Metal and susceptibility artifact in MRI: how to reduce it
Signal voids, bright pile-up and distortion near metal or air. These are the changes that help most, and what each one costs.
Susceptibility / metal artifact
Signal void with a bright rim and geometric distortion near metal, air-bone interfaces (sinuses, skull base) or blood products. Fat suppression fails nearby.
Materials with different magnetic susceptibility distort the local field: spins dephase faster (void) and are mapped to the wrong place (distortion).
- FSE instead of GRE; avoid EPI
- Widest receiver bandwidth, thin slices, small voxels, short TE, shorter echo spacing
- STIR or Dixon instead of spectral fat sat
- Frequency direction along the long axis of the implant
- Metal sequences: MAVRIC SL / O-MAR XD / Advanced WARP (SEMAC)
- Prefer 1.5 T over 3 T for implants
Wide bandwidth and small voxels lower SNR, so averages and time go up. Metal sequences are long and raise SAR. The same effect is useful in SWI and T2* for blood and calcium.
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.