Dear BraTS Organizing Team,
I am currently preprocessing the data from the BraTS 2023 Glioma Challenge and I noticed that some MRI scans contain negative intensity values, which I understand should generally not be present in MRI data.
In particular, I observed negative values in the following samples:
BraTS-GLI-00024-001
BraTS-GLI-00025-000
BraTS-GLI-00048-000
BraTS-GLI-00048-001
BraTS-GLI-00446-000
BraTS-GLI-00448-000
BraTS-GLI-00478-001
BraTS-GLI-00479-000
BraTS-GLI-00540-000
BraTS-GLI-00540-001
BraTS-GLI-00584-000
BraTS-GLI-00586-000
BraTS-GLI-00602-000
BraTS-GLI-00602-001
BraTS-GLI-00630-001
BraTS-GLI-00631-000
BraTS-GLI-01020-000
BraTS-GLI-01021-000
BraTS-GLI-01332-000
BraTS-GLI-01333-000
I would appreciate it if you could clarify why negative intensity values appear in these cases and whether this is expected due to specific preprocessing steps or if it indicates an issue with the data.
Kind regards,
Omar Carpentiero
AImageLab, University of Modena and Reggio Emilia