Time-of-flight (TOF) MRA: how it shows vessels
Flowing blood is bright because fresh blood enters the slice. This is how to set it up and what makes vessels disappear.
Time-of-flight (TOF) MRA
Blood flowing into the slice is bright; stationary tissue is saturated and dark.
Intracranial and neck arteries, and veins when the saturation band is reversed, without contrast.
Slow, turbulent or in-plane flow loses signal and exaggerates stenosis. Anything with short T1 (clot, fat) also appears bright.
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.