Features

Built around the DICOM standard

Slim reads images and their derived data from the same DICOMweb archive, and saves annotations back to it. Nothing is stored in a proprietary format.

Display

Whole slide images, brightfield and fluorescence

Vendor-neutral display of DICOM VL Whole Slide Microscopy Image instances, from H&E brightfield to multiplexed immunofluorescence.

Slim renders the tiled image pyramid of a DICOM whole slide image directly in the browser using dicom-microscopy-viewer. There is no server-side rendering and no proprietary format: if the archive serves DICOMweb, Slim can display it.

Interoperability with acquisition and archive systems from several vendors was demonstrated at the DICOM WG-26 Connectathon at Path Visions 2020 and the WG-26 Hackathon at Path Visions 2021.

Brightfield and multichannel fluorescence slides in the same viewer
Per-channel color, window and visibility under Optical paths
ICC color management, gamma and interpolation under Display options
Advanced Blending Presentation States restore a saved channel setup

See it in the demo

Vector annotations

Annotations at the scale of single cells

Display ROI annotations from DICOM Comprehensive 3D SR and millions of cell outlines from Microscopy Bulk Simple Annotations.

Annotations are DICOM objects too. Slim reads them from the same DICOMweb server as the images, matches them to the slide they reference, and lists them in the right-hand panel under Annotations, Annotation groups and Annotation categories.

Comprehensive 3D SR, TID 1500 measurement reports with TID 1410 planar ROIs
Microscopy Bulk Simple Annotations, grouped by label, with show/hide per group
Annotation groups and categories with counts and partial visibility states
Selecting a derived object in the URL loads its slide and turns it on

See it in the demo

Raster results

AI and analysis results as overlays

Overlay segmentations, label maps and parametric maps from image analysis pipelines, with legends and per-segment controls.

Fractional segmentations and parametric maps show a collapsible color legend in the viewport whenever an overlay is visible. Its per-item toggles stay in sync with the switches in the right-hand panel, and opacity is set per segment.

Binary and fractional DICOM Segmentation, including TILED_SPARSE at non-standard resolutions
Labelmap Segmentation (Supplement 243) with one segment per pixel value
Parametric Maps for saliency, attention and class activation maps
In-viewport color legend; click a segment to zoom to its bounding box

See it in the demo

Annotation tools

Draw, measure and save as DICOM

Create region-of-interest annotations with coded findings and store them back to the archive as DICOM Comprehensive 3D SR.

The tool pill compacts on narrow screens, and the Draw dialog keeps its fields when you close and reopen it. Saved annotations are ordinary DICOM SR instances, so other DICOM-aware tools such as highdicom can read them back for analysis. Saving needs a server configured with write: true; the public demo is read-only.

Draw, Modify, Translate, Remove, Hide, Save and Go to from one centered tool pill
Points, lines, boxes, circles, polygons and freehand lines or polygons
Findings coded in SNOMED CT or any terminology your deployment configures
Stored as SCOORD3D in millimeters (TID 1500 and TID 1410) via DICOMweb STOW-RS

See it in the demo

Worklist

A worklist that knows about derived data

Search studies, sort and page through results, and find the ones that hold segmentations, annotations, maps or presentation states.

The Contains filter searches by SOP Class UID at the instance level, and falls back to the series modality on servers that do not support it, such as Google Cloud. Rows on the current page are then checked for slides and the exact SOP class, and results are cached for the session.

Search by patient name, patient ID, study ID or accession number
The Contains filter finds studies with bulk annotations, 3D SR, segmentations, label maps, parametric maps or presentation states
Sortable columns, pagination and compact 32px rows
The Contains filter lives in the URL, so a filtered worklist is a shareable link

Viewer

A viewer layout built for slides

Collapsible side panels, viewport overlays and an overview map keep the slide in focus and the metadata one click away.

Each viewport overlay can be turned off in Preferences. The memory monitor checks usage every few seconds and warns before the browser runs out of room, which matters when several gigapixel slides are open in one session.

