display, or bslices workflow
- Use advanced viewer configuration options not yet available in the V3 viewer
Other viewers
Flywheel also supports two specialized viewers for specific data types:
- BrainBrowser — for visualizing 3D brain surface objects (
.objfiles) - Montage viewer — for viewing ultra-dense image sets packaged as montage zip files