T1-weighted MRI: what is bright, when to use it, what to watch
Fat and subacute blood are bright on T1, and water is dark. This is where T1 is the right sequence and where it misleads.
T1-weighted
Bright: fat, subacute blood (methaemoglobin), melanin, protein-rich fluid, gadolinium, the posterior pituitary. Dark: water, CSF, most pathology.
The anatomy sequence. Shows normal fatty marrow and anything that replaces it, fat planes around organs, and is the baseline that every post-contrast image is compared with.
Something bright before contrast is not enhancement. That is why the pre-contrast T1 must match the post-contrast T1.
This page is one entry from the MRI Technologist Reference
The full reference has 31 protocols, 9 dynamic study timelines, 19 artifacts, 16 scanner problems and 15 safety topics, as a PDF in English and Arabic plus an interactive tool.
Educational reference. It does not replace your site protocols, the radiologist's instructions, the MR safety officer, or the manufacturer's instructions for any implant, device or contrast agent. Parameter values are typical starting points at 1.5 T and must be adapted to the scanner, coil and patient.