Yeah you kinda have more data but it’s misleading bc you don’t have more region-specific subject variability. Data is definitely an issue… I train on a lot of subjects (a few thousand) from multiple large datasets… Also, the KEY to MRI segmentation is data augmentation and applying random affine transforms specifically since images differ that way across scanners - hence why I developed torchsample. With good augmentation we have done quite well with ~200 subjects.