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What to Look for in a Medical Image Annotation Platform in 2025: Who Offers What?

When building AI for radiology or diagnostic imaging, it’s not enough to have annotation tools alone. You need medical image annotation platforms that combine clinical-grade infrastructure, expert reviewers, regulatory alignment, and support for advanced data formats.

Here’s a breakdown of must-have capabilities for medical imaging annotation in 2025, and which platforms do and don’t offer them.

Healthcare professional in pink scrubs analyzes mammography scans on multiple monitors.

This market overview was developed by iMerit using publicly available information and is designed to assist healthcare AI developers and decision-makers in selecting the best radiology annotation tools for their projects.

1. Regulatory-Ready Workflows (HIPAA, 21 CFR Part 11, GxP)

Your AI won’t make it to market without compliant data pipelines. This means auditable workflows, secure access controls, and regulatory documentation. Platforms that provide regulatory frameworks give developers confidence in scaling into clinical deployments.

Offered by:

Ango Hub medical labeling editor showing segmented organs in multiple views with annotation tools.

 

 Not offered by: All Others (V7, Encord, Datature, ITK-Snap, 3D Slicer)

2. Support for Both DICOM and NIfTI Formats

Radiology teams require compatibility with standard medical imaging formats, particularly DICOM annotation for clinical PACS data and NIfTI/NRRD for MRI and fMRI research. Robust format handling allows seamless integration with diagnostic systems and machine learning pipelines.

Offered by:

  • iMerit + Ango Hub
  • V7
  • Encord RedBrick AI
  • ITK-Snap
  • 3D Slicer

Not offered by: Datature

3. Support for 16 Simultaneous DICOM Views

Reviewing complex multi-phase or multi-sequence studies requires the ability to view many images in parallel, essential for temporal comparisons or advanced radiology AI workflows.

Offered by:

  • iMerit + Ango Hub (newly supports up to 16 DICOMs simultaneously)

Not offered by:

  • V7 (offers multi-planar views, but not 16 series)
  • RedBrick AI (multi-series support, but not 16 simultaneous views)
  • Encord, Datature, ITK-Snap, 3D Slicer (no support)

4. In-house Radiologists and Domain Experts

Clinical annotation requires medically trained reviewers, not crowd workers or generic annotators. Platforms without expert-in-the-loop risk producing datasets unsuitable for regulatory approval.

Offered by:

Not offered by:

  • All others (V7, Encord, Datature, RedBrick AI, ITK-Snap, 3D Slicer)

5. Native 3D Multiplanar Annotation

3D multiplanar annotation tools are essential for segmenting CT and MRI scans at diagnostic quality. They allow accurate annotation across coronal, sagittal, and axial planes simultaneously.

Offered by:

  • iMerit + Ango Hub
  • RedBrick AI
  • ITK-Snap
  • 3D Slicer
  • V7

Not offered by:

  • Encord
  • Datature

6. 3D Volume Rendering

Beyond slice-by-slice annotation, volumetric visualization enhances segmentation workflows and supports tumor tracking, organ segmentation, and pathology mapping.

Offered by:

  • iMerit + Ango Hub
  • RedBrick AI (partial, not pixelwise)
  • ITK-Snap
  • 3D Slicer

Not offered by:

  • V7
  • Encord
  • Datature

7. Collaboration & Review Tools

Features like edge-case flagging, issue tracking, and real-time comments improve annotation accuracy and speed. Platforms with integrated review pipelines ensure that datasets undergo multi-level QC before use in radiology AI training.

Offered by:

  • iMerit + Ango Hub
  • V7
  • Encord
  • RedBrick AI

Not offered by:

  • Datature
  • ITK-Snap
  • 3D Slicer

8. Smart Automation Tools

Automation features like thresholding, voxel-based segmentation, or AI-assisted pre-labeling, help reduce manual work while maintaining dataset quality. These are critical for scaling medical image annotation projects.

Offered by:

  • iMerit + Ango Hub (level tracing, 3D cuboid brush, scissors, island remove/keep, hole fill, and more)
  • V7
  • Datature
  • RedBrick AI
  • 3D Slicer

Not offered by:

  • Encord
  • ITK-Snap

9. Workforce Management & Quality Control

Project-level task assignment, reviewer arbitration, consensus scoring, and multi-tier QC audits are essential for ensuring annotation reliability.

Offered by:

  • iMerit + Ango Hub
  • V7
  • Encord
  • Datature
  • RedBrick AI

Not offered by:

  • ITK-Snap
  • 3D Slicer

10. Model Integration for Active Learning

Platforms that ingest model predictions and update annotations dynamically allow faster iteration, critical for experimental pipelines in radiology AI and precision diagnostics.

Offered by:

  • iMerit + Ango Hub
  • V7
  • Datature
  • 3D Slicer

Not offered by:

  • Encord
  • RedBrick AI
  • ITK-Snap

Medical Image Annotation Platforms: Capability Comparison

Capability iMerit + Ango V7 Encord Datature RedBrick AI ITK-Snap 3D Slicer
Regulatory-Ready Workflows ✅ ❌ ❌ ❌ ✅ (510(k)) ❌ ❌
In-house Radiologists / Experts ✅ ❌ ❌ ❌ ❌ ❌ ❌
DICOM/NIfTI Support ✅ ✅ ✅ ❌ ✅ ✅ ✅
16 Simultaneous DICOM View Support ✅ ❌ ❌ ❌ ❌ ❌ ❌
Native 3D Multiplanar Annotation ✅ ✅ ❌ ❌ ✅ ✅ ✅
3D Volume Rendering ✅ ❌ ❌ ❌ ✅ (partial) ✅ ✅
Collaboration & Review Tools ✅ ✅ ✅ ❌ ✅ ❌ ❌
Smart Tool Automation ✅ ✅ ❌ ✅ ✅ ❌ ✅
Task & Workforce Management ✅ ✅ ✅ ✅ ✅ ❌ ❌
Model Integration / Feedback Loop ✅ ✅ ❌ ✅ ❌ ❌ ✅

Why iMerit Leads in 2025

iMerit is the only provider combining tooling, expert workforce, and regulatory workflows. If you’re building radiology AI and need:

  • Multi-sequence, multi-view imaging workflows
  • Domain-trained expert reviewers
  • HIPAA and 21 CFR Part 11 alignment
  • Custom QA and arbitration
  • Platform + people, not just software

iMerit with the Ango Hub Platform is your all-in-one solution.

Schedule a Demo to learn more about how iMerit’s medical annotation services accelerate AI development across radiology.

Explore more about our medical imaging annotation suite.