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facebookresearch / fastMRI

A large-scale dataset of both raw MRI measurements and clinical MRI images.
https://fastmri.org
MIT License
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Question about the brain data size of the fastMRI dataset #174

Closed NayeeC closed 2 years ago

NayeeC commented 2 years ago

Hello,

I have a question about the size of the brain data in fastMRI dataset.

I look into the brain data and find that the height and the width are (640, 320), but the brain stays in the middle of the image and looks normal.

However, I try to get some similar data, which has the same size (640, 320), from an MR machine, the brain looks stretched, just like below: image

Did the data in fastMRI dataset acquired from the machine directly? Or maybe the data was acquired in a square k-space originally, and then transform into another size (640, 320)? If it was acquired from the machine directly, how to make it looks normal, not stretched. If some transforms were performed to the data, what are they?

Thank you in advance.

NayeeC commented 2 years ago

Sorry for this question.

I just knew that some machines will do oversampling when they sample data, so the size will be (640, 320).