Left panel with patient, study and clinical trial details and slide cards with thumbnails
Right panel with slide label, specimens, equipment, optical paths and presentation states
Slide chip, zoom controls, scale bar, magnification and cursor position in millimeters
Footer with tile loading progress and live browser memory monitoring

See it in the demo

Interoperability

Any DICOMweb archive, any identity provider

Slim runs fully client-side in front of any DICOMweb-conformant PACS, VNA or cloud archive, with OpenID Connect sign-in.

There is no Slim backend. The app is a static bundle that talks to your archive with QIDO-RS, WADO-RS and STOW-RS, so it can be hosted on any static web server, a cloud bucket or Firebase Hosting. Authentication uses oidc-client-ts; providers can also be configured at runtime from the server dialog.

Google Cloud Healthcare API, dcm4chee-arc-light, Orthanc and other DICOMweb servers
Switch servers at runtime, including path-only Google Cloud DICOM store paths
OpenID Connect with authorization code + PKCE, or the implicit grant
Upgrades HTTP bulk data URLs to HTTPS when the archive returns internal links

Preferences

Light, dark and yours

Dark by default, light on request, and preferences that apply immediately without reloading the slide.

Preferences, Debug, Server, Tag browser and all viewer dialogs share one header and footer design, so the app feels the same wherever you are in it.

Dark and light themes, or follow the operating system
Annotation stroke style and confirm-before-remove settings
Toggle the overview map, the scale and position card, the slide name and zoom controls
DICOM tag browser and a debug dialog for troubleshooting data

DICOM support

Supported DICOM objects

What Slim can display, create and store, with a public example for each type. Open any row to see that object in the live demo.

DICOM objects supported by Slim, what it can do with each, and a public example from IDC
DICOM object	Display	Create	Store	Try it on IDC data
Slide images
VL Whole Slide Microscopy ImageBrightfield H&E and other stains, with ICC color management 1.2.840.10008.5.1.4.1.1.77.1.6	Yes	No	No	CPTAC-LSCC H&E brightfield slide Open in Slim
VL Whole Slide Microscopy ImageMultiplexed fluorescence Per-channel color, window and visibility 1.2.840.10008.5.1.4.1.1.77.1.6	Yes	No	No	HTAN-HMS Cyclic immunofluorescence (t-CyCIF), multiplexed channels Open in Slim
Vector annotations
Comprehensive 3D SRTID 1500 / TID 1410 ROIs with coded findings, saved via STOW-RS 1.2.840.10008.5.1.4.1.1.88.34	Yes	Yes	Yes	RMS-Mutation-Prediction Expert region annotations stored as Comprehensive 3D SR Open in Slim
Microscopy Bulk Simple Annotations Hundreds of thousands of cells per slide 1.2.840.10008.5.1.4.1.1.91.1	Yes	No	No	TCGA-READ AI nuclei outlines as Microscopy Bulk Simple Annotations Open in Slim
Raster results
SegmentationBinary Including TILED_SPARSE at non-standard resolutions 1.2.840.10008.5.1.4.1.1.66.4	Yes	No	No	TCGA-CESC AI nuclei segmentation, binary DICOM SEG Open in Slim
SegmentationFractional Probability maps with an in-viewport legend 1.2.840.10008.5.1.4.1.1.66.4	Yes	No	No	TCGA-CESC Tumor-infiltrating lymphocyte map, fractional DICOM SEG Open in Slim
Labelmap SegmentationSupplement 243 One segment per pixel value 1.2.840.10008.5.1.4.1.1.66.7	Yes	No	No	No public example in IDC v24 yet.
Parametric Map Saliency, attention and score maps 1.2.840.10008.5.1.4.1.1.30	Yes	No	No	TCGA-GBM Glioma aggressiveness score map, DICOM Parametric Map Open in Slim
Presentation
Advanced Blending Presentation State Restores a saved channel blending setup 1.2.840.10008.5.1.4.1.1.11.8	Yes	No	No	HTAN-HMS t-CyCIF slide with a saved Advanced Blending Presentation State Open in Slim

Examples are public data from the NCI Imaging Data Commons (v24), served through the IDC public proxy under its usage policy. Large slides can take a moment to load. Object names link to their definition in the DICOM standard.