← all work 3d-computer-vision

Volumetric segmentation

BraTS 2020 is 368 multi-modal brain MRI volumes with three annotated tumour subregions.

Result

The finding

The headline metric is blind to the failure that matters

On 6 of the 55 test patients the enhancing-tumour Dice is exactly 0.0000 — the model and the annotation share no enhancing voxel at all. The whole-tumour score does not notice:

Whole tumour falls by 0.02. Tumour core falls by 0.40. **Five of those six patients still clear the 0.80 whole-tumour bar.**

Case 361 is the clearest: a whole-tumour Dice of 0.8735, above the bar, with a tumour core of 0.0322. Whole tumour is the union of all three labels, and that union is dominated by peritumoural oedema — the largest and most separable region. A model can own the oedema and miss the enhancing rim entirely while the headline barely moves.

Had this project reported one number, it would have reported 0.8734 and been wrong about what the model does.

Elsewhere

Code and full results on GitHub

Every number is read from the file the run produced. github.com/hammasbuilds · kaggle.com/muhammadhammas13