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📂 Dataset Release: Training Batch 1 (N = 955)

The first batch of the ISLES'26 dataset is now available for model training and local development. This release consists of the Training and (previously labelled as) Validation sets from the ATLAS v2.0 archive.

[!NOTE] For the purposes of ISLES'26, ALL scans in this batch and the 2nd batch (still to come) are intended for training. We are releasing the "old" ATLAS v2.0 validation set with masks included to provide participants with a larger, more diverse training pool.

🔗 Data Download

Participants can access the files through the following link:

NITRC: ATLAS v2.0 Download Portal


⚠️ Critical Requirement: Use RAW Data

The ISLES'26 challenge focuses on algorithms operating in native space. * Mandatory: You must download and use the "Raw Data" folder. * Note: Do not use standardized or normalized versions of the dataset, as the official challenge evaluation will occur exclusively on raw, native-space MRI.


📝 Key Information

This release contains significant updates from the original ATLAS v2.0 publication:

  • Native Format: All images are provided in their raw native coordinate system.
  • Release of Validation Masks: Unlike the original ATLAS v2.0 publication, this release includes lesion masks for the old validation set, making them available for your training pipelines.
  • Skull-Stripped: All images have already been skull-stripped; no additional brain extraction is required.


📁 Batch #1 Summary

Feature Details
Total Scans 955
Challenge Phase Training Data (Includes ATLAS v2.0 Train + Validation)
Image Space Native / RAW
Preprocessing Skull-stripped
Annotations Lesion masks included for all subjects

[!TIP] Ensure your processing pipeline is designed to handle varying orientations and resolutions inherent to native-space (RAW) clinical data.