NII (.nii)
.nii file signature | application/octet-stream
The NII format is the single-file NIfTI variant of the Neuroimaging Informatics Technology Initiative specification, developed by the NIfTI working group and maintained by the neuroimaging community. It is used to store magnetic resonance, computed tomography, and other volumetric medical imaging data for analysis, visualization, and research. The format is generally safe, and its long-standing use in neuroscience and radiology has made it a common exchange format across imaging tools.
Magic Bytes
Offset 344
6E 2B 31 00
Sources: Wikipedia
Extension
.nii
MIME Type
application/octet-stream
Byte Offset
344
Risk Level
Safe
Validation Code
How to validate .nii files in Python
def is_nii(file_path: str) -> bool:
"""Check if file is a valid NII by magic bytes at offset 344."""
signature = bytes([0x6E, 0x2B, 0x31, 0x00])
with open(file_path, "rb") as f:
f.seek(344)
return f.read(4) == signatureHow to validate .nii files in Node.js
function isNII(buffer: Buffer): boolean {
const signature = Buffer.from([0x6E, 0x2B, 0x31, 0x00]);
if (buffer.length < 348) return false;
return buffer.subarray(344, 348).equals(signature);
}How to validate .nii files in Go
func IsNII(data []byte) bool {
signature := []byte{0x6E, 0x2B, 0x31, 0x00}
if len(data) < 348 {
return false
}
return bytes.Equal(data[344:348], signature)
}API Endpoint
/api/v1/nii
curl https://filesignature.org/api/v1/nii
See the full API documentation for all endpoints and parameters.
Frequently Asked Questions
What is a .nii file?
A .nii file is identified by the magic bytes 6E 2B 31 00 at byte offset 344. The NII format is the single-file NIfTI variant of the Neuroimaging Informatics Technology Initiative specification, developed by the NIfTI working group and maintained by the neuroimaging community. It is used to store magnetic resonance, computed tomography, and other volumetric medical imaging data for analysis, visualization, and research. The format is generally safe, and its long-standing use in neuroscience and radiology has made it a common exchange format across imaging tools.
What are the magic bytes for .nii files?
The magic bytes for NII files are 6E 2B 31 00 at byte offset 344. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .nii file?
To validate a .nii file, read the first bytes of the file and compare them against the known magic bytes (6E 2B 31 00) at offset 344. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .nii files?
There is no officially registered MIME type for .nii files. Systems typically use application/octet-stream as a generic fallback when handling this format.
Is it safe to open .nii files?
NII (.nii) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.